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The main vectors of Zika virus (ZIKV) and dengue virus (DENV) are Aedes aegypti and Ae. albopictus, with Ae. aegypti being more competent. However, the underlying mechanisms remain unclear. Here, we find Ae. albopictus shows comparable vector competence to ZIKV/DENV with Ae. aegypti by blood-feeding after antibiotic treatment or intrathoracic injection. This suggests that midgut microbiota can influence vector competence. Enterobacter hormaechei_B17 (Eh_B17) is isolated from field-collected Ae. albopictus and conferred resistance to ZIKV/DENV infection in Ae. aegypti after gut-transplantation. Sphingosine, a metabolite secreted by Eh_B17, effectively suppresses ZIKV infection in both Ae. aegypti and cell cultures by blocking viral entry during the fusion step, with an IC 50 of approximately 10 μM. A field survey reveals that Eh_B17 preferentially colonizes Ae. albopictus compared to Ae. aegypti. And field Ae. albopictus positive for Eh_B17 are more resistant to ZIKV infection. These findings underscore the potential of gut symbiotic bacteria, such as Eh_B17, to modulate the arbovirus vector competence of Aedes mosquitoes. As a natural antiviral agent, Eh_B17 holds promise as a potential candidate for blocking ZIKV/DENV transmission., (© 2024. The Author(s).)

Background: Hainan Island and the Leizhou Peninsula, the southernmost part of mainland China, are areas where Aedes aegypti and Ae. albopictus are sympatric and are also high-incidence areas of dengue outbreaks in China. Many studies have suggested that Aedes endogenous viral components (EVEs) are enriched in piRNA clusters which can silence incoming viral genomes. Investigation the EVEs present in the piRNA clusters associated with viral infection of Aedes mosquitoes in these regions may provide a theoretical basis for novel transmission-blocking vector control strategies., Methods: In this study, specific primers for endogenous Flaviviridae elements (EFVEs) and endogenous Rhabdoviridae elements (ERVEs) were used to detect the distribution of Zika virus infection associated EVEs in the genomes of individuals of the two Aedes mosquitoes. Genetic diversity of EVEs with a high detection rate was also analyzed., Results: The results showed that many EVEs associated with Zika virus infection were detected in both Aedes species, with the detection rates were 47.68% to 100% in Ae. aegypti and 36.15% to 92.31% in sympatric Ae. albopictus populations. EVEs detection rates in another 17 Ae. albopictus populations ranged from 29.39% to 89.85%. Genetic diversity analyses of the four EVEs (AaFlavi53, AaRha61, AaRha91 and AaRha100) of Ae. aegypti showed that each had high haplotype diversity and low nucleotide diversity. The number of haplotypes in AaFlavi53 was 8, with the dominant haplotype being Hap_1 and the other 7 haplotypes being further mutated from Hap_1 in a lineage direction. In contrast, the haplotype diversity of the other three ERVEs (AaRha61, AaRha91 and AaRha100) was more diverse and richer, with the haplotype numbers were 9, 15 and 19 respectively. In addition, these EVEs all showed inconsistent patterns of both population differentiation and dispersal compared to neutral evolutionary genes such as the Mitochondrial COI gene., Conclusion: The EFVEs and ERVEs tested were present at high frequencies in the field Aedes mosquito populations. The haplotype diversity of the EFVE AaFlavi53 was relatively lower and the three ERVEs (AaRha61, AaRha91, AaRha100) were higher. None of the four EVEs could be indicative of the genetic diversity of the Ae. aegypti population. This study provided theoretical support for the use of EVEs to block arbovirus transmission, but further research is needed into the mechanisms by which these EVEs are antiviral to Aedes mosquitoes., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests including financial and nonfinancial interests., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

As climate change alters Earth's biomes, it is expected the transmission dynamics of mosquito-borne viruses will change. While the effects of temperature changes on mosquito-virus interactions and the spread of the pathogens have been elucidated over the last decade, the impact of relative humidity changes is still relatively unknown. To overcome this knowledge gap, we exposed Aedes aegypti females to various humidity conditions. We measured different components of vectorial capacity such as survival, blood-feeding rates, and changes in infection and dissemination of Zika virus. Survival decreased as the humidity level decreased, while infection rates increased as the humidity level decreased. Alternatively, blood feeding rates and disseminated infection rates peaked at the intermediate 50% relative humidity treatment but were the same in the 30% and 80% relative humidity treatments. These results provide empirical evidence that Ae. aegypti exposure to low humidity can enhance Zika virus infection in the mosquito, which has important implications in predicting how climate change will impact mosquito-borne viruses.IMPORTANCEViruses transmitted by mosquitoes to humans are a major public health burden and are expected to increase under climate change. While we know that temperature is an important driver of variation in arbovirus replication in the mosquito, very little is known about how other relevant climate variables such as humidity will influence the interaction between mosquitoes and the viruses they transmit. Given the variability in humidity across environments, and the predicted changes in humidity under climate change, it is imperative that we also study the impact that it has on mosquito infection and transmission of arboviruses., Competing Interests: The authors declare no conflict of interest.

Arboviruses represent a threat to transfusion safety for several reasons: the presence of vectors and the notification of autochthonous cases in our region, the recent increase in the number of cases transmitted through blood and/or blood component transfusion, the high prevalence rates of RNA of the main arboviruses in asymptomatic blood donors, and their ability to survive processing and storage in the different blood components. In an epidemic outbreak caused by an arbovirus in our region, transfusion centres can apply different measures: reactive measures, related to donor selection or arbovirus screening, and proactive measures, such as pathogen inactivation methods. The study of the epidemiology of the main arboviruses and understanding the effectiveness of the different measures that we can adopt are essential to ensure that our blood components remain safe., (Copyright © 2024 Elsevier España, S.L.U. All rights reserved.)

This study presents a computational investigation of a stochastic Zika virus along with optimal control model using the Legendre spectral collocation method (LSCM). By accumulation of stochasticity into the model through the proposed stochastic differential equations, we appropriating the random fluctuations essential in the progression and disease transmission. The stability, convergence and accuracy properties of the LSCM are conscientiously analyzed and also demonstrating its strength for solving the complex epidemiological models. Moreover, the study evaluates the various control strategies, such as treatment, prevention and treatment pesticide control, and identifies optimal combinations that the intervention costs and also minimize the proposed infection rates. The basic properties of the given model, such as the reproduction number, were determined with and without the presence of the control strategies. For R 0 < 0 , the model satisfies the disease-free equilibrium, in this case the disease die out after some time, while for R 0 > 1 , then endemic equilibrium is satisfied, in this case the disease spread in the population at higher scale. The fundamental findings acknowledge the significant impact of stochastic phonemes on the robustness and effectiveness of control strategies that accelerating the need for cost-effective and multi-faceted approaches. In last the results provide the valuable insights for public health department to enabling more impressive mitigation of Zika virus outbreaks and management in real-world scenarios., (© 2024. The Author(s).)

