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Researchers: West Nile Risk Could Be Higher In Flooded Western Iowa

Courtesy of Iowa State University
Scientists are watching to see whether standing water from March’s flooding will bring more mosquitoes and the risk of West Nile Virus to western Iowa this summer.";

New research from Iowa State University scientists found western Iowa has the state’s largest presence of a type of mosquito that carries West Nile Virus. Scientists are watching to see whether standing water from March’s flooding will bring more mosquitoes and the risk of the virus to western Iowa this summer.
Scientists looked at 15 years of mosquito data and found a species called Culex tarsalis that carries West Nile Virus is most common in Iowa’s counties along the Missouri River. The research was published in the journal Scientific Reports.

Pools of water serve as breeding grounds for mosquitoes. Iowa State University entomologist Ryan Smith said water that remains in parts of western Iowa from March’s flooding raises questions about the potential increase of West Nile transmission.

“If these continue to last into later in the summer,” said Smith about the standing water, “we could potentially have some increased West Nile Virus transmission in these areas as a result of the increased mosquito populations.”

Smith said scientists hope to work with state and county health officials this summer to place traps in flooded areas. They’ll test to see if there is a high presence of West Nile Virus.

A health official from southwest Iowa’s Mills County, an area hit hard by flooding, says treatment of mosquitoes in standing water could be challenging and they’ll have to look at options this summer. In Fremont County, the emergency management coordinator said that as people have called recently to ask about any donations they can provide to flood victims, he has noted that they could use bug spray.

According to data from Iowa’s Department of Public Health, Sioux, Pottawattamie and Woodbury counties have the highest amount of confirmed West Nile Virus cases from 2002 to 2017, totaling 76.

Smith said it seems Culex tarsalis prefers the type of ecology and habitat that’s more common in western Iowa.

“Culex tarsalis like more open, rural areas, in wastewater or the kind of thing that might be found in your agricultural areas,” he said.

This does not mean other parts of the state are not prone to the disease, Smith said, but western Iowa has a higher risk because this mosquito is more common here. People can reduce the chances of getting the virus by using mosquito repellent, Smith said.