Mosquito-borne viruses may be spread at cooler temperatures than previously believed

Mosquito-borne viruses, such as Zika, dengue, and chikungunya, are being transmitted at lower temperatures than previously believed, according to a recent study published by researchers at the University of South Florida (USF) and Stanford University.

The study, which was published in a recent issue of the medical journal PLOS Neglected Tropical Diseases, found that transmission of flaviviruses is highest around 84 degrees Fahrenheit, compared to the previously-accepted peak temperature of 90 degrees.

Jeremy Cohen, postdoctoral researcher at USF and co-author of the study, said the findings meant that future transmission is much more likely to occur in subtropical and even temperate areas, such as the southern United States and northern Mexico.

The study collected data spanning from 2015-2016 on incidents of chikungunya, Zika, and dengue transmission, along with gross domestic product and tourism in Latin America and the Caribbean. Temperature was found to change behavior of mosquito populations, including how often they bite, how long it takes them to ingest a virus from one human and deposit it into another, and long they live.

“Given that the predominant thinking was that transmission was most likely to peak at very hot temperatures, which would mostly limit the diseases to the tropics, we were certainly surprised that the model and the field data suggested that high rates of transmission could occur at lower temperatures, possibly impacting more northern regions in the future,” Cohen said.