West Nile Virus

West Nile Virus (WNV) is a potentially serious illness. Experts believe WNV is established as a seasonal epidemic in North America that flares up in the summer and continues into the fall.

Virus Spread

Most often WNV is spread by the bite of an infected mosquito. Mosquitoes are WNV carriers that become infected when they feed on infected birds. Infected mosquitoes can then spread WNV to humans and other animals when they bite.

Animals That Get West Nile Virus


An infected mosquito can bite any animal, but only a few will get WNV. The disease infects birds, horses, and other animals as well. Wild birds are most often linked to the spread of WNV. More than 70 kinds of birds can be infected, but the most severe illness is found among corvine birds. Corvine birds include crows, ravens, jays, and magpies, but American crows are the birds most often found dead from WNV.


Horses can become infected with WNV. Unlike birds, all kinds of horses seem to be equally at risk to the virus. Signs that a horse may be infected include loss of control of balance and in movement. There is a vaccine available for horses against WNV. Contact your veterinarian for additional information about WNV, the vaccine and other kinds of encephalitis that infect horses.

West Nile Virus Reporting

Call the Health Department at 541-440-3571, fax 541-464-3914 to report WNV infection. All Oregon health care providers are required by law to report suspected cases of WNV to the Health Department within 24 hours. Oregon laboratories are required by law to report positive WNV lab results to the local health department within one working day. The timely identification of persons with WNV enables appropriate public health follow-up for patients.

Finding a Dead Bird

Call the Health Department at 541-464-3820 or 800-234-0985, or Animal Control at 541-440-4328, fax 541-440-4470. Do not touch it. The vast majority of infections have been identified in birds, especially crows and jays. There is no evidence that a person can get the virus from handling live or dead infected birds, but the Health Department would like you to leave the bird where you see it so they can investigate.