Temperature drives Zika virus transmission: evidence from empirical and mathematical models
Blanka Tesla1,2, Leah R. Demakovsky1, Erin, A. Mordecai3, Sadie J. Ryan4,5,6, Matthew H. Bonds7, Calistus N. Ngonghala8, Melinda A. Brindley1,9,10, Courtney C. Murdock*1,2,10,11,12,13
1Department of Infectious Diseases, University of Georgia; 2Center for Tropical and Emerging Global Diseases, University of Georgia; 3Biology Department, Stanford University; 4Department of Geography, University of Florida; 5Emerging Pathogen Institute, University of Florida; 6College of Life Sciences, University of KwaZulu-natal; 7Department of Global Health and Social Medicine, Harvard University; 8Department of Mathematics, University of Florida; 9Population Health, University of Georgia; 10Center for Vaccines and Immunology, University of Georgia; 11Odum School of Ecology, University of Georgia; 12Center for Ecology of Infectious Diseases, University of Georgia; 13River Basin Center, University of Georgia
Temperature is a strong driver of vector-borne disease transmission. Yet, for emerging arboviruses we lack fundamental knowledge on the relationship between transmission and temperature. Current models rely on the untested assumption that Zika virus responds similarly to dengue virus, potentially limiting our ability to accurately predict the spread of Zika. We conducted experiments to estimate the thermal performance of Zika virus (ZIKV) in field-derived Aedes aegypti across eight constant temperatures. We observed strong, unimodal effects of temperature on vector competence, extrinsic incubation period, and mosquito survival. We used thermal responses of these traits to update an existing temperature-dependent model to infer temperature effects on ZIKV transmission. ZIKV transmission was optimized at 29C, and had a thermal range of 22.7C - 34.7C. Thus, as temperatures move toward the predicted thermal optimum (29oC) due to climate change, urbanization, or seasonality, Zika could expand north and into longer seasons. In contrast, areas that are near the thermal optimum were predicted to experience a decrease in overall environmental suitability. We also demonstrate that the predicted thermal minimum for Zika transmission is 5oC warmer than that of dengue, and current global estimates on the environmental suitability for Zika are greatly over-predicting its possible range.