Almost half of the world's population is at risk of acquiring dengue virus (DENV) each year. However, no specific licensed prophylactic or antiviral treatment for dengue currently exists. Mosnodenvir, a novel DENV inhibitor, has been shown to inhibit DENV replication in vitro and in animal studies. Here, we provide new insights into the in vivo prophylactic inhibitory effect of mosnodenvir exposure on primary DENV-2 infection by fitting mechanistic within-host models of DENV infection to virological and serological data observed from pre-clinical challenge studies in AG129 mice and rhesus macaques. We estimated a median mosnodenvir concentration achieving 50% of maximal inhibitory effect (IC50) on viral replication of 8.35 (6.82, 9.22) ng ml-1 and 7.61 (5.67, 8.92) ng ml-1 for AG129 mice and rhesus macaques, respectively. A higher concentration is typically required to suppress viral replication in AG129 mice compared with rhesus macaques owing to a higher estimated within-host basic reproduction number (R0) in mice. By integrating multiple data types in a single framework, this study enhances our understanding of the within-host dynamics of primary DENV infection in non-human host species. Furthermore, the methods developed here could possibly assist in quantifying the prophylactic inhibitory effect of mosnodenvir on DENV infections in humans.

BACKGROUND:Mexico, and the Americas region more widely, have experienced increased dengue incidence in recent years, and there are concerns that the changing climate may enhance dengue virus (DENV) transmission in the future. Whilst previous studies have characterised spatial heterogeneities in the long-term average risk of DENV infection in Mexico, the extent to which DENV transmission changes year-to-year has not been investigated. Furthermore, the extent to which DENV's four serotypes (DENV-1, DENV-2, DENV-3 and DENV-4) may differ in their transmissibility remains poorly characterised, both in Mexico and globally. METHODS AND FINDINGS:In this study, we characterised the spatial and temporal variations in DENV transmission intensity, as defined by the force of infection, across 27 states in Mexico. We analysed annual dengue case data reported to the National Epidemiological Surveillance System (SINAVE) in Mexico between 2016 and 2023, which comprised 833,629 probable or confirmed cases, using established catalytic models and a new, serotype-specific extension of these models that characterises differences in the transmission intensity of the different serotypes. We found evidence of large spatial, temporal, and serotype-specific heterogeneities in transmission intensity across Mexico. Serotype-specific force of infection estimates suggest that DENV-1 and DENV-2 have historically circulated at high levels across Mexico, with DENV-4 showing a low transmission intensity throughout the study period. We found evidence of increasing DENV-3 transmission intensity across some states in recent years, coinciding with large outbreaks. The extent to which the serotype-specific transmission intensity estimates generated in this study are affected by potential heterogeneities in case reporting across states and through time remains to be validated in future studies. CONCLUSIONS:This work quantifies serotype-specific differences in DENV transmission intensity using routinely collected case-notification data and demonstrates how extensive RT-PCR testing and new rapid diagnostic tests capable of discerning infecting serotypes can help to better understand the contributions of different serotypes to DENV transmission. The methods developed in this study contribute to the development of a better understanding of the past and current burden of dengue infection, which can help to refine assessments of the potential impact of existing and new interventions in future analyses.

The increasing geographical spread, abundance and activity of invasive Aedes mosquitoes are cause of concern for public health at local and global scales. These species transmit diseases such as dengue, Chikungunya, Yellow Fever, and Zika, which can cause outbreaks in endemic and non-endemic settings. Unlike temperature, whose impact on key entomological traits has been extensively studied, the impact of water availability on Aedes traits and hence population dynamics has been largely overlooked. This scoping review aims to fill this gap by compiling the published laboratory evidence of the effect of precipitation and water availability on the bionomics of invasive Aedes species (including Ae. albopictus, Ae. aegypti, Ae. japonicus, and Ae. koreicus). We found eleven studies investigating the effect of water availability on the bionomics of invasive Aedes mosquitoes, none of which were conducted with Ae. japonicus or Ae. koreicus. The effect of rainfall intensity and duration on the survival and development of Ae. albopictus and Ae. aegypti was investigated by three studies, which showed that heavy and long-lasting precipitation leads to higher immature mortality in both species. The impact of water availability on the survival to adulthood, development, and oviposition behaviour of Ae. albopictus and Ae. aegypti was explored by seven studies. The studies reported higher survival and faster development in water volumes below 2 litres, and that the amount of water contained can favour oviposition, with females laying significantly more eggs in containers that are half full compared to those that are full. An additional two studies explored the relationship between evaporation and adult survival and body size of Ae. albopictus and Ae. aegypti. Evaporation was found to have a detrimental effect on the survival and egg hatching of Ae. albopictus, but not of Ae. aegypti. Interestingly Ae. albopictus was also found to have bigger body sizes when exposed to evaporation. This review provides a summary of the experimental evidence currently published on the effect of water availability on invasive Aedes traits, and highlights how key research questions and knowledge gaps still remain. These should be addressed by future experiments to be able to generate data-driven predictions of the geographical expansion of these species under changing rainfall patterns, and the potential impact of containment strategies.