Purpose of Review: Arbovirus infections are a challenge for immunocompromised hosts who travel to or live in endemic regions or who receive organs or tissues from donors who travel or live in such areas. This review addresses Dengue (DENV), Chikungunya (CHIKV), and Zika (ZIKV) infections in hematological patients, hematopoietic cell or solid organ transplant recipients, and people with HIV (PWH)., Recent Findings: Transmission is mainly due through Aedes mosquito bite. DENV and ZIKV may also be transmitted through blood, tissues or donor grafts. Clinical manifestations are quite similar and diagnosis requires laboratory confirmation to provide appropriate management. The best diagnostic method is PCR since serology may present false negative results in immunocompromised patients, or cross-reactivity as in the case of DENV and ZIKV. There is no specific treatment for any of these infections., Summary: Educational and preventive measures are the best strategy: vector control, knowledge of the vector's habits, protection against mosquito bites, avoiding travel to endemic areas or with a current epidemic, and avoiding nonvector transmission according to local recommendations for donor deferral. Vaccination, currently only available for DENV, has not yet been studied in immunocompromised patients and is not currently recommended., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

The 2016 outbreak of Zika virus (ZIKV) infected millions and resulted in thousands of infants born with malformations. Though the clusters of severe birth defects resulting from this outbreak have subsided, ZIKV continues to be a concern throughout much of Latin America and the Caribbean. Travel and sexual intercourse remain the dominant transmission risk factors for women of reproductive age and their partners. This is particularly true for communities in Brooklyn, New York, that comprise large immigrant and foreign-born populations. Practitioners of public health understand little about how women at risk for ZIKV are most likely to receive information about the virus or who they trust most to provide that information. In the context of five focus group discussions, this study explored the knowledge and communication preferences of 20 women of reproductive age in Central Brooklyn. Results derived from a thematic analysis suggest that while most women are familiar with mosquitos as ZIKV vectors, knowledge of sexual transmission is considerably lower. Many respondents believe that only women who are pregnant or trying to become pregnant are at risk, and public health agencies, such as the U.S. Centers for Disease Control and Prevention, remain the most trusted sources of information. These findings can support more effective communication about the risks of ZIKV infection and other vector-borne diseases to women in New York City and similar urban communities., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The dynamics that govern disease spread are hard to model because infections are functions of both the underlying pathogen as well as human or animal behavior. This challenge is increased when modeling how diseases spread between different spatial locations. Many proposed spatial epidemiological models require trade-offs to fit, either by abstracting away theoretical spread dynamics, fitting a deterministic model, or by requiring large computational resources for many simulations. We propose an approach that approximates the complex spatial spread dynamics with a Gaussian process. We first propose a flexible spatial extension to the well-known SIR stochastic process, and then we derive a moment-closure approximation to this stochastic process. This moment-closure approximation yields ordinary differential equations for the evolution of the means and covariances of the susceptibles and infectious through time. Because these ODEs are a bottleneck to fitting our model by MCMC, we approximate them using a low-rank emulator. This approximation serves as the basis for our hierarchical model for noisy, underreported counts of new infections by spatial location and time. We demonstrate using our model to conduct inference on simulated infections from the underlying, true spatial SIR jump process. We then apply our method to model counts of new Zika infections in Brazil from late 2015 through early 2016., (© The Author(s) 2024. Published by Oxford University Press on behalf of The International Biometric Society.)

Background: The spread of vector-borne infectious diseases is determined, among other things, by temperature. Thus, climate change will have an influence on their global distribution. In the future, Europe will approach the temperature optimum for the transmission of ZIKV and CHIKV. Climate scenarios and climate models can be used to depict future climatic changes and to draw conclusions about future risk areas for vector-borne infectious diseases., Methods: Based on the RCP 4.5 and RCP 8.5 climate scenarios, a geospatial analysis was carried out for the future temperature suitability of ZIKV and CHIKV in Europe. The results were presented in maps and the percentage of the affected areas calculated., Results: Due to rising temperatures, the risk areas for transmission of ZIKV and CHIKV spread in both RCP scenarios. For CHIKV transmission, Spain, Portugal, the Mediterranean coast and areas near the Black Sea are mainly affected. Due to high temperatures, large areas throughout Europe are at risk for ZIKV and CHIKV transmission., Conclusion: Temperature is only one of many factors influencing the spread of vector-borne infectious diseases. Nevertheless, the representation of risk areas on the basis of climate scenarios allows an assessment of future risk development. Monitoring and adaptation strategies are indispensable for coping with and containing possible future autochthonous transmissions and epidemics in Europe., 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.)

Background: Past findings demonstrate that arthropods can egest midgut microbiota into the host skin leading to dual colonization of the vertebrate host with pathogens and saliva microbiome. A knowledge gap exists on how the saliva microbiome interacts with the pathogen in the saliva. To fill this gap, we need to first define the microbial composition of mosquito saliva., Methods: The current study aimed at analyzing and comparing the microbial profile of Aedes albopictus saliva and midgut as well as assessing the impact of Zika virus (ZIKV) infection on the midgut and saliva microbial composition. Colony-reared Ae. albopictus strains were either exposed to ZIKV infectious or noninfectious bloodmeal. At 14 ays postinfection, the 16S V3-V4 hypervariable rRNA region was amplified from midgut and saliva samples and sequenced on an Illumina MiSeq platform. The relative abundance and diversity of midgut and saliva microbial taxa were assessed., Results: We observed a richer microbial community in the saliva compared with the midgut, yet some of the microbial taxa were common in the midgut and saliva. ZIKV infection did not impact the microbial diversity of midgut or saliva. Further, we identified Elizabethkingia spp. in the Ae. albopictus saliva., Conclusions: This study provides insights into the microbial community of the Ae. albopictus saliva as well as the influence of ZIKV infection on the microbial composition of its midgut and saliva. The identification of Elizabethkingia spp., an emerging pathogen of global health significance, in Ae. albopictus saliva is of medical importance. Future studies to assess the interactions between Ae. albopictus saliva microbiome and ZIKV could lead to novel strategies for developing transmission barrier tools., (© 2024. The Author(s).)

Background: The international flight network creates multiple routes by which pathogens can quickly spread across the globe. In the early stages of infectious disease outbreaks, analyses using flight passenger data to identify countries at risk of importing the pathogen are common and can help inform disease control efforts. A challenge faced in this modelling is that the latest aviation statistics (referred to as contemporary data) are typically not immediately available. Therefore, flight patterns from a previous year are often used (referred to as historical data). We explored the suitability of historical data for predicting the spatial spread of emerging epidemics., Methods: We analysed monthly flight passenger data from the International Air Transport Association to assess how baseline air travel patterns were affected by outbreaks of Middle East respiratory syndrome (MERS), Zika and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) over the past decade. We then used a stochastic discrete time susceptible-exposed-infected-recovered (SEIR) metapopulation model to simulate the global spread of different pathogens, comparing how epidemic dynamics differed in simulations based on historical and contemporary data., Results: We observed local, short-term disruptions to air travel from South Korea and Brazil for the MERS and Zika outbreaks we studied, whereas global and longer-term flight disruptions occurred during the SARS-CoV-2 pandemic. For outbreak events that were accompanied by local, small and short-term changes in air travel, epidemic models using historical flight data gave similar projections of the timing and locations of disease spread as when using contemporary flight data. However, historical data were less reliable to model the spread of an atypical outbreak such as SARS-CoV-2, in which there were durable and extensive levels of global travel disruption., Conclusion: The use of historical flight data as a proxy in epidemic models is an acceptable practice, except in rare, large epidemics that lead to substantial disruptions to international travel., (© International Society of Travel Medicine 2024. Published by Oxford University Press.)

Background: Dengue, Zika, and chikungunya, whose viruses are transmitted mainly by Aedes aegypti, significantly impact human health worldwide. Despite the recent development of promising vaccines against the dengue virus, controlling these arbovirus diseases still depends on mosquito surveillance and control. Nonetheless, several studies have shown that these measures are not sufficiently effective or ineffective. Identifying higher-risk areas in a municipality and directing control efforts towards them could improve it. One tool for this is the premise condition index (PCI); however, its measure requires visiting all buildings. We propose a novel approach capable of predicting the PCI based on facade street-level images, which we call PCINet., Methodology: Our study was conducted in Campinas, a one million-inhabitant city in São Paulo, Brazil. We surveyed 200 blocks, visited their buildings, and measured the three traditional PCI components (building and backyard conditions and shading), the facade conditions (taking pictures of them), and other characteristics. We trained a deep neural network with the pictures taken, creating a computational model that can predict buildings' conditions based on the view of their facades. We evaluated PCINet in a scenario emulating a real large-scale situation, where the model could be deployed to automatically monitor four regions of Campinas to identify risk areas., Principal Findings: PCINet produced reasonable results in differentiating the facade condition into three levels, and it is a scalable strategy to triage large areas. The entire process can be automated through data collection from facade data sources and inferences through PCINet. The facade conditions correlated highly with the building and backyard conditions and reasonably well with shading and backyard conditions. The use of street-level images and PCINet could help to optimize Ae. aegypti surveillance and control, reducing the number of in-person visits necessary to identify buildings, blocks, and neighborhoods at higher risk from mosquito and arbovirus diseases., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Laranjeira 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.)

