06/22/2006: "Statewide Monitoring For West Nile Virus"

West Nile virus was detected in a horse, a dead bird and two mosquito samples in Washington last summer, yet there still has not been a reported case of human illness acquired in our state. With the warmer months of spring and summer bringing a new mosquito season, the search resumes for West Nile virus exposure in Washington. The state Department of Health is working with local health agencies and other key partners to monitor dead birds and mosquito populations - important ways of tracking the presence of the virus.

"Environmental monitoring detected West Nile in mosquito samples and a dead bird in our state last summer, and we'll be looking intensively for the virus again this season," said Maryanne Guichard, director of the Department of Health's Office of Environmental Health and Safety. "We are testing certain species of dead birds and mosquitoes because they are usually affected by the disease before human cases are detected."

In 2005, 660 dead birds, 54 horses and 915 mosquito samples were tested in Washington. The tests detected West Nile virus in one dead magpie, one horse that had not traveled out of state and two mosquito samples. No human cases have been acquired in our state.

West Nile virus is primarily a bird disease. Mosquitoes become infected by feeding on infected birds, and then pass the virus to uninfected birds, humans, horses or other hosts. Crows, ravens, magpies and jays are especially susceptible to dying from the virus.

Local health agencies coordinate the dead bird monitoring efforts in their areas, working closely with the state Department of Health. Anyone who finds a dead bird that isn't decomposed should notify their local health officials, who may want to have some dead birds submitted for laboratory testing. People should avoid handling dead birds with bare hands. Gloves or shovels should be used to place the carcass inside two plastic bags. Keep the carcass in a cool place while the local health officials are notified.

In addition to monitoring dead birds, local and state health officials are collecting mosquitoes around the state to identify and test for the virus. At least one mosquito species that can be infected with West Nile virus has been found in every county in the state.

"The best defense is to avoid mosquito bites," Guichard added. "There are simple steps we can all take to reduce the risk."

Turning over old buckets or cans, emptying water from old tires, and frequently changing water in birdbaths, pet dishes and water troughs helps eliminate the small puddles of water in which many mosquito species breed. People can avoid mosquito bites by staying indoors around dawn and dusk when mosquitoes are most active; making sure that door and window screens are in good working condition; and using a mosquito repellent when outdoors in areas where mosquitoes are active. Always follow label instructions when using mosquito repellents.

Even after being bitten by a West Nile virus-infected mosquito, most people won't show any signs of illness. Some people may develop mild flu-like symptoms that go away without treatment. In a small number of cases the virus can cause serious illness including fever and inflammation of the brain. People over age 50 have the highest risk for serious illness.

The Department of Health West Nile virus information line 1-866-78-VIRUS (1-866-788-4787) and the agency's West Nile virus Web site are excellent resources for anyone who wants to learn more.

The Department of Health is working with local health partners as well as other state agencies, including the Departments of Agriculture, Ecology, and Fish and Wildlife on West Nile virus monitoring, planning, control and prevention.