BackgroundDengue incidence has increased sharply worldwide, placing nearly half of the global population at risk. In response, various innovative technologies and interventions, including biocontrol strategies that deploy Wolbachia-infected mosquitoes, are being explored. These can be used to either replace the existing mosquito population with one that is less likely to transmit infection or to suppress the existing mosquito population. We conducted a scoping review of economic evaluations of Wolbachia-based interventions for dengue control, aimed at summarising assumptions and results of existing studies.Methodology/principal findingsA scoping review of the published literature was conducted on the 29th of April 2024 using the MEDLINE (via OVID), Embase Classic+Embase (via OVID), Global Health - OVID, PubMed, and Econ Lit electronic databases. No date or language restrictions were applied to the searches. We identified nine studies that reported the results of economic evaluations of Wolbachia-based interventions for dengue control. The majority (eight out of nine studies) investigated Wolbachia replacement-based programmes. Overall, the results were supportive for the use of replacement-based programmes in large urban settings, with the intervention likely to generate cost savings from a societal perspective.Conclusions/significance.The available economic evaluations consistently suggest that Wolbachia-based replacement interventions can be cost-effective for dengue control when targeted to densely populated urban areas, and several studies indicate that they can generate substantial long‑term cost savings from a societal perspective. Further research is needed to understand how heterogeneity in epidemiological effectiveness influences long-term projected cost‑effectiveness and to investigate the combination of Wolbachia-based interventions with other dengue control/prevention measures (such as vaccination). To support more robust and comparable analyses, we provide recommendations for future studies in this area, emphasising the importance of reporting results disaggregated by cost and outcome components, and making important underlying assumptions related to the intervention more explicit.

BACKGROUNDWest Nile virus (WNV) is a zoonotic mosquito-borne pathogen increasingly reported in Europe.AIMWe aimed to characterise heterogeneities in the average annual human risk of WNV infection (force of infection, FOI) and in WNV surveillance across Europe.METHODSWe conducted a systematic review following the PRISMA guidelines to identify serological studies on WNV in humans with IgG-based assays in Europe. We then used mathematical models fitted to both age-stratified serosurvey and case data to reconstruct spatially explicit FOI estimates, the sensitivity of syndromic surveillance and age-dependent trends in case reporting.RESULTSWe extracted 92 serosurvey datasets from 21 countries. Based on 10 age-stratified serosurvey datasets from Greece, Hungary, Italy, Romania and Spain and case data from seven countries (Austria, Cyprus, Greece, Hungary, Italy, Romania and Spain), we estimated the WNV FOI for 119 European nomenclature of territorial units for statistics level (NUTS) 0-3 regions. We found evidence of spatial heterogeneities in transmission intensity and estimated that on average less than 0.2% of human WNV infections were notified, with country variability and age-dependent trends in the propensity of reporting WNV disease.CONCLUSIONThis study shows that the intensity of WNV transmission, the average annual incidence of infection and the sensitivity of surveillance are heterogeneous across Europe. Due to differences in case reporting across countries, the incidence of reported WNV cases does not necessarily reflect the same proportion of WNV infections and hence the actual infection incidence, which highlights the importance of conducting WNV seroprevalence surveys.