Zika (ZIKV) and chikungunya (CHIKV) are arboviruses that cause infections in humans and can cause clinical complications, representing a worldwide public health problem. Aedes aegypti is the primary vector of these pathogens and Culex quinquefasciatus may be a potential ZIKV vector. This study aimed to evaluate fecundity, fertility, survival, longevity, and blood feeding activity in Ae. aegypti after exposure to ZIKV and CHIKV and, in Cx. quinquefasciatus exposed to ZIKV. Three colonies were evaluated: AeCamp (Ae. aegypti-field), RecL (Ae. aegypti-laboratory) and CqSLab (Cx. quinquefasciatus-laboratory). Seven to 10 days-old females from these colonies were exposed to artificial blood feeding with CHIKV or ZIKV. CHIKV caused reduction in fecundity and fertility in AeCamp and reduction in survival and fertility in RecL. ZIKV impacted survival in RecL, fertility in AeCamp and, fecundity and fertility in CqSLab. Both viruses had no effect on blood feeding activity. These results show that CHIKV produces a higher biological cost in Ae. aegypti, compared to ZIKV, and ZIKV differently alters the biological performance in colonies of Ae. aegypti and Cx. quinquefasciatus. These results provide a better understanding over the processes of virus-vector interaction and can shed light on the complexity of arbovirus transmission., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Crespo 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.)

Background: Cord blood units (CBUs) that are ineligible for licensure due to incomplete compliance with FDA recommendations may be used for hematopoietic stem cell transplantation under urgent medical need and an Investigational Drug Application. The largest reason for CBU donor ineligibility is Zika virus (ZIKV) risk. The study's objective was to analyze the impact of current FDA recommendations for ZIKA risk on a large public cord blood bank and propose updated recommendations., Methods: We performed a retrospective analysis of Carolinas Cord Blood Bank (CCBB), an FDA licensed public CBB, using data from January 1, 2016 to November 21, 2023 and compared FDA recommendations for transfusion transmitted infections (TTI) for blood products and relevant communicable disease agents or diseases for human cell, tissue, or cellular or tissue-based products (HCT/Ps)., Results: CCBB: 9057 (84.3% licensed) CBUs were banked. 984/1682 (58.5%) of unlicensed CBUs had ZIKV risk. 22.0% of CBUs with ZIKV risk were from Hispanic parents, compared to 16.1% of all units. 31 of IND CBUs (11 due to ZIKV risk without reported ZIKV transmission) were safely infused. FDA Guidance: HCT/P ZIKV, HIV, and vCJD recommendations have not been updated since 2018 in contrast to FDA removal of ZIKV as a relevant TTI in 2021 and updating HIV and vCJD guidance related to TTI in 2023 and 2022, respectively., Discussion: The FDA should consider new data to revise the HCT/P donor eligibility recommendations, which will increase the number of eligible HCT/P donors, and potentially improve access to therapies for a more diverse patient population., (© The Author(s) 2024. Published by Oxford University Press.)

Arboviruses can be difficult to detect in the field due to relatively low prevalence in mosquito populations. The discovery that infected mosquitoes can release viruses in both their saliva and excreta gave rise to low-cost methods for the detection of arboviruses during entomological surveillance. We implemented both saliva and excreta-based entomological surveillance during the emergence of Zika virus (ZIKV) in French Guiana in 2016 by trapping mosquitoes around households of symptomatic cases with confirmed ZIKV infection. ZIKV was detected in mosquito excreta and not in mosquito saliva in 1 trap collection out of 85 (1.2%). One female Ae. aegypti L. (Diptera: Culicidae) was found with a ZIKV systemic infection in the corresponding trap. The lag time between symptom onset in a ZIKV-infected individual living near the trap site and ZIKV detection in this mosquito was 1 wk. These results highlight the potential of detection in excreta from trapped mosquitoes as a sensitive and cost-effective method to non invasively detect arbovirus circulation., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America.)

Zika, a viral disease transmitted to humans by Aedes mosquitoes, emerged in the Americas in 2015, causing large-scale epidemics. Colombia alone reported over 72,000 Zika cases between 2015 and 2016. Using national surveillance data from 1121 municipalities over 70 weeks, we identified sociodemographic and environmental factors associated with Zika's emergence, re-emergence, persistence, and transmission intensity in Colombia. We fitted a zero-state Markov-switching model under the Bayesian framework, assuming Zika switched between periods of presence and absence according to spatially and temporally varying probabilities of emergence/re-emergence (from absence to presence) and persistence (from presence to presence). These probabilities were assumed to follow a series of mixed multiple logistic regressions. When Zika was present, assuming that the cases follow a negative binomial distribution, we estimated the transmission intensity rate. Our results indicate that Zika emerged/re-emerged sooner and that transmission was intensified in municipalities that were more densely populated, at lower altitudes and/or with less vegetation cover. Warmer temperatures and less weekly-accumulated rain were also associated with Zika emergence. Zika cases persisted for longer in more densely populated areas with more cases reported in the previous week. Overall, population density, elevation, and temperature were identified as the main contributors to the first Zika epidemic in Colombia. We also estimated the probability of Zika presence by municipality and week, and the results suggest that the disease circulated undetected by the surveillance system on many occasions. Our results offer insights into priority areas for public health interventions against emerging and re-emerging Aedes-borne diseases., (© 2024. The Author(s).)

Mosquitoes transmit many disease-relevant flaviviruses. Efficient viral transmission to mammalian hosts requires mosquito salivary factors. However, the specific salivary components facilitating viral transmission and their mechanisms of action remain largely unknown. Here, we show that a female mosquito salivary gland-specific protein, here named A. aegypti Neutrophil Recruitment Protein (AaNRP), facilitates the transmission of Zika and dengue viruses. AaNRP promotes a rapid influx of neutrophils, followed by virus-susceptible myeloid cells toward mosquito bite sites, which facilitates establishment of local infection and systemic dissemination. Mechanistically, AaNRP engages TLR1 and TLR4 of skin-resident macrophages and activates MyD88-dependent NF-κB signaling to induce the expression of neutrophil chemoattractants. Inhibition of MyD88-NF-κB signaling with the dietary phytochemical resveratrol reduces AaNRP-mediated enhancement of flavivirus transmission by mosquitoes. These findings exemplify how salivary components can aid viral transmission, and suggest a potential prophylactic target., (© 2024. The Author(s).)

