Assessing vector competence for Indiana mosquito populations

Understanding mosquito-borne disease transmission

Close up of a mosquito on an arm.
Image from Wikimedia Commons

The Problem

Mosquito-transmitted viruses such as West Nile virus and eastern equine encephalitis virus present a significant threat to people and livestock in Indiana and around the world.

The risk is amplified as climate change pushes historically tropical mosquito species northward. For example, the Asian Tiger Mosquito (Aedes albopictus) has spread into parts of the Midwest where it previously did not exist, bringing with it new disease risks.

The Project

To better understand the prevalence of disease-causing pathogens in Indiana’s mosquito populations and the potential threat to Hoosiers’ health, IU Associate Professor Irene Newton, in collaboration with IU Professor Richard Hardy, is collecting and analyzing mosquitos from different parts of the state.

The researchers are particularly interested in studying the prevalence of the bacterium Wolbachia pipientis in collected specimens. Studies have shown that the presence of Wolbachia can inhibit the transmission of viruses in multiple generations of mosquitos, making it a potentially powerful agent for disease control.

Researchers are sorting mosquitos by species and screening for the presence of viruses and Wolbachia. Thus far, Newton’s team has analyzed around 1,000 specimens representing 19 species. So far, sampled specimens have revealed the presence of Wolbachia in a high percentage of Aedes albopictus, perhaps indicating a reduced risk of disease transmission for that species. Conversely, specimens of the Northern House Mosquito (Culex pipientis), the research team’s most frequently sampled species, harbored no Wolbachia, indicating the possibility of posing a greater disease risk to humans and livestock.

In parallel with the screening studies, the team aims to establish colonies of Indiana mosquitos harboring Wolbachia to study the virus-blocking capacity of the bacterium in a lab environment. The results of this study could help determine the risk of mosquito-borne disease transmission to Hoosiers and how to mitigate that risk.

The Path Forward

In Summer 2022, the team is continuing to screen sampled mosquitoes and is working to establish a lab colony. In this controlled environment, researchers will aim to determine the effectiveness of native strains of Wolbachia in protecting Hoosiers from the spread of mosquito-borne viruses or whether non-native strains of the bacteria may be more effective.

Project Data

Data for this project is not currently published, though plans to make research data available to other researchers are in place.