Abstract BACKGROUND West Nile virus (WNV) is a growing health burden in Italy. Anticipating human infection risk is hampered by the pathogen’s complex ecology, highlighting the need for comprehensive early-warning tools. AIM We aimed to model municipal-level WNV risk in Italy and characterize its decadal expansion in Italy, providing a comprehensive ecological understanding of viral emergence. METHODS We applied a machine learning framework to annual human WNV case data from 2014 to 2024. The model integrated a suite of environmental, socio-economic, and macroecological predictors to generate risk projections. We evaluated the model’s performance through multiple validation settings. We also performed an anticipation test for the 2025 epidemic season, using 2024 environmental data to assess the model’s predictive accuracy against observed 2025 human cases. RESULTS Our model achieved robust performance (True Skill Statistic > 0.4) and captured WNV progressive expansion from 184 predicted positive municipalities in 2014 to 2,012 in 2024 (an 11-fold increase in 11 years). Seasonal minimum temperature was the primary risk driver, followed by monitoring year and population density, indicating active spatial spread. Environmental suitability consistently preceded clinical detection. Municipalities with cases in 2023–2024 exhibited significantly higher predicted suitability during 2018–2022 than those without cases (average risk 0.58 vs 0.20). Our model successfully identified emerging risk hotspots along the Adriatic coast and southern Italy before the official human spillover of 2025. CONCLUSION Embedding macroecological drivers into WNV risk modelling provides an improved understanding of drivers of rapid WNV expansion. Our model enables proactive risk mapping, surveillance efforts, and targeted public health measures.

Background: Dengue is highly endemic in many tropical and subtropical regions, including Thailand. As no specific treatment is available, vaccination is an important preventive strategy. The Qdenga (TAK-003) live-attenuated quadrivalent dengue vaccine is recommended by the World Health Organization for routine immunisation programmes in high-transmission settings with substantial disease burden. However, an independent country-specific economic evaluation is needed before inclusion in Thailand's National Immunization Program. This study evaluated the cost-effectiveness and budget impact of Qdenga vaccination strategies in Thailand. Methods: Cost-utility and budget impact analyses were conducted using a previously developed dengue transmission model. Qdenga vaccination scenarios, varying by vaccination age, vaccine mode of action (protection against disease only or against both disease and infection), and duration of waning (5 or 10 years), were compared with a no vaccination comparator. Costs and health outcomes, measured in quality-adjusted life years (QALYs), were projected over a 30-year time horizon. Findings: A national vaccination programme cumulatively targeting 15 million children aged 6 years could prevent 1·7 million symptomatic dengue cases and 382,000 hospitalisations. In the base-case analysis, routine vaccination targeting 6-year-olds would generate incremental costs of US$1,186 million and gain of 41,169 QALYs, resulting in an ICER of US$30,458/QALY. This exceeds Thailand's cost-effectiveness threshold (US$4,739/QALY) and yields an incremental net monetary benefit of –US$996 million. The annual government budget impact over the first five years was estimated to vary between US$66·4–70·9 million. Interpretation: Qdenga vaccination could substantially reduce symptomatic dengue cases and hospitalisations in Thailand. However, at its current price, the programme is unlikely to be cost-effective and would have a considerable budget impact. Price negotiation is therefore recommended before inclusion in the national immunisation programme.

Global climate models (GCMs) are essential tools for understanding the climate system and projecting its evolution under different scenarios. However, differences in model construction introduce uncertainties, and GCMs have coarse resolution and inherent biases, limiting their effectiveness for informing local or regional adaptation and mitigation planning. We apply the statistical Double Bias-Corrected Constructed Analogues (DBCCA) method to generate bias-corrected and downscaled climate projections at daily and 0.1° spatial resolution for 1985–2100, with a specific focus on supporting tropical health-related impact research. Our quasi-global, high-resolution projections are based on six GCMs from Phase 6 of the Coupled Model Intercomparison Project (CMIP6) under two emission scenarios (SSP2-4.5 and SSP5-8.5), covering 12 land-only domains between 60°N and 60°S. Moreover, many impact researchers rely on accessible data aggregated to administrative units, often weighted by population, rather than gridded data, as these align more directly with policy- and decision-making. Based on our projections, we also provide user-ready (population-weighted) spatially aggregated climate variables at administrative unit levels (0–2) for 104 countries prioritized for tropical disease research.