Objectives: Arboviruses, such as dengue (DENV), zika (ZIKV), and chikungunya (CHIKV), constitute a growing urban public health threat. Focusing on Aedes aegypti mosquitoes, their primary vectors, is crucial for mitigation. While traditional immature-stage mosquito surveillance has limitations, capturing adult mosquitoes through traps yields more accurate data on disease transmission. However, deploying traps presents logistical and financial challenges, demonstrating effective temporal predictions but lacking spatial accuracy. Our goal is to identify smaller representative areas within cities to enhance the early warning system for DENV outbreaks., Methods: We created Sentinel Geographic Units (SGUs), smaller areas of 1 km 2 within each stratum, larger areas, with the aim of aligning the Trap Positivity Index (TPI) and Adult Density Index (ADI) with their respective strata. We conducted a two-step evaluation of SGUs. First, we examined the equivalence of TPI and ADI between SGUs and strata from January 2017 to July 2022. Second, we assessed the ability of SGU's TPI and ADI to predict DENV outbreaks in comparison to Foz do Iguaçu's Early-Warning System, which forecasts outbreaks up to 4 weeks ahead. Spatial and temporal analyses were carried out, including data interpolation and model selection based on Akaike information criteria (AIC)., Results: Entomological indicators produced in small SGUs can effectively replace larger sentinel areas to access dengue outbreaks. Based on historical data, the best predictive capability is achieved 2 weeks after infestation verification. Implementing the SGU strategy with more frequent sampling can provide more precise space-time estimates and enhance dengue control., Conclusions: The implementation of SGUs offers an efficient way to monitor mosquito populations, reducing the need for extensive resources. This approach has the potential to improve dengue transmission management and enhance the public health response in endemic cities., (© 2024 John Wiley & Sons Ltd.)

Aedes albopictus collected in 2023 in the greater Paris area (Île-de-France) were experimentally able to transmit five arboviruses: West Nile virus from 3 days post-infection (dpi), chikungunya virus and Usutu virus from 7 dpi, dengue virus and Zika virus from 21 dpi. Given the growing number of imported dengue cases reported in early 2024 in France, surveillance of Ae. albopictus should be reinforced during the Paris Olympic Games in July, when many international visitors including from endemic countries are expected.

The commensal microbiota of the mosquito gut plays a complex role in determining the vector competence for arboviruses. In this study, we identified a bacterium from the gut of field Aedes albopictus mosquitoes named Rosenbergiella sp. YN46 ( Rosenbergiella&#95; YN46) that rendered mosquitoes refractory to infection with dengue and Zika viruses. Inoculation of 1.6 × 10 3 colony forming units (CFUs) of Rosenbergiella&#95; YN46 into A. albopictus mosquitoes effectively prevents viral infection. Mechanistically, this bacterium secretes glucose dehydrogenase ( Ry GDH), which acidifies the gut lumen of fed mosquitoes, causing irreversible conformational changes in the flavivirus envelope protein that prevent viral entry into cells. In semifield conditions, Rosenbergiella&#95; YN46 exhibits effective transstadial transmission in field mosquitoes, which blocks transmission of dengue virus by newly emerged adult mosquitoes. The prevalence of Rosenbergiella&#95; YN46 is greater in mosquitoes from low-dengue areas (52.9 to ~91.7%) than in those from dengue-endemic regions (0 to ~6.7%). Rosenbergiella&#95; YN46 may offer an effective and safe lead for flavivirus biocontrol.

Zika virus infection, most oft n responsible for a benign arboviral disease or an asymptomatic infection, rarely Guillain-Barré syndrome, can become problematic in pregnant women, due to a risk of fetal malformations, in particular microcephaly linked to its neurotropism. The most recent large-scale epidemic was observed throughout Latin America between 2015 and 2017, causing several hundred thousand cases. Transmission is predominantly vector-borne, but sexual transmission has been described, mainly among travelers, although it undoubtedly accounts for a significant proportion of transmission in epidemic areas. The aim of this review is to describe this sexual transmission, mainly through examples linked to this large-scale epidemic in Latin America, to describe the link with prolonged excretion of infectious viral particles in genital secretions, especially semen but also vaginal secretions, and to highlight possible preventive measures apart from vector transmission, in particular the need for pregnant women or women wishing to become pregnant to avoid visiting countries where circulation of Zika virus is described., (Copyright © 2024 SFMTSI.)

Background: Several sporadic cases and outbreaks of Zika virus disease have been reported from different states of India., Objectives: This paper explored the possibility of any ongoing transmission of Zika virus (ZIKV) in the Bhopal region of Central India, where the last outbreak of this disease was reported in 2018., Materials and Methods: We screened a group of 75 febrile patients who had already tested negative for the locally endemic causes of fever like dengue, chikungunya, enteric fever, malaria, and scrub typhus and two groups of asymptomatic healthy individuals represented by blood donors (n = 75) and antenatal mothers (n = 75). We tested blood samples of febrile patients for ZIKV RNA using real-time polymerase chain reaction (PCR), and for the healthy individuals, we determined anti-zika immunoglobulin G (IgG) antibodies using enzyme-linked immunosorbent assay., Results: ZIKV RNA was not detected in any of the 75 samples tested by real-time PCR assay. Among the voluntary blood donors and antenatal mothers, a total of 10 (15.38%) and 5 (6.66%) individuals were found to be seropositive for anti-ZIKV IgG antibodies, respectively. The seropositive group was found to have higher age 33.06 (±10.83) years as compared to seronegative individuals 26.60 (±5.12) years (P = 0.037)., Conclusion: This study, which is the first survey of seroprevalence of anti-Zika antibodies from India, reports an overall seropositivity rate of 10% for anti-Zika antibodies among the healthy population, suggesting an ongoing, low level, silent transmission of ZIKV in the local community., (Copyright © 2024 Copyright: © 2024 Indian Journal of Public Health.)

Importance: Previously, we modeled direct transmission chains of Zika virus (ZIKV) by serially passaging ZIKV in mice and mosquitoes and found that direct mouse transmission chains selected for viruses with increased virulence in mice and the acquisition of non-synonymous amino acid substitutions. Here, we show that these same mouse-passaged viruses also maintain fitness and transmission capacity in mosquitoes. We used infectious clone-derived viruses to demonstrate that the substitution in nonstructural protein 4A contributes to increased virulence in mice., Competing Interests: The authors declare no conflict of interest.

Over the last decade, the release of Wolbachia-infected Aedes aegypti into the natural habitat of this mosquito species has become the most sustainable and long-lasting technique to prevent and control vector-borne diseases, such as dengue, zika, or chikungunya. However, the limited resources to generate such mosquitoes and their effective distribution in large areas dominated by the Aedes aegypti vector represent a challenge for policymakers. Here, we introduce a mathematical framework for the spread of dengue in which competition between wild and Wolbachia-infected mosquitoes, the cross-contagion patterns between humans and vectors, the heterogeneous distribution of the human population in different areas, and the mobility flows between them are combined. Our framework allows us to identify the most effective areas for the release of Wolbachia-infected mosquitoes to achieve a large decrease in the global dengue prevalence.

