Search

Background: Oviposition site selection is an important component of vector mosquito reproductive biology. The Asian Tiger mosquito, Aedes albopictus, is a major and important vector of arboviruses including Dengue. Previous studies documented the preference of gravid females for small, dark-colored water containers as oviposition sites, which they sought during the twilight period (dusk) of their locomotor activity. Vision plays an important role in this behavior, and factors such as the shape, size, and color of the container, light intensity, polarization, spectrum, and other visual cues guide the search for suitable oviposition sites, but the mechanistic factors driving this behavior are unclear. Methodology/Principal findings: We blindfolded adult female compound eyes and observed the effects of a lack of vision on the ability to discriminate and utilize preferred oviposition sites. Furthermore, the transcriptomes of blindfolded mosquitoes were screened to identify genes with vision-sensitive expression profiles and gene-editing was used to create non-functional mutations in two of them, rhodopsin-like (mutation designated 'rho-l△807') and kynurenine hydroxylase (mutation designated 'khw'). Behavioral tests of both mutant and control strains revealed that the rho-l△807 mutant mosquitoes had a significant decrease in their ability to search for preferred oviposition sites that correlated with a reduced ability to recognize long-wavelength red light. The khw mutant mosquitoes also had a reduced ability to identify preferred oviposition sites that correlated with reductions in their ability to respond to variations in daily brightness and their ability to discriminate among different color options of the containers and background monochromatic light. Conclusions/Significance: This study underscores the importance of visual cues in the oviposition site selection behavior of adult female Ae. albopictus. We demonstrate that wild-type rho-l and kh gene products play a crucial role in this behavior, as mutants exhibit altered sensitivity or recognition of light intensity and substrate colors. Author summary: Aedes albopictus (Asian Tiger mosquito) relies on vision to select oviposition sites, favoring small, dark containers during twilight hours. To understand the underlying mechanisms, we blindfolded female mosquitoes and screened their transcriptomes, identifying rho-l and kh genes as potential vision-related factors. Gene editing experiments provided crucial insights into the roles of rho-l and kh in Ae. albopictus oviposition behavior. Mutants lacking functional rho-l (rho-l△807) exhibited a significant decrease in their sensitivity to long-wavelength red light, leading to a reduced ability to locate preferred oviposition sites. Similarly, khw mutants displayed a decreased ability to respond to variations in daily brightness, as well as a reduced capacity to discriminate between different colors. This impaired color discrimination and sensitivity to brightness changes directly affected their ability to identify preferred oviposition sites. These findings highlight the crucial role of rho-l and kh in mosquito visual-mediated oviposition site selection, providing valuable insights into mosquito behavior and potential targets for vector control. [ABSTRACT FROM AUTHOR]

Objective: Oncomelania hupensis robertsoni is the only intermediate host of Schistosoma japonicum in hilly regions of south-west China, which plays a key role during the transmission of Schistosomiasis. This study aimed to sequence the complete mitochondrial genome of Oncomelania hupensis robertsoni and analyze genetic differentiation of Oncomelania hupensis robertsoni. Methods: Samples were from 13 villages in Yunnan Province of China, with 30 Oncomelania hupensis snails per village, and the complete mitochondrial genome was sequenced. A comprehensive analysis of the genetic differentiation of Oncomelania hupensis robertsoni was conducted by constructing phylogenetic trees, calculating genetic distances, and analyzing identity. Results: A total of 26 complete mitochondrial sequences were determined. The length of genome ranged from 15,181 to 15,187 bp, and the base composition of the genome was A+T (67.5%) and G+C content (32.5%). This genome encoded 37 genes, including 13 protein-coding genes, 2 rRNA genes, and 22 tRNA genes. The phylogenetic trees and identity analysis confirmed that Oncomelania hupensis robertsoni was subdivided into Oncomelania hupensis robertsoni Yunnan strain and Sichuan strain, with a genetic distance of 0.0834. Oncomelania hupensis robertsoni Yunnan strain was further subdivided into two sub-branches, corresponding to "Yunnan North" and "Yunnan South", with a genetic distance of 0.0216, and the samples exhibited over 97% identity. Conclusion: Oncomelania hupensis robertsoni is subdivided into Oncomelania hupensis robertsoni Yunnan strain and Sichuan strain. Oncomelania hupensis robertsoni Yunnan strain exhibits a higher level of genetic identity and clear north-south differentiation. This work reported the first mitochondrial genome of Oncomelania hupensis robertsoni Yunnan strain, which could be used as an important reference genome for Oncomelania hupensis, and also provide the important information for explaining the distribution pattern of Oncomelania hupensis robertsoni and control of Schistosoma japonicum. Author summary: Oncomelania hupensis robertsoni is the only intermediate host of Schistosoma japonicum in hilly regions of south-west China, its distribution area directly determines the epidemic range of schistosomiasis. This study sequenced 26 complete mitochondrial genomes of Oncomelania hupensis robertsoni and analyzed their genetic differentiation. Oncomelania hupensis robertsoni is subdivided into Oncomelania hupensis robertsoni Yunnan strain and Sichuan strain. Oncomelania hupensis robertsoni Yunnan strain exhibits a higher level of genetic identity and clear north-south differentiation. To the best of our knowledge, this work reported the first mitochondrial genome of Oncomelania hupensis robertsoni Yunnan strain, which could be used as an important reference genome for Oncomelania hupensis, and also provide the important information for explaining the distribution pattern of Oncomelania hupensis robertsoni and control of Schistosoma japonicum. [ABSTRACT FROM AUTHOR]

Background: Intestinal schistosomiasis caused by Schistosoma mansoni continues to be a significant public health problem in Ethiopia. This study investigated the prevalence and intensity of S.mansoni infection, and contributing factors in Alamata district of Tigray Region, Northern Ethiopia. Methods: A community-based cross-sectional study was conducted and 1762 participants were enrolled from five clusters in Alamata district. A questionnaire was used to collect socio-demographic data and risk factors. Stool samples were examined using Kato-katz technique to determine the prevalence and intensity of infection. The data were analyzed using SPSS version 25. Median, inter quartile range (IQR), mean, frequency, and percentage were used to descriptively summarize data. The Wilcoxon Mann–Whitney and Kruskal-Wallis tests were used to compare the differences in mean rank of egg load between different groups. Bivariate and multivariable logistic regression models were used to investigate the association between the odds of being infected with S.mansoni and the different socio-demographic and other factors. The strength of these associations was reported using odds ratio with corresponding 95% confidence intervals, and a P-value below 5% was used to report statistical significance. Results: Out of 1762 residents included in the study 941 (53.4%) were females. The age varied from 5–80 years, with a median age of 25 years (IQR = 27), the overall prevalence of S.mansoni was 21.5% with males accounting for 26% (204/821) of the infections. The proportion of infection was higher among the age groups of 15–19 and 20–29 years at 32.7% and 33.1%, respectively. The mean egg count among the infected study participants was 146.82 eggs per gram of feces (epg) ± (243.17 SD). Factors significantly associated with increased odds of infection were living in Waja cluster (AOR:8.9; 95% CI, 3.5–23.2; P< 0.001); being in the age groups 10–14 (AOR:6.0, 95% CI: 3.1–11.7, P<0.001), 15–19 (AOR:5.8, 95% CI:2.8–12.2, P<0.001), and 20–29 (AOR:3.5, 95% CI:1.8–6.8; P<0.001) years; having direct contact with water while crossing river (AOR: 2.4, 95% CI: 1.5–3.8, P<0.001); and swimming (AOR: 1.4, 95% CI: 1.01–2.0, P = 0.035). Conclusion: The study indicates a notable S.mansoni burden in the area, driven by various risk factors. To effectively address this, enhancing diagnostics, implementing targeted mass drug administration, and conducting comprehensive health education campaigns on disease transmission routes are imperative. Author summary: Schistosomiasis is one of the most prevalent neglected tropical diseases (NTDs) in Ethiopia posing a significant public health burden. Schistosomiasis causes significant morbidity and reduces economic productivity as affected people frequently have chronic health conditions. This study investigated the prevalence of Schistosoma mansoni and the risk factors linked with it in the Alamata District of Tigray Region, Northern Ethiopia. This study revealed a considerable prevalence of S.mansoni in the local community, notably among children and young adults. The study also identified several contributing factors to the high prevalence of S.mansoni. Conditions that promote contact with contaminated water such as proximity to water bodies, having direct contact with water while crossing, swimming habits and poor protective shoe wearing behaviors were among the potential factors associated with risk of S.mansoni infection in the Alamata District of Tigray Region. Furthermore, the findings underscore the need for integrated control strategies such as improved water and sanitation, regular health education campaigns, and community-based interventions to reduce the burden of Schistosomiasis in the study area in particular and in the region in general. Overall, this study sheds light on to the epidemiology of S.mansoni in Alamata District and highlights the importance of addressing risk factors through targeted public health interventions to improve health outcomes in the affected communities. [ABSTRACT FROM AUTHOR]

Acute arboviral infections like dengue have a significant negative socioeconomic and health impact on many tropical and subtropical areas of the world. About 3.9 billion Individuals are at risk of contracting the dengue virus and Asia bears the brunt of that load. Bangladesh, like other south-east Asian countries faced a massive outbreak of dengue in 2019. This cross sectional study was done in three tertiary care centers in Dhaka, Bangladesh during this worst outbreak of dengue. The study was conducted from 1st July to 31st December, 2019 with an aim to describe the clinical and laboratory variations among severe dengue cases and to conduct a serotype survey. This might help to understand the future changes in the clinical or serological profile of this virus. The study enrolled 1978 participants who were grouped into group B (Patients with warning signs or risk factors who should be admitted for close observation as they approach critical phase) and C (Patients having severe plasma leakage leading to dengue shock and/or fluid accumulation with respiratory distress, severe organ impairment and severe metabolic abnormalities) according to national guidelines. Furthermore, 81 samples were serotyped using Qiagen One step RT-PCR kit (Cat. No: 210212). In addition sequencing (ABI sequencing platform) of partial C-prM gene of five DENV-3 isolates were done and analyzed (BLAST tool of NCBI) for phylogenetics (MEGA6 software package). Among the 1978 enrolled participants group B and C patients were 1580 (80%) and 398 (20%) respectively. The median (IQR) age of the patients were 26(11 to 41). Maximum proportion of the enrolled were male (72.3%) (p = 0.0002). Most common co- morbidities were hypertension (90; 4.5%) and DM (70; 3.5%). Group C patients more commonly presented with vomiting (p 0.133), diarrhea (p<0.0001) and abdominal pain (p 0.0203). The common mode of bleeding was melaena (12%). Thirteen (0.7%) patients succumbed to death, 12 of them belonged to group B who mostly presented with GI manifestations (99.9%) and melaena (12%). Only 5.6% of the cases were secondarily infected. In group C cases low hemoglobin and hematocrit was observed with high AST (p 0.004, 0.006 and 0.0016 respectively). Fluid requirement was also more in the same group (p<0.0001). Group B patients had a higher platelet requirement (p = 0.0070). Twelve patients (0.7%) required ICU. The management profile of these cases are showcased here which highlights minimal use of antibiotics and no application of steroids, which abides by the current national protocol. Furthermore, 81 samples from enrolled participants were serotyped and majority (79%) yielded DENV-3, followed by DENV 2 & 3 co-infection (13.6%) and DENV-2 alone (7.4%). Following phylogenetic analysis DENV-3 and DENV2 were deemed to be of genotype I and cosmopolitan variety respectively. This study presents the first instance of heterogeneous co-infection with several serotypes since 2000 in Bangladesh. It also gives an overview of serotype prevalence, management evaluation and clinical results that promises to navigate future control planning. Author summary: Bangladesh experienced an unprecedented dengue surge in 2019. This cross sectional study was done in 3 hospitals in Dhaka, Bangladesh spanning from 1st July to 31st December, 2019 enrolling a total of 1978 participants. We observed a shift of clinical presentations and varied laboratory alterations in the severe groups which was portrayed according to national guideline case definitions. Most common co- morbidities were hypertension (4.5%). The major mode of bleeding was melaena (12%). Total 13 (0.7%) patients succumbed to death. The management received by these patients were also elaborated. Although Bangladesh is a hyper endemic region, the serotype survey is rarely done because of logistic and financial constraints. However it has become a burning need to study the infecting serotype of the severe cases to help navigate the control measures and predict the atypical manifestations and also for future vaccine deployment. Here, 81 samples were serotyped and most were serotyped as DENV-3 (79%), followed by DENV 2 (7.4%). Interestingly we also found cases co infected with these two serotypes (13.6%). These strains were sequenced and further molecular analysis were performed. This study presents the first instance of heterogeneous co-infection with several serotypes since 2000 in Bangladesh. [ABSTRACT FROM AUTHOR]

Background: Leishmaniasis has emerged as an escalating public health problem in Sri Lanka, with reported cases increasing nearly three folds over past decade, from 1,367 in 2014 to 3714 cases in 2023. Phlebotominae sand flies are the vectors of leishmaniasis. Their density is known to be influenced by context-specific climatic and land use patterns. Thus, we aimed to investigate how these factors drive sand fly density across Sri Lanka. Methodology/Principal findings: We analysed monthly collections of sand flies (n = 38,594) and weather data from ten sentinel sites representing three main geo-climatic zones across Sri Lanka, over 24 months. Site-specific land use data was also recorded. The influence of climate and land use patterns on sand fly density across the sentinel sites were estimated using distributed lag non-linear models and machine learning. We found that climate played a major role on sand fly density compared to land use structure. Increase in rainfall and relative humidity at real time, and ambient temperature and soil temperature with a 2-month lag were associated with a statistically significant increase in sand fly density. The maximum relative risk (RR) observed was 3.76 (95% CI: 1.58–8.96) for rainfall at 120 mm/month, 2.14 (95% CI: 1.04–4.38) for relative humidity at 82% (both at real time). The maximum RR was 2.81 (95% CI: 1.09–7.35) for ambient temperature at 34.5°C, and 11.6 (95% CI, 4.38–30.76) for soil temperature (both at a 2-month lag). The real-time increase in ambient temperature, sunshine hours, and evaporation rate, however, reduced sand fly density homogeneously in all study settings. The high density of chena and coconut plantations, together with low density of dense forests, homesteads, and low human footprint values, positively influenced sand fly density. Conclusions/Significance: The findings improve our understanding of the dynamic influence of environment on sand fly densities and spread of leishmaniasis. This knowledge lays a foundation for forecasting of sand fly densities and designing targeted interventions for mitigating the growing burden of leishmaniasis among the most vulnerable populations, particularly in an era of changing climate. Author summary: Leishmaniasis, a public health problem in the tropics is caused by Leishmania species parasites and transmitted by sand flies. Both climatic and non-climatic factors may affect sand fly ecology. The goal herein was to understand how these factors influence sand fly density in 10 field sites across Sri Lanka with varying eco-climatic conditions. Monthly collections of sand flies over 24 months were analysed, and the influence of climate and land use patterns on the sand fly density was estimated. The results indicated that climate has a more significant impact on sand fly density compared to land use factors. An increase in rainfall and relative humidity were associated with a prominent increase in sand fly density. Similar effects were seen with the rise of ambient and soil temperature, and evaporation rates, albeit with a 2-month lag period. The increase in ambient temperature, sunshine hours, and evaporation rate at real-time, however, uniformly reduced sand fly density. Large land areas of chena and coconut plantations, along with sparse forests, homesteads, and reduced human footprint indices, positively influenced sand fly density. The dry zone appeared to have an increased risk of higher sand fly densities compared to the wet zone. The findings promote a better understanding of the changing climatic and environmental influence on sand fly vectors, leishmaniasis spread, and providing a foundation for the development of targeted interventions for vector and disease control. [ABSTRACT FROM AUTHOR]

