Warming temperatures could expose more than 1.3 billion new people to Zika virus risk by 2050

Global Change Biology

An artists depiciton of Zika virus particles Corresponding author: Sadie Ryan, sjryan@ufl.edu

Summary by Ethan Hackmeyer

Zika virus is a tropical arbovirus that causes serious illness, infecting thousands of people every year. Pregnant women who become infected with Zika have a significantly higher chance of giving birth to children with microcephaly, a serious condition where the head is smaller than normally seen. Zika’s infectivity and harmful effects on future generations makes it important to understand how the disease will spread in the future, especially as climate change alters its range. CEID member Courtney Murdock is a coauthor on a paper, led by Sadie Ryan at the University of Florida, that predicts how the disease dynamics and range of the Zika virus will change by 2050.

In order to accurately predict how Zika dynamics will change, the research team constructed a complex model that accounts for environmental alterations expected with climate change, as well as socioeconomic scenarios. The Zika virus is spread by the Aedes aegypti mosquito, and changing thermal conditions stand to increase the range of these vectors.  Thus, the authors incorporated the thermal influence on mosquito range into the model, and found that a suitable range for transmission to be approximately 23.9–34.0°C. The authors also incorporated population growth and development, economic, education and urbanization trends in their model, as these important variables are likely to shift in the coming decades along with climate, and also affect Zika virus dynamics. 

The researchers found that more than 1.3 billion more people will be living in areas where Zika can spread by 2050 if nothing is done to combat warming temperatures. Of this 1.3 billion, 737 million of these people would face temperatures allowing Zika transmission year-round. The five regions found to likely have significant increases in newly vulnerable individuals are East Africa, the Middle East, East Asia, Western Europe and North America. Even in the simulation where there is partial mitigation of climate change, hundreds of millions of people are predicted to reside in newly exposed regions by 2050.

This research provides valuable information on the future of global Zika transmission and possible future outbreaks. Though potential exposure of hundreds of millions to a severe disease in the next three decades is daunting, these discoveries will allow decision makers to better prepare. With the knowledge that Zika prevalence is likely to increase in the future, more resources can be directed towards immunological research specific to Zika, as well as new prevention programs.

Ryan, Sadie et al. (2020). Warming temperatures could expose more than 1.3 billion new people to Zika virus risk by 2050. Global Change Biology DOI: 10.1111/gcb.15384