Area scientist tests mosquitoes of Missouri for West Nile virus

Thursday, August 15, 2002

Inside a tightly sealed laboratory in Rhodes Hall at Southeast Missouri State University, Dr. Christina Frazier runs another test for mosquito-borne viruses.

This test is similar to a home pregnancy test. If the sample changes color, it means the West Nile virus is present in area mosquitoes.

And it is. Cases have been confirmed in Cape Girardeau, Scott, Perry, Dunklin, New Madrid and Pemiscot counties.

Frazier's work studying mosquitoes alerted area health officials and cities to the virus' spread in Southeast Missouri. She sends her samples of ground-up mosquitoes to a Centers for Disease Control laboratory in Fort Collins, Colo., for confirmation.

Later this month, she will begin testing blood samples from birds to see if an antibody to the virus can be found. The samples are collected by the U.S. Department of Agriculture.

West Nile virus mimics encephalitis, which is an inflammation of the spinal cord and brain. Symptoms include fever, headaches, rashes and general flu-like complaints. Most people who contract the illness never experience any symptoms, though it can be fatal.

There is no vaccine or cure for West Nile virus.

Health officials in the region have not had any complaints, nor have they treated any patients for West Nile virus. However, last week, a Massachusetts woman became the first human case confirmed in the state. Health officials said the 38-year-old woman had contracted the virus after visiting St. Louis during late July.

Before her, the only confirmed cases of the virus in Missouri had been in birds or horses. The virus is transmitted locally by the northern house mosquito, or culex pipiens.

Frazier has been studying mosquitoes for 15 years, trapping them around the area and testing for five different viruses. Until now, she hadn't found any.

Discovering that the West Nile virus had invaded the mosquito population elicited mixed feelings for Frazier. The Cape Girardeau epidemiologist and arbovirologist was disappointed that the virus had reached Southeast Missouri but also excited to have made the discovery. "It sort of justifies your existence," she said.

Frazier's tests, commonly called surveillance, are part of a statewide program. Her's is the only lab that tests mosquitoes from 14 different counties.

She admits that she's only looking for the bad in the mosquitoes -- her work focuses on West Nile virus, St. Louis encephalitis, western and eastern equine encephalitis and La Crosse virus.

Frazier knows that most people dislike mosquitoes, and even after years of study, she hasn't been able to find any redeeming qualities in the pests, except that "some of them are gorgeous."

Looking at them under a microscope, she can see the silver flecks in their wings or the striped bands of the Asian tiger mosquito.

Nevertheless, these pests are necessary since other insects and birds feed off their larvae. Working to eradicate them will only compound the problem since the mosquitoes can develop resistances to the chemical sprays used to control them, she said.

The best prevention against West Nile virus is taking simple precautions, she said. Tips include not going outside during the dusk to dawn hours, wearing repellent with DEET, wearing light-colored clothing and eliminating any areas of standing water outdoors.

Once people know the disease is out there, then they can do more for prevention, Frazier said.

ljohnston@semissourian.com

335-6611, extension 126

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