Background: Rodent-borne orthohantaviruses are the causative agents of hemorrhagic fever with renal syndrome and hantavirus pulmonary syndrome. Apart from the classic rodent-borne hantaviruses, numerous species of hantaviruses have been identified in shrews and bats; however, their antigenicity and pathogenicity are unknown. This study focused on developing a serological method to detect antibodies against bat- and shrew-borne hantaviruses. Methodology/Principal findings: Five bat-borne (Brno, Dakrong, Quezon, Robina, and Xuan Song) and 6 shrew-borne (Asama, Altai, Cao Bang, Nova, Seewis, and Thottapalayam) viruses were selected based on the phylogenetic differences in their N proteins. The recombinant N (rN) proteins of these viruses were expressed as antigens in Vero E6 and 293T cell lines using the pCAGGS/MCS vector. Antisera against the Nus-tagged rN fusion proteins of these viruses (mouse anti-Brno, Dakrong, Quezon, Robina, Xuan Song, Asama, Cao Bang, and Nova, while rabbit anti-Altai, Seewis and Thottapalayam) were also generated. Antigenic cross-reactivity was examined in antisera and rN-expressing Vero E6 cells. The rN proteins of almost all the tested viruses, except for the Quezon and Robina viruses, showed independent antigenicity. For serological screening of bat samples, 5 rNs of the bat-borne viruses were expressed together in a single transfection protocol. Similarly, 6 rNs of shrew-borne viruses were expressed. Reactivities of the mixed antigen system were also examined across the singly transfected Vero cell lines to ensure that all antigens were expressed. Using these antigens, bat serum samples collected from Zambia were screened using the indirect immunofluorescence antibody test (IFAT). Selected positive samples were individually tested for the respective antigens by IFAT and western blot assays using rN-expressing 293T cell lysates. Of the 1,764 bat serum samples tested, 11.4% and 17.4% were positive for bat and shrew mixed antigens, respectively. These samples showed positive reactions to the Brno, Dakrong, Quezon, Xuan Son, Robina, Asama, Altai, Cao Bang, or Thottapalayam virus antigens. Conclusions/Significance: These observations suggest that the mixed-antigen screening system is useful for serological screening For Orthohantavirus infections and that bats in Zambia are likely exposed to not only bat-borne hantaviruses but also to shrew-borne hantaviruses. Author summary: Advancements in scientific research tools in areas of emerging and re-emerging zoonotic diseases of public health importance are crucial to understanding the epidemiology of these diseases. Hantaviruses are not an exception. Hantavirus pulmonary syndrome (HPS) and hemorrhagic fever with renal syndrome (HFRS) are the two main rodent-borne diseases of public health importance. However, bat- and shrew-borne hantaviruses have also been reported with serological detection of Thottapalayam and Altai shrew-borne hantavirus infections in humans in Sri Lanka and Thailand. Based on these recent public health discoveries, antigenic development and evaluation are part of the key components in efforts put forward to understand the epidemiology of these viruses. This study provides researchers with the first antigenic comparison between selected bat- and shrew-borne hantaviruses using their rN proteins with their application in screening epidemiological samples (Bat sera) from Zambia. Hence, this comprehensive study can serve as the basis for further scientific collaboration within research communities. [ABSTRACT FROM AUTHOR]

Gambiense human African trypanosomiasis (gHAT), a neglected tropical disease caused by a parasite transmitted by tsetse flies, once inflicted over 30,000 annual cases and resulted in an estimated half a million deaths in the late twentieth century. An international gHAT control program has reduced cases to under 1,000 annually, encouraging the World Health Organization to target the elimination of gHAT transmission by 2030. This requires adopting innovative disease control approaches in foci where transmission persists. Since the last decade, case detection and treatment, the mainstay of controlling the disease, is supplemented by vector control using Tiny Targets, small insecticide-treated screens, which attract and kill tsetse. The advantages of Tiny Targets lie in their relatively low cost, easy deployment, and effectiveness. The Democratic Republic of Congo (DRC), bearing 65% of the 799 gHAT cases reported globally in 2022, introduced Tiny Targets in 2015. This study estimates the annual cost of vector control using Tiny Targets in the health district of Yasa Bonga in the DRC and identifies the main cost drivers. Economic and financial costs, collected from the provider's perspective, were used to estimate the average cost of tsetse control expressed as cost (i) per target used, (ii) per target deployed, (iii) linear kilometre of river controlled, and (iv) square kilometres protected by vector control. Sensitivity analyses were conducted on key parameters for results robustness. The estimated annual economic cost for protecting an area of 1,925 km2 was 120,000 USD. This translates to 5.3 USD per target used each year, 11 USD per target deployed in the field, 573 USD per linear km treated, and 62 USD per km2 protected. These costs in the DRC are comparable to those in other countries. The study provides valuable information for practitioners and policymakers making rational, evidence-based decisions to control gHAT. Author summary: In the fight against Gambiense human African trypanosomiasis (gHAT), a devastating disease transmitted by tsetse flies, significant progress has been made through international efforts. Despite the annual cases being reduced to under 1,000, the World Health Organization aims to eliminate gHAT transmission by 2030. A key component of this strategy involves innovative approaches, such as the use of Tiny Targets–small, cost-effective, insecticide-treated screens that attract and kill tsetse flies. This study focuses on the Democratic Republic of Congo (DRC), which bears a substantial burden of gHAT cases, estimating the annual cost of vector control using Tiny Targets in the Yasa Bonga health district. The analysis, conducted from the provider's perspective, reveals an annual economic cost of 120,000 USD for protecting a 1,925 km2 area. This translates to 5.3 USD per target used, 11 USD per target deployed, 573 USD per linear km treated, and 62 USD per km2 protected. These findings, comparable to costs in other countries, offer valuable insights for practitioners and policymakers, guiding evidence-based decisions on cost-effective strategies for gHAT control. [ABSTRACT FROM AUTHOR]

Dengue virus (DENV) and chikungunya virus (CHIKV) are causes of endemic febrile disease among Kenyan children. The exposure risk to these infections is highly multifactorial and linked to environmental factors and human behavior. We investigated relationships between household, socio-economic, demographic, and behavioral risk factors for DENV and CHIKV seropositivity and seroconversion in four settlements in Kenya. We prospectively followed a pediatric cohort of 3,445 children between 2014–2018. We utilized the Kaplan–Meier curves to describe the temporal patterns of seroconversion among tested participants. We employed logistic regression built using generalized linear mixed models, to identify potential exposure risk factors for DENV and CHIKV seroconversion and seropositivity. Overall, 5.2% children were seropositive for DENV, of which 59% seroconverted during the study period. The seroprevalence for CHIKV was 9.2%, of which 54% seroconverted. The fraction of seroconversions per year in the study cohort was <2% for both viruses. Multivariable analysis indicated that older age and the presence of water containers ((OR: 1.15 [95% CI: 1.10, 1.21]), (OR: 1.50 [95% CI: 1.07, 2.10])) increased the odds of DENV seropositivity, whereas higher wealth (OR: 0.83 [95% CI: 0.73, 0.96]) decreased the odds of DENV seropositivity. Multivariable analysis for CHIKV seropositivity showed older age and the presence of trash in the housing compound to be associated with increased odds of CHIKV seropositivity ((OR: 1.11[95% CI: 1.07, 1.15]), (OR: 1.34 [95% CI: 1.04, 1.73])), while higher wealth decreased the odds of CHIKV seropositivity (OR: 0.74[95% CI: 0.66, 0.83]). A higher wealth index (OR: 0.82 [95% CI: 0.69, 0.97]) decreased the odds of DENV seroconversion, whereas a higher age (OR: 1.08 [95% CI: 1.02, 1.15]) and the presence of water containers in the household (OR: 1.91[95% CI: 1.24, 2.95]) were significantly associated with increased odds of DENV seroconversion. Higher wealth was associated with decreased odds for CHIKV seroconversion (OR: 0.75 [95% CI: 0.66, 0.89]), whereas presence of water containers in the house (OR: 1.57 [95% CI: 1.11, 2.21]) was a risk factor for CHIKV seroconversion. Our study links ongoing CHIKV and DENV exposure to decreased wealth and clean water access, underscoring the need to combat inequity and poverty and further enhance ongoing surveillance for arboviruses in Kenya to decrease disease transmission. The study emphasizes the co-circulation of DENV and CHIKV and calls for strengthening the targeted control strategies of mosquito borne diseases in Kenya including vector control, environmental management, public education, community engagement and personal protection. Author summary: Dengue virus (DENV) and chikungunya virus (CHIKV) are important arboviral infections that cause endemic febrile disease specially among children in Kenya. Since there is no active surveillance for DENV and CHIKV infections in Kenya, the actual burden of these infections and their associated risk factors remains unknown. In this longitudinal cohort study spanning over a period of five years between 2014–2018, we investigate relationships between household, socio-economic, demographic, and behavioral risk factors for DENV and CHIKV seropositivity and seroconversion in four settlements in Kenya and describe the temporal patterns of seroconversion among the tested participants. The study emphasizes the existence of active DENV and CHIKV disease transmission in Kenya. The results also highlight older age, presence of water containers and trash on the housing compounds to increase the odds of DENV and CHIKV seropositivity and seroconversion whereas a higher wealth index decreased the odds of DENV and CHIKV seropositivity and seroconversion. The results of our study link ongoing CHIKV and DENV exposure in Kenya to lower income and resources, underscoring the need to combat inequity and poverty and enhance ongoing surveillance for arboviruses in Kenya. [ABSTRACT FROM AUTHOR]

Background: The city of Abidjan, Côte d'Ivoire has increasingly faced multiple outbreaks of Aedes mosquito-borne arboviral diseases (e.g., dengue (DEN) and yellow fever (YF)) during the recent years, 2017–2023. Thus, we assessed and compared Aedes aegypti larval and adult population dynamics and Stegomyia indices in four urbanized areas with differential arboviral incidences in Abidjan, Côte d'Ivoire. Methods: From August 2019 to July 2020, we sampled Aedes mosquito immatures (larvae and pupae), adults and breeding habitats in Anono and Gbagba with high arboviral incidences and Ayakro and Entente with low arboviral incidences in the Abidjan city, using standardized methods. Sampling was conducted in the peridomestic and domestic (indoors and outdoors) premises during short dry season (SDS), short rainy season (SRS), long dry season (LDS) and long rainy season (LRS). The abdomens and ovaries of Ae. aegypti females were examined to determine their blood-meal and parity statuses. Stegomyia indices (container index: CI, house index: HI and Breteau index: BI), blood-meal status and parity rates were compared by study sites and seasons and with the World Health Organization (WHO)-established epidemic thresholds. Results: Overall, Aedes and arboviral risk indices were high and similar between the four study areas. In total, 86,796 mosquitoes were identified and dominated by Ae. aegypti species (97.14%, 84,317/86,796). The most productive larval breeding habitats were tires, discarded containers and water storage containers. CI, HI, and BI in Anono (22.4%, 33.5% and 89.5), Ayakro (23.1%, 43.8% and 91.0), Entente (15.9%, 24.8% and 48.5) and Gbagba (23.3%, 43.0% and 102.0) were high in the respective study sites. Stegomyia indices were higher than the WHO-established epidemic thresholds during any seasons for DEN, and LRS and SRS for YF. The numbers of Ae. aegypti-positive breeding sites were higher in the domestic premises (68.0%, 900/1,324) than in the peridomestic premises (32.0%, 424/1,324). In the domestic premises, Ae. aegypti-positive breeding sites (94.6%, 851/4,360) and adult individuals (93.4%, 856/916) were mostly found outdoors of houses. Aedes aegypti adult females were mostly unfed (51.3%, 203/396), followed by blood-fed (22.2%, 88/396), gravid (13.9%, 55/396) and half-gravid (12.6%, 50/396), and had parity rate of 49.7% (197/396) that was comparable between the study sites. Conclusions: The city of Abidjan, Côte d'Ivoire is highly infested with Ae. aegypti which showed comparable ecological patterns across study sites and seasons. Thus, the local communities are exposed to high and permanent risks of transmission of DEN and YF viruses that were above the WHO-established epidemic thresholds throughout. The results provide a baseline for future vector studies needed to further characterize the observed patterns of local Ae. aegypti abundances and behaviors, and risks of transmission of these arboviruses. Community-based larval source management of identified productive containers might reduce Ae. aegypti numbers and risks of transmission of Aedes-borne arboviruses in Abidjan, and other sub-Saharan African cities. Author summary: As most sub-Saharan African cities, Abidjan in Côte d'Ivoire has faced recently a considerable increase in the outbreaks of dengue (DEN) and yellow fever (YF). However, critical data are still lacking on the ecology of the main vector Aedes aegypti and the risk of transmission of DEN and YF viruses. We assessed the ecology of Ae. aegypti mosquitoes and the risk of DEN and YF virus transmission in areas with high and low DEN and YF occurrences in Abidjan. Our findings revealed a significant presence of Ae. aegypti, indicating a high risk of YF and DEN transmission across all study areas. Ae. aegypti larvae were mostly breeding in tires, discarded containers and water storage containers. Meanwhile, elderly adult females were abundant, alongside a significant presence of both unfed host-seeking and blood-fed individuals in and around residences. We observed seasonal risk patterns, with permanent and high threats for DEN observed throughout both rainy and dry seasons over the entire year, alongside elevated risks of YF during both short and long rainy seasons across all study areas. Our findings provide insights into the ecology of Ae. aegypti and the epidemiology of DEN and YF, crucial for strategically targeting and controlling this vector in areas both affected and unaffected by the disease outbreaks. Community-based intervention programs for managing identified larval breeding sites might reduce Ae. aegypti numbers to prevent future outbreaks of DEN and YF in Abidjan and other sub-Saharan African cities. [ABSTRACT FROM AUTHOR]

Background: Mycetoma is a fungal neglected tropical disease. Accurate dissemination of information is critical in endemic areas. YouTube, a popular platform for health information, hosts numerous videos on mycetoma, but the quality and reliability of these videos remain largely unassessed. Methods: We used modified DISCERN and Global Quality Score (GQS) for reliability and quality respectively. Video duration, views, likes, and comments were recorded. Spearman's rank correlation and Mann-Whitney U tests were used to identify correlations between metrices and quality scores. Results: We included 73 mycetoma-related YouTube videos were analyzed, the median GQS score was 4.00 ((IQR = 3.33–4.00), indicating generally high-quality content, while the median mDISCERN score was 3.00 (IQR = 3.00–3.00) reflecting moderate reliability. Videos produced by professionals had significantly higher scores compared to those from consumer-generated content (p < 0.001). A significantly positive correlation was observed between video duration and both GQS (r = 0.417, p < 0.001) and mDISCERN (r = 0.343, p = 0.003). However, views, likes and comments did not significantly correlate with video quality. Additionally, videos longer in duration (p < 0.001) and older in upload date (p = 0.014) had higher quality scores. Conclusions: The study shows that mycetoma-related videos on YouTube are generally of high quality, with moderate reliability. This emphasizes the need for expert involvement in content creation and efforts to improve health information online. Author summary: Mycetoma is a neglected tropical disease caused by fungi, and sharing accurate information about it is essential, especially in regions where the disease is common. YouTube, a popular platform for health information, contains many videos related to mycetoma, but their quality and reliability have not been fully assessed. In this study, we analyzed 73 YouTube videos on mycetoma to evaluate their quality and trustworthiness using established scoring methods. We found that most videos were of generally high quality, though their reliability was moderate. Videos created by healthcare professionals were significantly more reliable and of higher quality than those produced by non-professionals. Interestingly, longer videos and older uploads tended to score better. However, viewer engagement, such as the number of views, likes, or comments, did not seem to be linked to video quality. Our findings highlight the importance of expert involvement in producing reliable health content and the need for continued efforts to improve the accuracy of health information online. [ABSTRACT FROM AUTHOR]

Background: Surgical intervention is a crucial treatment for hepatic cystic echinococcosis. However, the choice between radical and conservative surgery remains controversial. This study aimed to compare the perioperative outcomes and hospitalization costs between radical and conservative surgery for hepatic cystic echinococcosis. Method: A retrospective cohort study was conducted on patients undergoing surgical treatment at the First People's Hospital of Kashi Prefecture from July 1, 2012, to October 1, 2023. Propensity score-matching analysis was utilized to mitigate patient selection bias between the two surgical groups. Result: Of the 434 patients included, 324 underwent conservative surgery and 110 underwent radical surgery. After propensity score-matching, 182 conservative surgery and 102 radical surgery patients were compared. Radical surgery patients experienced longer operative time, higher intraoperative blood loss, increased blood transfusion, and higher costs compared to conservative surgery patients. However, no differences were observed in short-term outcomes, including overall morbidity, death, bile leak, effusion, pulmonary infection, incision infection, intestinal obstruction, ICU stay, abdominal drainage time, and postoperative hospital stays. Conclusion: This study suggests that radical surgery is associated with greater surgical complexity and higher hospitalization costs, while it doesn't offer a significant short-term advantage. Conservative surgery may be a viable option in resource-limited settings or for patients unsuitable for complex procedures. Further research with long-term follow-up is needed to determine the optimal approach. Author summary: Surgical outcomes and hospitalization costs are crucial considerations for surgeons when selecting a treatment approach. This retrospective study compared perioperative outcomes and hospitalization costs between radical and conservative surgery for hepatic cystic echinococcosis. We analyzed data from patients treated at the First People's Hospital of Kashi Prefecture from July 1, 2012, to October 1, 2023, using propensity score matching to minimize selection bias. Our findings revealed that while radical surgery entailed longer operative times, greater blood loss, and higher costs, there were no significant differences in short-term outcomes such as mortality, complication rates, or length of hospital stay compared to conservative surgery. This suggests that conservative surgery may be a viable alternative, especially in resource-limited settings where the complexity and high costs of radical surgery pose challenges. Importantly, our study focused on short-term outcomes and hospitalization costs. Future research should incorporate long-term follow-up to assess the recurrence rates associated with each surgical approach. [ABSTRACT FROM AUTHOR]