Dengue severity prediction models are usually developed using hospitalized patient data, but triage and hospital admission are mainly evaluated in outpatient settings. This study developed models using clinical and laboratory data from patients in outpatient settings during the febrile phase. Data from two cohort studies in Vietnam and Thailand were used to develop and validate six models: logistic regression with warning signs, Lasso-selected logistic regression, random forest, extreme gradient boosted classification, support vector machine, and artificial neural network. Models predicted dengue shock syndrome (DSS) as the primary endpoint and moderate plasma leakage and/or DSS as the secondary endpoint. We assessed model performance, discrimination, and calibration, using sensitivity, specificity, accuracy, Brier score, AUROC, CITL, calibration slope, calibration plots, and decision curve analysis. The optimal model was the Lasso-selected logistic regression for predicting DSS and the combined endpoint of moderate plasma leakage and/or DSS (Brier score: 0.044 [95% CI 0.043, 0.044] and 0.104 [95% CI 0.104, 0.105]; AUROC: 0.789 [95% CI 0.787, 0.791] and 0.741 [95% CI 0.740, 0.742]). We identified hematocrit, platelet count, lymphocyte count, and aspartate aminotransferase as predictors for DSS, and abdominal pain or tenderness, vomiting, mucosal bleeding, white blood cell count, lymphocyte count, platelet count, aspartate aminotransferase, and serum albumin as predictors for the secondary endpoint. Logistic regression and machine learning models using clinical and laboratory data during the febrile phase can support early prediction of severe disease in outpatient settings. Integrating risk prediction models into a decision support system could improve triage and optimize healthcare and resource allocation in endemic and resource-limited areas.

Abstract Dengue virus is a severe threat to global health. Novel vaccine and Wolbachia technologies offer a potential path to dengue control; however, it remains unclear how to use these approaches in tandem. Using metapopulation transmission models, we simulated future dengue burden in Brazil. We estimated that w Mel releases in 300 municipalities could avert 12-22% of cases over the next 10 years, while a national vaccination campaign could avert 8-10% of cases in the total population and 39-45% within the vaccinated cohort. Projecting forward 40 years, we found w Mel releases would drive up the mean age of cases beyond increases due to the ageing population and increase population susceptibility to dengue. Finally, w Mel releases can help mitigate the future burden in southern Brazil where climate change is rapidly increasing dengue virus risk. These findings highlight the need to consider the two technologies in parallel to optimise efforts to combat future dengue burden.

Background Culex pipiens is the primary vector of West Nile virus (WNV) and Usutu virus (USUV) in Europe. Despite modelling studies suggest that global warming can facilitate WNV and USUV transmission in the European Mediterranean region, to date limited quantitative data on the effects of temperature on the longevity and reproductive traits of European Cx. pipiens mosquitoes have been generated. Methods We conducted a scoping review to identify existing data on how constant temperature affects Cx. pipiens longevity and reproductive traits, including fecundity and gonotrophic cycle length. To address key knowledge gaps, we carried out controlled laboratory experiments using field-derived Cx. pipiens reared from larvae collected in northern Italy. Female mosquitoes were kept at four constant temperatures (12°C, 25°C, 28°C, and 31°C), provided with blood meals, and monitored over time for survival and oviposition until death. Results The scoping review showed that the current evidence base is limited, with only five relevant studies identified. We also found evidence that life-history traits differ between laboratory colonies and field populations across geographic contexts. In our experiments, mosquito longevity declined monotonically with increasing temperature between 25 and 31°C, ranging from 62 to 33 days on average. Egg-laying rates peaked at 28°C, with reproductive traits showing substantial individual and seasonal variation and no clear temperature relationship. No mosquito completed more than one gonotrophic cycle. At 12°C, blood-fed females survived three months without further blood feeding or oviposition. Conclusions Our study integrates context-specific knowledge on how constant temperature affects Cx. pipiens longevity and reproduction and fills an important knowledge gap by providing experimental data based on field-collected European mosquitoes. We also provide preliminary evidence that seasonality, in addition to temperature, may influence mosquito reproduction. Importantly, field-collected, non-diapausing, blood-fed females appear to enter a state of quiescence at low temperatures, suggesting a potential overwintering mechanism for arboviruses. Together, these findings improve our understanding of Cx. pipiens biology and have implications for WNV and USUV transmission in European settings.

