Thursday, Sep. 04, 2008

Health district calls virus 'very active' in C. Washington

By Laura Kate Zaichkin and Franny White, Herald staff writers

Four dead birds from Benton and Yakima counties have tested positive for West Nile virus, the first positive birds tested in the state this year.

The infected bird found in Prosser is the first West Nile virus-positive bird found in the county since the Benton-Franklin Health District began monitoring West Nile in 2002, according to the health district.

Along with the two crows and two magpies collected last month for testing, the virus has been detected in 12 horses and 22 mosquito pools in Benton, Yakima and Grant counties this year, the state Department of Health said.

"Testing for West Nile virus in dead birds, mosquitoes and horses shows where the disease is active," said Liz Dykstra, a state public health entomologist. "With the results we're seeing this year, it's clear that West Nile virus is very active in the middle of our state."

The virus is primarily a bird disease. Mosquitoes become infected by feeding on an infected bird and can pass the virus to people, horses or other animals.

"Now more than ever, people should take precautions to avoid mosquito bites and limit mosquito habitats around their homes," said Gregg Grunenfelder, the assistant secretary for the state Department of Health's environmental health division.

The local health district suggests getting rid of old tires and other containers where water can accumulate and serve as a breeding ground for mosquitoes.

Also, avoid outdoor activities at dusk and dawn, wear long-sleeve shirts and long pants when in mosquito-infested areas, use mosquito repellents with DEET, and put screens on doors and windows.

"Although the weather is cooling, this is not the time to stop taking precautions against mosquito bites," said Susan Shelton, an environmental health specialist with the health district. "We know the virus is active in birds and mosquitoes in our area and the risk of West Nile infection in people traditionally increases in August and September."

West Nile virus is a potentially serious illness for people and can cause inflammation of the brain or spinal cord. However, about 80 percent of people infected with the virus don't show symptoms, according to the federal Centers for Disease Control and Prevention.

In Northeast Oregon, Umatilla County officials will spray 24 square miles with insecticide Thursday to prevent the spread of West Nile virus.

The aerial application, scheduled for 8 p.m. to midnight, will be the largest ever for the Umatilla County Vector Control District, the local agency that controls mosquito populations.

No people or animals have tested positive for the virus in Umatilla County and today's spray is intended to keep it that way, said district Manager Ron Montgomery.

The spray area is rural and northeast of Hermiston, where all the county's West Nile-positive mosquito samples have been located. It will cost the district about $25,000 to spray the area.

Genni Lehnert, administrator of Umatilla County Public Health, said continued spraying is needed to keep humans from becoming infected.

"It's really important that we're proactive and not reactive to West Nile virus," she said.

Four humans and seven animals have tested positive elsewhere in Oregon, according to the state Department of Human Services.

The infected birds in Washington were collected and submitted by the Yakima and Benton-Franklin health districts as part of a state monitoring program. Nearly 60 birds have been tested statewide this season, according to the state.

The local health district encourages people to report dead birds, especially crows, magpies and ravens.

Birds can be reported by calling 460-HAWK or at www.bfhd. wa.gov/wnv.