In Baringo County, Kenya, trachoma remains endemic despite repeated mass drug administration (MDA) efforts, with coverage in one of the wards consistently falling short of world health organization (WHO) targets. The disease is endemic in 12 out of the 47 counties in Kenya. Baringo county is a pastoral conflict, hard to reach area where eight rounds of mass drug administration (MDA) for trachoma have been implemented. In Loyamorok ward, treatment coverage has been below 68% against the WHO recommended threshold of 80%. Community engagements that promote participatory approaches are key to MDA success. In this study, we describe community-based participatory approaches qualitatively developed and implemented during the intervention phase of a study that involved a pre-intervention, intervention and post intervention phases and aimed to address barriers of community participation and access to trachoma MDA. Interviews and focus group discussions were used to identify barriers to community participation in MDA, that included power and gender dynamics, rampant insecurity, community myths and misconceptions, migration in search of water and pastures, vastness and terrain and ineffective teams which resulted to unsupervised swallowing of drugs during MDA campaigns. Stakeholders in trachoma were identified through meetings with national, county and sub-county health management teams. The stakeholders, community members and the research team used the identified barriers to formulate MDA strategies including effective stakeholder engagement, enhanced social mobilization, community awareness creation on trachoma, effective planning and execution of MDA and implementation monitoring of the MDA campaign, all aimed at increasing MDA coverage. Overall MDA coverage in the area increased from 67.6% in 2021 to 87% in 2023 thus meeting the WHO threshold of 80%. The use of community-based, participatory approaches in the development and implementation of data driven strategies has the potential to positively influence MDA coverage for trachoma, and other neglected tropical diseases. Author summary: Trachoma is a disease of the eye and a leading infectious cause of blindness in sub-Saharan Africa. It is caused by a bacterium called Chlamydia trachomatis. It is transmitted by directly or indirectly transferring of eye and nose discharges from people who already have the disease mostly by flies. The disease in controlled by among other things provision of drugs to communities where the disease is endemic through mass drug administration (MDA). For the MDA to be effective, more than 80% of the community members should be reached. In areas where communities record very low access to MDA, there is need to identify barriers and develop strategies to mitigate the same. In this study we describe community-based participatory approaches employed to develop and test implementation strategies aimed at increasing access to trachoma MDA in Loyamorok ward of Baringo county. The results showed an increase in community participation in the subsequent MDA, which could be attributed to the implemented strategies. [ABSTRACT FROM AUTHOR]

Background: Taenia solium neurocysticercosis is a zoonotic neglected tropical disease, for which adequate diagnostic management is paramount, especially in patients with active cysts for whom improved and timely management could prove beneficial. Immunodiagnosis can potentially partially mitigate the necessity for neuroimaging, shortening the diagnostic -and treatment- pathway. An up-to-date review of immunological test performance is however lacking. Methodology/Principal findings: Searches were performed in PubMed, EMBASE, Web of Science, and Scopus (up to January 2024), with included records fitting the review scope, i.e. accuracy evaluation of an antibody-/or antigen-detecting immunological test, using serum or urine of humans confirmed via reference standard (i.e. neuroimaging or surgery/biopsy). Record data was assessed, with classification of descriptive data on cyst localization and stage according to a developed confidence scale, and with selection of tests evaluated on a sufficiently high sample size. A QUADAS-2 risk of bias assessment was performed. After screening, 169 records were included for data collection, with 53 records—corresponding to 123 tests- selected for analysis. Absence of data and large data heterogeneity complicated result interpretation. The lentil lectin-bound glycoprotein enzyme-linked immunoelectrotranfser blot seems to fulfill high accuracy standards regarding detection of parenchymal active multiple cysts; also antigen-detecting tests on serum and urine performed well, additionally in detection of extraparenchymal neurocysticercosis. A novel multi-antigen print immunoassay is highly promising, with sensitivity for detection of extraparenchymal and parenchymal active single and multiple cysts of 100.0%, and specificity of 98.5%. Point-of-care tests showed promising results, however require further evaluation in targeted resource-poor settings. Conclusions/Significance: The review highlights the importance of transparent and unambiguous data reporting. With promising immunological tests in development, the challenge before usage in targeted settings will be to perform large-scale evaluations whilst holding into account both optimized test performance and ease of use. Accessibility to validated tests and feasibility of implementation should also be considered. Author summary: Neurocysticercosis is an important, but neglected disease in many low- and middle-income countries. In resource-poor areas, management of the disease is impeded by lack of availability of, and access to, adequate diagnostic techniques. Immunological tests, performed on serum or urine of affected humans, could be tools of interest in improving the diagnostic pathway. This systematic review provides an overview of immunological tests that have been evaluated so far, and especially focusses on test performance in detection of cysts with specific localization, stage and number. Results on test accuracy proved difficult to retrieve from published records. The comparison of obtained test results was exceedingly challenging due to large heterogeneity. With usable data meticulously selected, several known test formats, such as the LLGP-EITB and the antigen ELISA, showed expected performance results, and some novel test formats, such as the multi-antigen print immunoassay, were highly promising. Also, urine-based tests could provide a non-invasive alternative to serum-based tests. Evaluation of immunological tests in non-clinical settings requires a sufficient sample size for further analysis of data. To improve management of the disease in targeted resource-poor settings, immunological test formats will have to comply with high performance and ease-of-use standards, to optimize chances of future implementation. [ABSTRACT FROM AUTHOR]

Background: Giardia lamblia is an intestinal protozoan estimated to cause ~200 million symptomatic infections annually, mainly in children in low- and middle-income countries associated with intestinal damage, increased permeability, and malabsorption. Methods and results: We describe here the epidemiology, incidence, clinical characteristics, and risk factors of acute gastroenteritis episodes (AGE) with G. lamblia detection (GAGE) using a birth cohort of 443 Nicaraguan children followed weekly until 36 months of life. From June 2017 to July 2021, 1385 AGE samples were tested by qPCR. G. lamblia was detected in 104 (7.5%) of AGE episodes. In all, 69 (15.6%) children experienced at least one GAGE episode, and 25 of them (36.2%) experienced more than one episode. The incidence rate of the first episode of GAGE was 6.8/100 child-years (95% CI, 4.5–9.1). During GAGE, bloody stools, vomiting, and fever were uncommon, and children were less likely to be treated at a primary care clinic, suggesting that GAGE is typically mild and most cases did not receive medical attention, which could facilitate higher parasite loads with increased possibilities of establishing chronic carriage. GAGE was more common in children 12–24 months of age (13.9/100 child-years [95% CI, 10.7–17.1]) as compared to other age groups. In our birth-cohort, children living in a home with an indoor toilet (aHR, 0.52 [95%CI, 0.29–0.92]), and being breastfed in the first year of life (aHR: 0.10 [95%IC, 0.02, 0.57]) had a lower incidence of GAGE. In contrast, being breastfed for ≤ 6 months was associated with a higher incidence if the children were living in houses without indoor toilets and earthen floors (HR, 7.79 [95% CI, 2.07, 29.3]). Conclusion: Taken together, GAGE is more frequent under poor household conditions. However, breastfeeding significantly reduces the incidence of GAGE in those children. Author summary: G. lamblia is an intestinal protozoan having mixed associations with acute gastroenteritis, yet positive associations with impaired child growth. G. lamblia infects millions of people worldwide annually and is more prevalent in children residing in low- and middle-income countries, making it an important target for prevention and control efforts. Although G. lamblia carriage is widespread, its epidemiology, natural history, genetic diversity, host genetic susceptibility factors, and post-infectious sequelae in children are still under investigation. As no human vaccine is available, understanding its risk factors in an endemic country is the first step for reducing the burden and mitigating its sequelae. In a birth cohort in León, Nicaragua, we found that children living in households with poor sanitation conditions are at higher risk of AGE with G. lamblia detection (GAGE), but prolonged duration of breastfeeding despite these conditions may reduce the risk in these children. The study highlights the importance of breastfeeding and the need to better understand how G. lamblia contributes to the global burden of disease in children, and the mechanisms of host protection to guide future interventions. [ABSTRACT FROM AUTHOR]

Dogs represent the primary reservoir for Leishmania infantum human visceral leishmaniasis (VL) through phlebotomine sand flies. Public health initiatives targeting zoonotic VL commonly focus on dogs with severe clinical disease, often in renal failure, as they have previously been considered the most infectious to sand flies. However, more recent studies suggest that dogs with mild to moderate clinical disease may be more infectious than dogs with severe disease. The mechanisms of infectiousness from the skin and how this relates to transmissibility as clinical disease progresses is largely unknown. We evaluated dermal parasitism in dogs naturally infected with L. infantum across the four LeishVet clinical stages of disease. We establish the relationship between dermal parasitism, critical, frequently observed, clinical parameters such as anemia and creatinine, and infectiousness. Using RNAscope and confocal microscopy, we found notable variation in dermal parasitism between dogs, particularly within LeishVet II. Dogs with mild disease had significantly less dermal inflammation and parasitism than dogs with moderate or severe disease. We found significant correlations between anemia, dermal parasitism, and infectiousness (p = 0.0098, r = -0.4798; p = 0.0022, r = -0.8364). In contrast, we did not observe significant correlation between creatinine, a measure of renal function, and dermal parasitism or infectiousness. Host blood cell abnormalities, including anemia, correlate with infectiousness to sand flies. As these signs of disease often appear earlier in the course of disease, this indicates that classical measures of disease severity do not necessarily correlate with infectiousness or epidemiological importance. Public health initiatives attempting to break the zoonotic cycle of L. infantum infection should therefore focus on preventing transmission from infectious, anemic dogs, and not those with the most severe disease. Author summary: Dogs infected with Leishmania can transmit parasites to humans and other dogs through sand flies. This causes human visceral leishmaniasis (VL) and canine leishmaniosis (CanL). Public health interventions removing clinically ill dogs from the population have not significantly decreased rates of human or canine disease. Additionally, studies found that dogs with mild to moderate clinical disease transmitted the most parasites to feeding sand flies. We evaluated skin sections from L. infantum-infected dogs and characterized the dermal and systemic factors associated with infectiousness to sand flies. We found that the number of parasitized immune cells positively correlated with infectiousness to sand flies. Additionally, anemia, measured by a decreasing hematocrit, significantly correlated with increased parasitized dermal immune cells and infectiousness to sand flies. In contrast, parasitized dermal immune cells did not significantly change as chronic kidney disease, measured by creatinine, progressed, even though these were the sickest animals based on the LeishVet clinical scoring system. These initial findings suggest that early host cell-parasite interactions underlying clinical parameters, more than overall clinical severity, influences infectiousness to sand flies. Public health initiatives should focus on breaking the cycle of zoonotic infection by providing insecticide intervention to dogs most infectious to sand flies. [ABSTRACT FROM AUTHOR]

Oxidative stress promotes T. cruzi growth and development of chronic Chagas heart dysfunction. However, the literature contains gaps that must be fulfilled, largely due to variations in parasite DTU sources, cell types, mouse strains, and tools to manipulate redox status. We assessed the impact of oxidative environment on parasite burden in cardiomyoblasts and the effects of the Nrf2-inducer COPP on heart function in BALB/c mice infected with either DTU-II Y or DTU-I Colombian T. cruzi strains. Treatment with antioxidants CoPP, apocynin, resveratrol, and tempol reduced parasite burden in cardiomyoblasts H9C2 for both DTUI- and II-strains, while H2O2 increased it. CoPP treatment improved electrical heart function when administered during acute stage of Y-strain infection, coinciding with an overall trend towards increased survival and reduced heart parasite burden. These beneficial effects surpassed those of trypanocidal benznidazole, implying that CoPP directly affects heart physiology. CoPP treatment had beneficial impact on heart systolic function when performed during acute and evaluated during chronic stage. No impact of CoPP on heart parasite burden, electrical, or mechanical function was observed during the chronic stage of Colombian-strain infection, despite previous demonstrations of improvement with other antioxidants. Treatment with CoPP also did not improve heart function of mice chronically infected with Y-strain. Our findings indicate that amastigote growth is responsive to changes in oxidative environment within heart cells regardless of the DTU source, but CoPP influence on heart parasite burden in vivo and heart function is mostly confined to the acute phase. The nature of the antioxidant employed, T. cruzi DTU, and the stage of disease, emerge as crucial factors to consider in heart function studies. Author summary: Chagas disease, caused by Trypanosoma cruzi, can lead to serious heart complications, known as Chagas cardiomyopathy. This study investigates the role of oxidative stress on the growth of T. cruzi and the effects of antioxidants, particularly protoporphyrin cobalt (CoPP), on heart health using two distinct strains of the parasite (Y and Colombian strains). We found that CoPP and other antioxidants, including apocynin, resveratrol, and tempol, reduced parasite levels in heart cells, while oxidative stress increased it. In mice infected with the Y strain of T. cruzi, CoPP treatment during the acute phase improved heart function, reduced parasite burden, and increased survival, outperforming the standard treatment with benznidazole. However, CoPP's benefits were mostly confined to the early stages of infection. When treatment was administered during the chronic phase, it did not improve heart function or reduce parasite levels in mice infected with the Colombian strain, despite previous studies showing that other antioxidants can be beneficial in this stage. These findings suggest that the type of antioxidant and the timing of treatment are crucial in managing Chagas disease. This work underscores the potential of early antioxidant treatments like CoPP to protect heart function and prevent long-term damage, potentially offering better treatment strategies. [ABSTRACT FROM AUTHOR]

Background: Benzimidazole derivatives are widely used anthelmintic drugs, particularly in mass campaigns for intestinal parasitosis treatment. Despite their generally good safety profile, serious adverse reactions have been reported. This study aims to identify potential pharmacovigilance signals for benzimidazole derivatives using disproportionality analysis in the WHO database. Methodology: A case/non-case study was conducted using data from the WHO VigiBase database (2000–2023). Cases were individual case safety reports (ICSRs) where at least one suspected serious adverse event of interest was reported, while non-cases were ICSRs reporting any adverse events other than the serious adverse events of interest. Reporting Odds Ratios (RORs) and 95% confidence intervals were calculated to assess disproportionate reporting. Analyses were adjusted for potential confounding factors and a sensitivity analysis with imputed missing data was performed. Principal findings: Among 19,068 serious reports analyzed, significant disproportionality signals were found for benzimidazole derivatives compared to other anthelmintic drugs, notably for bone marrow failure and hypoplastic anemia (adjusted ROR 9.44 [5.01–18.9]), serious leukopenia (3.89 [2.64–5.76]), serious hepatic disorders (3.10 [2.59–3.71]), hepatitis (2.88, 95% CI 2.29–3.63) and serious urticaria (2.02, 95% CI 1.36–2.99). We have also highlighted a new signal not mentioned in the summaries of product characteristics for seizures with benzimidazole derivatives. Secondary analysis revealed these signals were primarily reported with albendazole. Conclusions/Significance: This study identified potential pharmacovigilance signals for serious hematological and hepatic adverse events for benzimidazole derivatives, particularly albendazole. New signal for benzimidazole derivatives has been described for seizures. These findings underscore the need for vigilant monitoring during benzimidazole derivatives use and warrant further pharmacoepidemiologic studies to confirm these signals and investigate underlying mechanisms. Author summary: Benzimidazole derivatives, including albendazole and mebendazole, are widely used anthelmintics known for their broad spectrum of activity and general tolerability. Some adverse reactions have been reported with benzimidazole derivatives, including hematological, immune, neurological, gastrointestinal, hepatobiliary, and skin disorders. This is the first analysis of serious adverse events reported with benzimidazole derivatives using the WHO global pharmacovigilance database, VigiBase. The study identifies potential pharmacovigilance signals for benzimidazole derivatives, including increased reporting of bone marrow failure, hypoplastic anemia, leukopenia, and hepatic disorders. It also reveals that albendazole is more frequently reported in several serious adverse events compared to other benzimidazole derivatives and anthelmintic drugs, particularly for hematological and hepatotoxic effects. We have also highlighted a new signal, not mentioned in the summaries of product characteristics, for benzimidazole derivatives. These findings highlight the importance of careful monitoring when using benzimidazole derivatives and suggest the need for further studies to confirm these observations and explore the underlying mechanisms. [ABSTRACT FROM AUTHOR]

Wolbachia pipientis (= Wolbachia) has promise as a tool to suppress virus transmission by Aedes aegypti mosquitoes. However, Wolbachia can have variable effects on mosquito-borne viruses. This variation remains poorly characterized, yet the multimodal effects of Wolbachia on diverse pathogens could have important implications for public health. Here, we examine the effects of transient somatic infection with two strains of Wolbachia (wAlbB and wMel) on the alphaviruses Sindbis virus (SINV), O'nyong-nyong virus (ONNV), and Mayaro virus (MAYV) in Ae. aegypti. We found variable effects of Wolbachia including enhancement and suppression of viral infections, with some effects depending on Wolbachia strain. Both wAlbB- and wMel-infected mosquitoes showed enhancement of SINV infection rates one week post-infection, with wAlbB-infected mosquitoes also having higher viral titers than controls. Infection rates with ONNV were low across all treatments and no significant effects of Wolbachia were observed. The effects of Wolbachia on MAYV infections were strikingly strain-specific; wMel strongly blocked MAYV infections and suppressed viral titers, while wAlbB had more modest effects. The variable effects of Wolbachia on vector competence underscore the importance of further research into how this bacterium impacts the virome of wild mosquitoes including the emergent human pathogens they transmit. Author summary: In recent years, wild populations of Aedes aegypti mosquitoes in over a dozen countries have been deliberately infected with Wolbachia pipientis ("Wolbachia"); an intracellular bacterium that, in some circumstances, helps to curb the spread of mosquito-brone pathogens including dengue virus. But how does Wolbachia affect the ability of mosquitoes to become infected with and spread the many different viruses they encounter in nature? Here, we use transient somatic infections in Aedes aegypti to characterize the effects of Wolbachia on three different alphaviruses that cause illness in humans: Sindbis virus, O'nyong-nyong virus, and Mayaro virus. We find that transient Wolbachia infections have variable effects on these different pathogens, ranging from significant suppression of Mayaro virus to significant enhancement of Sindbis virus. Our research has important implications for the design of vector control strategies, and suggests further research is needed to understand how Wolbachia shapes the replication and transmission of diverse viruses in mosquitoes. [ABSTRACT FROM AUTHOR]