Zika virus (ZIKV), classified as a priority pathogen by the World Health Organization, is an Aedes-borne arbovirus that can cause neurological complications and birth defects in newborns of mothers infected during pregnancy. We conducted a systematic review of peer-reviewed studies reporting ZIKV epidemiological parameters, transmission models and outbreaks (PROSPERO CRD42023393345) to characterize its transmissibility, seroprevalence, risk factors, disease sequelae and natural history. We performed meta-analyses of the proportions of congenital Zika syndrome, pregnancy loss among ZIKV-infected mothers and symptomatic cases. We extracted information from 574 studies. Across 418 included studies assigned a high-quality score, we extracted 969 parameters, 127 outbreak records and 154 models. Using random-effects models, we estimated proportions of congenital Zika syndrome (4.65%, 95% confidence interval (CI): 3.38-6.67%), pregnancy loss (2.48%, 95% CI: 1.62-3.78%) and symptomatic cases (51.20%, 95% CI: 38.00-64.23%). Seroprevalence estimates (n = 354) were retrieved beyond South America and French Polynesia. Basic reproduction number estimates (n = 77) ranged between 1.12 and 7.4. We found 66 human epidemiological delay estimates, including the intrinsic incubation period (n = 11, range: 4-12.1 days), infectious period (n = 15, range: 3-50 days), extrinsic incubation period (n = 22, range: 5.1-24.2 days) and serial interval (n = 27, range: 7.4-32.9 days). These data are available in the R package 'epireview' (version 1.4.5). We provide a comprehensive systematic summary of ZIKV epidemiology, revealing large heterogeneities and inconsistencies in the reporting of parameter estimates, study designs and parameter definitions and underscoring the need for standardized epidemiological definitions.

Background: The recent licensure of the TAK-003 dengue vaccine, and advances in vector management provide new opportunities for dengue control. To evaluate their local impact, it is necessary to characterise dengue virus (DENV) transmission intensity. Age-stratified case-notification data from routine surveillance can help estimate transmission intensity over time and space, revealing hidden infection burden and transmission hotspots, even in areas with unequal surveillance or healthcare access. Methods: We applied time-constant and time-varying catalytic models to age-stratified dengue incidence data (2017-2024) across Sri Lankan districts, to characterise heterogeneities in the Force of Infection (FOI), the per-capita annual risk of infection for a susceptible person. We reconstructed the sensitivity of surveillance by estimating the proportion of infections reported and also explored associations between the FOI and climatic and socioeconomic factors using spatiotemporal regression models within the Integrated Nested Laplace Approximations (INLA) framework. Findings: FOI estimates and reporting rates were highly heterogeneous across the country, with the estimated seroprevalence at age 9 years ranging from 7.9% (95% Credible Interval CrI: 6.0, 10.0%) in Polonnaruwa to 46.4% (95%CrI: 37.1, 55.5%) in Jaffna. In the multivariable analysis no climatic or socioeconomic variable showed a statistically significant association with the dengue yearly average FOI, after adjustment for spatial and temporal random effects. Interpretation: These results suggest that the dengue FOI and the sensitivity of surveillance are highly heterogeneous across Sri Lanka and the introduction of the TAK-003 dengue vaccine needs to be carefully evaluated. Wellcome Trust Grant Number(s): 213494/Z/18/Z, 226072/Z/22/Z, 226727/Z/22/Z and 228185/Z/23/Z Data Availability Statement: The code and the Shinyapp to estimate the dengue FOI are available at https://github.com/mrc-ide/SriLanka_FOI/ together with a simulated dataset of the Sri Lanka number of cases by year, district and age-group. The reported case-notification data collected by the Ministry of Health of Sri Lanka can be accessed upon request. Requests should be addressed to the National Disease Control Unit which can be contacted at ndcu2010@yahoo.com

