Drought Likely Fueled Brazil's Urban Yellow Fever Outbreak, Says New Study

On August 14, a study in Science Advances revealed that a rare drought, occurring once every century, played a role in Brazil's first urban yellow fever outbreak in decades, which lasted from 2016 to 2018 and resulted in over 2,000 cases and nearly 750 fatalities. Conducted by Jamie Caldwell from Princeton University, the research utilized simulations to demonstrate how the drought affected the behavior of howler monkeys, marmosets, and mosquitoes, leading them to urban environments and increasing mosquito bites. The findings, which focused on data from Minas Gerais, identified Haemagogus mosquitoes as the primary vector of the outbreak, rather than Aedes aegypti. Experts highlighted the public health implications, emphasizing that drought conditions can provide crucial time for vaccine distribution. Yellow fever continues to pose a serious risk, causing between 67,000 and 173,000 severe infections each year.