EPI researchers receive RAPID grants to study Zika virus

Two researchers at the Emerging Pathogens Institute received RAPID awards from the National Science Foundation in May to study the prevalence of the Zika virus and its potential impact on vulnerable populations.

Dr. Derek Cummings, a professor of biology at the University of Florida, will develop estimates detailing the risk the virus poses around the globe. In a separate project, Dr. Sadie Ryan, an assistant professor of geography at the University of Florida, will focus her efforts on determining the prevalence of Zika virus and dengue virus co-infections and the effect household climatic factors have on disease transmission. Cummings is the principal investigator for his award, and Ryan is the co-principal investigator for hers.

Cummings is partnering with researchers in multiple international locations in order to estimate the potential threat Zika and several other vector-borne diseases pose to the global community.

“We’re utilizing a novel technique developed by the Institut Pasteur to understand the interplay of multiple arboviruses,” he said.

Arboviruses are viruses transmitted by insects, arachnids, and other types of arthropods. Scientists determine whether someone has contracted an arbovirus by testing serum samples, which are blood samples that have had their blood cells and clotting factors removed.

Cummings plans to analyze serum samples from eight countries across the globe to see if they contain antibodies for dengue, Zika, chikungunya, and other arboviruses. He wants to use that data to build maps estimating the risk of Zika transmission while also developing a greater understanding of the interplay between Zika, dengue, and chikungunya – all of which are carried by Aedes aegypti.

Ryan and her colleagues will focus on Zika virus and dengue virus transmission by Aedes mosquitoes in southern coastal Ecuador.

Ecuador is one of 26 countries in the Americas that has reported active transmission of the Zika virus according to the Centers for Disease Control and Prevention. By analyzing blood samples, collecting climate sensor data, and conducting socio-ecological surveys in the region, the researchers hope to learn more about the relationship between Zika and dengue, and how the spread of both viruses is affected by variation in climate, altitude, and socioeconomic status.

“We’re interested in what’s happening at the household level in terms of how household characteristics influence the presence of vectors, particularly the Aedes mosquitoes,” Ryan said.

The researchers collect mosquito samples from people’s homes to find out how many Aedes mosquitoes are present, and then conduct DNA analyses to determine what viruses the mosquitoes are carrying. Funds from the RAPID award will help Ryan and her colleagues test for the Zika virus in addition to dengue and other vector-borne diseases.

Cummings’ current project builds upon a study showing a strong correlation between the incidence of Zika and the force of infection of dengue. While the earlier investigation centered on South America, the current study will incorporate serological data from several regions in order to estimate the global threat of the Zika virus in relation to similar viruses such as chikungunya, Japanese encephalitis, and dengue.

One question Cummings hopes to answer is whether having had dengue in the past increases or decreases the risk of acquiring Zika. Dengue infections are often worse the second time due to the way dengue antibodies interact with the virus, and because Zika’s genetics are very similar to dengue, Cummings suspects that dengue antibodies may impact Zika infections.

“We’re generating maps of transmission intensity,” Cummings said. “One challenge in generating these maps is to understand the interplay of immunity to dengue and Zika. Accurate maps will help us to understand where interventions should be targeted, the potential impact of vaccines, and where the greatest risk is.”