BOARDMAN – Lab results revealed mosquitoes in Irrigon have West Nile virus, but this year no one has reported human, avian or equine cases of the disease in Morrow County.

Greg Barron, manager of North Morrow Vector Control District, said the State University Animal Diagnostic Laboratory in Corvallis confirmed the positive mosquito pool for insects the district collected on Sept. 5 from a trap in south rural Irrigon.

This year, 20 out of 36 counties in Oregon have reported finding the virus in humans or other animals. Last year the Centers for Disease Control and Prevention reported 73 confirmed human cases in Oregon, as well as 996 human cases in Idaho.

Barron explained he and the district’s small crew routinely set about 20 adult mosquito traps baited with dry ice twice a week in the Irrigon and Boardman areas. Then Field Technician Anita Baumgart counts the caught mosquitoes while they are alive but unconscious, identifies the insects according to species, pools them into groups of 50 and sends them to the OSU lab for testing.

“It’s an interesting process if you’ve never seen it,” Barron said.

Barron said there can be more than one pool per species and there are usually up to 53 species of mosquitoes in the Irrigon and Boardman areas.

“But we do have all the bad mosquitoes here,” he said, meaning the area has the species that transmit West Nile virus.

“When we see those disease transmitting mosquitoes,” Barron said, “then we get after them.”

Barron said while trapping is needed to find if a mosquito population has the virus, trapping also allows the district to monitor mosquito population density and helps pin down where mosquitoes are coming from.

Barron explained the district uses this information to determine what actions to take to control the insects and thereby meet its primary goal of eradicating the bugs that transmit disease.

Trapping also allows the district to achieve its secondary goal of controlling more typical nuisance mosquitoes.

Barron said finding West Nile means the district’s staff will increase surveillance and control measures in the area of the positive mosquito pool.

The district also maintains six chicken flocks in the Irrigon and Boardman areas that act as “sentinels” for mosquito borne diseases such as West Nile Virus.

The district collects blood samples from the sentinel chickens’ combs every two weeks and send the samples to the Oregon State Laboratory in Portland for testing. This year, the lab found the virus in 13 humans, 14 sentinel chickens, 45 birds, eight horses, one dog and 30 mosquito pools throughout Oregon.

But again, Barron confirmed West Nile hasn’t been found in humans, birds or horses in Morrow County.

Barron said people who notice sick or dead birds such as crows, magpies, jays and robins should contact the district to pick up the birds for testing.

Jennifer Jaca, communicable disease nurse for the Morrow County Health Department, said the risk of West Nile virus is low. Most people who become infected with West Nile virus don’t become sick. Some may develop mild flu-like symptoms such as fever, headache, body aches and occasionally swollen lymph glands or a rash.

In rare cases West Nile may cause encephalitis, or inflammation of the brain. Individuals with severe or unusual headaches should seek medical care as soon as possible.

Jaca said the county encourages people to take appropriate precautions to protect against mosquito bites.

Jaca offered the following suggestions to reduce the risk of exposure to West Nile Virus:

?Eliminate all sources of standing water, such as watering troughs, birdbaths, clogged gutters and old tires, that can be a breeding ground for biting mosquitoes.

?Avoid outdoor activities at dusk and dawn when mosquitoes are most active.

?Wear long-sleeved shirts and long pants when in mosquito-infested areas.

?Use mosquito repellents containing DEET or oil of lemon eucalyptus and Picaridin, two alternative the Center for Disease Control has recommended.

?Make sure all screen doors and windows are in good repair and fit tightly.

Local officials and health care providers in Morrow County have been notified of the virus detection. The state of Oregon has set up a West Nile virus hotline at (800) 702-4636. Additional information on West Nile virus is on the Web at:

?U.S. Centers for Disease Control and Prevention: http://www.cdc.gov/ncidod/dvbid/westnile/

?Oregon Department of Human Services: http://oregon.gov/DHS/ph/acd/diseases/wnile/survey.shtml

?Morrow County: http://morrowcountyoregon.com/