The genus Prototheca (alga) comprises a unique group of achlorophyllic saprotrophic and mammalian pathogen species. Despite its rare occurrence in humans and animals, protothecosis is considered an emerging clinical entity with relevance in immunocompromised patients. In this study, the characterization of spherical structures with endospores recovered from a blood culture in an HIV patient was investigated using phenotypic and molecular methodologies. On 2% Sabouraud dextrose agar, the isolate displayed morphological and biochemical characteristics found on isolates identified as Prototheca wickerhamii. To validate these analyses, molecular phylogeny of the internal transcript space (ITS) partial gene confirmed the identity of the isolate as P. wickerhamii. This is the first case of systemic human protothecosis in Brazil. The present case of human Prototheca and those reported in the medical literature highlight the need for novel methodologies to identify pathogenic algae in the clinical laboratory, improving in this way the diagnosis and treatment of this group of neglected pathogens. Author summary: Species of Prototheca are achlorophyllous algae widespread in aquatic and wet environments, exhibiting the surprising ability to act as a pathogen of mammals, including humans. With no tendency to self-resolve and the potential for fatal outcomes in immunocompromised patients, protothecosis has emerged as a concerning infection in the last decades. In this study, we identified a Prototheca isolate from a fatal case of systemic protothecosis, using traditional assays, and phylogenetic analysis. Traditional assays identified the pathogen as Prototheca wickerhamii, findings later confirmed by molecular methodologies. Because of its unique classification, clinical diagnosis and laboratory identification are challenging. For instance, the macro morphology of the colonies on culture mimics those in Candida species, a fact contributing to delay therapy. Therefore, the accurate identification and characterization of clinical isolates using molecular methodologies may have a positive impact on the diagnosis and treatment of this unusual infection. [ABSTRACT FROM AUTHOR]

Background: Schistosomiasis, a chronic parasitic disease, remains a public health issue in tropical and subtropical regions, especially in low and moderate-income countries lacking assured access to safe water and proper sanitation. A national prevalence survey carried out by the Brazilian Ministry of Health from 2011 to 2015 found a decrease in human infection rates to 1%, with 19 out of 26 states still classified as endemic areas. There is a risk of schistosomiasis reemerging as a public health concern in low-endemic regions. This study proposes an integrated landscape-based approach to aid surveillance and control strategies for schistosomiasis in low-endemic areas. Methodology/Principal findings: In the Middle Paranapanema river basin, specific landscapes linked to schistosomiasis were identified using a comprehensive methodology. This approach merged remote sensing, environmental, socioeconomic, epidemiological, and malacological data. A team of experts identified ten distinct landscape categories associated with varying levels of schistosomiasis transmission potential. These categories were used to train a supervised classification machine learning algorithm, resulting in a 92.5% overall accuracy and a 6.5% classification error. Evaluation revealed that 74.6% of collected snails from water collections in five key municipalities within the basin belonged to landscape types with higher potential for S. mansoni infection. Landscape connectivity metrics were also analysed. Conclusions/Significance: This study highlights the role of integrated landscape-based analyses in informing strategies for eliminating schistosomiasis. The methodology has produced new schistosomiasis risk maps covering the entire basin. The region's low endemicity can be partly explained by the limited connectivity among grouped landscape-units more prone to triggering schistosomiasis transmission. Nevertheless, changes in social, economic, and environmental landscapes, especially those linked to the rising pace of incomplete urbanization processes in the region, have the potential to increase risk of schistosomiasis transmission. This study will help target interventions to bring the region closer to schistosomiasis elimination. Author summary: Schistosomiasis is a Neglected Tropical Disease whose transmission in Brazil is related to human contact with water contaminated by the trematode parasite Schistosoma mansoni. The national prevalence survey from 2011–2015 revealed a decline in schistosomiasis positivity rates to 1%, marking areas in the Middle Paranapanema river basin in SP-Brazil (MP) as low endemic. However, control programs face additional challenges due to the new dynamics connected with the social, environmental, and economic developments fueled by an urban-industrial urbanization model in the MP region. To address this, our study proposes a landscape-based methodological approach that categorizes and assesses schistosomiasis transmission potential in different regional landscape patterns. By combining remote sensing, environmental, socioeconomic, epidemiological, and malacological data, a multidisciplinary team identified ten distinct landscape-unit types associated with varying levels of schistosomiasis transmission potential. Using a decision-tree based machine learning classification method, we mapped schistosomiasis risk across the basin at a landscape scale. The identification of landscape features associated with schistosomiasis transmission risk will help to fine tune suitable surveillance and control strategies at both local and regional levels. Our findings indicate that landscape-units with higher transmission potentials are less interconnected across the basin. Low connectivity at the landscape scale, in part, explains the MP low endemic areas, contributing to the low endemicity in the Middle Paranapanema region. This approach offers promise for local and regional schistosomiasis management efforts aimed at eradicating the disease. [ABSTRACT FROM AUTHOR]

Network analysis may improve the understanding of malaria epidemiology in rural areas of the Amazon region by explicitly representing the relationships between villages as a proxy for human population mobility. This study tests a comprehensive set of connectivity metrics and their relationship with malaria incidence across villages with contrasting PAMAFRO (a malaria control initiative) coverage levels in the Loreto department of Peru using data from the passive case detection reports from the Peruvian Ministry of Health between 2011 and 2018 at the village level. A total of 24 centrality metrics were computed and tested on 1608 nodes (i.e., villages/cities). Based on its consistency and stability, the betweenness centrality type outperformed other metrics. No appreciable differences in the distributions of malaria incidence were found when using different weights, including population, deforested area, Euclidian distance, or travel time. Overall, villages in the top quintile of centrality have a higher malaria incidence in comparison with villages in the bottom quintile of centrality (Mean Difference in cases per 1000 population; P. vivax = 165.78 and P. falciparum = 76.14). The mean difference between villages at the top and bottom centrality quintiles increases as PAMAFRO coverage increases for both P. vivax (Tier 1 = 155.36; Tier 2 = 176.22; Tier 3 = 326.08) and P. falciparum (Tier 1 = 48.11; Tier 2 = 95.16; Tier 3 = 139.07). The findings of this study support the shift in current malaria control strategies from targeting specific locations based on malaria metrics to strategies based on connectivity neighborhoods that include influential connected villages. Author summary: In our study, we explored how the connections between villages in the Amazon region can help us better understand the spread of malaria. By examining how people move between these villages, we identified key locations that play a significant role in the spread of the disease. We used data from 2011 to 2018, collected from the Peruvian Ministry of Health, focusing on the Loreto department. Our analysis involved 1608 villages, where we computed and tested 24 different connectivity metrics to see which one best predicted malaria cases. We found that the "betweenness centrality" metric, which measures how often a village serves as a bridge between others, was the most reliable predictor of malaria incidence. Interestingly, we discovered that villages with higher connectivity tended to have more malaria cases. This trend was even more pronounced in areas with stronger malaria control efforts. Our findings suggest that current malaria control strategies could be improved by focusing not just on individual villages with high malaria rates but also on those that are well-connected to others. This approach could lead to more effective interventions and a better understanding of how diseases like malaria spread in rural areas. [ABSTRACT FROM AUTHOR]

We conducted a large-scale survey of arboviruses in mosquitoes and biting midges to assess the presence and spread of mosquito-borne pathogens currently circulating on Hainan Island, China. RT-PCR assays were used to detect the arbovirus species, distribution, and infection rates in mosquitoes and biting midges. Cell inoculation and high throughput sequencing were performed to isolate the viruses and assemble full viral genomes. Phylogenetic analysis was conducted to identify the viral genotypes and evolutionary relationships with known viruses. During 2019–2023, 32,632 mosquitoes and 21,000 biting midges were collected from 14 of 18 cities/counties on Hainan Island. Japanese encephalitis virus (JEV) was detected in Culex mosquitoes from five cities/counties, where the minimum infection rate (MIR) was 1.6 (0.6–2.6) per 1,000 females tested. Tembusu virus (TMUV) was detected in Culex mosquitoes from three cities/counties with MIR1.0 (0–2.2) per 1,000. Getah virus (GETV) was detected in Armigeres mosquitoes from Qionghai city with MIR 7.1 (0–15.2) per 1,000. Oya virus (OYAV) and Bluetongue virus (BTV) were detected in biting midges from Wanning city with MIRs of 0.4 (0–1.2) and 0.1 (0–10.2) per 1,000, respectively. Three JEV strains were isolated and clustered within the genotype I group, which is presently the dominant genotype in China. Three TMUV strains were isolated for the first time on Hainan Island that belonged to Cluster 3. Three isolated GETVs were identified as Group 3. BTV was reported for the first time on Hainan Island, and the complete genome for one BTV strain was successfully assembled, which was classified as serotype 1 based on the sequences of segment 2. These results stress the need to develop adequate surveillance plan measures to better control the public health threat of arboviruses carried by mosquitoes and biting midges in local regions. Author summary: In the early 1990s, a large-scale survey for arboviruses in vectors was conducted in Hainan Island. However, in the past 30 years, with climate change, urbanization, and the increasing population and trades, whether the arboviruses spectrum changed on this Island is unclear. We screened arboviruses in mosquitoes and biting midges from 2019 to 2023 to assess the presence of arbovirus and the genetic evolution currently circulating on this Island. Except for arboviruses such as JEV, GTEV, and OYAV, which have been previously reported circulating on Hainan Island, TMUV and BTV were detected for the first time during this survey. These findings highlight the increasing risk of arbovirus transmission in Hainan Island. It is crucial to prioritize extensive and continuous surveillance of arboviruses carried by mosquitoes and biting midges in local regions to help prevent the spread of emerging and re-emerging arboviral diseases. [ABSTRACT FROM AUTHOR]

Background: Schistosomiasis japonica is a serious threat to human health. It causes damage to the intestine and liver. Probiotic therapy has been shown to be effective in alleviating intestinal diseases and improving host health. Previous studies have found that Bacillus amyloliquefaciens could alleviate the pathological symptoms of schistosomiasis japonica, but the regulatory mechanism of alleviating schistosomiasis japonica is still unknown. Principal findings: This study analyzed the dynamic changes of intestinal microbiome in mice infected with Schistosoma japonicum after the intervention of B. amyloliquefaciens and its connection to host metabolism by multi-omics sequencing technology. B. amyloliquefaciens was found to significantly regulate the homeostasis of intestinal microbiota by promoting the growth of beneficial bacteria and inhibiting potential pathogenic bacteria and protect the number of core microbes. Meanwhile, the genes related to the metabolism of glycerophospholipids and amino acid from intestinal microbiome changed significantly, and were shown to be significantly positively correlated with the associated metabolites of microbial origin. Moreover, host metabolism (lipid metabolism and steroid hormone biosynthesis) was also found to be significantly regulated. Conclusions: The recovery of intestinal microbial homeostasis and the regulation of host metabolism revealed the potential probiotic properties of B. amyloliquefaciens, which also provided new ideas for the prevention and adjuvant treatment of schistosomiasis japonica. Author summary: Schistosomiasis, which seriously threatens human health, is the world's second largest tropical disease caused by schistosome infection. Praziquantel has many problems such as side effects and drug resistance, so it is urgent to develop new prevention strategies. Bacillus amyloliquefaciens has been reported to alleviate the pathological damage of intestinal diseases, which can be used as a potential strategy to alleviate granuloma and fibrosis induced by schistosomiasis japonica in intestine and liver. However, the mechanism of B. amyloliquefaciens regulating schistosomiasis japonica through the mediation of intestinal microbiome is still unclear. In this study, we conducted joint analysis of the gut microbiome and host serum metabolites through mouse models and multi-omics sequencing technology, and found that the intragastric administration of B. amyloliquefaciens could regulate the restoration of intestinal microbiome and the secretion of metabolites derived from intestinal microbiome in mice, improve lipid metabolism disorder and hormone secretion in mice, and ultimately reduce the pathological response of mice infected with Schistosoma japonicum. This study highlights the crosstalk between intestinal microbiome and the host, providing an important reference for the precise treatment based on targeted microbiota, and also providing a new strategy for the prevention and adjuvant treatment of schistosomiasis japonica. [ABSTRACT FROM AUTHOR]

Background: The prevalence of intestinal schistosomiasis remains a challenge despite government efforts to eliminate the disease. This study aims to assess the prevalence of intestinal schistosomiasis in school-age children living in the villages surrounding Lake Chamo in southern Rift Valley of Ethiopia. Methodology/Principal findings: A cross-sectional study was conducted from January to July 2023 in Shele Mela Kebele in Gamo Zone, South Ethiopia. Stool samples were collected from 597 school-age children. A singe Kato-Katz for helminths and formalin-ether concentration technique for protozoan parasites were used to process the samples. The intensity of Schistosoma mansoni infection among school-age children was determined by counting the number of eggs per gram of stool. Of the 597 children screened, 52.3% (95% CI: 48.4.4–56.4) were positive for Schistosoma mansoni. These findings showed that 55% of the infections were light, 30.3% were moderate, and 14.7% were heavy. The mean egg count of S. mansoni parasites was 182.1 eggs per gram. The prevalence of other intestinal parasites (Hymenolopis nana, Ascaris lumbricoides, Hookworm, Taenia species, Giardia lamblia and Entamoeba histolytica) was found to be 7.7% (46/597). The overall prevalence of S. mansoni co-infection with other intestinal parasites was 5.0% (30/597). Specifically, the co-infection rates were 1.5% for A. lumbricoides, 1.3% for H. nana, 1.0% for Taenia species, 0.2% for Hookworm, 0.2% for E. histolytica, and 0.2% for G. lamblia. Conclusions/Significances: The study showed a high rate of S. mansoni infection among school-age children. This calls for immediate action, such as school-based deworming, to protect these children from the disease and reduce the burden. Further research is needed to understand the transmission of the infection by the intermediate host. Author summary: Schistosomiasis is a neglected tropical parasitic disease that affects over 220 million people globally. Although there is a deworming mass drug administration (MDA) program for soil-transmitted helminths, the study area still needs to be integrated into the Praziquantel MDA. The study focused on school-age children to better understand the prevalence of the disease and recommend interventions. Hence, we assessed the prevalence and intensity of intestinal schistosomiasis among school-age children living in selected villages near Lake Chamo in the southern Rift Valley of Ethiopia. The results revealed that the prevalence of Schistosoma mansoni was 52.3%. The overall prevalence of other intestinal parasites (Hymenolopis nana, Ascaris lumbricoides, Hookworm, Taenia species, Giardia lamblia, and Entamoeba histolytica) was 7.7%. We documented a 5% S. mansoni co-infection with all other intestinal parasites including A. lumbricoides, H. nana, Taenia species, Hookworm, E. histolytica, and G. lamblia. This implies a high prevalence of intestinal parasites in school-age children, necessitating immediate action to alleviate this burden. Implementing school-based mass drug administration (MDA) for schistosomiasis is advisable in the study villages. [ABSTRACT FROM AUTHOR]

Background: Patients with an active cancer are more likely to develop melioidosis, but the characteristics and clinical course of melioidosis in patients with cancer have not been examined in detail. Trimethoprim/sulfamethoxazole (TMP-SMX) prophylaxis is prescribed to prevent melioidosis in patients receiving immune suppressing anti-cancer therapy in some jurisdictions–and is recommended in national Australian guidelines–however the risks and benefits of this strategy are incompletely defined. Methods: The study took place in Far North Queensland (FNQ) in tropical Australia. The characteristics and clinical course of patients with melioidosis diagnosed in the FNQ region between January 1, 1998, and June 1, 2023, who had–and did not have–an active cancer were compared. We also determined the subsequent incidence of melioidosis in patients receiving immune suppressing anti-cancer therapy in the FNQ region between January 1, 2008, and June 1, 2023, who did–and did not–receive TMP-SMX chemoprophylaxis for Pneumocystis jirovecii infection. Results: An active cancer was present in 47/446 (11%) cases of melioidosis diagnosed between January 1, 1998, and June 1, 2023; there was no association between melioidosis and any cancer type. Patients with melioidosis and cancer were more likely to be older (odds ratio (OR) (95% confidence interval (CI): 1.05 (1.03–1.08) P<0.0001) and immunosuppressed (OR (95% CI): 11.54 (5.41–24.6), p<0.0001) than patients without cancer. Immune suppressing anti-cancer therapy had been prescribed to 17/47 (36%) in the 12 months prior to their diagnosis of melioidosis. Only 10/47 (21%) with cancer and melioidosis in the cohort had received no immune suppressing anti-cancer therapy and had no other risk factors for melioidosis. Twelve months after the diagnosis of melioidosis, 25/47 (53%) were still alive; 9/22 (41%) deaths were due to melioidosis and 13/22 (59%) were due to the underlying cancer. Between 2008 and June 2023, there were 4400 individuals who received myelosuppressive anti-cancer therapy in the FNQ region. There was no significant difference in the incidence of melioidosis between patients who did–and did not–receive TMP-SMX chemoprophylaxis with their myelosuppressive anti-cancer therapy (1/737 (0.15%) versus 16/3663 (0.44%); relative risk (95% confidence interval): 0.31 (0.04–2.34), p = 0.20) and no significant difference in the incidence of fatal melioidosis (0/737 versus 3/3663 (0.08%), p = 0.58). Conclusions: Patients with cancer are predisposed to developing melioidosis and immune suppressing anti-cancer therapy increases this risk further. However, in this region of Australia, there was no significant difference in the subsequent development of melioidosis in patients who did–and did not–receive TMP-SMX chemoprophylaxis during their myelosuppressive anti-cancer therapy. Author summary: In this study from a tertiary hospital in tropical Australia, an active cancer was present in 11% of 446 patients with cultured-confirmed melioidosis, However, no solid organ or haematological cancer diagnosis appeared to be associated with developing the infection. Approximately half of the individuals with cancer who developed melioidosis died within 12 months of their melioidosis diagnosis, however, deaths were more commonly due to their underlying cancer than their melioidosis. Immune suppressing anti-cancer therapy had been prescribed in the prior 12 months in 36% of the individuals with cancer and melioidosis. Trimethoprim-sulfamethoxazole (TMP-SMX) is not prescribed routinely to prevent melioidosis in local patients receiving myelosuppressive anti-cancer therapy, but individuals receiving twice weekly TMP-SMX chemoprophylaxis against Pneumocystis jirovecii pneumonia did not have a statistically lower rate of melioidosis than individuals who did not receive this chemoprophylaxis. Melioidosis was a rare complication of myelosuppressive anti-cancer therapy in the region. Only 16/3663 (0.44%) individuals not receiving TMP-SMX chemoprophylaxis developed melioidosis, and only 3/3663 died from the disease (0.08%). As TMP-SMX has a range of potential side effects–and has the potential to interrupt the delivery of anti-cancer therapy and drive resistance to an important antibiotic–our data do not presently support TMP-SMX prophylaxis for melioidosis in patients receiving anti-cancer therapies in this region of Australia. [ABSTRACT FROM AUTHOR]