Background:Panama is a dengue endemic country which experienced a large outbreak in 2024 with over 32,000 reported cases and an incidence rate exceeding 700 cases per 100,000 inhabitants. Despite decades of circulation, the epidemiology of dengue and its heterogeneity in transmission intensity across Panama have not yet been characterised. Methods:We used 25 years of dengue case notification and population data from across Panama's 16 health regions and 82 districts to characterise dengue epidemiology and transmission intensity in the country. The analytic dataset comprised 128,890 dengue cases, of whom 52% were female and 48% were male; the mean age was 32.4 years (range 0-108 years). Ethnicity data are not collected in Panama's national dengue surveillance system and were therefore unavailable for this analysis. We characterised spatial heterogeneities in delay distributions by fitting parametric probability distributions to epidemiological delays, and demographic differences in the incidence risk ratio of dengue, and of dengue attributable hospitalisations and deaths. We also implemented catalytic models to infer the time-constant dengue force-of-infection (FOI) (i.e. the long-term average annual per capita risk of infection for a susceptible individual) from the age-stratified case notification data reported across Panama during 2000-2024 and explored age- and sex-related differences in dengue case reporting in sensitivity analyses. Findings:We observed spatial variation in delay distributions across health regions. The mean of the regional average time from symptoms onset to (i) reporting was 4.78 days (95% CI: 4.72-4.84 days), (ii) hospitalisation was 4.49 days (95% CI: 4.22-4.76), and (iii) recovery was 7.82 days (95% CI: 6.47-8.85 days). The dengue transmission intensity also showed spatial heterogeneity, with a mean regional per-serotype FOI of 0.008 (95% CrI: 0.004-0.015). The mean regional probability of detecting a secondary case was 0.415 (95% CrI: 0.233-0.871) and the probability of detecting a primary case relative to a secondary case was 0.131 (95% CrI: 0.049-0.348). We found evidence of age- and sex-related differences in dengue reporting. Given the estimated seroprevalence at nine years (obtained from the analysis of case-notification data) is below 40% across the whole country, dengue vaccination with TAK-003 is currently not recommended in Panama according to the WHO guidelines. In the future, age-stratified seroprevalence surveys would be useful to validate these estimates. Interpretation:This analysis provides a characterisation of dengue epidemiology and estimates of dengue FOI and infection burden in Panama across the last 25 years. This work will inform policy decisions at the Ministry of Health of Panama, providing guidance on resource allocation to strengthen the local surveillance system and to decision making on the potential implementation of new interventions. Funding:SENACYT-IFARHU (Panamá), UK Medical Research Council and Wellcome Trust.

Dengue, a vector-borne disease caused by the dengue virus, has emerged as a global public health concern, given the tenfold rise in reported cases over the last two decades. In light of the upcoming dengue interventions, country-specific cost-of-illness estimates are required to evaluate the cost-effectiveness of new interventions against dengue. This study aims to conduct an updated systematic review of dengue cost-of-illness studies, extracting the relevant data, and conducting regression analysis to explore potential factors contributing to the cost variations among countries. We used the MEDLINE, EMBASE, PubMed, and Web of Science databases to systematically search for published dengue cost-of-illness studies reporting primary data on costs per dengue episode. A descriptive analysis was conducted across all extracted studies. Linear regression analysis was performed to investigate the association between the GDP per capita and cost per episode. The quality of the included studies was also assessed. Fifty-six studies were included, of which 22 used the societal perspective. The reported total cost per episode ranged from 15.0 for outpatients in Burkina Faso to9,386.1 for intensive care unit patients in Mexico. Linear regression analysis revealed that the cost of dengue illness varies significantly across countries and regions, and was positively related to the setting’s GDP per capita. The quality assessment demonstrated that improvements are needed in future studies, particularly in the reporting of the methodology. Cost of dengue illness varies widely across countries and regions. Future research should focus on understanding other drivers of cost variations beyond GDP per capita to improve the cost estimates for economic evaluation studies. The results presented in this study can serve as crucial input parameters for future economic evaluations, supporting decision makers in allocating resources for dengue intervention programmes.