Objective: Zika virus (ZIKV) targets neural stem cells in the developing brain. However, the majority of ZIKV-exposed children are born without apparent neurological manifestations. It remains unclear if these children were protected from ZIKV neurotropism or if they harbour subtle pathology that is disruptive to brain development. We assess this by comparing neurodevelopmental outcomes in normocephalic ZIKV-exposed children relative to a parallel control group of unexposed controls., Design: Cohort study., Setting: Public health centres in Grenada, West Indies., Patients: 384 mother-child pairs were enrolled during a period of active ZIKV transmission (April 2016-March 2017) and prospectively followed up to 30 months. Child exposure status was based on laboratory assessment of prenatal and postnatal maternal serum., Main Outcome Measures: The INTERGROWTH-21st Neurodevelopment Assessment (INTER-NDA) package and Cardiff Vision Tests, administered and scored by research staff masked to child's exposure status., Results: A total of 131 normocephalic ZIKV exposed (n=68) and unexposed (n=63) children were assessed between 22 and 30 months of age. Approximately half of these children completed vision testing. There were no group differences in sociodemographics. Deficits in visual acuity (31%) and contrast sensitivity (23%) were apparent in the ZIKV-exposed infants in the absence of cognitive, motor, language or behavioural delays., Conclusions: Overall neurodevelopment is likely to be unaffected in ZIKV-exposed children with normal head circumference at birth and normal head growth in the first 2 years of life. However, the visual system may be selectively vulnerable, which indicates the need for vision testing by 3 years of age., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Zika virus (ZIKV), a re-emerging virus, causes congenital brain abnormalities and Guillain-Barré syndrome. It is mainly transmitted by Aedes mosquitoes, but infections are also linked to sexual transmissions. Infectious ZIKV has been isolated, and viral RNA has been detected in semen over a year after the onset of initial symptoms, but the mode of long-term persistence is not yet understood. ZIKV can proliferate in human Sertoli cells (HSerC) for several weeks in vitro, suggesting that it might be a reservoir for persistent ZIKV infection. This study determined proteomic changes in HSerC during ZIKV infections by TMT-mass spectrometry analysis. Levels of 4416 unique Sertoli cell proteins were significantly altered at 3, 5, and 7 days after ZIKV infection. The significantly altered proteins include enzymes, transcription regulators, transporters, kinases, peptidases, transmembrane receptors, cytokines, ion channels, and growth factors. Many of these proteins are involved in pathways associated with antiviral response, antigen presentation, and immune cell activation. Several immune response pathway proteins were significantly activated during infection, e.g., interferon signaling, T cell receptor signaling, IL-8 signaling, and Th1 signaling. The altered protein levels were linked to predicted activation of immune response in HSerC, which was predicted to suppress ZIKV infection. ZIKV infection also affected the levels of critical regulators of gluconeogenesis and glycolysis pathways such as phosphoglycerate mutase, phosphoglycerate kinase, and enolase. Interestingly, many significantly altered proteins were associated with cardiac hypertrophy, which may induce heart failure in infected patients. In summary, our research contributes to a better understanding of ZIKV replication dynamics and infection in Sertoli cells.

Background: On 1 February 2016, the World Health Organization declared Zika transmission a public health emergency of international concern. Monitoring and responding to community awareness, concern, and possible knowledge gaps are critical during public health emergencies. Here, we describe the review and analysis of micro-blogs posted on Sina-Weibo, China's largest social media platform, to develop and disseminate a Zika virus education campaign., Methods: We used CYYUN Voice Express' Weibo Spider tool and the search terms of "Zhaika" OR "Zika" OR "Zikv" to capture microblogs about Zika virus retrospectively from February 1 to December 31, 2016 and prospectively from June 1 to November 15, 2017. We described microblogs meeting our inclusion criteria by month and Zika virus outbreaks in Asia and by source (e.g., government agency, individual, or other). We identified common misleading or inaccurate content authored by individual micro-bloggers (i.e., not supported by available scientific evidence) through a qualitative review. We used this information to develop and disseminate health awareness material about the Zika virus through China CDC's 12320 Health Hotline Weibo account. An online survey was conducted to obtain feedback on the material., Results: We captured 15,888 microblogs meeting our inclusion criteria. Zika-related microblogs peaked in September 2016, corresponding to news reports about the Zika outbreak in Singapore (August to November 2016). Most microblogs (12,994 [82%]) were authored by individual users, followed by media agencies (842 [5%]), businesses (829 [5%]), international organizations (370 [2%]), and Chinese government agencies (235 [1%]). Relevant microblogs primarily focused on clinical symptoms and health risks, modes of transmission, and actions taken by individuals to prevent infection and seek health care. Incorrect and/or mis-leading information from individual users concentrated on modes of transmission and possible treatments. The microblog "#Zika is that far and this close" health campaign was posted on Sina-Weibo and Baidu (Internet search engine in China) on September 18, 2016. Younger respondents (p-value = 0.01), and those with at least a college education (p-value = 0.03), were more likely than other respondents to consider the online campaign reliable and trustworthy., Conclusion: Routine review of Sina-Weibo and other social media platforms could enhance the ability of public health staff to effectively respond to community concerns and awareness during public health emergencies. Advancements of social media monitoring tools and staff training could help to promote health awareness during emergencies by directly addressing public perceptions and concerns. Various approaches may be needed to reach different at-risk populations, particularly older and less educated populations who may prefer more traditional modes of communication., Competing Interests: The authors have declared that no competing interests exist.

Background: Aedes albopictus and Aedes japonicus, two invasive mosquito species in the United States, are implicated in the transmission of arboviruses. Studies have shown interactions of these two mosquito species with a variety of vertebrate hosts; however, regional differences exist and may influence their contribution to arbovirus transmission., Methods: We investigated the distribution, abundance, host interactions, and West Nile virus infection prevalence of Ae. albopictus and Ae. japonicus by examining Pennsylvania mosquito and arbovirus surveillance data for the period between 2010 and 2018. Mosquitoes were primarily collected using gravid traps and BG-Sentinel traps, and sources of blood meals were determined by analyzing mitochondrial cytochrome b gene sequences amplified in PCR assays., Results: A total of 10,878,727 female mosquitoes representing 51 species were collected in Pennsylvania over the 9-year study period, with Ae. albopictus and Ae. japonicus representing 4.06% and 3.02% of all collected mosquitoes, respectively. Aedes albopictus was distributed in 39 counties and Ae. japonicus in all 67 counties, and the abundance of these species increased between 2010 and 2018. Models suggested an increase in the spatial extent of Ae. albopictus during the study period, while that of Ae. japonicus remained unchanged. We found a differential association between the abundance of the two mosquito species and environmental conditions, percent development, and median household income. Of 110 Ae. albopictus and 97 Ae. japonicus blood meals successfully identified to species level, 98% and 100% were derived from mammalian hosts, respectively. Among 12 mammalian species, domestic cats, humans, and white-tailed deer served as the most frequent hosts for the two mosquito species. A limited number of Ae. albopictus acquired blood meals from avian hosts solely or in mixed blood meals. West Nile virus was detected in 31 pools (n = 3582 total number of pools) of Ae. albopictus and 12 pools (n = 977 total pools) of Ae. japonicus., Conclusions: Extensive distribution, high abundance, and frequent interactions with mammalian hosts suggest potential involvement of Ae. albopictus and Ae. japonicus in the transmission of human arboviruses including Cache Valley, Jamestown Canyon, La Crosse, dengue, chikungunya, and Zika should any of these viruses become prevalent in Pennsylvania. Limited interaction with avian hosts suggests that Ae. albopictus might occasionally be involved in transmission of arboviruses such as West Nile in the region., (© 2022. The Author(s).)