Bacillus thuringiensis crystal (Cry) proteins have been expressed in commercial transgenic crops for nearly 30 years, providing safe and effective control of insect pests and significantly reducing the application of hazardous chemical pesticides. B. thuringiensis crystal proteins have also been shown to target parasitic nematodes, including plant parasitic nematodes. Recently, transgenic soybean crops expressing Cry14Ab have been shown to provide control against the soybean cyst nematode Heterodera glycines, marking the first time a crystal protein is being commercialized in transgenic crops for control of a nematode pest. However, apart from H. glycines and the free-living nematode, Caenornabditis elegans, the breadth of nematode activity of Cry14Ab, e.g., against gastrointestinal parasitic nematodes (GINs), has not been reported. Here we study the efficacy of Cry14Ab against a wide range of gastrointestinal nematode parasites (GINs) in vitro and in vivo. We find that Cry14Ab is effective in vitro against the barber's pole worm Haemonchus contortus larvae, small strongyles cyathostomin larvae, the hookworm Ancylostoma ceylanicum adults, the roundworm Ascaris suum L4 larvae, and the whipworm Trichuris muris adults. In rodents infected with GIN parasites, Cry14Ab is effective as an in vivo anthelmintic against the hookworms A. ceylanicum and N. americanus, against the mouse parasite Heligmosomoides polygyrus bakeri, and against the roundworm A. suum. Cry14Ab also variably reduces the reproduction of the whipworm T. muris in vivo. Using optimized profile Markov Models, we looked for other putative anthelmintic Cry proteins and, within this list, identified a Bt crystal protein, GenBank accession no. MF893203, that we produced and demonstrated intoxicated GINs. This protein, with 90% amino acid identity to Cry14Ab, is active against C. elegans, A. ceylanicum adults, and A. suum L4 larvae in vitro. MF893203 was given the official designation of Cry14Ac. Cry14Ac is also an effective in vivo anthelmintic against A. ceylanicum hookworms in hamsters and intestinal A. suum in mice. Taken together, our results demonstrate that Cry14Ab and Cry14Ac have wide therapeutic utility against GINs. Author summary: Gastrointestinal parasitic nematodes or worms pose a significant threat to global health, causing illness in millions-billions of people and animals. Current treatments have limitations, including concerns about drug resistance. We are exploring a promising new approach using natural Crystal (Cry) proteins from Bacillus thuringiensis (Bt) bacteria, which are already widely used as safe and effective insecticides. To date, we have focused on the anthelmintic (deworming) properties of Bt Cry protein Cry5Ba. Here, our research demonstrates that a newly characterized and different Bt Cry protein, Cry14Ab, can also effectively target and kill various types of harmful parasitic nematodes in both laboratory and animal models. Moreover, we identify another related Bt protein, Cry14Ac, with similar activities against parasitic nematodes. These findings highlight the potential of Bt proteins as a novel class of deworming medications, offering hope for the development and clinical deployment of safer and more effective treatments against parasitic nematode infections. [ABSTRACT FROM AUTHOR]

Background: Some regions of Spain are withdrawing their pregnancy screening program for congenital toxoplasmosis (CT). The Spanish Research Network of Congenital Toxoplasmosis (REIV-TOXO) was created to describe the current status of CT in Spain. The aims of this study were to describe the epidemiological and clinical characteristics of CT and to evaluate the effect of prenatal treatment on clinical outcomes to inform decision-making policies. Methods: Ambispective observational study including CT cases recorded in the REIV-TOXO database that includes 122 hospitals (2015–2022). Inclusion criteria were one or more of the following: positive PCR in maternal amniotic fluid; positive Toxoplasma gondii-specific IgM or IgA antibodies at birth; positive PCR in the placenta, newborn blood, urine or CSF; increase of specific IgG levels during infant follow-up; or specific IgG persistence beyond age 12 months. Findings: Fifty-six newborns (54 pregnancies) were included. Prenatal screening allowed 92.8% of cases to be identified. The time of maternal infection was well documented in 90.7% of cases, with 61.1% occurring in the third trimester. A total of 66.6% (36/54) pregnant women received antiparasitic treatment: 24/36 spiramycin, 8/36 pyrimethamine, sulfadiazine, and folinic acid, and 4/36 both treatments sequentially. Most cases were asymptomatic at birth (62.5%, 35/56), and 84% (47/56) newborns completed one year of treatment. Median follow-up was 24 months (IQR = 3–72): 14.2% children exhibited new complications, mainly ocular. Newborns born to mothers treated prenatally had four-fold lower risk of CT clinical features at birth (p = 0.03) and six-fold lower risk of further complications during follow-up (p = 0.04) with no treatment-related differences during pregnancy. Conclusions: While diagnosis based only on neonatal assessment misses a significant number of CT cases, prenatal screening allows treatment to be started during pregnancy, with better clinical outcomes at birth and during follow-up. REIV-TOXO provides valuable information about CT in Spain, highlighting the need for universal maternal screening. Author summary: Spain is presumed to have a low burden of congenital toxoplasmosis, but the true incidence of the disease is currently unknown. To describe and analyze the status of congenital toxoplasmosis in Spain, in 2018 we created a multicenter registry known as the Spanish Research Network of Congenital Toxoplasmosis (REIV-TOXO) to collect data on all children diagnosed with congenital toxoplasmosis born in Spain from January 1, 2015 to the present. In this paper, we describe the main characteristics of cases included in REIV-TOXO between 2015 and 2022. We also focused on the effect of prenatal treatment on clinical outcomes at birth and during follow-up, since its effectiveness has been questioned in the past and may raise several concerns. One of these issues is the actual benefit of serological screening during pregnancy as part of a public health strategy to mitigate the disease. Although the implementation of prenatal screening is still under debate, it remains the only tool available that allows any potentially infected children to be identified and afford them an opportunity for early follow-up and treatment. In view of the progressive withdrawal of prenatal screening in Spain in recent years, the results of our cohort are relevant, as they provide data that could aid public health decision-making policies. [ABSTRACT FROM AUTHOR]

Background: Podoconiosis is a stigmatising neglected tropical condition, but the nature of podoconiosis stigma has not been fully explored. There is a growing understanding that the experience of stigma is intersectional, yet no research has been done on this matter in relation to podoconiosis. The aim of this paper is to contribute to the understanding of podoconiosis-related stigma by illustrating how multiple individuals' positionalities intersect to shape the experience of stigma due to podoconiosis. Methods: We used qualitative research to explore the experience of stigma among people affected by podoconiosis. Data were gathered using participant observation, interviews, focus group discussions and participatory methods. A total of 59 participants, including patients, local leaders, community health workers, and family members, were purposively selected to participate in this study. Findings: We identified three features in which stigma related to podoconiosis was grounded. These were bodily deformation, illness contamination and bodily weakness. The experience of stigma was shaped by the convergence of multiple individual positionalities and identities. Social positionalities and identities based on socio-economic, gender, age and illness status intersected to shape podoconiosis stigma. Conclusion: Our study demonstrates that the experience of stigma due to podoconiosis is intersectional, going beyond biological features of podoconiosis. The stigma experienced by affected individuals is complex, and shaped by the convergence of social structures and many individual identities such as socio-economic status, gender, disability and age. This understanding is crucial to analysing stigma related to podoconiosis, or other NTDs, and for designing interventions that address stigma that arise from biological aspects of disease and social factors simultaneously. Such holistic interventions can significantly improve the well-being of those affected by podoconiosis. Author summary: Podoconiosis is a neglected tropical disease that causes swelling of the feet and legs leading to bodily disfigurement. An estimated 4 million people are affected worldwide, while in Rwanda, more than six thousand are affected with the disease. Those affected experience social exclusion and discrimination, which cause profound socio-economic and psychological impacts. The nature of this experience has not yet been fully explored. The aim of this paper is to explore the social nuances of podoconiosis-related stigma to contribute to better understanding of the experience of podoconiosis. We explored the experience of stigma of people affected by podoconiosis. We identified various features of podoconiosis-related stigma, such as bodily deformation, illness contamination and bodily weakness. We also noted that socio-economic status, gender, age and severity of podoconiosis fuelled the experience of stigma. Participants explained how affected people experienced stigma that was influenced by many factors: their living conditions, age, gender and illness status, on which their social acceptance or rejection was judged. The experience of affected people is multi-layered, and varies from individual to individual. Therefore, our understanding and actions should rest on an approach that enables us to analyse and identify intersected social features to reduce podoconiosis-related stigma holistically. [ABSTRACT FROM AUTHOR]

Background: Spatiotemporal dengue forecasting using machine learning (ML) can contribute to the development of prevention and control strategies for impending dengue outbreaks. However, training data for dengue incidence may be inflated with frequent zero values because of the rarity of cases, which lowers the prediction accuracy. This study aimed to understand the influence of spatiotemporal resolutions of data on the accuracy of dengue incidence prediction using ML models, to understand how the influence of spatiotemporal resolution differs between quantitative and qualitative predictions of dengue incidence, and to improve the accuracy of dengue incidence prediction with zero-inflated data. Methodology: We predicted dengue incidence at six spatiotemporal resolutions and compared their prediction accuracy. Six ML algorithms were compared: generalized additive models, random forests, conditional inference forest, artificial neural networks, support vector machines and regression, and extreme gradient boosting. Data from 2009 to 2012 were used for training, and data from 2013 were used for model validation with quantitative and qualitative dengue variables. To address the inaccuracy in the quantitative prediction of dengue incidence due to zero-inflated data at fine spatiotemporal scales, we developed a hybrid approach in which the second-stage quantitative prediction is performed only when/where the first-stage qualitative model predicts the occurrence of dengue cases. Principal findings: At higher resolutions, the dengue incidence data were zero-inflated, which was insufficient for quantitative pattern extraction of relationships between dengue incidence and environmental variables by ML. Qualitative models, used as binary variables, eased the effect of data distribution. Our novel hybrid approach of combining qualitative and quantitative predictions demonstrated high potential for predicting zero-inflated or rare phenomena, such as dengue. Significance: Our research contributes valuable insights to the field of spatiotemporal dengue prediction and provides an alternative solution to enhance prediction accuracy in zero-inflated data where hurdle or zero-inflated models cannot be applied. Author summary: In our study, we tackled the complex challenge of predicting dengue fever outbreaks, a crucial task in the field of epidemiology. Dengue prediction is complicated because it relies on the quality of data, which may be affected by the temporal and spatial resolution. We explored different machine learning algorithms across various spatial (village, city and region) and temporal resolutions (weekly and monthly). A key hurdle we encountered was the high frequency of zero values in reported dengue cases, a common issue known as zero-inflated data. This phenomenon makes accurate predictions difficult, especially at finer resolutions. To overcome this obstacle, we first made qualitative predictions about the presence or absence of dengue cases. Then, in scenarios indicating disease presence, we estimated the magnitude of cases quantitatively. This innovative method we designated as hybrid approach and significantly enhanced prediction accuracy in zero-inflated data. This approach can be applied to continuous data where zero-inflated or hurdle models cannot be applied. Our findings have broader implications beyond dengue prediction, shedding light on the challenges of dealing with zero-inflated data in various real-world situations. By improving our understanding of these complexities, our research contributes valuable insights that not only benefit scientists working in epidemiology but also have practical applications in public health strategies ensuring more effective and targeted interventions. [ABSTRACT FROM AUTHOR]

Background: Variation in snake venoms is well documented, both between and within species, with intraspecific venom variation often correlated with geographically distinct populations. The puff adder, Bitis arietans, is widely distributed across sub-Saharan Africa and into the Arabian Peninsula where it is considered a leading cause of the ~310,000 annual snakebites across the region, with its venom capable of causing substantial morbidity and mortality. Despite its medical importance and wide geographic distribution, there is little known about venom variation between different B. arietans populations and the potential implications of this variation on antivenom efficacy. Methodology: We applied a range of analyses, including venom gland transcriptomics, in vitro enzymatic assays and reverse phase chromatography to comparatively analyse B. arietans venoms originating from Nigeria, Tanzania, and South Africa. Immunological assays and in vitro enzymatic neutralisation assays were then applied to investigate the impact of venom variation on the potential efficacy of three antivenom products; SAIMR Polyvalent, EchiTAb-Plus and Fav-Afrique. Findings: Through the first comparison of venom gland transcriptomes of B. arietans from three geographically distinct regions (Nigeria, Tanzania, and South Africa), we identified substantial variation in toxin expression. Findings of venom variation were further supported by chromatographic venom profiling, and the application of enzymatic assays to quantify the activity of three pathologically relevant toxin families. However, the use of western blotting, ELISA, and in vitro enzymatic inhibition assays revealed that variation within B. arietans venom does not appear to substantially impact upon the efficacy of three African polyvalent antivenoms. Conclusions: The large distribution and medical importance of B. arietans makes this species ideal for understanding venom variation and the impact this has on therapeutic efficacy. The findings in this study highlight the likelihood for considerable venom toxin variation across the range of B. arietans, but that this may not dramatically impact upon the utility of treatment available in the region. Author summary: The puff adder (Bitis arietans) is found across sub-Saharan Africa and the Arabian Peninsula and is capable of causing life threatening pathology due to its potent venom. The extensive range of B. arietans exposes populations to different ecological pressures which may impact upon the composition of venom toxins. In this study, we examined the venom composition of B. arietans from three countries separated by large geographic distance: Nigeria, Tanzania and South Africa. By integrating venom gland transcriptomes, venom chromatography, and in vitro functional assays to profile B. arietans venom composition, we uncovered extensive variation between the three locales. Given that venom variation can have a significant impact on the efficacy of antivenom treatment, we also investigated the ability of three African antivenoms to recognise and inhibit in vitro venom activity. Through these analyses, we were able to determine that venom variation did not have a substantial impact on the neutralising effect of selected antivenoms. This study has highlighted the potentially extensive venom variation found across the range of B. arietans and initiated valuable investigations into the efficacy of African antivenoms to protect human populations vulnerable to snakebite envenoming. [ABSTRACT FROM AUTHOR]

Zika virus (ZIKV) and dengue virus (DENV) are closely related flaviviruses co-circulating in the same endemic areas. Infection can raise cross-reactive antibodies that can be either protective or increase risk of severe disease, depending on the infection sequence, DENV serotype and elapsed time between infection. On the contrast, T cell-mediated immunity against DENV and ZIKV is considered protective. Therefore, we have developed a T cell vaccine enriched in immunodominant T cell epitopes derived from ZIKV and evaluated its immunogenicity and efficacy against ZIKV and DENV infection. Mice were vaccinated using DNA vaccine platform using the tetrafunctional amphiphilic block copolymer 704. We show that vaccination of 2 different HLA class I transgenic mice with the ZIKV non-structural (NS) poly-epitope elicits T cell response against numerous ZIKV epitopes. Moreover, vaccination induces a significant protection against ZIKV infection, in the absence of neutralizing or enhancing antibodies against ZIKV. However, vaccination does not induce a significant protection against DENV2. In contrast, immunization with a DENV1-NS poly-epitope induces a significant protection against both DENV1 and DENV2, in the absence of humoral immunity. Taken together, we have shown that T-cell based vaccination could protect against multiple flavivirus infections and could overcome the complexity of antibody-mediated enhancement. Author summary: Dengue virus (DENV) and Zika virus (ZIKV) are two closely related flaviviruses transmitted by Aedes species mosquito. In endemic regions with high circulation of ZIKV and multiple DENV serotypes, and the presence of cross-reactive or sub-neutralizing antibodies that could enhance dengue disease severity, alternative approaches to antibody-induced vaccination must be considered. This work describes a novel strategy for the development of a T-cell based vaccine composed of immunodominant T cell epitopes from ZIKV. This vaccine induces a significant protection against ZIKV infection in mice expressing different HLA class I molecules, in the absence of neutralizing antibodies. Likewise, DNA vaccination with mosaic sequence enriched in DENV T cell epitopes with identical sequences between DENV1 and DENV2 induces a significant protection against these 2 DENV serotypes, without inducing neutralizing antibodies. This study paves the way for T-cell based vaccines that could overcome the risk for antibody-mediated enhancement and protect against multiple flavivirus infections. [ABSTRACT FROM AUTHOR]