BackgroundWest Nile Virus (WNV) is a zoonotic arbovirus maintained in a transmission cycle between Culex mosquitoes and birds, occasionally spilling over into humans. The impact of avian biodiversity on WNV circulation remains debated, with studies reporting both negative and positive correlations (dilution and amplification effects respectively) across different settings. In Europe, this relationship remains largely unexplored, particularly in regions with high WNV transmission, such as Emilia-Romagna in Northern Italy.MethodsWe explored the association between avian biodiversity and WNV circulation in Culex mosquitoes in Emilia-Romagna using 11 years (2013-2023) of entomological surveillance data paired with two avian data sources. We calculated avian biodiversity indices (Shannon's, Simpson's, and Chao2) from observation records from the Farmland Bird Index project and applied linear regression models to assess their relationship with WNV detection frequency. Moreover, we used Bayesian spatiotemporal regression models and gridded weekly avian abundance estimates from the eBird project to analyse the associations between avian species richness indices and WNV transmission risk quantified by vector index (VI) at 68 geolocated mosquito traps across the region.ResultsWe observed consistent negative associations between WNV detection frequency in the Culex population and avian biodiversity indices, supporting the dilution effect hypothesis (DEH). We found that non-passerine species richness was negatively associated with VI while passerine species richness showed a positive association after adjusting for covariates and spatial random effects. These findings suggest that passerines may amplify WNV transmission, whereas the presence of non-passerine species is associated with reductions in WNV circulation.SignificanceThis study provides the first empirical evidence supporting the DEH for WNV in Europe. These findings have important implications for biodiversity conservation and integrated public health surveillance activities across Europe.

Oropouche virus (OROV) spread across the Americas in 2024, yet Panama’s Darién migration corridor saw no outbreak until nearly a year after Brazil’s January 2024 peak, raising two hypotheses: cryptic circulation masked by diagnostic gaps, or recent introduction under permissive climatic conditions. Here we resolve this paradox using integrated clinical, genomic, and climate-informed surveillance. Among 1,040 individuals tested, 43% were OROV-positive and showed a clinical signature distinct from co-circulating arboviruses, including headache more frequent than in dengue (RR 2.38, 95% CI 1.74-3.24). The household secondary attack rate was 56%, and waste burning independently predicted infection. Phylogeographic reconstruction identified a single recent introduction in October 2024 with no evidence of adaptive evolution, excluding prolonged cryptic persistence. Climate-informed models indicate broad outbreak susceptibility across Panama, with Bocas del Toro and Los Santos as the next highest-risk provinces. These findings identify a Central American foothold for OROV with potential for further northward spread.

Context. The relationship between biodiversity and zoonotic disease risk is a central topic in community ecology, yet empirical evidence in Europe remains scarce and often contradictory compared to North American studies. Addressing this gap is fundamental to better anticipate zoonotic disease dynamics. Objectives. We investigated the transmission dynamics of West Nile virus (WNV) in Veneto (Italy), a major European hotspot. Because this vector-borne pathogen is primarily transmitted by Culex mosquitoes and maintained by several avian hosts, we analysed how multiple facets of both avian and mosquito biodiversity influence its transmission. Methods. Using Generalized Additive Models (GAMs) trained on longitudinal entomological and ornithological surveillance data, we modelled the probability of WNV presence in mosquito pools as a function of host and vector community structure. To isolate the effects of biodiversity, we explicitly controlled for climatic and landscape covariates. Results. In agricultural landscapes, we found that higher avian diversity leads to higher viral presence, driven by the dominance of highly competent synanthropic hosts. Conversely, a dilution effect emerges across the broader regional landscape where areas of higher ecological integrity allow for more complex and functionally diverse avian communities. Furthermore, we identified significant vector-mediated regulation, where high abundances of mammophilic vectors effectively suppress viral prevalence through larval competition. Conclusions. Our findings suggest that the dilution effect is a property of intact ecosystems which can be lost, or even locally reversed, in anthropogenically altered environments. Because such habitat degradation fundamentally alters zoonotic transmission dynamics, landscape planning must prioritize ecological restoration. Ultimately, embedding these practices into One Health strategies represents a proactive approach to mitigating disease emergence.