Severe human arboviral diseases can be transmitted by the mosquito Aedes aegypti (Linnaeus), including dengue, chikungunya, Zika, and yellow fever. Adult control using spatial sprays with adulticides is recommended only when dengue outbreaks occur. In Argentina, mainly pyrethroids, like cis-permethrin, have been used as an adulticide, especially since 2008. The evolution and spread of resistance to insecticides is a major concern for vector control. This study reports for the first time pyrethroid resistance in Ae. aegypti adults from Argentina, in the city of Salvador Mazza (Salta). WHO discriminating doses of 0.75% were used for permethrin, 0.05% for deltamethrin, and 5% for malathion. Also the discriminating dose for cis-permethrin (0.6%) was calculated and evaluated for the first time. We found a resistance ratio 50 (RR50) of 10.3 (9.7-10.4) for cis-permethrin, which is considered as high resistance. Our results also indicated resistance to deltamethrin (22.6% mortality) and permethrin (53.6% mortality), and a total susceptibility to malathion (100% mortality). Results from this study highlight the importance of the correct use of insecticides within an Integrated Vector Management (IVM) approach and of early detection of resistance to enable Ae. aegypti control in Argentina. More studies are needed to determine the spread of mosquito resistance to pyrethroids., (© The Author(s) 2021. Published by Oxford University Press on behalf of Entomological Society of America.All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Zika virus (ZIKV) infection has caused severe unexpected clinical outcomes in neonates and adults during the recent outbreak in Latin America, particularly in Brazil. Congenital malformations associated with ZIKV have been frequently reported; nevertheless, the mechanism of vertical transmission and the involvement of placental cells remains unclear. In this study, we applied quantitative proteomics analysis in a floating explant model of chorionic villi of human placental tissues incubated with ZIKV and with ZIKV pre-adsorbed with anti-ZIKV envelope protein. Proteomic data are available via ProteomeXchange with identifier PXD025764. Altered levels of proteins were involved in cell proliferation, apoptosis, inflammatory processes, and the integrin-cytoskeleton complex. Antibody-opsonized ZIKV particles differentially modulated the pattern of protein expression in placental cells; this phenomenon may play a pivotal role in determining the course of infection and the role of mixed infections. The expression of specific proteins was also evaluated by immunoperoxidase assays. These data fill gaps in our understanding of early events after ZIKV placental exposure and help identify infection control targets., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Decades after its discovery in East Africa, Zika virus (ZIKV) emerged in Brazil in 2013 and infected millions of people during intense urban transmission. Whether vertebrates other than humans are involved in ZIKV transmission cycles remained unclear. Here, we investigate the role of different animals as ZIKV reservoirs by testing 1723 sera of pets, peri-domestic animals and African non-human primates (NHP) sampled during 2013-2018 in Brazil and 2006-2016 in Côte d'Ivoire. Exhaustive neutralization testing substantiated co-circulation of multiple flaviviruses and failed to confirm ZIKV infection in pets or peri-domestic animals in Côte d'Ivoire ( n =259) and Brazil ( n =1416). In contrast, ZIKV seroprevalence was 22.2% (2/9, 95% CI, 2.8-60.1) in West African chimpanzees ( Pan troglodytes verus ) and 11.1% (1/9, 95% CI, 0.3-48.3) in king colobus ( Colobus polycomos ). Our results indicate that while NHP may represent ZIKV reservoirs in Africa, pets or peri-domestic animals likely do not play a role in ZIKV transmission cycles.

During pregnancy, a series of physiological changes are determined at the molecular, cellular and macroscopic level that make the mother and fetus more susceptible to certain viral and bacterial infections, especially the infections in this and the companion review. Particular situations increase susceptibility to infection in neonates. The enhanced susceptibility to certain infections increases the risk of developing particular diseases that can progress to become morbidly severe. For example, during the current pandemic caused by the SARS-CoV-2 virus, epidemiological studies have established that pregnant women with COVID-19 disease are more likely to be hospitalized. However, the risk for intensive care unit admission and mechanical ventilation is not increased compared with nonpregnant women. Although much remains unknown with this particular infection, the elevated risk of progression during pregnancy towards more severe manifestations of COVID-19 disease is not associated with an increased risk of death. In addition, the epidemiological data available in neonates suggest that their risk of acquiring COVID-19 is low compared with infants (<12 months of age). However, they might be at higher risk for progression to severe COVID-19 disease compared with older children. The data on clinical presentation and disease severity among neonates are limited and based on case reports and small case series. It is well documented the importance of the Zika virus infection as the main cause of several congenital anomalies and birth defects such as microcephaly, and also adverse pregnancy outcomes. Mycoplasma infections also increase adverse pregnancy outcomes. This review will focus on the molecular, pathophysiological and biophysical characteristics of the mother/placental-fetal/neonatal interactions and the possible mechanisms of these pathogens (SARS-CoV-2, ZIKV, and Mycoplasmas) for promoting disease at this level., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Arthropod-borne viruses comprise a significant global disease burden. Surveillance and mitigation of arboviruses like Zika virus (ZIKV) require accurate estimates of transmissibility by vector mosquitoes. Although Aedes species mosquitoes are established as competent ZIKV vectors, differences in experimental protocols across studies prevent direct comparisons of relative transmissibility. An understudied factor complicating these comparisons is differential environmental microbiota exposures, where most vector competence studies use mosquitoes reared in laboratory tap water, which does not represent the microbial complexity of environmental water where wild larvae develop. We simulated natural larval development by rearing Californian Aedes aegypti larvae with microbes obtained from cemetery headstone water compared to conventional tap water. A. aegypti larvae reared in environmental cemetery water pupated 3 days faster and at higher rates. Mosquitoes reared in environmental water were less competent vectors of ZIKV than laboratory water-reared A. aegypti, as evidenced by significantly reduced infection and transmission rates. Microbiome comparisons of laboratory water- and environment water-reared mosquitoes and their rearing water showed significantly higher bacterial diversity in environment water. Despite this pattern, corresponding differences in bacterial diversity were not consistently observed between the respective adult mosquitoes. We also observed that the microbial compositions of adult mosquitoes differed more by whether they ingested a bloodmeal than by larval water type. Together, these results highlight the role of transient microbes in the larval environment in modulating A. aegypti vector competence for ZIKV. Laboratory vector competence likely overestimates the true transmissibility of arboviruses like ZIKV when conventional laboratory water is used for rearing. IMPORTANCE We observed that A. aegypti mosquitoes reared in water from cemetery headstones instead of the laboratory tap exhibited a reduced capacity to become infected with and transmit Zika virus. Water from the environment contained more bacterial species than tap water, but these bacteria were not consistently detected in adult mosquitoes. Our results suggest that rearing mosquito larvae in water collected from local environments as opposed to laboratory tap water, as is conventional, could provide a more realistic assessment of ZIKV vector competence since it better recapitulates the natural environment in which larvae develop. Given that laboratory vector competence is used to define the species to target for control, the use of environmental water to rear larvae could better approximate the microbial exposures of wild mosquitoes, lessening the potential for overestimating ZIKV transmission risk. These studies raise the question of whether rearing larvae in natural water sources also reduces vector competence for other mosquito-borne viruses.

Serological cross-reactivity has proved to be a challenge to diagnose Zika virus (ZIKV) infections in dengue virus (DENV) endemic countries. Confirmatory testing of ZIKV IgM positive results by plaque reduction neutralization tests (PRNTs) provides clarification in only a minority of cases because most individuals infected with ZIKV were previously exposed to DENV. The goal of this study was to evaluate the performance of a ZIKV/DENV DUO IgM antibody capture ELISA (MAC-ELISA) for discriminating between DENV and ZIKV infections in endemic regions. Our performance evaluation included acute and convalescent specimens from patients with real-time reverse transcription polymerase chain reaction (RT-PCR)-confirmed DENV or ZIKV from the Sentinel Enhanced Dengue Surveillance System in Ponce, Puerto Rico. The ZIKV/DENV DUO MAC-ELISA specificity was 100% for DENV (N = 127) and 98.4% for ZIKV (N = 275) when specimens were tested during the optimal testing window (days post-onset of illness [DPO] 6-120). The ZIKV/DENV DUO MAC-ELISA sensitivity of RT-PCR confirmed specimens reached 100% for DENV by DPO 6 and for ZIKV by DPO 9. Our new ZIKV/DENV DUO MAC-ELISA was also able to distinguish ZIKV and DENV regardless of previous DENV exposure. We conclude this novel serologic diagnostic assay can accurately discriminate ZIKV and DENV infections. This can potentially be useful considering that the more labor-intensive and expensive PRNT assay may not be an option for confirmatory diagnosis in areas that lack PRNT capacity, but experience circulation of both DENV and ZIKV.

