A jay found dead in Grants Pass has tested positive for West Nile virus.

A jay found dead in Grants Pass has tested positive for West Nile virus.

The jay, collected Sunday in an area near 10th Street and tested at a state lab this week, was the first bird with the disease in Josephine County this year. The county didn't have any activity from the virus reported last year.

Jackson County found the virus in mosquitoes trapped two weeks ago at a pond in the East Gregory Road area, but subsequent tests around the area haven't turned up any additional pockets of the disease-causing agent, said Gary Stevens, director of Jackson County's environmental health division.

The virus, first isolated in the West Nile district of Uganda in 1937, showed up in New York in 1999 and gradually spread across North America. Mosquitoes spread the virus by biting infected birds and transferring it when they bite other birds, horses and humans.

Only 20 percent of people bitten by an infected mosquito will get sick, the federal Centers for Disease Control and Prevention reports. Most infections are mild, with fever and flu-like symptoms, but severe cases, mostly in people with compromised immune systems, can cause inflammation of the brain and, rarely, death.

Public health officials advise people to avoid mosquito bites by using an effective repellent, preferably one that contains DEET, picardin or oil of lemon eucalyptus. People can also avoid being outside at dawn and dusk when mosquitoes are most active and wearing long pants and shirts with long sleeves.

Keeping screens on windows and doors in good repair and eliminating standing water where mosquitoes breed provide additional protection.