Introduction: A limited number of dengue seroprevalence surveys have been conducted across Africa, with only 21 studies reported to date. Implementing new surveys to assess dengue transmission can be costly, time-consuming and resource intensive. In SERODEN we developed new simulation-based methods to calculate the optimal number and age-distribution of existing blood samples –collected in the context of previous household and community-based surveys, most notably against SARS-CoV-2 – to be tested for dengue. We used three different assays, namely the enzyme-linked immunosorbent assay (ELISA) IgG type 1-4, ELISA IgG NS1 type 1-4 and Plaque Reduction Neutralization Test (PRNT) for the 4 dengue serotypes, to characterise age-specific seroprevalence and dengue transmission intensity in 19 locations across Senegal, the Democratic Republic of the Congo (DRC), and Ghana. Method: We designed a simulation-based framework to inform serosurvey design when leveraging existing blood samples. We also developed a Bayesian approach to combine the results obtained from the different assays in unifying age-stratified seroprevalence and force of infection estimates, estimating and accounting for the tests’ specificity and sensitivity. Results: Our simulation-based framework identified the optimal sample sizes and age-distribution of the available blood samples, and overall, we reduced the total number of samples required for testing by 20%. The age-group prioritised for testing depended on the expected transmission intensity, with younger age-groups targeted for testing in high transmission settings. By combining multiple tests, including IgG ELISA type 1-4, ELISA IgG NS1, and PRNTs, we were able to quantify the specificity and sensitivity of each test and the dengue transmission in different African settings. Discussion: Our results unveiled significant heterogeneity in dengue transmission both within and across countries and underscored the endemic nature of dengue transmission in Senegal, DRC, and Ghana. The methods developed in the SERODEN study demonstrates the feasibility and benefits of utilising existing blood samples for the implementation of dengue serosurveys. Conclusion: By leveraging existing resources and combining different tests, we can provide valuable insights into dengue transmission intensity in Africa, which sheds new light on the dengue infection burden and can help inform dengue surveillance.

Introduction: In the context of the ongoing global SARS-CoV-2 pandemic and potential future viral epidemics, seroepidemiological studies are essential for understanding epidemic dynamics. Panama, a country with a strategic geographic position that serves as a regional hub for international travel and commerce. As such, understanding local transmission patterns is critical for developing evidence based on interventions that can effectively anticipate and mitigate emerging viral threats. Methodology: We conducted a population based cross sectional study in the provinces of Panama and Panama Oeste, targeting the 10 townships with the highest cumulative COVID 19 incidence. A multistage cluster sampling strategy was employed using the 2010 National Housing Framework. The first survey was conducted from November 30 to December 4, 2020. A follow-up survey was carried out from June 14 to July 10, 2021, to assess seroconversion and seroreversion. Serum samples were analyzed using two electrochemiluminescence immunoassays (Cobas and Vitros) to detect SARS-CoV-2-specific IgG, IgM, and IgA. We estimated the effective reproduction number (Rt) and fitted modified Poisson regression models to identify risk factors associated with seropositivity. Results: A total of 2198 participants were recruited in the first round, and 547 were successfully followed up in the second round. SARS CoV 2 seroprevalence increased from 24.7% (95% CI: 23.0 to 27.0%) in the first round to 66.2% (95% CI: 62.0 to 70.0%) in the second. The seroconversion rate was 42.9% (95% CI: 38.0 to 47.0%), while seroreversion was rare (0.9%; 95% CI: 0.3 to 2.0%). The most parsimonious multivariable model identified Indigenous ethnicity, contact with a confirmed case, cohabiting with an infected household member, and prior COVID-19 diagnosis as significant risk factors for seropositivity. In contrast, higher education, belonging to other ethnic groups, and consistent mask use at work were protective factors. Conclusions: SARS-CoV-2 transmission persisted in Panama despite strict public health interventions. Household transmission, particularly among Indigenous and socioeconomically vulnerable populations, was a major driver of infection. Higher education and adherence to preventive behaviors emerged as protective factors. These findings emphasize the importance of targeted, equity focused strategies to strengthen epidemic control in Panama and comparable settings. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement Clarendon Scholarship from the University of Oxford and the Lincoln-Kingsgate Scholarship from Lincoln College, University of Oxford [grant number SFF1920\_CB2\_MPLS_1293647]. This work was supported by SENACYT [grant number FID-COVID19-080], #TodoPanama, and Global.health consortium, grant to JPC. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study protocol was reviewed and approved by the Panamanian Ministry of Health [1522] and the National Bioethics Committee [PT-023]. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors