West Nile Virus

West Nile Virus (WNV) is present across the United States, and in Oregon. WNV is spread by mosquitoes and can result in serious, life altering outcomes and even death. WNV mainly infects birds, but when a mosquito bites an infected bird the mosquito carries the virus and can then transmit the disease to humans.

Disease Transmission

Although humans and some other animals may get sick when infected with West Nile virus, it is thought that they usually do not develop enough virus in the bloodstream to infect mosquitoes. For this reason, humans and animals such as horses are referred to as incidental hosts. West Nile virus is generally not spread from person to person.

However, in a very small number of cases, it has been transmitted through blood transfusions, organ transplants, breastfeeding, and even during pregnancy from mother to baby. It is not transmitted by casual contact such as kissing or touching.

Positive Tests in Oregon

In Oregon positive tests for West Nile Virus have occurred. In August 2010, mosquitoes tested positive for West Nile Virus at a site near Irrigon in Morrow County. This is the first positive test in Oregon this year.