Background: Dengue is the most re-emergent infection, with approximately 100 million new cases reported annually, yet no effective treatment or vaccine exists. Here, we aim to define the microbial community structure and their functional profiles in the dengue positive patients with varying disease severity. Methodology/Principal findings: Hospital admitted 112 dengue-positive patients blood samples were analyzed by dual RNA-sequencing to simultaneously identify the transcriptionally active microbes (TAMs), their expressed genes and associated pathways. Results highlight that patients with severe dengue exhibited increased microbial diversity and presence of opportunistic species (unique and core) which includes Bacillus cereus, Burkholderia pseudomallei, Streptococcus suis, and Serratia marcescens. The functional profile analysis revealed enriched metabolic pathways such as protein degradation, nucleotide biosynthesis, ion transport, cell shape integrity, and ATP formation in severe cases, indicating the high energy demands and adaptability of these microbes. Conclusion: Our metatranscriptomic approach provides a species-level characterization of blood microbiome composition and reveals a heightened diversity of TAMs in patients with severe dengue, underscoring the need for further research into the role of blood microbiota in disease progression. Comparing the microbial signatures across the severity classes early in the disease offers unique potential for convenient and early diagnosis of dengue infection. Author summary: Dengue poses a significant public health challenge in tropical and subtropical regions. The lack of a specific treatment or broadly effective vaccine highlights the critical need for novel approaches. In this study, we investigated the transcriptionally active microbial species (TAMs) in 112 dengue-positive patients from MAX Hospital in Delhi, India, to identify their correlations with disease severity. RNA-seq analysis revealed an increased abundance of opportunistic TAMs in severe dengue patients, with some species showing significant associations with platelet counts and total leukocyte count (TLC). Our findings underscore the underappreciated importance of the blood microbiome in dengue, particularly the heightened metabolic activity of these opportunistic species in severe cases. This study offers valuable insights for early infection diagnosis for dengue management. The species-level data identified here could pave the way for systematic exploration of microbial involvement in dengue virus (DENV) infections, potentially serving as an indicator for new adjuvant treatment strategies. [ABSTRACT FROM AUTHOR]

Introduction: Tuberculosis (TB) treatment demands strict adherence to multidrug regimens. Directly Observed Therapy (DOT) poses challenges, especially regarding adherence. With the popularization of smartphones, Video-Observed Therapy (VOT) has emerged as a promising alternative, allowing healthcare providers to remotely supervise patients taking their medications via video calls. Objectives: This systematic review critically assesses VOT's effectiveness compared to DOT, focusing on adherence, treatment costs, time spent supervising treatment, and patient satisfaction, aiming to optimize TB supervision methods worldwide. Methods: Only studies that met the following criteria were eligible for inclusion in the systematic review: randomized trials; studies that compared VOT to DOT; studies involving patients diagnosed with pulmonary or extrapulmonary tuberculosis; studies that reported any of the desired outcomes; full-text articles available for review; and studies conducted in the English language. We excluded studies with the following attributes: studies that lacked a control group; case series or case reports; and previous systematic reviews. The search engines and databases MEDLINE, Embase, and Cochrane were used to find studies comparing Video-Observed Therapy (VOT) to Directly Observed Therapy (DOT). The following search phrases were used to look for papers that contained them in their title or abstract: ("Electronic Directly Observed Therapy" OR "Video-observed therapy" OR "Telemedicine" OR "Wirelessly observed therapy" OR "Smartphone-enabled video-observed") AND ("TUBERCULOSIS"). Results: A systematic review of the literature revealed the following findings: in all Randomized Controlled Trials (RCTs), video-observed therapy (VOT) demonstrated non-inferiority in terms of treatment adherence compared to traditional directly observed therapy (DOT); VOT reduced costs where these outcomes were assessed in the RCTs; the use of VOT reduced the amount of time healthcare professionals spent supervising treatment in RCTs evaluating this aspect; VOT contributed to higher treatment satisfaction in RCTs where this outcome was measured. Conclusion: In this systematic review we emphasize the importance of Video-Observed Therapy (VOT) in the digital age for patients that have access to internet. Our findings show that VOT is comparable to DOT in terms of treatment adherence, but it is also cost-effective, improves patient satisfaction and takes less time for healthcare professionals to supervise. Author summary: Our study compares two methods of monitoring tuberculosis treatment: Video-observed therapy (VOT) and directly observed therapy (DOT). Tuberculosis is an infectious disease that requires strict adherence to treatment, and traditionally, healthcare workers physically observe patients taking their medication (DOT). However, this can be time-consuming and costly. VOT, where patients are observed via video, has emerged as a possible alternative. In this systematic review, we evaluated how VOT and DOT compare in terms of patient adherence, the costs associated with treatment observation, the time required to observe treatment, and patient satisfaction. We found that VOT generally leads to similar or better adherence compared to DOT, while also being more cost-effective and time-efficient. Patients also reported higher satisfaction with VOT, likely due to its convenience and flexibility. Our findings suggest that VOT could be a valuable tool in improving tuberculosis treatment outcomes, especially in resource-limited settings. [ABSTRACT FROM AUTHOR]

Background: Diarrhoeal diseases cause a heavy burden in developing countries. Although studies have described the seasonality of diarrhoeal diseases, the association of weather variables with diarrhoeal diseases has not been well characterized in resource-limited settings where the burden remains high. We examined short-term associations between ambient temperature, precipitation and hospital visits due to diarrhoea among children in seven low- and middle-income countries. Methodology: Hospital visits due to diarrhoeal diseases under 5 years old were collected from seven sites in The Gambia, Mali, Mozambique, Kenya, India, Bangladesh, and Pakistan via the Global Enteric Multicenter Study from December 2007 to March 2011. Daily weather data during the same period were downloaded from the ERA5-Land. We fitted time-series regression models to examine the relationships of daily diarrhoea cases with daily ambient temperature and precipitation. Then, we used meta-analytic tools to examine the heterogeneity between the site-specific estimates. Principal findings: The cumulative relative risk (RR) of diarrhoea for temperature exposure (95th percentile vs. 1st percentile) ranged from 0.24 to 8.07, with Mozambique and Bangladesh showing positive associations, while Mali and Pakistan showed negative associations. The RR for precipitation (95th percentile vs. 1st percentile) ranged from 0.77 to 1.55, with Mali and India showing positive associations, while the only negative association was observed in Pakistan. Meta-analysis showed substantial heterogeneity in the association between temperature–diarrhoea and precipitation–diarrhoea across sites, with I2 of 84.2% and 67.5%, respectively. Conclusions: Child diarrhoea and weather factors have diverse and complex associations across South Asia and Sub-Saharan Africa. Diarrhoeal surveillance system settings should be conceptualized based on the observed pattern of climate change in these locations. Author summary: Diarrhoeal diseases remain a significant public health concern, particularly in low- and middle-income nations, and understanding the environmental factors that influence their occurrence is crucial for effective prevention and management strategies. Here, we study the weather factors, such as temperature and precipitation, that could influence the prevalence of diarrhoeal diseases in children. We found that higher temperatures were associated with an increased risk of diarrhoea in some regions. Increased precipitation was associated with a higher incidence of diarrhoea in some sites. In certain sites, diarrhoeal cases decreased with rising temperatures and precipitation. These findings offer insights into the climate and geographic patterns of childhood diarrhoea, which are essential for developing targeted and efficient public health interventions. Recognizing the significant role of weather-related variables in driving child diarrhoea, it is imperative to identify the conditions associated with these patterns to enhance our understanding of the complex interplay between environmental factors and disease prevalence. [ABSTRACT FROM AUTHOR]

Background: Thromboembolic events are a well-recognized cause of in-hospital deaths of patients with infectious diseases. However, thromboembolic events in patients with scrub typhus, caused by Orientia tsutsugamushi have rarely been reported. This study aimed to assess risk factors associated with thromboembolic events in patients with scrub typhus. Methods: All 93 scrub typhus patients' diagnoses were confirmed serologically or by positive nested polymerase chain reaction (PCR). The clinical and laboratory findings from 12 scrub typhus patients with thromboembolic events and 81 scrub typhus patients with nonthromboembolic events were retrospectively studied. To determine the factors implicated in thromboembolic events, we performed multivariate logistic regression analysis using the six independent factors identified by the univariate analysis. Findings: The mean age of the patients in the thromboembolic group was 76.4 years (median, 76 years), and in nonthromboembolic group it was 64.6 years (median, 65 years) (P<0·001). Thromboembolic events were observed in 12 patients. These events included acute coronary syndrome (n = 5), acute limb ischemia (n = 4), ischemic stroke (n = 1), deep vein thrombosis combined with pulmonary thromboembolism (n = 1), and left common iliac artery aneurysm with a thrombus (n = 1). According to multivariate analysis, the following four factors were significantly associated with the thromboembolic events: 1) treatment with rifampin (OR = 57.6; CI 1.2–2700.3), 2) Taguchi genotype (OR = 41.5, P = 0.028; CI 1.5–1154.6), 3) atrial fibrillation (OR = 9.4, P = 0.034; CI 1.2–74.0), and 4) age (OR = 1.1, P = 0.046; CI 1.0–1.3). Conclusions: Our study suggests that clinicians should be cautious when managing patients with scrub typhus to avoid the development of thromboembolic events, especially in patients with risk factors such as treatment with rifampin, Taguchi genotype, atrial fibrillation, and advanced age. Author summary: Scrub typhus, a disease caused by Orientia tsutsugamushi, is typically treated with antibiotics. It can sometimes lead to serious complications, including thromboembolic events. These events can be life-threatening but have been rarely reported due to under-suspicion in clinical practice, as their rarity often leads to them being overlooked. In this regard, our study suggests that clinicians should be cautious when managing patients with scrub typhus to prevent the development of thromboembolic events, especially in patients with risk factors such as treatment with rifampin, Taguchi genotype, atrial fibrillation, and advanced age. [ABSTRACT FROM AUTHOR]

Q fever (QF) and Rift Valley fever (RVF) are endemic zoonotic diseases in African countries, causing significant health and economic burdens. Accurate prevalence estimates, crucial for disease control, rely on robust diagnostic tests. While enzyme-linked immunosorbent assays (ELISA) are not the gold standard, they offer rapid, cost-effective, and practical alternatives. However, varying results from different tests and laboratories can complicate comparing epidemiological studies. This study aimed to assess the agreement of test results for QF and RVF in humans and livestock across different laboratory conditions and, for humans, different types of diagnostic tests. We measured inter-laboratory agreement using concordance, Cohen's kappa, and prevalence and bias-adjusted kappa (PABAK) on 91 human and 102 livestock samples collected from rural regions in Chad. The serum aliquots were tested using ELISA in Chad, and indirect immunofluorescence assay (IFA) (for human QF and RVF) and ELISA (for livestock QF and RVF) in Switzerland and Germany. Additionally, we examined demographic factors influencing test agreement, including district, setting (village vs. camp), sex, age, and livestock species of the sampled individuals. The inter-laboratory agreement ranged from fair to moderate. For humans, QF concordance was 62.5%, Cohen's kappa was 0.31, RVF concordance was 81.1%, and Cohen's kappa was 0.52. For livestock, QF concordance was 92.3%, Cohen's kappa was 0.59, RVF concordance was 94.0%, and Cohen's kappa was 0.59. Multivariable analysis revealed that QF test agreement is significantly higher in younger humans and people living in villages compared to camps and tends to be higher in livestock from Danamadji compared to Yao, and in small ruminants compared to cattle. Additionally, RVF agreement was found to be higher in younger humans. Our findings emphasize the need to consider sample conditions, test performance, and influencing factors when conducting and interpreting epidemiological seroprevalence studies. Author summary: Q fever (QF) and Rift Valley fever (RVF) are zoonotic diseases that can be transmitted from animals to humans, causing health problems and economic losses in African countries. While various diagnostic tests for these diseases are available, they can be impractical, especially in resource-limited settings. For this study, human and livestock samples from Chad were first tested in a local laboratory using a routine test (enzyme-linked immunosorbent assay). Serum aliquots were then sent to laboratories in Germany or Switzerland for retesting, using the same test type for livestock and a different test type for human samples. We analysed the agreement between the test results and investigated the influence of the demographic characteristics of the sampled individual on this agreement. Our findings are crucial as they reveal discrepancies in test results, even though the samples originated from the same individuals. Additionally, we found that factors such as the age of the sampled individual influenced test agreement. This study underscores the importance of considering sample conditions, test performance, and influencing factors when conducting and interpreting disease prevalence studies. Enhancing diagnostic procedures will aid in more effective disease control management, benefiting local communities and global health efforts. [ABSTRACT FROM AUTHOR]

Background: With decades of containment efforts, the prevalence of C. sinensis infection in Korea has shown a declining trend. However, well-tailored intervention assessments remain challenging, particularly when considering the potential impacts of cohort variations in raw freshwater fish consumption behavior, a major transmission route to humans, on this observed decline. Methodology: We applied an age-period-cohort modeling approach to nationally representative C. sinensis infection prevalence data from 1981–2012 in Korea to assess age, period, and cohort effects on its secular trend and to project the age-stratified prevalence up to 2023. Principal findings: Our analysis suggests that both cohort and period effects have substantially contributed to the declining prevalence of C. sinensis infection in Korea. Age-stratified projections up to 2023 suggest a decline in prevalence across all age groups, while those aged over 40 are anticipated to maintain prevalences above the elimination threshold of 1%. Conclusions: Our study highlights the importance of incorporating cohort effects into intervention assessments aimed at controlling C. sinensis infection. The effectiveness of interventions remains evident in Korea despite adjusting for the cohort effect. This approach, applicable to other endemic countries, would provide valuable insights for intervention assessments and inform future public health planning to eliminate C. sinensis infection. Author summary: Clonorchis sinensis (C. sinensis) infection, a neglected chronic parasitic infection, continues to be a significant public health concern with severe implications. Despite ongoing containment efforts leading to a decline in prevalence in Korea, assessing interventions remains challenging, due to variations in infection risk across different birth cohorts, driven by generational differences in raw freshwater fish consumption. We applied the age-period-cohort modeling approach to nationally representative C. sinensis infection prevalence data from 1981–2012 in Korea. Our analysis showed both cohort and period effects have significantly contributed to the observed decline in the prevalence of C. sinensis infection in Korea throughout the study period. Notably, the effectiveness of interventions remains evident even after adjusting for the cohort effect. Projections of age-stratified prevalence up to 2023 suggest a downward trend across all age groups. However, those aged over 40 are expected to maintain a prevalence exceeding 1%, highlighting the imperative for ongoing sustained efforts toward disease elimination. The age-period-cohort modeling framework offers broad applicability in other liver fluke endemic countries, particularly where data on host reservoirs beyond humans is limited. This approach provides valuable insights for future public health planning and resource allocation, aiming to mitigate the disease burden in affected regions. [ABSTRACT FROM AUTHOR]

