Seasonal variations in dengue virus transmission suitability in the Americas

Abstract

Dengue fever (DF) is associated with significant morbidity across the tropics and sub-tropics. Here, we used a temperature-based model of the extrinsic incubation period (EIP) and a temperature and humidity-based model for adult mosquito survival to explore the relationship between seasonal climate variability and DF in Brazil from 2014 to 2019. We found that municipalities with higher mosquito survival probabilities and shorter EIPs were more likely to be associated with DF case reports, but with significant intra-annual variability. A 0.012 or above probability of Aedes aegypti surviving the EIP was associated with a greater than 50% probability of DF being reported in the municipality. We extrapolated these results to the Americas using climate data over the last decade (2010-2019) to map the seasonal change in the range of areas suitable for dengue virus transmission and the magnitude of the population living in those areas. Areas near the Equator exhibited high suitability throughout the year whereas suitability in the subtropics and temperate regions varied seasonally, especially moving poleward. Strengthening our understanding of DF seasonality is essential to mitigating risks, particularly as the Americas experience the impacts of climate change.