Into the woods: Researchers study birds in effort to curb the spread of West Nile virus


Tuesday, June 9, 2015

The sun won’t be up for a couple hours, but Dan Finnell and Ryan Levering are driving slowly through the darkness of Joseph Bryan Park, scanning the shrubs and trees with a thermal imaging camera attached to the passenger side window.

The two Virginia Commonwealth University senior environmental studies majors are hunting for infrared hotspots that might indicate the presence of nests of American robins or other birds.

“When we find a nest, we mark the spot with flagging tape,” Finnell said. “And as the sun rises, we get back out there to check it out, see how many eggs or nestlings there are, and collect nestling temperatures, incubating female temperature, and ambient temperature, and observe the female’s activity — she might be incubating eggs or brooding nestlings.”

The bird nesting data collected in Bryan Park is part of a major interdisciplinary study at VCU —involving ornithologists, mathematicians, entomologists and others — that aims to gain a better understanding of how West Nile virus spreads and how authorities can more effectively prevent outbreaks.

“Our goal is to be able to develop a model of West Nile virus transmission,” said Lesley Bulluck, Ph.D., an assistant professor in the Center for Environmental Studies in VCU Life Sciences and the Department of Biology in the College of Humanities and Sciences, and an affiliate researcher for the VCU Rice Rivers Center. “We know that American robins and some other birds are good hosts for West Nile virus, and so we want to understand the dynamics between the timing of their nesting, the time of mosquito abundance and then toward the end of the season [the time when] mosquitoes shift to feeding on mammals, including humans.”

Bulluck, an expert on avian ecology who is overseeing the field work in Bryan Park, said the information being collected will serve as empirical data that will feed into the model of West Nile virus transmission.

“The basic question is, How does the timing of bird nesting activity influence West Nile virus transmission dynamics?” she said.

Mosquitoes, baby birds and math

A nest of American robins in Bryan Park that was identified by the researchers.

West Nile virus is a pathogen spread primarily between mosquitoes and birds, and can spread to people by the bite of an infected mosquito. Most humans infected with the virus do not develop symptoms. However, about one in five people who are infected develop a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea or rash, and less than 1 percent will develop a serious, sometimes fatal, neurologic illness such as encephalitis or meningitis.

The project — “The impact of temporal variation in host life-stage abundance on the regional transmission and control of West Nile virus” — is supported by a $100,000 grant from the Jeffress Trust Awards Program in Interdisciplinary Research, which supports interdisciplinary research in Virginia.

Suzanne Robertson, Ph.D., an assistant professor in the Department of Mathematics and Applied Mathematics, is leading the project and developing a differential equations model for avian and human hosts.

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