Climate Change Could Worsen Future Enterovirus Outbreaks, Study Warns

A recent study highlights the potential impact of climate change on future enterovirus outbreaks, including hand, foot, and mouth disease (HFMD) and polio. Using data from 14 different climate models, researchers from Brown University, Princeton University, and Johns Hopkins University have examined how rising temperatures could influence the transmission of these diseases, which predominantly affect young children.

HFMD, known for causing fever and rash in children, typically occurs during the summer, similar to historic polio outbreaks in the United States. Both diseases are caused by enteroviruses, a large genus of RNA viruses. Despite their seasonal patterns, the underlying factors driving these outbreaks have remained unclear.

Published in Nature Communications, the study reveals that temperature plays a significant role in increasing enterovirus transmission. Rachel Baker, the John and Elizabeth Irving Family Assistant Professor of Climate and Health at Brown University and the study's first author, explained, "Even after controlling for other factors, we find that temperature appears to increase enterovirus transmission. Crucially, we see a similar-sized effect for polio historically and more recent enterovirus serotypes that cause HFMD."

Saki Takahashi, Assistant Professor of Epidemiology at Johns Hopkins University and co-author of the study, noted the spatial patterns of enterovirus outbreaks. "At higher latitudes, we see large outbreaks of HFMD every two or three years, but closer to the tropics, outbreaks occur twice a year. Our results are able to capture these large-scale patterns."

The researchers used an epidemiological model to demonstrate that both temperature and demographic factors, such as the timing of school semesters, explain the biannual HFMD outbreaks in southern China. In more northern regions, temperature plays a more dominant role, while the influence of school schedules diminishes.

"What really matters is the seasonal range of climate, specifically the maximum and minimum temperatures," said Wenchang Yang, Associate Research Scholar of Geosciences at Princeton University. "This has implications for how we think about the future effects of climate change on disease dynamics."

The study also found that climate change could increase the peak size of enterovirus outbreaks by up to 40%, although the effects vary depending on location and climate model. Enhanced surveillance of enterovirus circulation, such as through serological surveys, is crucial for tracking susceptibility and potential impacts.

Gabriel Vecchi, the Knox Taylor Professor of Geosciences and Director of the High Meadows Environmental Institute at Princeton University, emphasized the importance of understanding climate variability in relation to disease dynamics. "The impact of climate variability on disease dynamics is underexplored, and this study represents a significant advance in addressing this topic."

The findings underscore the need for improved public health strategies to mitigate the effects of climate change on infectious diseases, particularly for vulnerable populations like young children.