UA Zika Virus Research Aims to Predict Outbreaks

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A team of University of Arizona researchers has been awarded a rapid response grant from the National Science Foundation to investigate the incubation and transmission of Zika virus in mosquitoes.

According to an NSF press release, “To find new ways of halting the spread of Zika – fast becoming a major public health threat – the National Science Foundation Division of Environmental Biology’s Ecology and Evolution of Infectious Diseases Program has funded nine rapid response, or RAPID, grants totaling $1.7 million.”

“Each new infectious disease presents an ongoing challenge to public health,” said James Olds, NSF assistant director for Biological Sciences. “Recognizing the need for urgency, NSF is making these RAPID awards to understand the rate of spread, number of people infected, and likely persistence of Zika as a public health threat, and to help us prepare for the next outbreak.”

The University of Arizona team has already begun its research project and is comprised of Michael Riehle, associate professor of entomology, Kathleen Walker, assistant specialist in entomology, and Kacey Ernst, associate professor of public health.

There are two critical gaps in our collective knowledge of how Zika spreads through a population. The first is its incubation period in a mosquito and the second is its transmission. The team will investigate both with the nearly $200,000 grant.

Specifically, they are studying how environmental temperature and humidity—and their fluctuations—affect the incubation of Zika virus within a mosquito.

As of now, the consensus within the scientific community is that the hotter it is in the mosquito’s environment, the faster the virus will incubate. But, according to Walker, how fluctuating temperatures and humidity affect this pattern is less understood.

In the Sonoran Desert, for example, it can be very hot. This is good news for the virus. But it can also be very dry, and the temperature changes drastically overnight.

“Mosquitos are delicate creatures,” said Walker, and a drier environment generally shortens their lifespan. Their research on incubation conditions may answer questions about the geographic spread of Zika.

The team is also studying transmission. Unlike most mosquito-borne diseases, there is some evidence that Zika virus can be transmitted directly from a mother mosquito to her offspring even before birth. To test this, they are infecting large numbers of female mosquitos with the virus, waiting for them to lay eggs, and then screening the eggs for Zika.

The end goal of the research is not to control Zika virus, but to help predict where it will show up.

Said Walker, “At a local level, the question is ‘How can we use models to help county health departments figure out where the risk is great?’”

With funding from the NSF grant, the researchers will spend the next year addressing this question.