The global spread of invasive mosquito species increases arbovirus infections. In addition to the invasive species Aedes albopictus and Aedes japonicus, Aedes koreicus has spread within Central Europe. Extensive information on its vector competence is missing. Ae. koreicus from Germany were investigated for their vector competence for chikungunya virus (CHIKV), Zika virus (ZIKV) and West Nile virus (WNV). Experiments were performed under different climate conditions (27 ± 5 °C; 24 ± 5 °C) for fourteen days. Ae. koreicus had the potential to transmit CHIKV and ZIKV but not WNV. Transmission was exclusively observed at the higher temperature, and transmission efficiency was rather low, at 4.6% (CHIKV) or 4.7% (ZIKV). Using a whole virome analysis, a novel mosquito-associated virus, designated Wiesbaden virus (WBDV), was identified in Ae. koreicus. Linking the WBDV infection status of single specimens to their transmission capability for the arboviruses revealed no influence on ZIKV transmission. In contrast, a coinfection of WBDV and CHIKV likely has a boost effect on CHIKV transmission. Due to its current distribution, the risk of arbovirus transmission by Ae. koreicus in Europe is rather low but might gain importance, especially in regions with higher temperatures. The impact of WBDV on arbovirus transmission should be analyzed in more detail.

Zika virus (ZIKV) is a flavivirus transmitted by mosquitoes of the genus Aedes , but unlike other flaviviruses, ZIKV can be sexually transmitted by vaginal intercourse. The healthy vaginal pH ranges from 4.0 to 6.0, reaching values of 6.0-7.0 after semen deposition. Here, we report that low extracellular pH values (range 6.2-6.6) dramatically increase ZIKV infection on cell lines of different origin including some derived from the female genital tract and monocyte-derived macrophages. Furthermore, low pH significantly increased ZIKV infection of human ectocervix and endocervix cultured ex-vivo. Enhancement of infection by low pH was also observed using different ZIKV strains and distinct methods to evaluate viral infection, i.e. plaque assays, RT-PCR, flow cytometry, and fluorescence microscopy. Analysis of the mechanisms involved revealed that the enhancement of ZIKV infection induced by low pH was associated with increased binding of the viral particles to the heparan sulphate expressed on the target cell surface. Acidosis represents a critical but generally overlooked feature of the female genital tract, with major implications for sexual transmission diseases. Our results suggest that low vaginal pH might promote male-to-female transmission of ZIKV infection.

ABSTRACT The two main Zika virus (ZIKV) vectors, Aedes albopictus and Aedes aegypti (invasive and native species, respectively), are present in Gabon (Central Africa). The aim of this study was to determine the entomological ZIKV risk associated with these mosquito species in Gabon by evaluating their vector competence for an African (i.e. representative of the endemic strains circulating in sub-Saharan Africa) and two Asian (i.e. representatives of exogenous epidemic strains that could be introduced) ZIKV strains. The transmission efficiency of one Ae. aegypti and two Ae. albopictus field-collected populations from Libreville and Franceville was assayed at day 7, 14 and 21 after experimental oral infection. The two mosquito species could transmit all three ZIKV strains already at day 7 post-infection, but transmission efficiency was higher for the African strain than the non-African strains (>60% versus <14%; incubation period of 14-21 days). The two mosquito species exhibited comparable vector competence for ZIKV, although the amount of viral particles (African strain) in saliva was significantly higher in Ae. albopictus than Ae. aegypti at day 14 post-infection. These findings suggest that overall, ZIKV risk in Gabon is mainly related to virus strains that circulate endemically across sub-Saharan Africa, although the transmission of non-African strains remain possible in case of introduction. Due to its high infestation indexes and ecological/geographical ranges, this risk appears mainly associated with Ae. albopictus . Vector surveillance and control methods against this invasive mosquito must be strengthened in the region to limit the risk of future outbreaks.

To date, no vaccines or antivirals are available against Zika virus (ZIKV). In addition, the mechanisms underlying ZIKV-associated pathogenesis of the central nervous system (CNS) are largely unexplored. Getting more insight into the cellular pathways that ZIKV recruits to facilitate infection of susceptible cells will be crucial for establishing an effective treatment strategy. In general, cells secrete a number of vesicles, known as extracellular vesicles (EVs), in response to viral infections. These EVs serve as intercellular communicators. Here, we investigated the role of EVs derived from ZIKV-infected human brain microvascular endothelial cells on the blood-brain barrier (BBB) system. We demonstrated that ZIKV-infected EVs (IEVs) can incorporate viral components, including ZIKV RNA, NS1, and E-protein, and further transfer them to several types of CNS cells. Using label-free impedance-based biosensing, we observed that ZIKV and IEVs can temporally disturb the monolayer integrity of BBB-mimicking cells, possibly by inducing structural rearrangements of the adherent protein VE-cadherin (immunofluorescence staining). Finally, differences in the lipidomic profile between EVs and their parental cells possibly suggest a preferential sorting mechanism of specific lipid species into the vesicles. To conclude, these data suggest that IEVs could be postulated as vehicles (Trojan horse) for ZIKV transmission via the BBB.

Background: Vector-borne pathogens must survive and replicate in the hostile environment of an insect's midgut before successful dissemination. Midgut microbiota interfere with pathogen infection by activating the basal immunity of the mosquito and by synthesizing pathogen-inhibitory metabolites., Methods: The goal of this study was to assess the influence of Zika virus (ZIKV) infection and increased temperature on Aedes albopictus midgut microbiota. Aedes albopictus were reared at diurnal temperatures of day 28 °C/night 24 °C (L) or day 30 °C/night 26 °C (M). The mosquitoes were given infectious blood meals with 2.0 × 10 8 PFU/ml ZIKV, and 16S rRNA sequencing was performed on midguts at 7 days post-infectious blood meal exposure., Results: Our findings demonstrate that Elizabethkingia anophelis albopictus was associated with Ae. albopictus midguts exposed to ZIKV infectious blood meal. We observed a negative correlation between ZIKV and E. anophelis albopictus in the midguts of Ae. albopictus. Supplemental feeding of Ae. albopictus with E. anophelis aegypti and ZIKV resulted in reduced ZIKV infection rates. Reduced viral loads were detected in Vero cells that were sequentially infected with E. anophelis aegypti and ZIKV, dengue virus (DENV), or chikungunya virus (CHIKV)., Conclusions: Our findings demonstrate the influence of ZIKV infection and temperature on the Ae. albopictus microbiome along with a negative correlation between ZIKV and E. anophelis albopictus. Our results have important implications for controlling vector-borne pathogens., (© 2021. The Author(s).)

Arthropod-borne viruses (arboviruses) require replication across a wide range of temperatures to perpetuate. While vertebrate hosts tend to maintain temperatures of approximately 37°C-40°C, arthropods are subject to ambient temperatures which can have a daily fluctuation of > 10°C. Temperatures impact vector competence, extrinsic incubation period, and mosquito survival unimodally, with optimal conditions occurring at some intermediate temperature. In addition, the mean and range of daily temperature fluctuations influence arbovirus perpetuation and vector competence. The impact of temperature on arbovirus genetic diversity during systemic mosquito infection, however, is poorly understood. Therefore, we determined how constant extrinsic incubation temperatures of 25°C, 28°C, 32°C, and 35°C control Zika virus (ZIKV) vector competence and population dynamics within Aedes aegypti and Aedes albopictus mosquitoes. We also examined fluctuating temperatures which better mimic field conditions in the tropics. We found that vector competence varied in a unimodal manner for constant temperatures peaking between 28°C and 32°C for both Aedes species. Transmission peaked at 10 days post-infection for Aedes aegypti and 14 days for Aedes albopictus. Conversely, fluctuating temperature decreased vector competence. Using RNA-seq to characterize ZIKV population structure, we identified that temperature alters the selective environment in unexpected ways. During mosquito infection, constant temperatures more often elicited positive selection whereas fluctuating temperatures led to strong purifying selection in both Aedes species. These findings demonstrate that temperature has multiple impacts on ZIKV biology, including major effects on the selective environment within mosquitoes., Competing Interests: The authors have declared that no competing interests exist.