Background: Endemic to Central Africa, loiasis, caused by the vector-borne worm Loa loa, affects approximately 10 million individuals. Clinical manifestations include transient angioedema (Calabar swellings), migration of the adult worm under the eye conjunctiva (eye worm) and less specific general symptoms. Loiasis presents a significant public health challenge because L. loa-infected individuals can develop serious adverse events after taking ivermectin, the drug used to combat onchocerciasis. In this context, alternative interventions and rigorous diagnostic approaches are needed. Diagnosing loiasis is challenging because its main clinical manifestations are sporadic and non-specific. The definitive diagnosis relies on identifying adult worms migrating beneath the conjunctiva, or microfilariae (pre-larvae) in blood smears. However, "occult loiasis" (infection without blood microfilariae) is frequent. Serological rapid antibody diagnostic tests (ARTs) can provide an alternative diagnostic method. We compared a novel ART simultaneously targeting onchocerciasis (IgG4 to Ov-16 and OvOC3261, test line 1) and loiasis (IgG4 to L1-SXP-1, test line 2), called IgG4-SXP-1 biplex test) to the already established Loa-ART (all IgG isotypes to Ll-SXP-1, called pan-IgG-SXP-1 test). Methodology: Blood samples underwent both ARTs, read qualitatively and semi-quantitatively. Additionally, blood smears, skin snips, Kato-Katz method for soil-transmitted helminthiases identification and eosinophilia measurements were performed. Questionnaires gathered demographic details and loiasis-related signs. ARTs performance was compared using specific loiasis-related signs and microfilaremia as references. Discordances between the two ARTs were investigated using logistic regression models. Principal findings: Out of 971 participants, 35.4% had L. loa microfilaremia, 71.9% had already experienced loiasis-related signs, 85.1% were positive in the pan-IgG-SXP-1 test and 79.4% were positive in the IgG4-SXP-1 biplex test. In the microfilariae-positive population, the sensitivity of the rapid tests was 87.4% for the pan-IgG-SXP-1 test and 88.6% for the prototype IgG4-SXP-1 biplex test. Sensitivity was similar for both ARTs when using eye worm or Calabar swelling as references, but diagnostic performance varied based on microfilaremia levels and occult loiasis. Overall, IgG4-SXP-1 biplex test demonstrated a sensitivity of 84.1% and specificity of 47.6% for loiasis compared to the pan-IgG-SXP-1 test, leading to a Kappa coefficient estimated at 0.27 ± 0.03 for the qualitative results of the 2 ARTs. In the group that tested positive with the Pan-IgG test but negative with the IgG4-specific test, there was a lower prevalence of STH infection (p = 0.008) and elevated eosinophilia (p<0.001) compared to the general tested population. Conclusion/Significance: The sensitivity of each test was good (84–85%) but the diagnostic agreement between the two ARTs was poor, suggesting that IgG and IgG4 antibody responses should be interpreted differently. The assessment of the innovative rapid diagnostic IgG4-SXP-1 biplex test, designed for onchocerciasis and loiasis, shows encouraging sensitivity but underlines the necessity for further in vitro assessment. Author summary: Loiasis, a disease caused by the parasite Loa loa impacting approximately 10 million people in Central Africa, causes transient angioedemas called Calabar swellings and eye worm episodes. Treatment is challenging, particularly in regions where onchocerciasis, another type of filariasis, is also prevalent. We tested a new kind of test that can detect both diseases at once and compared its performance with a previously available test for loiasis. We took blood samples from 971 people living in an area of Congo where loiasis is endemic. Out of the participants, 35.4% had L. loa pre-larvae in the blood–known as microfilariae, and 72.0% had experienced loiasis-related signs. The new test demonstrated promise in detecting the disease, albeit with some likelihood of false positives. Additionally, its performance varied according to the density of microfilariae in the blood. While the results exceeded expectations, further testing is essential to ensure its reliability. If validated, this test could prove instrumental in diagnosing both loiasis and onchocerciasis, offering a valuable tool for public health interventions in affected regions. [ABSTRACT FROM AUTHOR]

Trypanosoma cruzi, the causative agent of Chagas disease, has a complex life cycle that involves triatomine insects as vectors and mammals as hosts. The differentiation of epimastigote forms into metacyclic trypomastigotes within the insect vector is crucial for the parasite's life cycle progression. Factors influencing this process, including temperature, pH, and nutritional stress, along with specific metabolite availability, play a pivotal role. Amino acids like proline, histidine, and glutamine support cell differentiation, while branched-chain amino acids (BCAAs) inhibit it. Interestingly, combining the pro-metacyclogenic amino acid proline with one of the anti-metacyclogenic BCAAs results in viable metacyclics with significantly reduced infectivity. To explore the characteristics of metacyclic parasites differentiated in the presence of BCAAs, proteomics analyses were conducted. Metacyclics obtained in triatomine artificial urine (TAU) supplemented with proline alone and in combination with leucine, isoleucine, or valine were compared. The analyses revealed differential regulation of 40 proteins in TAU-Pro-Leu, 131 in TAU-Pro-Ile, and 179 in TAU-Pro-Val, as compared to metacyclics from TAU-Pro. Among these, 22%, 11%, and 13% of the proteins were associated with metabolic processes, respectively. Notably, enzymes related to glycolysis and the tricarboxylic acid (TCA) cycle were reduced in metacyclics with Pro-BCAAs, while enzymes involved in amino acid and purine metabolic pathways were increased. Furthermore, metacyclics with Pro-Ile and Pro-Val exhibited elevated enzymes linked to lipid and redox metabolism. The results revealed five proteins that were increased and four that were decreased in common in the presence of Pro+BCAAs, indicating their possible participation in key processes related to metacyclogenesis. These findings suggest that the presence of BCAAs can reshape the metabolism of metacyclics, contributing to the observed reduction in infectivity in these parasites. Author summary: Trypanosoma cruzi, the parasite causing Chagas disease, infects 6–7 million people in the Americas. Its life cycle involves the infection of triatomine insects which transmit the infection to humans and other mammals. Inside the insects, the parasite proliferates as non-infective forms, and its transmission to mammals depends on their differentiation into infective forms. Proline is a factor supporting this differentiation, while valine, leucine and isoleucine (known collectively as BCAA for branched-chain amino acids) do not. Combining proline with each BCAA results in a diminished number of viable parasites, with significantly reduced infectivity. To explore the causes of such diminished infectivity, we performed a proteomics analysis to compare parasites obtained with proline, in the presence or absence of BCAA. We observed that BCAA differentially regulated different proteins associated with metabolic processes: BCAA diminished enzymes related to glycolysis and the tricarboxylic acid (TCA) cycle while increased enzymes involved in amino acid and purine metabolism. Furthermore, isoleucine or valine increased enzymes linked to lipid and redox metabolism. These findings suggest that the presence of BCAAs can reshape the metabolism of the parasite, contributing to the observed reduction in infectivity. [ABSTRACT FROM AUTHOR]

Leishmaniasis poses a significant health burden, particularly among immunocompromised patients. In Thailand, Leishmania infection caused by Leishmania martiniquensis and Leishmania orientalis lacks information about the incidence and risk factors among HIV-infected populations. This longitudinal cohort study aimed to investigate the incidence and persistence of Leishmania infection among HIV-infected individuals in an affected area, Trang Province, Southern Thailand. The study also identified risk factors associated with the incidence of Leishmania infection. The study enrolled 373 participants in the HIV clinic, Trang Hospital, who initially tested negative for Leishmania infection during 2015–2016, and 133 individuals initially tested positive for Leishmania infection. Thus, follow-up visits of 506 participants occurred during 2018–2019. Direct Agglutination Test (DAT) and nested PCR (nPCR) identified incidents and persistent cases of Leishmania infection. Cox proportional-hazards regression analyses were performed to assess risk factors for the incidence of Leishmania infection. Among the initially negative group, 12 incident cases comprised one L. orientalis infection and 11 seropositive cases using DAT, resulting in a cumulative incidence of 3.2% and an incidence density of 10.38 per 1000 person-years. Increasing age was a significant predictor of the incidence of Leishmania infection. Five persistent cases comprised one Leishmania donovani complex and four seropositive cases using DAT in the initially positive group, with a cumulative persistence rate of 3.7% and a persistence density of 12.85 per 1000 person-years. All patients were asymptomatic. This study sheds light on the incidence and persistence of Leishmania infection among HIV-infected individuals in Trang Province, Southern Thailand, underscoring the importance of continued monitoring and tailored interventions to mitigate the impact of this co-infection. Author summary: In Thailand, Leishmania martiniquensis and Leishmania orientalis are the causative agents of cutaneous (CL) and visceral leishmaniasis (VL) reported in immunocompetent and immunocompromised individuals. VL poses a significant health threat, especially to those with HIV infection. Our study conducted a cohort study among HIV-infected patients in Trang Hospital, Trang Province, Southern Thailand, to explore the incidence and persistence of Leishmania infection, a topic not extensively studied in this region. Our findings are crucial for multiple reasons. Firstly, this study reveals a significant incidence rate of 3.2% among HIV patients, and increasing age was a significant predictor of incident Leishmania infection. Secondly, the persistence of Leishmania infection in 3.7% of initially positive cases underscores the challenges in managing this co-infection. It has immediate implications for healthcare providers, policymakers, and public health officials, aiding them in implementing targeted interventions and preventive measures to reduce the impact of leishmaniasis among HIV-infected individuals. By shedding light on this understudied issue, we hope to contribute to better health outcomes for this vulnerable population. [ABSTRACT FROM AUTHOR]

Diarrheal disease is the second leading cause of death among children under five in developing communities, despite active interventions to improve access to water, sanitation, and hygiene resources. Even interventions with high fidelity and compliance saw minimal improvements in health outcomes, necessitating a need for looking beyond traditionally targeted exposure pathways. This study focuses on the pathogen exposure a young child may receive while playing in the public spaces of informal settlements, where animal feces, human feces, and garbage are frequently observed. The study utilized 79 soil samples previously collected across ten cluster sites in Corail, Haiti and processed using DelAgua cultural assays and quantitative Polymerase Chain Reaction methods. Molecular assays screened for Aeromonas, Vibrio cholera, and several pathogenic Escherichia coli species. Behavioral observations of young children (<5 years old) were also conducted in overlapping areas with the environmental sampling to quantify frequency of risky and mitigating behaviors. Environmental and behavioral data were combined to obtain the posterior distribution of children's pathogen exposure from playing in a public space for one hour. The model estimated that children have a likelihood of approximately 70% of being exposed to a pathogen during one hour of play and a greater than 30% chance of being exposed to multiple pathogens in the same period. While children and toddlers practice fewer risky behaviors compared to infants, they were shown to have higher likelihood of exposure and slightly higher pathogen dose per exposure. As anticipated, a high correlation between genes from the same E. coli species was observed in the model output. These findings demonstrate the need to consider public spaces as an important exposure pathway for young children for both future research and interventions. Author summary: Diarrheal disease is the second leading infectious cause of death among children under five worldwide; however, much is being done through interventions to improve conditions and reduce exposure to pathogens. Despite these efforts, little progress has been made on health outcomes. This study looks at an often-overlooked area in interventions, the public spaces in communities where children frequently play. Soil samples were collected and analyzed for pathogens and children were observed to understand frequency of risky behaviors that could lead to soil ingestion. This data was then fed into a statistical model to replicate thousands of instances of a child playing in a public space for one hour and found that the likelihood of pathogen exposure was high at about 70% with a greater than 30% chance of exposure to multiple pathogens in one instance. This has implications for how we plan interventions to include public spaces. It further serves as a methodologic model for combining site specific behavior and environmental data into a statistical model as a robust way to achieve pathogen exposure frequency and dose. [ABSTRACT FROM AUTHOR]

Background: Mycetoma is an uncommon and neglected tropical disease in Uganda. We aimed to assess baseline knowledge and provide community health workers (CHWs) in Northern Uganda with knowledge to identify and refer presumptive mycetoma cases. Methodology: Between March and August 2023, we conducted a concurrent triangulation mixed methods study among CHWs in Gulu and Pader districts on mycetoma. We conducted a 1 day in person training on mycetoma. Quantitative data were collected before (pretest), immediately (immediate posttest) and six months (6-month posttest) after the training and results compared using paired sample t test or one-way ANOVA. Qualitative data were collected using four focused group discussions, audio recorded, and analyzed using thematic content analysis. Principal findings: Forty-five CHWs were enrolled, mostly male (66.7%, n = 30), with a median age of 36 years (IQR 29 43). Out of a total score of 18, the baseline mean knowledge score was 7±2.42, improving to 11±1.99 immediately posttest (p<0.001), and 10±2.35 at 6 months (p<0.001), without additional training. Significant knowledge improvements at 6 months were observed among female participants (p = 0.004), those aged 30 40 years (p = 0.031) or 40+ years (p = 0.035), and those with secondary education (p = 0.007). Over 6 months, CHWs screened 2,773 adults, identifying and referring 30 presumptive mycetoma cases. Qualitative findings revealed challenges and barriers to early identification and referral of mycetoma presumptive cases including limited knowledge, stigma, myths, lack of an indigenous name for mycetoma, delayed decision making, and transportation barriers. Conclusions: This study highlights a significant knowledge gap among CHWs about mycetoma, with substantial improvement following training. The identification of presumptive cases by CHWs reflects their potential in community-based surveillance, emphasizing the need to integrate well-trained CHW to lead efforts for mycetoma surveillance and capacity building to enhance health outcomes in Uganda. Author summary: Mycetoma is a rare neglected tropical disease that affects the skin and the tissues beneath skin, causing severe health issues if not diagnosed and treated early. It disproportionately affects people in rural and impoverished communities in sub-Saharan Africa, including Uganda. Mycetoma often affects mostly young adults in their productive years especially those participating in agricultural activities. In our study, we trained community health workers (CHWs) in Northern Uganda for one day to improve their knowledge and skills in identifying and referring cases of mycetoma. Our results showed that the CHWs had significant knowledge improvement that persisted for at least six months without more training. Furthermore, they were able to identify 30 possible cases of mycetoma after assessing nearly 3,000 people in the communities. Furthermore, we found challenges and barriers to early detection of this disease such as limited initial knowledge, stigma, myths about the disease, and practical issues like transportation difficulties and long distances to health facilities. Therefore, our study shows that by empowering local health workers, we can improve early detection and treatment of mycetoma, ultimately enhancing health in affected regions. [ABSTRACT FROM AUTHOR]

Introduction: Leprosy is a chronic, slowly developing infectious disease that affects the peripheral nerves, specifically Schwann cells. Individuals with the multibacillary type exhibit a propensity for developing chronic pain and a decrease in sensitivity in the plantar region, which directly interferes with balance maintenance. The evaluation of static balance in this population is made through the measurement of the center of pressure (COP) oscillations. Therefore, there is a need to investigate the association between postural control and COP oscillations using a force platform and finding accelerations of the center of mass (COM) from inertial sensors for reliable and portable balance assessment in leprosy patients. Objective: To validate the application of inertial sensors for patients with leprosy by establishing a correlation with the outcomes obtained from a force platform. Methods: This is an observational study with a case-control design, in which 30 participants with leprosy and 30 healthy participants were recruited to evaluate static balance using an inertial sensor and a force platform. Participants underwent balance assessment under two conditions (Eyes Open: OE and Eyes Closed: CE), and data from the platform and sensor were processed using Matlab computational routines. The data were quantified using four parameters: Total Displacement (TD), Area, Antero-Posterior Displacement (APdisp), and Medio-Lateral Displacement (MLdisp). Results: The evaluated parameters showed significantly different values between the groups, where the Leprosy group exhibited significantly higher values compared to the control group, both in the OE and CE conditions for all four parameters. The sensor corroborated the differences demonstrated by the platform and followed the same trend for medio-lateral displacements and accelerations. It can be observed that the evaluated parameters exhibited a varied correlation ranging from moderate to large between the platform and the sensor. Among the four variables, MLdisp had the lowest correlation. Discussion: The results partially confirmed the first hypothesis of concurrent validation, showing a moderate to large correlation between the force platform and the inertial sensor. The second hypothesis of clinical validation was also partially confirmed, as not all group differences observed in the COP measurements from the force platform were reflected in the COM measurements from the inertial sensor. Specifically, the force platform indicated greater oscillations in participants with multibacillary leprosy compared to controls, a finding statistically confirmed by the sensor for all measures except MLdisp. Conclusion: This research confirmed the concurrent validity of the inertial sensor with the force platform and its clinical validation, demonstrating that this instrument can be applied in clinical settings due to its low cost and ease of use. The findings may contribute to public health by identifying postural control tools for patients with multibacillary leprosy. Author summary: Our study aimed to validate the application of inertial sensors for patients with leprosy by establishing a correlation with the outcomes obtained from a force platform. Due to the disease's impact on sensory perception and chronic pain in the plantar region, maintaining balance becomes challenging for affected individuals. Using a force platform and an inertial sensor, we evaluated balance in 30 leprosy patients and 30 healthy participants under Eyes Open and Eyes Closed conditions. Results revealed significantly higher values in balance parameters for the leprosy group compared to controls, indicating greater instability. The inertial sensor confirmed these differences, particularly in medio-lateral displacements and accelerations. While correlation between the platform and sensor varied, our study validated the sensor's concurrent and clinical efficacy. This research underscores the potential of inertial sensors as reliable, cost-effective tools for assessing balance in clinical settings, especially for patients with multibacillary leprosy. Our findings contribute to enhancing public health efforts by offering practical solutions for monitoring and managing balance deficits in this neglected disease population. [ABSTRACT FROM AUTHOR]

The study aimed to optimize qPCR reactions using oligonucleotides from the first Brazilian molecular diagnostic kit for leprosy on a portable platform (Q3-Plus). In addition, we sought to develop a simplified protocol for DNA extraction that met point-of-care criteria. During optimization on the Q3-Plus, optical parameters, thresholds, and cutoffs for the 16S rRNA and RLEP targets of M. leprae were established using synthetic DNA, purified DNA from M. leprae, and pre-characterized clinical samples. For the simplified extraction protocol, different lysis solutions were evaluated using chaotropic agents, and purification was carried out by transferring the lysed material to FTA cards. The complete protocol (simplified extraction + qPCR on the portable platform) was then evaluated with pre-characterized clinical skin biopsy samples and compared with standard equipment (QuantStudio-5). LOD95% for the optimized reactions was 113.31 genome-equivalents/μL for 16S rRNA and 17.70 genome-equivalents/μL for RLEP. Among the lysis solutions, the best-performing was composed of urea (2 M), which provided good dissolution of the skin fragment and a lower Ct value, indicating higher concentrations of DNA. The complete technological solution showed a sensitivity of 52% in reactions. Our results highlight the need for additional optimization to deal with paucibacillary samples, but also demonstrate the feasibility of the portable platform for the qPCR detection of M. leprae DNA in low infrastructure settings. Author summary: The diagnosis of tropical or neglected infectious diseases, such as leprosy, is highly dependent on techniques that are not very sensitive or very laborious, such as optical microscopy or culture. More sensitive and specific molecular tests are only available in urban centers, where there is a specialized workforce and adequate infrastructure. However, a large portion of the population does not have access to such medical services, either due to financial or distance issues. Thus, performing diagnostic tests at the point of care (POC) provides agility in diagnosis, avoiding the need for patients to travel to medical centers or transport biological samples to clinical analysis centers, ensuring that this population has access to diagnostic tests, even in remote areas or with poor infrastructure. In this work, we optimize and validate, on a laboratory scale, simplified versions of all the procedures necessary to perform molecular tests, from collection and DNA extraction to the detection of genomic targets using portable qPCR equipment. The results presented here are the basis of a novel tool with potential to increase a leprosy screening test in remote areas, facilitating the active search of positive cases and monitoring by health authorities responsible for underserved populations. [ABSTRACT FROM AUTHOR]

Background: Rising antimicrobial resistance (AMR) in Salmonella Typhi restricts typhoid treatment options, heightening concerns for pan-oral drug-resistant outbreaks. However, lack of long-term temporal surveillance data on AMR in countries with high burden like Bangladesh is scarce. Our study explores the AMR trends of Salmonella Typhi isolates from Bangladesh, drawing comparisons with antibiotic consumption to optimize antibiotic stewardship strategies for the country. Methodology/Principal findings: The typhoid fever surveillance from 1999 to 2022 included two pediatric hospitals and three private clinics in Dhaka, Bangladesh. Blood cultures were performed at treating physicians' discretion; cases were confirmed by microbiological serological, and biochemical tests. Antibiotic susceptibility was determined following CLSI guidelines. National antibiotic consumption data for cotrimoxazole, ciprofloxacin, and azithromycin was obtained from IQVIA-MIDAS database for comparison. Over the 24 years of surveillance, we recorded 12,435 culture-confirmed typhoid cases and observed declining resistance to first-line drugs (amoxicillin, chloramphenicol, and cotrimoxazole); multidrug resistance (MDR) decreased from 38% in 1999 to 17% in 2022. Cotrimoxazole consumption dropped from 0.8 to 0.1 Daily defined doses (DDD)/1000/day (1999–2020). Ciprofloxacin non-susceptibility persisted at >90% with unchanged consumption (1.1–1.3 DDD/1000/day, 2002–2020). Low ceftriaxone resistance (<1%) was observed, with slightly rising MIC (0.03 to 0.12 mg/L, 1999–2019). Azithromycin consumption increased (0.1 to 3.8 DDD/1000/day, 1999–2020), but resistance remained ≤4%. Conclusion: Our study highlights declining MDR amongst Salmonella Typhi in Bangladesh; first-line antimicrobials could be reintroduced as empirical treatment options for typhoid fever if MDR rates further drops below 5%. The analysis also provides baseline data for monitoring the impact of future interventions like typhoid conjugate vaccines on typhoid burden and associated AMR. Author summary: Our study addresses the pressing issue of antimicrobial resistance (AMR) in Salmonella Typhi, which severely limits treatment options for typhoid fever. Globally, it also raises concerns for a potential pan-oral drug-resistant outbreak. We conducted typhoid fever surveillance, spanning 24 years (1999–2022) across two pediatric hospitals and three private clinics in Dhaka, the capital city of Bangladesh. Our aim was to understand how the AMR landscape of Salmonella Typhi has changed over the years and its correlation with antibiotic consumption. Our findings reveal a notable decline in resistance to first-line drugs including cotrimoxazole, whose decreasing consumption showed a statistically significant correlation with reduced resistance. Ciprofloxacin non-susceptibility persisted at >90%. Ceftriaxone resistance remained low, but there was an upward trend in its minimum inhibitory concentration (MIC). Azithromycin resistance is emerging and currently at <4% but is expected to increase due to the observed 38-fold rise in azithromycin consumption. Taken together, our results establish a baseline to assess the impact of interventions like typhoid conjugate vaccines on typhoid and associated AMR in Bangladesh. Our work also suggests that decreasing resistance to the first line of drugs in Salmonella Typhi may allow for the re-introduction of first line of antimicrobials as empirical treatment options for typhoid fever. [ABSTRACT FROM AUTHOR]

Background: Serology (the detection of antibodies formed by the host against an infecting pathogen) is frequently used to assess current infections and past exposure to specific pathogens. However, the presence of cross-reactivity among host antibodies in serological data makes it challenging to interpret the patterns and draw reliable conclusions about the infecting pathogen or strain. Methodology/Principal findings: In our study, we use microscopic agglutination test (MAT) serological data from three host species [California sea lion (Zalophus californianus), island fox (Urocyon littoralis), and island spotted skunk (Spilogale gracilis)] with confirmed infections to assess differences in cross-reactivity by host species and diagnostic laboratory. All host species are known to be infected with the same serovar of Leptospira interrogans. We find that absolute and relative antibody titer magnitudes vary systematically across host species and diagnostic laboratories. Despite being infected by the same Leptospira serovar, three host species exhibit different cross-reactivity profiles to a 5-serovar diagnostic panel. We also observe that the cross-reactive antibody titer against a non-infecting serovar can remain detectable after the antibody titer against the infecting serovar declines below detectable levels. Conclusions/Significance: Cross-reactivity in serological data makes interpretation difficult and can lead to common pitfalls. Our results show that the highest antibody titer is not a reliable indicator of infecting serovar and highlight an intriguing role of host species in shaping reactivity patterns. On the other side, seronegativity against a given serovar does not rule out that serovar as the cause of infection. We show that titer magnitudes can be influenced by both host species and diagnostic laboratory, indicating that efforts to interpret absolute titers (e.g., as indicators of recent infection) must be calibrated to the system under study. Thus, we implore scientists and health officials using serological data for surveillance to interpret the data with caution. Author summary: Serology is frequently used for disease surveillance, especially in systems that are resource constrained or logistically challenging. Serological testing involves analyzing blood serum samples to detect antibodies with reactivity toward specific pathogens (or more generally, molecular antigens), with the goal of characterizing past exposure to those pathogens. However, these antibodies can be non-specific and may react against other related pathogens or strains–a phenomenon known as cross-reactivity. Interpretation of serological data exhibiting cross-reactivity is difficult and simplifying assumptions are often made (e.g., to interpret the strain that elicits the highest antibody titer level as the infecting pathogen strain). Our work shows that interpreting antibody data requires more nuance and more caution. Both absolute titers and relative reactivity against different strains can vary across host species and diagnostic laboratories, so it is essential to interpret these data in the appropriate context. These host species differences in antibody reactivity and cross-reactivity patterns make direct comparisons across species inadvisable. [ABSTRACT FROM AUTHOR]

Background: Ae. aegypti mosquitoes are considered a global threat to public health due to its ability to transmit arboviruses such as yellow fever, dengue, Zika and Chikungunya to humans. The lack of effective arboviral vaccines and etiological treatments make vector control strategies fundamental in interrupting the transmission cycle of these pathogens. This study evaluated Ae. aegypti mosquito populations pre- and post-intervention period with disseminating stations of the larvicide pyriproxyfen to understand its potential influence on the genetic structure and population diversity of these vectors. Methodology/Principal findings: This study was conducted in Manacapuru city, Amazonas, Brazil, where 1,000 pyriproxyfen dissemination stations were deployed and monitored from FEB/2014 to FEB/2015 (pre-intervention) and AUG/2015 to JAN/2016 (post-intervention). Low-coverage whole genome sequencing of 36 individuals was performed, revealing significant stratification between pre- and post-intervention groups (pairwise FST estimate of 0.1126; p-value < 0.033). Tajima's D estimates were -3.25 and -3.07 (both p-value < 0.01) for pre- and post-intervention groups, respectively. Molecular diversity estimates (Theta(S) and Theta(Pi)) also showed divergences between pre- and post-intervention groups. PCA and K-means analysis showed clustering for SNP frequency matrix and SNP genotype matrix, respectively, being both mainly represented by the first principal component. PCA and K-means clustering also showed significant results that corroborate the impact of pyriproxyfen intervention on genetic structure populations of Ae. aegypti mosquitoes. Conclusions/Significance: The results revealed a bottleneck effect and reduced mosquito populations during intervention, followed by reintroduction from adjacent and unaffected populations by this vector. We highlighted that low-coverage whole genome sequencing can contribute to genetic and structure population data, and also generate important information to aid in genomic and epidemiological surveillance. Author summary: The Aedes aegypti mosquito is a global public health threat, transmitting diseases like yellow fever, dengue, zika and Chikungunya, requiring several vector control strategies. Traditional methods such as active search and treatment of accessible breeding sites by control agents can be supplemented using PPF dissemination stations. The tactic uses adult mosquitoes themselves to disseminate the larvicide adhered to their bodies, between treated and untreated breeding sites, which are usually cryptic and inaccessible. This tactic can easily be incorporated into integrated vector management strategies, reducing the emergence of adult mosquitoes and, consequently, arboviruses transmission. However, its impact on Ae. aegypti genetic and population structure remain unknown. The PPF intervention caused a bottleneck in the genetic structure, an event in which a population undergoes a drastic reduction in population density, in this case due to the pressure caused by the larvicide, followed by reintroduction of adult mosquitoes from nearby areas not exposed to PPF. This study uses a cost-effective low-coverage whole genome sequencing method to analyze Ae. aegypti genetic population structure based on mitochondrial genome, comparing pre- and post-intervention periods with pyriproxyfen. This approach can reveal both short and long-term effects of this control strategy in the vector genome dynamics. These findings have direct implications for planning control activities, enhancing genomic surveillance and epidemiological surveillance, contributing to global efforts against vector-borne diseases. [ABSTRACT FROM AUTHOR]

Leishmaniasis represents a severe global health problem. In the last decades, there have been significant challenges in controlling this disease due to the unavailability of licensed vaccines, the high toxicity of the available drugs, and an unrestrained surge of drug-resistant parasites, and human immunodeficiency virus (HIV)–Leishmania co-infections. Leishmania spp. preferentially invade macrophage lineage cells of vertebrates for replication after subverting cellular functions of humans and other mammals. These early events in host–parasite interactions are likely to influence the future course of the disease. Thus, there is a continuing need to discover a simple cellular model that reproduces the in vivo pathogenesis. Acanthamoeba spp. are non-mammalian phagocytic amoeba with remarkable similarity to the cellular and functional aspects of macrophages. We aimed to assess whether the similarity reported between macrophages and Acanthamoeba spp. is sufficient to reproduce the infectivity of Leishmania spp. Herein, we analyzed co-cultures of Acanthamoeba castellanii or Acanthamoeba polyphaga with Leishmania infantum, Leishmania amazonensis, Leishmania major, and Leishmania braziliensis. Light and fluorescence microscopy revealed that the flagellated promastigotes attach to the A. castellanii and/or A. polyphaga in a bipolar and or random manner, which initiates their uptake via pseudopods. Once inside the cells, the promastigotes undergo significant changes, which result in the obligatory amastigote-like intracellular form. There was a productive infection with a continuous increase in intracellular parasites. However, we frequently observed intracellular amastigotes in vacuoles, phagolysosomes, and the cytosol of Acanthamoeba spp. Our findings corroborate that Leishmania spp. infects Acanthamoeba spp. and replicates in them but does not cause their rapid degeneration or lysis. Overall, the evidence presented here confirms that Acanthamoeba spp. have all prerequisites and can help elucidate how Leishmania spp. infect mammalian cells. Future work exposing the mechanisms of these interactions should yield novel insights into how these pathogens exploit amoebae. Author summary: Leishmaniasis represents a severe global health problem, and drug resistance is a growing concern. Leishmania spp. are obligate intracellular parasites that survive within cells of the vertebrate macrophage, modulating their activation. Understanding the multilayered relationship between metabolism and function of innate immune cells during infection has great therapeutic and preventive potential. Mammalian macrophages and Acanthamoeba spp. display similarities in the molecular mechanisms involved in directional motility, recognition, binding, engulfment, and the phagolysosomal processes, and they express similar receptors. Hence, we hypothesize that Acanthamoeba spp. represent a model that can be used to evaluate macrophage–pathogen interactions from the perspective of innate immunity. However, it has not yet been described whether Leishmania spp. can survive in Acanthamoeba spp. We found that Acanthamoeba spp. support Leishmania growth. Acanthamoeba spp. contain ancient pathogen recognition mechanisms, and Leishmania spp. could manipulate amoeboid functions to favor their survival and replication based on strategies of ancestral metabolic pathways. Our robust evidence highlights that amoebae could be used as a model to understand the biology and evolution of host–Leishmania interactions. [ABSTRACT FROM AUTHOR]

Crimean-Congo Hemorrhagic Fever virus (CCHFV) is a tick-borne pathogen that causes severe acute fever disease in humans and requires a biosafety level 4 laboratory for handling. Hazara virus (HAZV), belonging to the same virus genus as CCHFV, does not exhibit pathogenesis in humans. To investigate host RNA-binding proteins (RBPs) that regulate CCHFV replication, we generated a series of mutant RAW264.7 cells by CRISPR/Cas9 system and these cells were infected with HAZV. The viral titers in the supernatant of these cells was investigated, and HuR (ELAVL1) was identified. HuR KO RAW264.7 cells reduced HAZV replication. HuR is an RBP that enhances mRNA stability by binding to adenyl-uridine (AU)-rich regions in their 3′ non-coding region (NCR). HuR regulates innate immune response by binding to host mRNAs of signaling molecules. The expression of cytokine genes such as Ifnb, Il6, and Tnf was reduced in HuR KO cells after HAZV infection. Although HuR supports the innate immune response during HAZV infection, we found that innate immune activation by HAZV infection did not affect its replication. We then investigated whether HuR regulates HAZV genome RNA stability. HAZV RNA genome was precipitated with an anti-HuR antibody, and HAZV genome RNA stability was lowered in HuR KO cells. We found that HuR associated with HAZV RNA and stabilized it to enhance HAZV replication. Furthermore, HuR-deficiency reduced CCHFV minigenome replication. CCHFV is a negative-strand RNA virus and positive-strand RNA is produced during replication. HuR was associated with positive-strand RNA rather than negative-strand RNA, and AU-rich region in 3'-NCR of S segment was responsible for immunoprecipitation with anti-HuR antibody and minigenome replication. Additionally, HuR inhibitor treatment reduced CCHFV minigenome replication. Our results indicate that HuR aids replication of the CCHFV minigenome by associating with the AU-rich region in the 3′-NCR. Author summary: Crimean-Congo Hemorrhagic Fever virus (CCHFV) is a tick-borne pathogen that causes severe acute fever disease in humans and requires a biosafety level 4 laboratory for handling. Hazara virus (HAZV), the same genus of CCHFV, has been used as a model virus to reveal the molecular mechanism of CCHFV infection. To investigate host factors for CCHFV replication, we generated a series of mutant RAW264.7 cells and conducted screening for host genes that regulate the replication of HAZV, identifying HuR (ELAVL1). HuR is an RNA-binding protein (RBP) that enhances mRNA stability by binding to its 3′ non-coding region (NCR). We found that HuR is associated with the CCHFV RNA stability by binding to its 3'-NCR, and the minigenome assay showed that CCHFV replication is supported by HuR. HuR inhibitor treatment also reduced CCHFV minigenome replication. These findings present a possible starting point for the future development of antiviral drug targeting host RBPs. Combination treatment with RdRp and RBP inhibitors may be a potential therapeutic strategy in the future. [ABSTRACT FROM AUTHOR]

Human immunodeficiency virus (HIV) co-infection is a major challenge for visceral leishmaniasis (VL) control, particularly in Ethiopia where the incidence of both pathogens is high. VL-HIV often leads to high rates of antileishmanial treatment failure and recurrent VL disease relapses. Considering the high prevalence of HIV and Leishmania in the Ethiopian population, preventing the progression of asymptomatic Leishmania infection to disease would be a valuable asset to VL disease control and to the clinical management of people living with HIV (PLWH). However, such a strategy requires good understanding of risk factors for VL development. In immunocompetent individuals living in Brazil, India, or Iran, the Human Leukocyte Antigen (HLA) gene region has been associated with VL development. We used NanoTYPE, an Oxford Nanopore Technologies sequencing-based HLA genotyping method, to detect associations between HLA genotype and VL development by comparing 78 PLWH with VL history and 46 PLWH that controlled a Leishmania infection, all living in a VL endemic region of North-West Ethiopia. We identified an association between HLA-A*03:01 and increased risk of VL development (OR = 3.89). These data provide candidate HLA alleles that can be further explored for inclusion in a potential Leishmania screen-and-treat strategy in VL endemic regions. Author summary: Human immunodeficiency virus (HIV) co-infection is a major challenge for the control of visceral leishmaniasis (VL), particularly in Ethiopia where both frequently occur. VL-HIV disease is often hard to treat, and some treated patients will relapse after initially thought to be cured. However, there is a long period of asymptomatic Leishmania infection prior to the development of VL-HIV symptoms, and tackling the infection at this stage will be valuable in the effort to combat VL-HIV disease. However, this requires good understanding of human risk factors for VL development. In this work, we tested the Human Leukocyte Antigen gene region and the association with VL disease development, as genetic risk factors. We identified a preliminary association between the HLA-A*03:01 gene variant and an increased risk for VL development. This would need to be tested again in a larger study, to assess whether it can be used to see if asymptomatic Leishmania-infected individuals will develop VL disease. [ABSTRACT FROM AUTHOR]