Global warming could limit spread of dengue fever, new research finds

Interestingly, Ware-Gilmore said, the two agents – the dengue virus and the Wolbachia bacteria – did not have an additive effect on the thermal tolerance of mosquitoes.

“You might expect mosquitoes infected with both the dengue virus and Wolbachia to immobilize even faster than mosquitoes infected with just one or the other, but we couldn’t find any. additive effect, ”she said. “However, we are the first to show that viral infection can affect the thermal tolerance of mosquitoes, notably by reducing mosquito survival when exposed to high heat. And, while there are known interactions between heat and Wolbachia, especially in the immature stages, this is also the first study to show that infected adult mosquitoes have reduced survival during heat stress.

Ware-Gilmore noted that future climate models indicate an increasing frequency of extreme temperature events, making short exposures to high temperatures a threat to the survival of mosquitoes infected with dengue and Wolbachia.

“At lower temperatures, we know that the dengue virus may not replicate quickly enough to pass through the mosquito’s body and be transmitted, thereby reducing the risk of transmission,” she said. “At higher temperatures, while the virus can replicate faster, our work suggests that a corresponding reduction in mosquito thermal tolerance may act as a counter-powerful force on mosquito survival, which could help reduce the transmission and potentially the incidence of human diseases in warmer and more climate-changeable regions. . Likewise, our work suggests that Wolbachia may not function as a biological control agent in warmer regions given its effect on mosquito survival.

Other Penn State authors on the paper include Heverton Dutra, postdoctoral researcher in entomology; Matthew Jones, research assistant, Huck Institutes of the Life Sciences; and Katriona Shea, professor of biology and former professor of biological sciences. Also on paper are Carla Sgrò, professor of biological sciences, and Matthew Hall, senior lecturer in biological sciences, Monash University; Zhiyong Xi, professor of microbiology and molecular genetics, Michigan State University; and Matthew Thomas, Director and Professor, York Environmental Sustainability Institute, University of York.

International Networks of Excellence and Penn State supported this research.