A Walla Walla County man is the first Washington resident in 2014 known to have been infected with West Nile virus in our state. The man in his 20s was likely exposed near his home and was hospitalized. The infection was confirmed by testing at the Washington State Public Health Laboratories in Shoreline. This is the first in-state acquired case in 2014 is also first in-state case since 2012.

West Nile virus
Culex quinquefasciatus

Two other Washington residents have been diagnosed with the infection this year, both with exposures in other states. A King County man in his 70s and a Grays Harbor woman in her 50s were infected with West Nile virus this year while traveling out of state. Additional reports of possible infections are currently under investigation.

“The mosquito samples that have tested positive for West Nile virus in eastern Washington this season are a reminder that the virus is here and we should protect ourselves,” said State Health Officer Dr. Kathy Lofy. “The best prevention is to avoid mosquito bites — at home and while traveling.”

Year after year, south central Washington has been a “hot spot” for the virus, with most in-state acquired human and animal cases having been exposed in this area. Mosquito testing shows the virus is in our state, and the mosquito species that transmit the virus are found throughout Washington.

Most people infected with West Nile virus will have no symptoms at all. Others may develop fever, headache, or body aches. For a small percentage of people, West Nile virus infection can be very serious, resulting in encephalitis, meningitis, or other complications. People over age 50 have the highest risk for serious illness.

Last year, only two human infections of West Nile virus were reported, and both were exposed out of state. During 2012, four cases were reported, two of which were in-state acquired while the other two were travel-associated. The state most active year was 2009, in which there were 38 human cases. For more infectious disease news and information, visit and “like” the Infectious Disease News Facebook page