Following the recent outbreak of Zika virus (ZIKV) infections in Latin America, ZIKV has emerged as a global health threat due to its ability to induce neurological disease in both adults and the developing fetus. ZIKV is largely mosquito-borne and is now endemic in many parts of Africa, Asia, and South America. However, several reports have demonstrated persistent ZIKV infection of the male reproductive tract and evidence of male-to-female sexual transmission of ZIKV. Sexual transmission may broaden the reach of ZIKV infections beyond its current geographical limits, presenting a significant threat worldwide. Several mouse models of ZIKV infection have been developed to investigate ZIKV pathogenesis and develop effective vaccines and therapeutics. However, the majority of these models focus on mosquito-borne infection, while few have considered the impact of sexual transmission on immunity and pathogenesis. This review will examine the advantages and disadvantages of current models of mosquito-borne and sexually transmitted ZIKV and provide recommendations for the effective use of ZIKV mouse models.

Dengue virus (DENV) and Zika virus (ZIKV) belong to the same viral family, the Flaviviridae. They cause recurring threats to the public health systems of tropical countries such as Brazil. The primary Brazilian vector of both viruses is the mosquito Aedes aegypti. After the mosquito ingests a blood meal from an infected person, the viruses infect and replicate in the midgut, disseminate to secondary tissues and reach the salivary gland (SG), where they are ready to be transmitted to a vertebrate host. It is thought that the intrinsic discrepancies among mosquitoes could affect their ability to deal with viral infections. This study confirms that the DENV and ZIKV infection patterns of nine Ae. aegypti field populations found in geographically separate health districts of an endemic Brazilian city vary. We analyzed the infection rate, disseminated infection, vector competence, and viral load through quantitative PCR. Mosquitoes were challenged using the membrane-feeding assay technique and were tested seven and fourteen days post-infection (early and late infection phases, respectively). The infection responses varied among the Ae. aegypti populations for both flaviviruses in the two infection phases. There was no similarity between DENV and ZIKV vector competencies or viral loads. According to the results of our study, the risk of viral transmission overtime after infection either increases or remains unaltered in ZIKV infected vectors. However, the risk may increase, decrease, or remain unaltered in DENV-infected vectors depending on the mosquito population. For both flaviviruses, the viral load persisted in the body even until the late infection phase. In contrast to DENV, the ZIKV accumulated in the SG over time in all the mosquito populations. These findings are novel and may help direct the development of control strategies to fight dengue and Zika outbreaks in endemic regions, and provide a warning about the importance of understanding mosquito responses to arboviral infections., Competing Interests: The authors have declared that no competing interests exist.

Species differences are among the main reasons for the high failure rate of preclinical studies. A better awareness and understanding of these differences might help to improve the outcome of preclinical research. In reproduction, the placenta is the central organ regulating fetal exposure to a substance circulating in the maternal organism. Exact information about placental transfer can help to better estimate the toxic potential of a substance. From an evolutionary point of view, the chorioallantoic placenta is the organ with the highest anatomical diversity among species. Moreover, frequently used animal models in reproduction belong to rodents and lagomorphs, two groups that are characterized by the generation of an additional type of placenta, which is crucial for fetal development, but absent from humans: the inverted yolk sac placenta. Taken together, the translatability of placental transfer studies from laboratory animals to humans is challenging, which is supported by the fact that numerous species-dependent toxic effects are described in literature. Thus, reliable human-relevant data are frequently lacking and the toxic potential of chemicals and pharmaceuticals for humans can hardly be estimated, often resulting in recommendations that medical treatments or exposure to chemicals should be avoided for safety reasons. Although species differences of placental anatomy have been described frequently and the need for human-relevant research models has been emphasized, analyses of substances with species-dependent placental transfer have been performed only sporadically. Here, we present examples for species-specific placental transfer, including that of nanoparticles and pharmaceuticals, and discuss potential underlying mechanisms. With respect to the COVID 19-pandemic it might be of interest that some antiviral drugs are reported to feature species-specific placental transfer. Further, differences in placental structure and antibody transfer may affect placental transfer of ZIKA virus., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: Zika fever has been a global health security threat, especially in the tropical and subtropical regions where most of the cases occur. The disease is caused by Zika virus (ZIKV), which belongs to the family Flaviviridae, genus Flavivirus. The virus is transmitted by Aedes mosquitoes, mostly by Aedes aegypti, during its blood meal. In this study we present a descriptive analysis, by transmission electron microscopy (TEM), of ZIKV infection in A. aegypti elected tissues at the 3rd day of infection. ZIKV vertical transmission experiments by oral infection were conducted to explore an offspring of natural infection., Results: Gut and ovary tissues harbored a higher number of viral particles. The ZIKV genome was also detected, by RT-qPCR technique, in the organism of orally infected female mosquitoes and in their eggs laid., Conclusions: The data obtained suggest that the ovary is an organ susceptible to be infected with ZIKV and that virus can be transmitted from mother to a fraction of the progeny., (© 2021. The Author(s).)

Zika virus (ZIKV) received worldwide attention over the past decade when outbreaks of the disease were found to be associated with severe neurological syndromes and congenital abnormalities. Unlike most other flaviviruses, ZIKV can spread through sexual and transplacental transmission, adding to the complexity of Zika pathogenesis and clinical outcomes. In addition, the spread of ZIKV in flavivirus-endemic regions, and the high degree of structural and sequence homology between Zika and its close cousin Dengue have raised questions on the interplay between ZIKV and the pre-existing immunity to other flaviviruses and the potential immunopathogenesis. The Zika epidemic peaked in 2016 and has affected over 80 countries worldwide. The re-emergence of large-scale outbreaks in the future is certainly a possibility. To date, there has been no approved antiviral or vaccine against the ZIKV. Therefore, continuing Zika research and developing an effective antiviral and vaccine is essential to prepare the world for a future Zika epidemic. For this purpose, an in-depth understanding of ZIKV interaction with many different pathways in the human host and how it exploits the host immune response is required. For successful infection, the virus has developed elaborate mechanisms to escape the host response, including blocking host interferon response and shutdown of certain host cell translation. This review provides a summary on the key host factors that facilitate ZIKV entry and replication and the mechanisms by which ZIKV antagonizes antiviral innate immune response and involvement of adaptive immune response leading to immunopathology. We also discuss how ZIKV modulates the host immune response during sexual transmission and pregnancy to induce infection, how the cross-reactive immunity from other flaviviruses impacts ZIKV infection, and provide an update on the current status of ZIKV vaccine development., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Lee, Komarasamy, Adnan, James and RMT Balasubramaniam.)

Mosquito bites transmit a number of pathogens via salivary droplets deposited during blood-feeding, resulting in potentially fatal diseases. Little is known about the genomic content of these nanodroplets, including the transmission dynamics of live pathogens. Here we introduce Vectorchip, a low-cost, scalable microfluidic platform enabling high-throughput molecular interrogation of individual mosquito bites. We introduce an ultra-thin PDMS membrane which acts as a biting interface to arrays of micro-wells. Freely-behaving mosquitoes deposit saliva droplets by biting into these micro-wells. By modulating membrane thickness, we observe species-dependent differences in mosquito biting capacity, utilizable for selective sample collection. We demonstrate RT-PCR and focus-forming assays on-chip to detect mosquito DNA, Zika virus RNA, as well as quantify infectious Mayaro virus particles transmitted from single mosquito bites. The Vectorchip presents a promising approach for single-bite-resolution laboratory and field characterization of vector-pathogen communities, and could serve as a powerful early warning sentinel for mosquito-borne diseases., (© 2021. The Author(s).)