Understanding transmission risk and predicting environmental suitability for Mayaro Virus in the Americas

BackgroundMayaro virus (MAYV) is a mosquito-borne Alphavirus that is widespread in South America. MAYV infection often presents with non-specific febrile symptoms but may progress to debilitating chronic arthritis or arthralgia. Despite the pandemic threat of MAYV, its true distribution remains unknown. The objective of this study was to clarify the geographic distribution of MAYV using an established risk mapping framework. This consisted of generating evidence consensus scores for MAYV presence, modeling the potential distribution of MAYV across the Americas, and estimating at-risk population residing in areas suitable for MAYV transmission. MethodsWe compiled a georeferenced compendium of MAYV occurrence in humans, animals, and arthropods. Based on an established evidence consensus framework, we integrated multiple information sources to assess the total evidence supporting ongoing transmission of MAYV within each country in our study region. We then developed high resolution maps of the diseases estimated distribution using a boosted regression tree approach. Models were developed using ten climatic and environmental covariates that are related to the MAYV transmission cycle. Using the output of our boosted regression tree models, we estimated the total population living in regions suitable for MAYV transmission. FindingsThe evidence consensus scores revealed high or very high evidence of MAYV transmission in Brazil (especially the states of Mato Grosso and Goias), Venezuela, Peru, Trinidad and Tobago, Colombia, Bolivia, and French Guiana. According to the boosted regression tree models, a substantial region of South America is suitable for MAYV transmission, including north and central Brazil, French Guiana, and Suriname. Some regions (e.g., Guyana) with low or moderate evidence of transmission were identified as highly suitable for MAYV. We estimate that approximately 77 million people in the Americas live in areas that may be suitable for MAYV transmission, including 43{middle dot}4 million people in Brazil. Our results can assist public health authorities in prioritizing high-risk areas for vector control, human disease surveillance and ecological studies. FundingThis work was financially supported by the Armed Forces Health Surveillance Division--Global Emerging Infections Surveillance (AFHSD-GEIS) under awards P0065_22_WR and P0050_23_WR. The activities undertaken at WRBU were performed in part under a Memorandum of Understanding between the Walter Reed Army Institute of Research (WRAIR) and the Smithsonian Institution, with institutional support provided by both organizations.