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Background: The course of kidney function and outcomes of severe malaria infection in pregnant women is poorly understood. The indications for renal replacement therapy in pregnant patients with AKI are similar to the general population. This is the case of a pregnant patient with severe Plasmodium falciparum infection that caused cerebral malaria, acute kidney injury (AKI) who required renal replacement therapy and kidney biopsy during her hospitalization., Case Presentation: A 29-year-old pregnant woman from Equatorial Guinea was admitted to the hospital with haemolytic anaemia, hyperbilirubinaemia and thrombocytopenia. During hospitalization, a thick blood smear was performed where parasitaemia by P. falciparum were observed and confirmed by real-time PCR assay. The patient developed cerebral malaria secondary to an ischaemic-type cerebral vascular event, hypotension and severe. After confirming diagnosis of P. falciparum infection, artesunate, artemether/lumefantrine and primaquine were started. Kidney biopsy revealed an active tubulointerstitial nephritis with acute tubular lesion and pigment tubulopathy with negative immunofluorescence. After CVVHDF, the patient received intermittent haemodialysis until the recovery of kidney function. After discharge, follow-up was carried until the successful resolution of the pregnancy by cesarean delivery and not shown deterioration in kidney function or proteinuria., Conclusion: In this case, intensive dialysis was started and dialysis intensity progressively reduced when kidney function improved. Due to the evolution of kidney function, a kidney biopsy was performed which showed tubulointerstitial nephritis as a manifestation of the infection. While the kidney biopsy was of interest for discriminating between tubular and glomerular involvement, the availability of placental biomarkers (sflt1-PlGF) would have been of help for ruling out preeclampsia and placental damage. The multidisciplinary approach to AKI during pregnancy should be the rule, with diligent care of maternal-fetal well-being during pregnancy and monitoring of kidney function after delivery., Competing Interests: Declarations Ethics approval and consent to participate Not applicable. Consent for publication The authors declare that they have obtained consent from the patient/relatives discussed in the report. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

This study aimed to analyze polymorphisms in Pfcrt, Pfmdr1, and Pfk13 genes' markers of resistance to Artemisinin-based combination therapy (ACT), in Plasmodium falciparum isolates from southern Brazzaville, 15 years after the adoption of ACT in the Republic of Congo. A total of 369 microscopy-confirmed malaria-infected individuals were enrolled from March to October 2021 in the community and in health facilities during a cross-sectional study. The K76T mutation in the Pfcrt gene, N86Y and Y184F mutations in the Pfmdr1 gene were investigated using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) while the codons region (1005-1300) of the Pfmdr1gene, and Pfk13 gene were sequenced. The prevalences of K76T, N86Y, Y184F mutations were 26.0%, 6.8%, and 27.7%, respectively. However, no mutations were detected in codons 1034, 1042, and 1246 of the Pfmdr1 gene. None of the mutations previously associated with artemisinin-based resistance were detected in the Pfk13 gene. The results reveal a significant decrease in the prevalence of K76T, N86Y, Y184F mutations, in Plasmodium falciparum isolates following the change of therapeutic policy. As artemisinin resistance is emerging throughout Africa, continued surveillance for early detection of these mutations and relevant partner markers of drug resistance are recommended in the Republic of Congo., Competing Interests: Declarations Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Current malaria diagnostics are invasive, lack sensitivity, and rapid tests are plagued by deletions in target antigens. Here we introduce the Cytophone, an innovative photoacoustic flow cytometer platform with high-pulse-rate lasers and a focused ultrasound transducer array to noninvasively detect and identify malaria-infected red blood cells (iRBCs) using specific wave shapes, widths, and time delays generated from the absorbance of laser energy by hemozoin, a universal biomarker of malaria infection. In a population of Cameroonian adults with uncomplicated malaria, we assess our device for safety in a cross-sectional cohort (n = 10) and conduct a performance assessment in a longitudinal cohort (n = 20) followed for 30 ± 7 days after clearance of parasitemia. Longitudinal cytophone measurements are compared to point-of-care and molecular assays (n = 94). Cytophone is safe with 90% sensitivity, 69% specificity, and a receiver-operator-curve-area-under-the-curve (ROC-AUC) of 0.84, as compared to microscopy. ROC-AUCs of Cytophone, microscopy, and RDT compared to quantitative PCR are not statistically different from one another. The ability to noninvasively detect iRBCs in the bloodstream is a major advancement which offers the potential to rapidly identify both the large asymptomatic reservoir of infection, as well as diagnose symptomatic cases without the need for a blood sample., (© 2024. The Author(s).)

Background: Submicroscopic Plasmodium infections can be a source of persistent malaria transmission. The aim of this study was to assess their frequency, distribution, morbidity and associated factors in a pre-elimination malaria setting in sub-Saharan Africa, Guinea-Bissau, where the Plasmodium falciparum is the predominant Plasmodium species., Methods: Dried fingerprick whole blood samples from 601 participants in the 2017 national, household-based, cross-sectional survey to estimate malaria prevalence were subjected to DNA extraction. The DNA was used in nested end-point PCR assays targeting genus- and species-specific regions of the Plasmodium 18S rRNA genes. Statistical analysis of socio-demographic, clinical and molecular data was carried out using the Statistical Package for the Social Sciences, version 29. Factors associated with submicroscopic P. falciparum infections and their magnitude were sought using Chi-square test and multiple logistic regression models, respectively. Statistically significant level was considered at P-value < 0.05., Results: Nested PCR assays detected submicroscopic P. falciparum infections in 20.3% (95% CI = 16.8-23.8) of individuals microscopically negative for Plasmodium species in the general population and in 21.4% (95% CI = 9.9-36.5) of microscopically negative pregnant women. Submicroscopic Plasmodium malariae infections were also detected as co-infections in 3.0% individuals who were microscopically positive only for P. falciparum. Infections with other Plasmodium species were not detected. Submicroscopic P. falciparum infections were not associated with age, sex, or the presence of fever. A logistic regression model adjusted for ethnicity and health region showed that individuals from the Balanta and Bijagos ethnic groups, most of whom live in the low malaria-transmission areas of Quinara and Bissau, and the Bijagos archipelago, respectively, were less likely to have submicroscopic P. falciparum infections than individuals from the large Fula ethnic group, most of whom live in the high malaria-transmission area of Gabu. Submicroscopic P. falciparum infections were not associated with anaemia in children under 5 years of age., Conclusion: The results obtained highlight the contribution of asymptomatic and submicroscopic P. falciparum infections to malaria transmission in high malaria-transmission areas and the need for molecular-based tools to detect submicroscopic Plasmodium species., (© 2024. The Author(s).)

Background: Malaria prevention and control strategies have been hampered by urbanization and the spread of Anopheles stephensi. The spread of this vector into Africa further complicates the already complex malaria situation, that could put about 126 million Africans at risk of infection. Hence, this study aimed to assess the determinants of urban malaria, focusing on the role of urbanization and the distribution of An. stephensi in Eastern Ethiopia., Methods: A matched case control study was conducted among febrile urban residents of Dire Dawa (malaria positive as cases and negative as a control). A capillary blood sample was collected for parasite identification using microscopic examination and an interviewer administered questionnaire was used to collect additional data. Centers for Disease Control and Prevention miniature light traps (CDC-LT) and Prokopack aspirator were used to collect adult mosquito vectors from the selected cases and control houses to identify the mosquito vector species. Then, the data were exported to STATA for analysis. Conditional logistic regression was done to identify determinants, and principal component Analysis (PCA) was done for some independent variables., Results: This study enrolled 132 cases and 264 controls from urban setting only. Of the 132 cases, 90 cases were positive for Plasmodium falciparum, 34 were positive for Plasmodium vivax and 8 had mixed infections. All cases and controls were similar with regard to their respective age and sex. Travel history (AOR: 13.1, 95% CI 2.8-61.4), presence of eves and holes on walls (AOR: 2.84, 95% CI 1.5-5.5), history of malaria diagnosis (AOR: 2.4, 95% CI 1.1-5.3), owning any livestock (AOR: 7.5, 95% CI 2.4-22.8), presence of stagnant water in the area (AOR: 3.2, 95% CI 1.7-6.1), sleeping under bed net the previous night (AOR: 0.21, 95% CI 0.1-0.6) and knowledge on malaria and its prevention (AOR: 2.2, 95% CI 1.2-4.1) were determinants of urban malaria infection. About 34 adult Anopheles mosquitoes were collected and identified from those selected cases and control houses and 27 of them were identified as An. stephensi., Conclusion: Among the cases, the dominant species were P. falciparum. This study identified travel history, house condition, past infection, livestock ownership, stagnant water, bed net use, and malaria knowledge as determinants of infection. This study also found the dominance of the presence of An. stephensi among the collected mosquito vectors. This suggests that the spread of An. stephensi may be impacting malaria infection in the study area. Hence, strengthening urban-targeted malaria interventions should be enhanced to prevent and control further urban malaria infection and spread., (© 2024. The Author(s).)

BackgroundIn European France, the bulk of malaria cases are travel-related, and only locally acquired cases are notifiable to assess any risk of re-emergence.AimsWe aimed to contribute to assessing the health impact of locally acquired malaria and the potential of malaria re-emergence in European France by documenting modes of transmission of locally acquired malaria, the Plasmodium species involved and their incidence trends.MethodsWe retrospectively analysed surveillance and case investigation data on locally acquired malaria from 1995 to 2022. We classified cases by most likely mode of transmission using a classification derived from the European Centre for Disease Prevention and Control. A descriptive analysis was conducted to identify spatial and temporal patterns of cases.ResultsFrom 1995 to 2022, European France reported 117 locally acquired malaria cases, mostly due to Plasmodium falciparum (88%) and reported in Île-de-France (54%), Paris Region. Cases were classified as Odyssean malaria (n = 51), induced malaria (n = 36), cryptic malaria (n = 27) and introduced malaria (n = 3). Among the 117 patients, 102 (93%) were hospitalised, 24 (22%) had severe malaria and seven (7%) died.ConclusionLocally acquired malaria remains infrequent in European France, with four reported cases per year since 1995. However, with the recent increasing trend in Odyssean malaria and climate change, the risk of re-emergence in non-endemic countries should be monitored, particularly in areas with autochthonous competent vectors. The vital risk of delayed diagnosis should make physicians consider locally acquired malaria in all patients with unexplained fever, especially when thrombocytopenia is present, even without travel history.

Objectives: The isolated Príncipe is at the malaria pre-elimination stage. Autochthonous clinical cases have been reported sporadically on the island, signaling the possibility of a sizable subpatent (i.e., rapid diagnostic test- and microscopy-negative and polymerase chain reaction [PCR]-positive) parasite reservoir., Methods: Asymptomatic low-density infections were detected by quantitative PCR (qPCR) targeting Plasmodium falciparum multicopy genes (pfr364 and varATS). Positivity rates were assayed for samples surveyed by active case detection (n = 112) and reactive case detection (n = 221) in 2022., Results: qPCR unveiled 70% of low parasitemia carriers, reaching >90% in reactive case detection. The high P. falciparum prevalence was confirmed by the two high-sensitivity qPCR protocols. Higher positivity rates were observed in the localities where most malaria cases were reported in 2022. Most parasitemias were very low (<2 Pf /µl)., Conclusions: These findings suggest that pre-elimination surveillance can benefit from the routine application of highly sensitive tools to unveil otherwise invisible but potentially relevant parasite populations., Competing Interests: Declarations of competing interest The authors have no competing interests to declare., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objectives: In low malaria transmission areas, the elimination of the disease has been hampered partly by the existence of a reservoir of subpatent Plasmodium falciparum infections within communities. This reservoir, often undetected, serves as a source of parasites and contributes to ongoing transmission and clinical malaria cases., Methods: This study, spanning a period of 9 years from June 2014 to December 2022, examined individual variations and long-term subpatent P. falciparum carriage in two matched cohorts of 44 individuals each living in Dielmo village in the Sudanian area of Senegal. Biannual blood samples, collected in June/July and December of each year, underwent P. falciparum diagnosis by quantitative polymerase chain reaction. QGIS and R analytical tools were used to map infections, assess the occurrence and clustering of subpatent and clinical P. falciparum infections, and determine the risk of infection in the vicinity of asymptomatic P. falciparum carriers., Results: The point frequency and long-term P. falciparum carriage were significantly higher among the quantitative polymerase chain reaction (qPCR) positive cohort compared to the negative cohort across the 16 cross-sectional surveys analyzed in this study (19.76% vs 10.99%, P-value <0.001). Asymptomatic carriage events in qPCR-positive group were 18.86 ± 1.72% and significantly greater (P-value = 0.001) than in the qPCR-negative group (11.32 ± 1.32%). The relative risk of P. falciparum infection or clinical malaria calculated with a 95% confidence interval significantly increased in the vicinity of infected individuals and was 1.44 (P-value = 0.53) and 2.64 (P-value = 0.04) when at least one individual in the direct (household) or indirect (block of households) vicinity is infected, respectively. The risk increased to 3.64 (P-value <0.001) if at least 1/5 of individuals in the indirect vicinity were P. falciparum-infected., Conclusions: The study provides a detailed qualitative and quantitative analysis of the asymptomatic P. falciparum reservoir and its temporal and spatial dynamics within two subgroups of P. falciparum-infected and non-infected individuals in Dielmo village. It identified high-risk populations known as "hotpops" and hotspots that could be targeted by innovative interventions to accelerate the elimination of malaria in Dielmo village., Competing Interests: Declarations of competing interest The authors have declared that no competing interests exist., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Malaria is the parasitic disease with the highest morbimortality worldwide. The World Health Organization (WHO) estimates that there were approximately 249 million cases in 2022, of which 3.4% were in Angola. Diagnosis is based on parasite identification by microscopy examination, antigen detection, and/or molecular tests, such as polymerase chain reaction (PCR). This study aimed to evaluate the usefulness of real-time PCR as a diagnostic method for malaria in an endemic area (Cubal, Angola)., Methods: A cross-sectional study was carried out at the Hospital Nossa Senhora da Paz in Cubal, Angola, including 200 patients who consulted for febrile syndrome between May and July 2022. From each patient, a capillary blood sample was obtained by finger prick for malaria field diagnosis [microscopy and rapid diagnostic test (RDT)] and venous blood sample for real-time PCR performed at the Hospital Universitario Vall d'Hebron in Barcelona, Spain. Any participant with a positive result from at least one of these three methods was diagnosed with malaria., Results: Of the 200 participants included, 54% were female and the median age was 7 years. Malaria was diagnosed by at least one of the three techniques (microscopy, RDT, and/or real-time PCR) in 58% of the participants, with RDT having the highest percentage of positivity (49%), followed by real-time PCR (39.5%) and microscopy (33.5%). Of the 61 discordant samples, 4 were only positive by microscopy, 13 by real-time PCR, and 26 by RDT. Plasmodium falciparum was the most frequent species detected (90.63%), followed by P. malariae (17.19%) and P. ovale (9.38%). Coinfections were detected in ten participants (15.63%): six (60%) were caused by P. falciparum and P. malariae, three (30%) by P. falciparum and P. ovale, and one (10%) triple infection with these three species. In addition, it was observed that P. falciparum and P. malariae coinfection significantly increased the parasite density of the latter., Conclusions: RDT was the technique with the highest positivity rate, followed by real-time PCR and microscopy. The results of the real-time PCR may have been underestimated due to suboptimal storage conditions during the transportation of the DNA eluates. However, real-time PCR techniques have an important role in the surveillance of circulating Plasmodium species, given the epidemiological importance of the increase in non-falciparum species in the country, and can provide an estimate of the intensity of infection., (© 2024. The Author(s).)

Background: Reactive case detection (RCD) aims to reduce malaria transmission stemming from asymptomatic carriers. Symptomatic individuals diagnosed with malaria at a health centre are followed to their households, where members of the index case and neighbouring households are tested and treated for malaria. An RCD programme was tested in the Ashanti region of Ghana in order to study diagnostic accuracy in the hospital and household settings, assess the prevalence of subclinical infections and possible clustering in index case households, and identify operational challenges for future RCD programmes. Currently, transmission in this region is high, but reactive interventions might become an option once transmission is reduced., Methods: 264 febrile individuals were enrolled at the Mankranso Government Hospital and tested for malaria using rapid diagnostic tests (RDT). From the pool of RDT-positive febrile index cases, 14 successful RCD follow-ups were conducted, and 233 individuals were enrolled from the index case, neighbour, and control households. The sensitivity of diagnostic tools for clinical and subclinical cases was compared, including RDT, expert microscopy by World Health Organization-certified microscopists, field microscopy, and qPCR., Results: Poor diagnosis and low receptivity to RCD-style follow-ups were major limitations to a successful and effective RCD programme. Field microscopy detected only 49% of clinical infections compared to RDT. 54% of individuals did not agree to a follow-up, and 66% of attempted follow-ups failed. The system effectiveness of RCD, calculated as the product of correctly diagnosed index cases, successful follow-ups, and proportion of asymptomatic infections detected by RDT, was very low at 4.0%., Conclusions: Due to low system effectiveness and the endemic nature of the disease setting in which asymptomatic prevalence is high and infections are not clustered around index case households, RCD is currently not a feasible option for malaria control in this region. The operational challenges identified through this study may help inform future reactive intervention programme designs once transmission is reduced., (© 2024. The Author(s).)

Background: Endemic African malaria vectors are poorly adapted to typical urban ecologies. However, Anopheles stephensi, an urban malaria vector formerly confined to South Asia and the Persian Gulf, was recently detected in Africa and may change the epidemiology of malaria across the continent. Little is known about the public health implications of An. stephensi in Africa. This study is designed to assess the relative importance of household exposure to An. stephensi and endemic malaria vectors for malaria risk in urban Sudan and Ethiopia., Methods: Case-control studies will be conducted in 3 urban settings (2 in Sudan, 1 in Ethiopia) to assess the association between presence of An. stephensi in and around households and malaria. Cases, defined as individuals positive for Plasmodium falciparum and/or P. vivax by microscopy/rapid diagnostic test (RDT), and controls, defined as age-matched individuals negative for P. falciparum and/or P. vivax by microscopy/RDT, will be recruited from public health facilities. Both household surveys and entomological surveillance for adult and immature mosquitoes will be conducted at participant homes within 48 hours of enrolment. Adult and immature mosquitoes will be identified by polymerase chain reaction (PCR). Conditional logistic regression will be used to estimate the association between presence of An. stephensi and malaria status, adjusted for co-occurrence of other malaria vectors and participant gender., Conclusions: Findings from this study will provide evidence of the relative importance of An. stephensi for malaria burden in urban African settings, shedding light on the need for future intervention planning and policy development., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Ashine et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Malaria in pregnancy causes adverse consequences and prompt and accurate diagnosis is essential for case management. In malaria endemic countries, diagnosis is mainly based on rapid diagnostic tests (RDT) and microscopy. However, increasing reports of false negatives caused by low parasitemia and pfhrp2/3 deletions raise concerns about HRP2-based RDT usefulness. This study aimed to assess RDT and microscopy performance and to describe pfhrp2/3 deletions in a cohort of 418 pregnant women in Burkina Faso. Malaria was diagnosed using RDT and microscopy and blood samples were collected during antenatal care visits. Diagnostic results were compared to PCR as gold standard. Pfhrp2 and pfhrp3 deletions were characterized for patients with confirmed P. falciparum infection. RDT had better sensitivity (76%) but lower specificity (83%) than microscopy (sensitivity = 57%; specificity = 98%). Low parasitemia (<150 parasites/µL), especially in multigravidae, was the principal factor causing false negatives by both methods. Moreover, pfhrp2 deletion frequency among overall false negatives by RDT was 21.43%. Higher frequency of deletions was found among all samples, independently of RDT result, for example around 2% of samples had double deletions meaning that the majority of deletions had no effect on RDT testing. Finally, it was found higher pfhrp2 deletion in women with lower uterine height during the first trimester. Wider and National surveillance study of deletions is recommended among pregnant women and in Burkina Faso.

Background: The majority of Plasmodium spp infections in endemic countries are asymptomatic and a source of onward transmission to mosquitoes. We aimed to examine whether Plasmodium falciparum transmission and malaria burden could be reduced by improving early detection and treatment of infections with active screening approaches., Methods: In this 18-month cluster randomised study in Sapone, Burkina Faso, households were enrolled and randomly assigned (1:1:1) to one of three groups: group 1 (control) received standard of care only, group 2 received active weekly, at home, fever screening by a community health worker regardless of symptoms, participants with a fever received a rapid diagnostic test (RDT) and treatment if RDT positive, and group 3 received active weekly fever screening (as in group 2) plus a monthly RDT regardless of symptoms, and treatment if RDT positive. Eligible households had a minimum of three eligible residents, one in each age group (<5 years, 5-15 years, and >15 years). The primary outcome was parasite prevalence by quantitative PCR (qPCR) in the end-of-study cross-sectional survey. Secondary outcomes included parasite and gametocyte prevalence and density in all three end-of-season cross-sectional surveys, incidence of infection, and the transmissibility of infections to mosquitoes. This trial was registered at ClinicalTrials.gov (NCT03705624) and is completed., Findings: A total of 906 individuals from 181 households were enrolled during two phases, and participated in the study. 412 individuals were enrolled between Aug 9 and 17, 2018, and participated in phase 1 and 494 individuals were enrolled between Jan 10 and 31, 2019, in phase 2. In the end-of-study cross-sectional survey (conducted between Jan 13 and 21, 2020), Pfalciparum prevalence by qPCR was significantly lower in group 3 (29·26%; 79 of 270), but not in group 2 (45·66%; 121 of 265), when compared with group 1 (48·72%; 133 of 273; risk ratio 0·65 [95% CI 0·52-0·81]; p=0·0001). Total parasite and gametocyte prevalence and density were also significantly lower in group 3 in all surveys. The largest differences were seen at the end of the dry season, with gametocyte prevalence 78·4% and predicted transmission potential 98·2% lower in group 3 than in group 1., Interpretation: Active monthly RDT testing and treatment can reduce parasite carriage and the infectious reservoir of P falciparum to less than 2% when used during the dry season. This insight might inform approaches for malaria control and elimination., Funding: Bill & Melinda Gates Foundation, European Research Council, and The Netherlands Organization for Scientific Research., Competing Interests: Declaration of interests We declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Robust diagnostic tools and surveillance are crucial for malaria control and elimination efforts. Malaria caused by neglected Plasmodium parasites is often underestimated due to the lack of rapid diagnostic tools that can accurately detect these species. While nucleic-acid amplification technologies stand out as the most sensitive methods for detecting and confirming Plasmodium species, their implementation in resource-constrained settings poses significant challenges. Here, we present a Pan Plasmodium recombinase polymerase amplification lateral flow (RPA-LF) assay, capable of detecting all six human infecting Plasmodium species in low resource settings. The Pan Plasmodium RPA-LF assay successfully detected low density clinical infections with a preliminary limit of detection between 10-100 fg/µl for P. falciparum. When combined with crude nucleic acid extraction, the assay can serve as a point-of-need tool for molecular xenomonitoring. This utility was demonstrated by screening laboratory-reared Anopheles stephensi mosquitoes fed with Plasmodium-infected blood, as well as field samples of An. funestus s.l. and An. gambiae s.l. collected from central Africa. Overall, our proof-of-concept Pan Plasmodium diagnostic tool has the potential to be applied for clinical and xenomonitoring field surveillance, and after further evaluation, could become an essential tool to assist malaria control and elimination., (© 2024. The Author(s).)

Background: Accurate diagnosis and timely treatment are crucial in combating malaria., Methods: A total of 449 samples were screened for Plasmodium falciparum infection by expert microscopy, qPCR, and three RDTs, namely Rapigen Biocredit Malaria Ag Pf (detecting HRP2 and pLDH on separate bands), Abbott NxTek Eliminate Malaria Ag Pf (detecting HRP2), and SD Bioline Malaria Ag Pf (detecting HRP2). hrp2/3 deletion typing was done by digital PCR., Results: 45.7% (205/449) individuals tested positive by qPCR for P. falciparum with a mean parasite density of 12.5 parasites/μL. Using qPCR as reference, the sensitivity of microscopy was 28.3% (58/205), the Biocredit RDT was 52.2% (107/205), the NxTek RDT was 49.3% (101/205), and the Bioline RDT was 39.5% (81/205). When only samples with densities > 20 parasites/μL were included (n = 89), sensitivity of 62.9% (56/89) by microscopy, 88.8% (79/89) by Biocredit, 88.8% (79/89) by NxTek, and 78.7% (70/89) by Bioline were obtained. All three RDTs demonstrated specificities > 95%. The limits of detection (95% probability that a sample tested positive) was 4393 parasites/μL (microscopy), 56 parasites/μL (Biocredit, considering either HRP2 or pLDH), 84 parasites/μL (NxTek), and 331 parasites/μL (Bioline). None of the three qPCR-confirmed P. falciparum positive samples, identified solely through the pLDH target, or eight samples negative for all RDTs but qPCR-positive at densities > 20 parasites/µL carried hrp2/3 deletions., Conclusion: The Biocredit and NxTek RDTs demonstrated comparable diagnostic efficacies. All three RDTs performed better than microscopy., (© 2024. The Author(s).)

Australian Defence Force (ADF) personnel train and operate in malarious regions that include neighboring countries with high burden and species with latent hepatic parasites.1 We summarized longitudinal malaria case data, following a prior 10-year period review to 2007.2 Malaria case entries within the ADF Malaria and Infectious Diseases Institute (ADFMIDI)-managed Central Malaria Register (CMR) were examined. Data from cases confirmed between January 1, 2008 through December 31, 2022 were analyzed. Sixty ADF members were diagnosed with malaria, including 1 with a mixed Plasmodium falciparum and P. vivax infection. Of 61 malaria infections, 69% (42 of 61) were P. vivax. P. vivax infection resulted in delayed initial case presentation (more than 4 weeks after exposure) in at least 36% (15 of 42) of cases, and 5 personnel experienced further relapse. Most P. vivax infections were acquired in the U.S. Indo-Pacific Command (INDOPACOM) and P. falciparum in the U.S. Africa Command (AFRICOM) regions. The ADF experienced ongoing reduced malaria case incidence following high rates in the early 2000s. Maintenance of prophylactic vigilance, both for eradicating dormant hypnozoites and preventing P. vivax relapse, remains important, however.

Introduction: According to the World Health Organization, Microscopy is the gold standard for diagnosing malaria. However, the performance of this examination depends on the experience of the microscopist and the level of parasitemia. Thus, molecular biology detection of malaria could be an alternative technique., Aim: evaluate the contribution of molecular biology in detecting imported malaria., Methods: This was a descriptive, prospective study, including all students, from the Monastir region, and foreigners, from countries endemic to malaria. The study period was from September 2020 to April 2021. Each subject was screened for malaria by three methods: direct microscopic detection of Plasmodium, detection of plasmodial antigens, and detection of plasmodial DNA by nested PCR., Results: Among the 127 subjects screened, only one had a positive microscopic examination for Plasmodium falciparum. Among the 126 subjects with a negative microscopic examination, twelve students had a positive nested PCR result, i.e. 9.5%. Molecular sequencing allowed the identification of ten isolates of Plasmodium falciparum, one Plasmodium malariae and one Plasmodium ovale. Our study showed that the results of nested PCR agreed with those of microscopy in 90.6% of cases., Conclusion: Nested PCR seems more sensitive for the detection of low parasitemias. Hence the importance of including molecular biology as a malaria screening tool to ensure better detection of imported cases.

Introduction: the diversity of Plasmodium falciparum genotypes affects the dynamics of malaria transmission and is thought to be one of the factors hampering malaria control efforts. This study aimed to investigate the relationship between Plasmodium falciparum genetic diversity and chloroquine and sulfadoxine-pyrimethamine resistance markers in malaria endemic areas of Burkina Faso., Methods: in a cross-sectional study, populations residing in Nouna health district were randomly recruited. Blood samples were used for microscopic malaria diagnosis, and genetic polymorphism alleles of msp1 and msp2 genotyping by nested PCR. Restricted fragment length polymorphism analysis was used to identify antimalarial resistance markers. Logistic regression analysis explored the association between msp1/msp2 alleles and antimalarial drug resistance markers. ANOVA was used to explore the association between the mean complexity of infection (mCOI) and prevalence of resistance markers., Results: the overall prevalence of Plasmodium falciparum infection was 27.1%. The proportions of K1, MAD20, RO33, FC27, 3D7 individuals with mutations in the pfcrt76T gene were 4.3%, 6.9%, 7.0%, 6.8% and 7.1% respectively. Those with mutations in pfmdr1 were 2.7%, 2%, 2.3%, 6.8% and 7.1%. No significant associations were detected between msp1/msp2 alleles and chloroquine or sulfadoxine-pyrimethamine resistance markers. However, the mean complexity of infection (mCOI) was significantly higher in individuals with the pfcrt76T mutation., Conclusion: overall, this study showed that the genetic diversity of Plasmodium falciparum does not significantly affect the presence of antimalarial drug resistance genes. The competition between different strains (polyclonality) of the parasite within the host was probably unfavorable for mutant strains., Competing Interests: The authors declare no competing interests., (Copyright: Moustapha Nikiema et al.)

Hard-to-reach communities represent Peru's main challenge for malaria elimination, but information about transmission in these areas is scarce. Here, we assessed Plasmodium vivax (Pv) and P. falciparum (Pf) transmission dynamics, resistance markers, and Pf hrp2/3 deletions in Nueva Jerusalén (NJ), a remote, indigenous community in the Peruvian Amazon with high population mobility. We collected samples from November 2019 to May 2020 by active (ACD) and passive case detection (PCD) in NJ. Parasites were identified with microscopy and PCR. Then, we analyzed a representative set of positive-PCR samples (Pv = 68, Pf = 58) using highly-multiplexed deep sequencing assays (AmpliSeq) and compared NJ parasites with ones from other remote Peruvian areas using population genetics indexes. The ACD intervention did not reduce malaria cases in the short term, and persistent malaria transmission was observed (at least one Pv infection was detected in 96% of the study days). In Nueva Jerusalen, the Pv population had modest genetic diversity (He = 0.27). Pf population had lower diversity (He = 0.08) and presented temporal clustering, one of these clusters linked to an outbreak in February 2020. Moreover, Pv and Pf parasites from NJ exhibited variable levels of differentiation (Pv Fst = 0.07-0.52 and Pf Fst = 0.11-0.58) with parasites from other remote areas. No artemisin resistance mutations but chloroquine (57%) and sulfadoxine-pyrimethamine (35-67%) were detected in NJ's Pf parasites. Moreover, pfhrp2/3 gene deletions were common (32-50% of parasites with one or both genes deleted). The persistent Pv transmission and the detection of a Pf outbreak with parasites genetically distinct from the local ones highlight the need for tailored interventions focusing on mobility patterns and imported infections in remote areas to eliminate malaria in the Peruvian Amazon., (© 2024. The Author(s).)

Asymptomatic malaria can impact existing malaria control and elimination efforts around the world, particularly in Africa, where the majority of malaria cases and death occurs. This is a cross-sectional study aimed to determine the prevalence and predictors of asymptomatic malaria among migrant farmworkers from June to July 2020 in the Upper Awash Agro-industry, East Shewa zone, Oromia Regional State, Ethiopia. A total of 254 migrant farmworkers without signs and symptoms of malaria were enrolled. Data on socio-demographic characteristics and malaria prevention practices were obtained through a structured questionnaire. Venous blood samples were collected and diagnosed using microscopy, rapid diagnostic tests, and polymerase chain reaction (PCR). Data were coded, entered, and analyzed using SPSS version-21 statistical software. Multivariable logistic regression was used to assess associated factors. A p < 0.05 was considered statistically significant. The overall prevalence of asymptomatic malaria among farmworkers in this study was 5.1% [95% CI 1.6, 6.7]. The proportions of Plasmodium falciparum was 90.0% (9/10) while it was 10.0% (1/10) for Plasmodium vivax. Out of the microscopy and/or RDT-confirmed malaria cases, (n = 9; 100%) were confirmed to be P. falciparum by nested PCR, while (n = 3/122; 2.46%) were found to be P. falciparum among 50% negative cases with the microscopy and/or RDT. The gametocyte stage was detected in 40% of microscopically positive cases out of which 44.4% belongs to P. falciparum. Home area/origin of migrant laborers [AOR = 6.08, (95% CI 1.08, 34.66)], family history of malaria [AOR = 8.15, (95% CI 1.43, 46.44)], and outdoor sleeping [AOR = 10.14, (95% CI 1.15, 89.14)] were significantly associated with asymptomatic malaria. In conclusion, asymptomatic malaria was detected among farmworkers in the study area and it was significantly associated with outdoor sleeping, home area, and family history of malaria. Prevention tools and control strategies, particularly focusing on migrant farmworkers, should be considered to support the ongoing malaria control and elimination effort in Ethiopia., (© 2024. The Author(s).)

Ethiopia has a plan to eliminate malaria in selected low-transmission districts by 2025. However, complex factors such as seasonality, focal heterogeneity, and coendemicity of Plasmodium vivax and Plasmodium falciparum, and asymptomatic cases, along with other factors, pose challenges. This longitudinal study assessed these dynamics and associated factors in three elimination-targeted settings in southern Ethiopia. The study included rural districts (Wonago and Yirgacheffe) and an urban setting (Dilla town) with 504 participants from 168 households per season. The study covered the peak and minor malaria transmission seasons and the dry season. Finger-prick blood was collected for microscopy, rapid diagnostic tests, and 18S-rRNA-based quantitative polymerase chain reaction (qPCR). During the dry season, P. vivax accounted for most infections (64.5%, 71/110) and symptomatic malaria (50.9%, 29/57), whereas P. falciparum dominated during the peak transmission season (45.7%, 42/92 infections and 58.1%, 25/43 of symptomatic cases). Treatment-seeking behavior was low, with 65.3% (143/219) of symptomatic individuals not seeking treatment. Dilla town had significantly higher infection prevalence (29.6%, 149/504, P <0.001) in all seasons compared with the rural sites. The incidence rate was 12/1,000 person-seasons by qPCR and 5/1,000 person-seasons by microscopy. Urban residents, those with low hemoglobin levels, nonuse of mosquito nets, and proximity to stagnant water had a significantly higher risk of infection (P <0.001). Tailored approaches are needed in elimination-targeted areas, focusing on urban settings, Plasmodium species, and strengthening community-level interventions for behavioral change and active case detection.

Background Objectives: The correct association between Plasmodium falciparum parasite density and the cellular constituents of blood is not known in entirety in Nigerian children. Thus, we decided to study the association between cellular blood constituents and malaria parasite density in malaria infected children attending a Nigerian hospital., Methods: A study of all children diagnosed with malaria fever at the Pediatric out-patient clinic, Cedar Crest Hospital, Abuja, Nigeria, was conducted. Packed cell volume, white blood cells with differentials and platelet counts and malaria parasite densities obtained from blood samples were studied. Malaria parasite densities more than 2 pluses were classified as significant parasitemia and 1 plus as non-significant. Information obtained was recorded and analysed with SPSS 22 software., Results: A total 143 children (74 boys and 69 girls) diagnosed with malaria of ages between 5 months to 17 years (mean 5.24 ±4.60) were studied. The majority of 141 (98.6%) had non-significant P. falciparum parasitemia, while 2 (2.4%) had significant parasitemia. Of the 143 children with malaria, 116 (81.1%) had a normal leucocyte count. All children with significant parasitemia had a normal leucocyte count. Of the 143 children, 11 (7.7%) had anemia and 10 (7.0%) thrombocytopenia. Anemia, monocytosis and thrombocytopenia were significantly associated with significant malaria parasitemia (p<0.05). Mean platelet counts was significantly less amongst those with significant parasitemia (p<0.01)., Interpretation Conclusion: All patients with significant malaria parasitemia had normal leucocyte count. Significant malaria parasitemia is significantly associated with anemia, thrombocytopenia and monocytosis. Blood film appearances showing these changes are suggestive of significant malaria parasitemia., (Copyright © 2024 Copyright: © 2024 Journal of Vector Borne Diseases.)

Although the overall burden of malaria is decreasing in Ethiopia, a recent report of an unpredictable increased incidence may be related to the presence of community-wide gametocyte-carrier individuals and a high proportion of infected vectors. This study aimed to reveal the current prevalence of gametocyte-carriage and the sporozoite infectivity rate of Anopheles vectors for Plasmodium parasites. A community-based cross-sectional study was conducted from May 01 to June 30/2019. A total of 53 households were selected using systematic random sampling and a 242 study participants were recruited. Additionally,515 adult female Anopheles mosquitoes were collected using Center for Diseases Control and Prevention (CDC) light traps and mouth aspirators. Parasite gametocytemia was determined using giemsa stain microscopy, while sporozoite infection was determined by giemsa staining microscopy and enzyme linked immunosorbent assay (ELISA). Among the total 242 study participants, 5.4% (95%, CI = 2.9-8.3) of them were positive for any of the Plasmodium species gametocyte. Furthermore, being female [AOR = 15.5(95%, CI = 1.71-140.39)], age group between 15-29 years old [AOR = 16.914 (95%, CI = 1.781-160.63)], no ITNs utilization [AOR = 16.7(95%, CI = 1.902 -146.727)], and high asexual parasite density [(95%, CI = 0.057-0.176, P = 0.001, F = 18.402)] were identified as statistically significant factors for gametocyte carriage. Whereas sporozoite infection rate was 11.6% (95%, CI = 8.2-15.5) and 12.7% (95%, CI = 9.6-16.3) by microscopy and ELISA, respectively. Overall, this study indicated that malaria remains to be an important public health problem in Gondar Zuria district where high gametocyte carriage rate and sporozoite infection rate could sustain its transmission and burden. Therefore, in Ethiopia, where malaria elimination program is underway, frequent, and active community-based surveillance of gametocytemia and sporozoite infection rate is important., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Minwuyelet et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Malaria-causing protozoa of the genus Plasmodium have exerted one of the strongest selective pressures on the human genome, and resistance alleles provide biomolecular footprints that outline the historical reach of these species 1 . Nevertheless, debate persists over when and how malaria parasites emerged as human pathogens and spread around the globe 1,2 . To address these questions, we generated high-coverage ancient mitochondrial and nuclear genome-wide data from P. falciparum, P. vivax and P. malariae from 16 countries spanning around 5,500 years of human history. We identified P. vivax and P. falciparum across geographically disparate regions of Eurasia from as early as the fourth and first millennia BCE, respectively; for P. vivax, this evidence pre-dates textual references by several millennia 3 . Genomic analysis supports distinct disease histories for P. falciparum and P. vivax in the Americas: similarities between now-eliminated European and peri-contact South American strains indicate that European colonizers were the source of American P. vivax, whereas the trans-Atlantic slave trade probably introduced P. falciparum into the Americas. Our data underscore the role of cross-cultural contacts in the dissemination of malaria, laying the biomolecular foundation for future palaeo-epidemiological research into the impact of Plasmodium parasites on human history. Finally, our unexpected discovery of P. falciparum in the high-altitude Himalayas provides a rare case study in which individual mobility can be inferred from infection status, adding to our knowledge of cross-cultural connectivity in the region nearly three millennia ago., (© 2024. The Author(s).)

Background: Application of numerous malaria control interventions has led to reduction in clinical malaria cases and deaths but also the realisation that asymptomatic parasite carriers play a key role in sustaining transmission. This study assessed the effectiveness of using the Ultra-sensitive NxTek eliminate RDT (uRDT) and conventional SD Bioline HRP2 RDT (cRDT) in diagnosing asymptomatic parasitaemia while measuring the impact of mass testing, treatment and tracking (MTTT) on the prevalence of asymptomatic malaria over a 1-year period in Ghana., Methods: A total of 4000 targeted participants from two towns, Obom and Kofi Kwei, with their surrounding villages, were tested for asymptomatic malaria four times over the study period using uRDT (intervention) and the cRDT (control) respectively. Participants carrying malaria parasites were followed by home visit and phone calls for compliance to treatment, and filter paper blood blots collected from participants were used to determine true parasite carriage by PET-PCR. A mathematical model of the study site was developed and used to test the impact of test sensitivity and mass migration on the effect of MTTT., Results: The start and end point sensitivities of the cRDT were 48.8% and 41.7% and those for the uRDT were 52.9% and 59.9% respectively. After a year of MTTTs, asymptomatic parasite prevalence, as determined by PCR, did not differ statistically in the control site (40.6% to 40.1%, P = 0.730) but decreased at the intervention site (55.9% to 46.4%, P < 0.0001). Parasite prevalence by RDT, however, indicated statistical reduction in the control site (25.3% to 22.3%, P = 0.017) and no change in the intervention site (35.1% to 36.0%, P = 0.614). The model predicted a mild effect of both diagnostic sensitivity and human movement in diminishing the impact of MTTT in the study sites., Conclusions: Asymptomatic parasite prevalence at the molecular level reduced significantly in the site where the uRDT was used but not where the cRDT was used. Overall, the uRDT exhibited higher sensitivity relative to the cRDT. Highly sensitive molecular techniques such as PET-PCR should be included in parasite prevalence estimation during MTTT exercises., (© 2024. The Author(s).)

Background: The Zanzibar archipelago of Tanzania has become a low-transmission area for Plasmodium falciparum . Despite being considered an area of pre-elimination for years, achieving elimination has been difficult, likely due to a combination of imported infections from mainland Tanzania and continued local transmission., Methods: To shed light on these sources of transmission, we applied highly multiplexed genotyping utilizing molecular inversion probes to characterize the genetic relatedness of 282 P. falciparum isolates collected across Zanzibar and in Bagamoyo district on the coastal mainland from 2016 to 2018., Results: Overall, parasite populations on the coastal mainland and Zanzibar archipelago remain highly related. However, parasite isolates from Zanzibar exhibit population microstructure due to the rapid decay of parasite relatedness over very short distances. This, along with highly related pairs within shehias , suggests ongoing low-level local transmission. We also identified highly related parasites across shehias that reflect human mobility on the main island of Unguja and identified a cluster of highly related parasites, suggestive of an outbreak, in the Micheweni district on Pemba island. Parasites in asymptomatic infections demonstrated higher complexity of infection than those in symptomatic infections, but have similar core genomes., Conclusions: Our data support importation as a main source of genetic diversity and contribution to the parasite population in Zanzibar, but they also show local outbreak clusters where targeted interventions are essential to block local transmission. These results highlight the need for preventive measures against imported malaria and enhanced control measures in areas that remain receptive to malaria reemergence due to susceptible hosts and competent vectors., Funding: This research was funded by the National Institutes of Health, grants R01AI121558, R01AI137395, R01AI155730, F30AI143172, and K24AI134990. Funding was also contributed from the Swedish Research Council, Erling-Persson Family Foundation, and the Yang Fund. RV acknowledges funding from the MRC Centre for Global Infectious Disease Analysis (reference MR/R015600/1), jointly funded by the UK Medical Research Council (MRC) and the UK Foreign, Commonwealth & Development Office (FCDO), under the MRC/FCDO Concordat agreement and is also part of the EDCTP2 program supported by the European Union. RV also acknowledges funding by Community Jameel., Competing Interests: SC, NB, MM, BN, OA, VG, KN, DG, ZP, CH, ZP, AM, JO, RV, SM, SS, LM, UM, AM, JL, AB, JJ, JB No competing interests declared, (© 2023, Connelly et al.)

Background: Malaria remains a severe parasitic disease, posing a significant threat to public health and hindering economic development in sub-Saharan Africa. Ethiopia, a malaria endemic country, is facing a resurgence of the disease with a steadily rising incidence. Conventional diagnostic methods, such as microscopy, have become less effective due to low parasite density, particularly among Duffy-negative human populations in Africa. To develop comprehensive control strategies, it is crucial to generate data on the distribution and clinical occurrence of Plasmodium vivax and Plasmodium falciparum infections in regions where the disease is prevalent. This study assessed Plasmodium infections and Duffy antigen genotypes in febrile patients in Ethiopia., Methods: Three hundred febrile patients visiting four health facilities in Jimma town of southwestern Ethiopia were randomly selected during the malaria transmission season (Apr-Oct). Sociodemographic information was collected, and microscopic examination was performed for all study participants. Plasmodium species and parasitaemia as well as the Duffy genotype were assessed by quantitative polymerase chain reaction (qPCR) for all samples. Data were analysed using Fisher's exact test and kappa statistics., Results: The Plasmodium infection rate by qPCR was 16% (48/300) among febrile patients, of which 19 (39.6%) were P. vivax, 25 (52.1%) were P. falciparum, and 4 (8.3%) were mixed (P. vivax and P. falciparum) infections. Among the 48 qPCR-positive samples, 39 (13%) were negative by microscopy. The results of bivariate logistic regression analysis showed that agriculture-related occupation, relapse and recurrence were significantly associated with Plasmodium infection (P < 0.001). Of the 300 febrile patients, 85 (28.3%) were Duffy negative, of whom two had P. vivax, six had P. falciparum, and one had mixed infections. Except for one patient with P. falciparum infection, Plasmodium infections in Duffy-negative individuals were all submicroscopic with low parasitaemia., Conclusions: The present study revealed a high prevalence of submicroscopic malaria infections. Plasmodium vivax infections in Duffy-negative individuals were not detected due to low parasitaemia. In this study, an improved molecular diagnostic tool was used to detect and characterize Plasmodium infections, with the goal of quantifying P. vivax infection in Duffy-negative individuals. Advanced molecular diagnostic techniques, such as multiplex real-time PCR, loop-mediated isothermal amplification (LAMP), and CRISPR-based diagnostic methods. These techniques offer increased sensitivity, specificity, and the ability to detect low-parasite-density infections compared to the employed methodologies., (© 2024. The Author(s).)

Background: Effective testing for malaria, including the detection of infections at very low densities, is vital for the successful elimination of the disease. Unfortunately, existing methods are either inexpensive but poorly sensitive or sensitive but costly. Recent studies have shown that mid-infrared spectroscopy coupled with machine learning (MIRs-ML) has potential for rapidly detecting malaria infections but requires further evaluation on diverse samples representative of natural infections in endemic areas. The aim of this study was, therefore, to demonstrate a simple AI-powered, reagent-free, and user-friendly approach that uses mid-infrared spectra from dried blood spots to accurately detect malaria infections across varying parasite densities and anaemic conditions., Methods: Plasmodium falciparum strains NF54 and FCR3 were cultured and mixed with blood from 70 malaria-free individuals to create various malaria parasitaemia and anaemic conditions. Blood dilutions produced three haematocrit ratios (50%, 25%, 12.5%) and five parasitaemia levels (6%, 0.1%, 0.002%, 0.00003%, 0%). Dried blood spots were prepared on Whatman ™ filter papers and scanned using attenuated total reflection-Fourier Transform Infrared (ATR-FTIR) for machine-learning analysis. Three classifiers were trained on an 80%/20% split of 4655 spectra: (I) high contrast (6% parasitaemia vs. negative), (II) low contrast (0.00003% vs. negative) and (III) all concentrations (all positive levels vs. negative). The classifiers were validated with unseen datasets to detect malaria at various parasitaemia levels and anaemic conditions. Additionally, these classifiers were tested on samples from a population survey in malaria-endemic villages of southeastern Tanzania., Results: The AI classifiers attained over 90% accuracy in detecting malaria infections as low as one parasite per microlitre of blood, a sensitivity unattainable by conventional RDTs and microscopy. These laboratory-developed classifiers seamlessly transitioned to field applicability, achieving over 80% accuracy in predicting natural P. falciparum infections in blood samples collected during the field survey. Crucially, the performance remained unaffected by various levels of anaemia, a common complication in malaria patients., Conclusion: These findings suggest that the AI-driven mid-infrared spectroscopy approach holds promise as a simplified, sensitive and cost-effective method for malaria screening, consistently performing well despite variations in parasite densities and anaemic conditions. The technique simply involves scanning dried blood spots with a desktop mid-infrared scanner and analysing the spectra using pre-trained AI classifiers, making it readily adaptable to field conditions in low-resource settings. In this study, the approach was successfully adapted to field use, effectively predicting natural malaria infections in blood samples from a population-level survey in Tanzania. With additional field trials and validation, this technique could significantly enhance malaria surveillance and contribute to accelerating malaria elimination efforts., (© 2024. The Author(s).)

Among the factors affecting the effectiveness of malaria control is poor knowledge of the entomologic drivers of the disease. We investigated anopheline populations as part of a baseline study to implement house screening of windows and doors as a supplementary malaria control tool towards elimination in Jabi Tehnan district, Amhara Regional State of Ethiopia. The samples were surveyed monthly using CDC light traps between June 2020 and May 2021. Mosquito trap density (< 3 mosquitoes/trap) was low, however, with a high overall Plasmodium sporozoite rate (9%; indoor = 4.3%, outdoor = 13.1%) comprising P. falciparum (88.9%) and P. vivax (11.1%). Anopheles gambiae s.l., mostly An. arabiensis, comprised > 80% of total anopheline captures and contributed ~ 42% of Plasmodium-infected mosquitoes. On the other hand, morphologically scored Anopheles funestus s.l., constituting about 6% of anopheline collections, accounted for 50% of sporozoite-infected mosquitoes. Most of the infected An. funestus s.l. specimens (86.7%) were grouped with previously unknown or undescribed Anopheles species previously implicated as a cryptic malaria vector in the western Kenyan highlands, confirming its wider geographic distribution in eastern Africa. Other species with Plasmodium infection included An. longipalpis C, An. theileri, An. demillioni, and An. nili. Cumulatively, 77.8% of the infected mosquitoes occurred outdoors. These results suggest efficient malaria parasite transmission despite the low vector densities, which has implications for effective endpoint indicators to monitor malaria control progress. Additionally, the largely outdoor infection and discovery of previously unknown and cryptic vectors suggest an increased risk of residual malaria transmission and, thus, a constraint on effective malaria prevention and control., (© 2024. The Author(s).)

Herein, we report a case of uncomplicated falciparum malaria with late parasitological failure in a 45-year-old businessman returning from Ghana. The patient visited the emergency department with high fever, headache, and dizziness. He traveled without antimalarial chemoprophylaxis. Laboratory tests led to the diagnosis of uncomplicated falciparum malaria with an initial density of 37,669 parasites per μL of blood (p/μL). The patient was treated with intravenous artesunate followed by atovaquone/proguanil. He was discharged with improved condition and decreased parasite density of 887 p/μL. However, at follow-up, parasite density increased to 7,630 p/μL despite the absence of any symptoms. Suspecting treatment failure, the patient was administered intravenous artesunate and doxycycline for seven days and then artemether/lumefantrine for three days. Blood smear was negative for asexual parasitemia after re-treatment but positive for gametocytemia until day 101 from the initial diagnosis. Overall, this case highlights the risk of late parasitological failure in patients with imported uncomplicated falciparum malaria., Competing Interests: The authors have no potential conflicts of interest to disclose., (© 2024 The Korean Academy of Medical Sciences.)

Background: Neonatal malaria is defined as the detection of asexual stages of Plasmodium species in the cord blood within the first 28 days of life. It can be congenital or acquired through mosquito bites or blood transfusions. Neonates are generally considered to be relatively protected due to the multiple innate and acquired physiological protective effects present in neonates. However, in areas where malaria is endemic, the prevalence of malaria in neonates is high. The predominant clinical feature of malaria in neonates is fever. Other clinical manifestations of neonatal malaria include respiratory distress, pallor and anaemia, hepatomegaly, refusal to feed, jaundice and diarrhoea. Atypical presentations without fever can lead to inaccurate diagnosis and contribute to neonatal morbidity and mortality. Neonates from endemic areas with any of the above symptoms should be screened for malaria., Case Presentation: We present a series of three cases of neonatal Plasmodium falciparum malaria that presented atypically without febrile episodes and were diagnosed and managed at Mizan-Tepi University Teaching Hospital between July and September 2023. The first patient presented with vomiting, refusal to feed, pallor, severe anaemia, and splenomegaly. The second patient presented with an inconsolable cry, failure to pass feces, abdominal distention, and anaemia. The third patient presented with vomiting and anaemia. All patients received a 7-day course of intravenous artesunate; the first patient also received a blood transfusion. All patients recovered and were discharged., Conclusions: Partial immunity resulting from repeated malaria infections in endemic regions may result in the transfer of high levels of maternal Immunoglobulin G (IgG) antibodies through the placenta and can produce different atypical clinical presentations. In malaria-endemic areas, neonates presenting with any of the presenting signs and symptoms of malaria, including afebrile presentation, require malaria screening to avoid delays in diagnosis., (© 2024. The Author(s).)

Malaria is a deadly disease that is transmitted through mosquito bites. Microscopists use a microscope to examine thin blood smears at high magnification (1000x) to identify parasites in red blood cells (RBCs). Estimating parasitemia is essential in determining the severity of the Plasmodium falciparum infection and guiding treatment. However, this process is time-consuming, labor-intensive, and subject to variation, which can directly affect patient outcomes. In this retrospective study, we compared three methods for measuring parasitemia from a collection of anonymized thin blood smears of patients with Plasmodium falciparum obtained from the Clinical Department of Parasitology-Mycology, National Reference Center (NRC) for Malaria in Paris, France. We first analyzed the impact of the number of field images on parasitemia count using our framework, MALARIS, which features a top-classifier convolutional neural network (CNN). Additionally, we studied the variation between different microscopists using two manual techniques to demonstrate the need for a reliable and reproducible automated system. Finally, we included thin blood smear images from an additional 102 patients to compare the performance and correlation of our system with manual microscopy and flow cytometry. Our results showed strong correlations between the three methods, with a coefficient of determination between 0.87 and 0.92., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Acherar et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Following a 2-week trip to Kazakhstan, a 42-year-old woman presented at the emergency department in Germany with fever, headache, nausea, and neurological symptoms. An infection with Plasmodium falciparum was rapidly diagnosed. The patient was immediately treated with intravenous artesunate and transferred to an intensive care unit. The initial parasite density was as high as 30% infected erythrocytes with 845,880 parasites/µL. Since Kazakhstan was declared malaria-free in 2012, molecular testing for Plasmodium has been initiated to identify a possible origin. Genotyping of the msp-1 gene and microsatellite markers showed that the parasites are of African origin, with two different alleles indicating a polyclonal infection. After a hospitalization of 10 days, the patient was discharged in good health. Overall, our results emphasize that malaria must be on the list of differential diagnoses for patients with fever of unknown origin, even if they come from countries where malaria does not commonly occur., Competing Interests: Declarations of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Objective: A 15-month longitudinal study was conducted to determine the duration and infectivity of asymptomatic qPCR-detected Plasmodium falciparum and Plasmodium vivax infections in Ethiopia., Method: Total parasite and gametocyte kinetics were determined by molecular methods; infectivity to Anopheles arabiensis mosquitoes by repeated membrane feeding assays. Infectivity results were contrasted with passively recruited symptomatic malaria cases., Results: For P. falciparum and P. vivax infections detected at enrolment, median durations of infection were 37 days (95% confidence interval [CI], 15-93) and 60 days (95% CI, 18-213), respectively. P. falciparum and P. vivax parasite densities declined over the course of infections. From 47 feeding assays on 22 asymptomatic P. falciparum infections, 6.4% (3/47) were infectious and these infected 1.8% (29/1579) of mosquitoes. No transmission was observed in feeding assays on asymptomatic P. vivax mono-infections (0/56); one mixed-species infection was highly infectious. Among the symptomatic cases, 4.3% (2/47) of P. falciparum and 73.3% (53/86) of P. vivax patients were infectious to mosquitoes., Conclusion: The majority of asymptomatic infections were of short duration and low parasite density. Only a minority of asymptomatic individuals were infectious to mosquitoes. This contrasts with earlier findings and is plausibly due to the low parasite densities in this population., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

The human infectious reservoir of Plasmodium falciparum is governed by transmission efficiency during vector-human contact and mosquito biting preferences. Understanding biting bias in a natural setting can help target interventions to interrupt transmission. In a 15-month cohort in western Kenya, we detected P. falciparum in indoor-resting Anopheles and human blood samples by qPCR and matched mosquito bloodmeals to cohort participants using short-tandem repeat genotyping. Using risk factor analyses and discrete choice models, we assessed mosquito biting behavior with respect to parasite transmission. Biting was highly unequal; 20% of people received 86% of bites. Biting rates were higher on males (biting rate ratio (BRR): 1.68; CI: 1.28-2.19), children 5-15 years (BRR: 1.49; CI: 1.13-1.98), and P. falciparum-infected individuals (BRR: 1.25; CI: 1.01-1.55). In aggregate, P. falciparum-infected school-age (5-15 years) boys accounted for 50% of bites potentially leading to onward transmission and had an entomological inoculation rate 6.4x higher than any other group. Additionally, infectious mosquitoes were nearly 3x more likely than non-infectious mosquitoes to bite P. falciparum-infected individuals (relative risk ratio 2.76, 95% CI 1.65-4.61). Thus, persistent P. falciparum transmission was characterized by disproportionate onward transmission from school-age boys and by the preference of infected mosquitoes to feed upon infected people., (© 2024. The Author(s).)

Field-derived metrics are critical for effective control of malaria, particularly in sub-Saharan Africa where the disease kills over half a million people yearly. One key metric is entomological inoculation rate, a direct measure of transmission intensities, computed as a product of human biting rates and prevalence of Plasmodium sporozoites in mosquitoes. Unfortunately, current methods for identifying infectious mosquitoes are laborious, time-consuming, and may require expensive reagents that are not always readily available. Here, we demonstrate the first field-application of mid-infrared spectroscopy and machine learning (MIRS-ML) to swiftly and accurately detect Plasmodium falciparum sporozoites in wild-caught Anopheles funestus, a major Afro-tropical malaria vector, without requiring any laboratory reagents. We collected 7178 female An. funestus from rural Tanzanian households using CDC-light traps, then desiccated and scanned their heads and thoraces using an FT-IR spectrometer. The sporozoite infections were confirmed using enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR), to establish references for training supervised algorithms. The XGBoost model was used to detect sporozoite-infectious specimen, accurately predicting ELISA and PCR outcomes with 92% and 93% accuracies respectively. These findings suggest that MIRS-ML can rapidly detect P. falciparum in field-collected mosquitoes, with potential for enhancing surveillance in malaria-endemic regions. The technique is both fast, scanning 60-100 mosquitoes per hour, and cost-efficient, requiring no biochemical reactions and therefore no reagents. Given its previously proven capability in monitoring key entomological indicators like mosquito age, human blood index, and identities of vector species, we conclude that MIRS-ML could constitute a low-cost multi-functional toolkit for monitoring malaria risk and evaluating interventions., (© 2024. The Author(s).)

Cross-border human population movement contributes to malaria transmission in border regions, impeding national elimination. However, its impact in low-to-moderate transmission settings is not well characterized. This community-based study in Mutasa District, Zimbabwe, estimated the association of parasite prevalence with self-reported overnight travel to Mozambique and household distance to the border from 2012-2020. A fully adjusted Poisson regression model with robust variance estimation was fit using active surveillance data. The population attributable fraction of parasite prevalence from overnight travel was also estimated. The relative risk of testing positive for malaria by rapid diagnostic test declined 14% (prevalence ratio [PR] = 0.86, 95% CI = 0.81-0.92) per kilometer from the border up to 12 km away. Travel to Mozambique was associated with a 157% increased risk (PR = 2.57, 95% CI = 1.38-4.78), although only 5.8% of cases were attributable to overnight travel (95% CI = -1.1% to 12.7%), reflecting infrequent overnight trips (1.3% of visits). This study suggests that transmission in eastern Zimbabwe is driven by increasingly conducive social or environmental conditions approaching the border and low levels of importation from overnight travel. Although day trips to Mozambique during peak biting hours were not assessed, the contribution of such trips to ongoing transmission may be significant. Future malaria control efforts should prioritize high coverage of existing interventions and continued support for community health workers and health facilities at the border, which provide free case management.

Background: Malaria is a major public health concern in Ethiopia, where more than half of the population lives in malaria risk areas. While several studies have been conducted in different eco-epidemiological settings in Ethiopia, there is a notable scarcity of data on the prevalence of malaria in the Gindabarat district. Therefore, this study aimed to analyse 10-year trend of malaria prevalence in Gindabarat district, West Shawa Zone of Oromia, Western Ethiopia., Methods: A retrospective laboratory record review was conducted at Gindabarat General Hospital and Gindabarat District Health Office from September 2011 to August 2020. The retrieved data included the date of examination, age, sex and laboratory results of the blood smears, including the Plasmodium species identified. Data were summarized and presented in the form of tables, figures, and frequencies to present the results. The data were analysed using SPSS (version 25.0) and Microsoft Excel., Results: Over the course of 10 years, a total of 11,478 blood smears were examined in the public health facilities in the district. Of the total blood smears examined, 1372 (11.95%) were microscopically confirmed malaria. Plasmodium falciparum, Plasmodium vivax and mixed infections (P. falciparum and P. vivax) accounted for 70.77%, 20.55% and 8.67% of the cases, respectively. Malaria prevalence was significantly higher among individuals aged ≥ 15 years (12.60%, x 2  = 13.6, df = 2, p = 0.001) and males (14.21%, x 2  = 59.7, df = 1, p = 0.001). The highest number of malaria cases was recorded from September to November., Conclusion: Malaria remains a public health problem in the district. P. falciparum was the most predominant parasite species in the area. Malaria prevalence was significantly higher among individuals aged ≥ 15 years and males. There was a remarkable fluctuation in the number of malaria cases in different months and years. In the study area malaria cases peaked in 2015 and 2017 then decreasing from 2017 to 2019, with sharp increase in 2020. Moreover, this study showed malaria cases were reported in all seasons and months, but the highest was observed from September to November. Strengthening malaria control activities is essential to further reduce the burden of malaria and pave the way for the anticipated elimination., (© 2024. The Author(s).)

Background: Malaria in pregnancy remains a major public health problem in the globe, especially in sub-Saharan Africa. In malaria endemic areas, most pregnant women remain asymptomatic, but malaria could still cause complications on the mother and her offspring; as well as serve as reservoirs to transmit infection. Despite these effects, no attention is given to the diagnosis of asymptomatic Plasmodium infections (APIs) using highly sensitive and specific laboratory diagnostic tools in Ethiopia. Therefore, the goal of this study was to compare the performance of Rapid Diagnostic Test (RDT), microscopy and real-time polymerase chain reaction (RT-PCR) to detect APIs among pregnant women., Methods: A health facility based cross -sectional study was conducted among pregnant women attending antenatal care at Fendeka town health facilities Jawi district, northwest Ethiopia from February to March, 2019. A total of 166 participants were enrolled by using convenient sampling technique. Socio-demographic features were collected using a semi structured questionnaire. Dried blood spot (DBS) samples were collected for molecular analysis. Asymptomatic Plasmodium infection on pregnant women was diagnosed using RDT, microscopy and RT-PCR. Descriptive statistics were used to determine the prevalence of APIs. Method comparison was performed, and Cohen's kappa coefficient (k) was used to determine the degree of agreement among the diagnostic methods. Parasite densities were also calculated., Results: The prevalence of API was 9.6%, 11.4% and 18.7% using RDT, microscopy and RT-PCR, respectively. The overall proportion of API was 19.3%. Sensitivity of the RDT was 83.3% as compared with microscopy. Rapid Diagnostic Test and microscopy also showed sensitivity of 50% and 60%, respectively, as compared with RT-PCR. The mean parasite density was 3213 parasites/µl for P falciparum and 1140 parasites/µl of blood for P. vivax., Conclusion: Prevalence of API in the study area was high. Both RDT and microscopy had lower sensitivity when compared with RT-PCR. Therefore, routine laboratory diagnosis of API among pregnant women should be given attention and done with better sensitive and specific laboratory diagnostic tools., (© 2024. The Author(s).)

Background: Despite continuous prevention and control strategies in place, malaria remains a major public health problem in sub-Saharan Africa including Ethiopia. Moreover, prevalence of malaria differs in different geographical settings and epidemiological data were inadequate to assure disease status in the study area. This study was aimed to determine the prevalence of malaria and associated risk factors in selected rural kebeles in South Ethiopia., Methods: A community-based cross-sectional study was conducted between February to June 2019 in eight malaria-endemic kebeles situated in four zones in South Ethiopia. Mult-stage sampling techniques were employed to select the study zones, districts, kebeles and households. Blood sample were collected from 1674 participants in 345 households by finger prick and smears were examined by microscopy. Sociodemographic data as well as risk factors for Plasmodium infection were collected using questionnaires. Bivariate and multivariate logistic regressions were used to analyse the data., Results: The overall prevalence of malaria in the study localities was 4.5% (76/1674). The prevalence was varied among the study localities with high prevalence in Bashilo (14.6%; 33/226) followed by Mehal Korga (12.1%; 26/214). Plasmodium falciparum was the dominant parasite accounted for 65.8% (50/76), while Plasmodium vivax accounted 18.4% (14/76). Co-infection of P. falciparum and P. vivax was 15.8% (12/76). Among the three age groups prevalence was 7.8% (27/346) in age less than 5 years and 7.5% (40/531) in 5-14 years. The age groups > 14years were less likely infected with Plasmodium parasite (AOR = 0.14, 95% CI 0.02-0.82) than under five children. Non-febrile individuals 1638 (97.8%) were more likely to had Plasmodium infection (AOR = 28.4, 95% CI 011.4-70.6) than febrile 36 (2.2%). Individuals living proximity to mosquito breeding sites have higher Plasmodium infection (AOR = 6.17, 95% CI 2.66-14.3) than those at distant of breeding sites., Conclusions: Malaria remains a public health problem in the study localities. Thus, malaria prevention and control strategies targeting children, non-febrile cases and individuals living proximity to breeding sites are crucial to reduce malaria related morbidity and mortality., (© 2024. The Author(s).)

Malaria rapid diagnostic test (mRDT) kit is one of the techniques for diagnosing malaria. Due to its inherent advantages over the microscopy technique, several brands of the kit have flooded malaria endemic countries, without prior in-country evaluation. Two of such mRDT kits are Oscar (India) and Standard Q (Korea Republic). In this study, the performance of Oscar and Standard Q mRDT kits were compared to First Response (India) and CareStart (USA) mRDTs, which have been evaluated and deployed for use approved by the Ministry of Health (MOH). In this comparative study, whole blood samples were collected from patients suspected of malaria. Plasmodium falciparum was detected in each sample using nested polymerase chain reaction (nPCR), microscopy and the four mRDTs. The sensitivities, specificities, accuracies, positive and negative predictive values and accuracies of the mRDTs were determined using nPCR as a reference technique. Kappa statistic was used to determine the level of agreement among the techniques. Two hundred (200) blood samples were analyzed in this study. The overall detection rates of P. falciparum by microscopy, First Response, CareStart, Oscar-PfHRP2, Standard Q mRDT kits and nPCR were 31.5%, 34.5%, 33.5%, 32%, 31% and 43% (x2 = 6.1, p = 0.046), respectively. The accuracies of CareStart and First Response were comparable (90.5% vs. 89.5%). Further, comparing their sensitivities, Oscar-PfHRP2 was 74.4% (95% confidence interval (CI): 63.9-83.2) while that of Standard Q was 72.1% (95% CI: 61.4-81.2), with comparable accuracies (Oscar-PfHRP2-89% and Standard Q -88%). Apart from First Response that was 98.3% specific, the others were 100% specific. Kappa test revealed perfect diagnostic agreement (κ = 0.90-0.98) among the four mRDTs. That notwithstanding, Oscar-PfHRP2 agreed better with CareStart (κ = 0.94) and First Response (κ = 0.92) compared to the agreement between Standard Q and, CareStart (κ = 0.92) and First Response (κ = 0.90). Taken together, the diagnostic performance of the four mRDT kits were statistically similar. That notwithstanding, new mRDT kits should be evaluated prior to deployment for use., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Aninagyei et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The Plasmodium is responsible for malaria which poses a major health threat, globally. This study is based on the estimation of the relative abundance of mosquitoes, and finding out the correlations of meteorological parameters (temperature, humidity and rainfall) with the abundance of mosquitoes. In addition, this study also focused on the use of nested PCR (species-specific nucleotide sequences of 18S rRNA genes) to explore the Plasmodium spp. in female Anopheles. In the current study, the percentage relative abundance of Culex mosquitoes was 57.65% and Anopheles 42.34% among the study areas. In addition, the highest number of mosquitoes was found in March in district Mandi Bahauddin at 21 °C (T max  = 27, T min  = 15) average temperature, 69% average relative humidity and 131 mm rainfall, and these climatic factors were found to affect the abundance of the mosquitoes, directly or indirectly. Molecular analysis showed that overall, 41.3% of the female Anopheles pools were positive for genus Plasmodium. Among species, the prevalence of Plasmodium (P.) vivax (78.1%) was significantly higher than P. falciparum (21.9%). This study will be helpful in the estimation of future risk of mosquito-borne diseases along with population dynamic of mosquitoes to enhance the effectiveness of vector surveillance and control programs., (© 2024. The Author(s).)

Background: Pregnancy Associated Malaria (PAM) include malaria in pregnancy (MiP), placental malaria (PM), and congenital malaria (CM). The evidence available in Colombia on PAM focuses on one of the presentations (MiP, PM or CM), and no study longitudinally analyses the infection from the pregnant woman, passing through the placenta, until culminating in the newborn. This study determined the frequency of MiP, PM, and CM caused by Plasmodium vivax, Plasmodium falciparum, or mixed infections, according to Thick Blood Smear (TBS) and quantitative Polymerase Chain Reaction (qPCR). Identifying associated factors of PAM and clinical-epidemiological outcomes in northwestern Colombia., Methods: Prospective study of 431 pregnant women, their placenta, and newborns registered in the data bank of the research Group "Salud y Comunidad César Uribe Piedrahíta" which collected information between 2014 and 2020 in endemic municipalities of the departments of Córdoba and Antioquia. The frequency of infection was determined with 95% confidence intervals. Comparisons were made with the Chi-square test, Student t-test, prevalence ratios, and control for confounding variables by log-binomial regression., Results: The frequency of MiP was 22.3% (4.6% using TBS), PM 24.8% (1.4% using TBS), and CM 11.8% (0% using TBS). Using TBS predominated P. vivax. Using qPCR the proportions of P. vivax and P. falciparum were similar for MiP and PM, but P. falciparum predominated in CM. The frequency was higher in nulliparous, and women with previous malaria. The main clinical effects of PAM were anaemia, low birth weight, and abnormal APGAR score., Conclusions: The magnitude of infections was not detected with TBS because most cases were submicroscopic (TBS-negative, qPCR-positive). This confirmed the importance of improving the molecular detection of cases. PAM continue being underestimated in the country due to that in Colombia the control programme is based on TBS, despite its outcomes on maternal, and congenital health., (© 2024. The Author(s).)

Malaria elimination is one of the top health care priorities in India, necessitating accessible and accurate diagnosis for effective treatment. A malaria slide bank in India is a collection of quality-controlled malaria-positive and -negative slides and is considered a vital asset for quality diagnosis. The collection of blood samples, preparation of blood smears, staining, quality control, molecular characterizations, and slide validation were carried out according to standard operating procedures in accordance with the WHO reference laboratory. The true count and parasite density per microliter were computed in accordance with WHO guidelines. Over 27 months, 48 batches (8,196 slides) were prepared. Overall, the majority of slide batches were Plasmodium vivax (45.9%; 22/48), followed by Plasmodium falciparum (25%; 12/48), malaria-negative infections (25%; 12/48), and mixed infections (4.1%; 2/48). All 48 batches passed internal validation by WHO-certified level-1 microscopists. For a batch, the true count was the median of the validators' counts (range, 111-280,795 parasites/µL). Except for mixed infections, the PCR results agreed with the verified microscopy results. Malaria slide bank slides would be a valuable tool for quality control, assurance, and microscopist training.

Delays in malaria diagnosis increase treatment failures and deaths. In endemic regions, standard diagnostic methods are microscopy and malaria rapid diagnostic tests (mRDTs) detecting Plasmodium falciparum histidine-rich protein 2/3 (PFHRP2/PFHRP3), but gene deletions can allow certain parasites to remain undetected. We enlisted a cohort comprising 207 symptomatic individuals, encompassing both children and adults, at a hospital in Nnewi, Nigeria. The prevalence of parasites was determined using a highly sensitive, species-specific quantitative polymerase chain reaction (SS-qPCR). Within a subset of 132 participants, we assessed the sensitivity and specificity of microscopy and HRP2-mRDTs in comparison to SS-qPCR for the detection of P. falciparum. We also investigated the prevalence of pfhrp2/pfhrp3 gene deletions. Greater sensitivity was achieved with mRDTs (95%) compared with microscopy (77%). Also, mRDTs exhibited greater specificity (68%) than microscopy (44%). The positive predictive value of mRDTs (89%) surpassed that of microscopy (80%), suggesting a greater probability of accurately indicating the presence of infection. The negative predictive value of mRDTs (82%) was far greater than microscopy (39%). Of the 165 P. falciparum-positive samples screened for pfhrp2/pfhrp3 gene deletions, one gene deletion was detected in one sample. Regarding infection prevalence, 84% were positive for Plasmodium spp. (by reverse transcription [RT]-qPCR), with P. falciparum responsible for the majority (97%) of positive cases. Thus, exclusive reliance on microscopy in endemic areas may impede control efforts resulting from false negatives, underscoring the necessity for enhanced training and advocating for high-throughput molecular testing such as RT-qPCR or qPCR at referral centers to address limitations.

As part of malaria nationwide monitoring and evaluation initiatives, there is an increasing trend of incorporating malaria rapid diagnostic tests (mRDTs) in surveys conducted within primary schools to detect malaria parasites. However, mRDTs based on the detection of histidine-rich protein 2 (HRP2) are known to yield false-positive results due to persistent antigenemia, and false-negative results may result from low parasitemia or Plasmodium falciparum hrp2/3 gene deletion. We evaluated diagnostic performance of an HRP2 and pan-parasite lactate dehydrogenase (HRP2/pLDH) mRDT against polymerase chain reaction (PCR) for detection of P. falciparum among 17,051 primary school-age children from eight regions of Tanzania in 2017. According to PCR, the prevalence of P. falciparum was 19.2% (95% CI: 18.6-19.8). Using PCR as reference, the sensitivity and specificity of mRDT was 76.2% (95% CI: 74.7-77.7) and 93.9% (95% CI: 93.5-94.3), respectively. Test agreement was lowest in low transmission areas, where true-positive mRDTs were outnumbered by false-negatives due to low parasitemia. Discordant samples (mRDT-negative but PCR-positive) were screened for pfhrp2/3 deletion by real-time PCR. Among those with a parasite density sufficient for analysis, pfhrp2 deletion was confirmed in 60 samples, whereas pfhrp3 deletion was confirmed in two samples; one sample had both pfhrp2 and pfhrp3 deletions. The majority of samples with gene deletions were detected in the high-transmission Kagera region. Compared with mRDTs, PCR and other molecular methods offer increased sensitivity and are not affected by pfhrp2/3 deletions, making them a useful supplement to mRDTs in schools and other epidemiological surveys.

Background Malaria in pregnancy (MIP) is a major public health problem due to the vulnerability of pregnant women to infections, resulting in adverse maternal/foetal outcomes in endemic areas. Methods We did a field-based study to assess the burden of MIP (prevalence at the time of enrolment and follow-up) and to identify risk factors for MIP in the Birsa and Baihar blocks of district Balaghat in Madhya Pradesh, which have perennial malaria transmission. Malaria screening (during 2015-2017) was done by microscopy and bivalent rapid diagnostic test (SD Bioline RDT, malaria antigen Plasmodium falciparum/Plasmodium vivax Pf/Pv). Dried blood spots were used for haemoglobin estimation. Sociodemographic details with past and present pregnancy status were obtained. A subset of pregnant women were followed up for malaria during pregnancy. Women were also screened for malaria post delivery. Malaria treatment was given as per the National Guidelines of 2013. Multivariate analysis was done to assess independent risk factors for malaria. Results A total of 1728 pregnant women were screened, of which 1651 were included in the final analysis. Malaria prevalence at first screening was 23.4% (Pf 88%). Prevalence and Pf parasitaemia both were significantly higher among primigravid (G1) compared to multigravid (G>2; p value 0.012 and 0.019, respectively). Pregnant women of the Baiga ethnic group were more likely to have malaria compared to those belonging to the Gond group (OR [95% CI]; 2.4 [1.7-3.4]; p<0.00001) and non-indigenous group (OR [95% CI]; 8.3 [3.9-19.7]; p<0.00001). Primigravid status of women, first and second trimester of pregnancy, women belonging to indigenous ethnic tribal group and cash crop insufficiency for whole year (a socioeconomic indicator) in the family were the independent risk factors for malaria. Conclusion MIP is a major public health problem in forested tribal settlements of Birsa and Baihar blocks of Balaghat district in Madhya Pradesh and requires immediate intervention.

Background: Plasmodium vivax malaria is one of the major infectious diseases of public health concern in Nouakchott, the capital city of Mauritania and the biggest urban setting in the Sahara. The assessment of the current trends in malaria epidemiology is primordial in understanding the dynamics of its transmission and developing an effective control strategy., Methods: A 6 year (2015-2020) prospective study was carried out in Nouakchott. Febrile outpatients with a clinical suspicion of malaria presenting spontaneously at Teyarett Health Centre or the paediatric department of Mother and Children Hospital Centre were screened for malaria using a rapid diagnostic test, microscopic examination of Giemsa-stained blood films, and nested polymerase chain reaction. Data were analysed using Microsoft Excel and GraphPad Prism and InStat software., Results: Of 1760 febrile patients included in this study, 274 (15.5%) were malaria-positive by rapid diagnostic test, 256 (14.5%) were malaria-positive by microscopy, and 291 (16.5%) were malaria-positive by PCR. Plasmodium vivax accounted for 216 of 291 (74.2%) PCR-positive patients; 47 (16.1%) and 28 (9.6%) had P. falciparum monoinfection or P. vivax-P. falciparum mixed infection, respectively. During the study period, the annual prevalence of malaria declined from 29.2% in 2015 to 13.2% in 2019 and 2.1% in 2020 (P < 0.05). Malaria transmission was essentially seasonal, with a peak occurring soon after the rainy season (October-November), and P. vivax infections, but not P. falciparum infections, occurred at low levels during the rest of the year. The most affected subset of patient population was adult male white and black Moors. The decline in malaria prevalence was correlated with decreasing annual rainfall (r = 0.85; P = 0.03) and was also associated with better management of the potable water supply system. A large majority of included patients did not possess or did not use bed nets., Conclusions: Control interventions based on prevention, diagnosis, and treatment should be reinforced in Nouakchott, and P. vivax-specific control measures, including chloroquine and 8-aminoquinolines (primaquine, tafenoquine) for treatment, should be considered to further improve the efficacy of interventions and aim for malaria elimination., (© 2023. The Author(s).)

Background: Despite significant progress in eliminating malaria from the state of Odisha, India, the disease is still considered endemic. Artesunate plus sulfadoxine-pyrimethamine (AS + SP) has been introduced since 2010 as first-line treatment for uncomplicated Plasmodium falciparum malaria. This study aimed to investigate the prevalence of mutations associated with resistance to chloroquine (CQ), sulfadoxine-pyrimethamine (SP), and artesunate (ART) in P. falciparum parasites circulating in the state., Methods: A total of 239 isolates of P. falciparum mono infection were collected during July 2018-November 2020 from the four different geographical regions of the state. Genomic DNA was extracted from 200 µL of venous blood and amplified using nested polymerase chain reaction. Mutations on gene associated with CQ (Pfcrt and Pfmdr1) were assessed by PCR amplification and restriction fragment length polymorphism, artemisinin (Pfk13) gene by DNA sequencing and SP (Pfdhfr and Pfdhps) genes by allele-specific polymerase chain reaction (AsPCR)., Results: The point mutation in Pfcrt (K76T) was detected 2.1%, in Pfmdr1 (N86Y) 3.4%, and no mutations were found in Pfkelch13 propeller domain. Prevalence of Pfdhfr, Pfdhps and Pfhdfr-Pfdhps (two locus) gene mutations were 50.43%, 47.05% and 49.79% respectively. The single, double, triple and quadruple point mutations in Pfdhfr gene was 11.2%, 8.2%, 17.2% and 3.4% while, in Pfdhps gene was 10.9%,19.5%, 9.5% and 2.7% respectively. Of the total 13 haplotypes found in Pfdhfr, 8 were detected for the first time in the state and of the total 26 haplotypes found in Pfdhps, 7 were detected for the fisrt time in the state. The linked quintuple mutation Pfdhfr (N51I-C59R-S108N)-Pfdhps (A437G-K540E) responsible for clinical failure (RIII level of resistance) of SP resistance and A16V-S108T mutation in Pfdhfr responsible for cycloguanil was absent., Conclusion: The study has demonstrated a low prevalence of CQ resistance alleles in the study area. Despite the absence of the Pfkelch13 mutations, high prevalence of Pfdhfr and Pfdhps point mutations undermine the efficacy of SP partner drug, thereby threatening the P. falciparum malaria treatment policy. Therefore, continuous molecular and in vivo monitoring of ACT efficacy is warranted in Odisha., (© 2022. The Author(s).)

Malaria control interventions target nocturnal feeding of the Anopheles vectors indoors to reduce parasite transmission. Mass deployment of insecticidal bed nets and indoor residual spraying with insecticides, however, may induce mosquitoes to blood-feed at places and at times when humans are not protected. These changes can set a ceiling to the efficacy of these control interventions, resulting in residual malaria transmission. Despite its relevance for disease transmission, the daily rhythmicity of Anopheles biting behavior is poorly documented, most investigations focusing on crepuscular hours and nighttime. By performing mosquito collections 48-h around the clock, both indoors and outdoors, and by modeling biting events using circular statistics, we evaluated the full daily rhythmicity of biting in urban Bangui, Central African Republic. While the bulk of biting by Anopheles gambiae, Anopheles coluzzii, Anopheles funestus, and Anopheles pharoensis occurred from sunset to sunrise outdoors, unexpectedly ∼20 to 30% of indoor biting occurred during daytime. As biting events did not fully conform to any family of circular distributions, we fitted mixtures of von Mises distributions and found that observations were consistent with three compartments, corresponding indoors to populations of early-night, late-night, and daytime-biting events. It is not known whether these populations of biting events correspond to spatiotemporal heterogeneities or also to distinct mosquito genotypes/phenotypes belonging consistently to each compartment. Prevalence of Plasmodium falciparum in nighttime- and daytime-biting mosquitoes was the same. As >50% of biting occurs in Bangui when people are unprotected, malaria control interventions outside the domiciliary environment should be envisaged.