Washington state has its first two cases of West Nile virus this year: a man in his 50s from Yakima County who was hospitalized, and a man in his 60s from Benton County who hasn’t been hospitalized.
West Nile virus is usually spread via bites from mosquitoes that were infected when feeding on birds that carry the virus. There’s no evidence West Nile virus spreads through direct contact among humans or animals.
West Nile virus can be serious or even fatal, although most people who get it don’t get sick, according to the Washington State Department of Health (DOH). About one in five people infected will get a fever or other symptoms that go away without medical treatment; about one in 150 develop severe symptoms, according to DOH.
Symptoms of West Nile virus can include headache, high fever, neck stiffness, stupor, disorientation, tremors, convulsions, muscle weakness, paralysis and coma.
“Spending time outdoors can help with social distancing to prevent COVID-19, but it can also put you at risk for mosquito-borne disease,” epidemiologist Hanna Oltean said in a DOH news release. “People throughout Washington should take precautions to prevent mosquito bites.”
West Nile virus first appeared in the United States in 1999, in New York City. It has spread through the country since then, with the first related illnesses in Washington state being reported in 2006. Five people in Washington were diagnosed last year, three in 2018, 13 in 2017, nine in 2016 and 24 in 2015, according to the DOH. The virus was detected most heavily in Washington in 2009, when 38 people tested positive.
The virus has been detected this year in mosquitoes in Benton, Franklin and Yakima counties. Washington state has limited resources to monitor dead birds and mosquitoes for West Nile virus, but it is tracking known West Nile virus activity at doh.wa.gov/wnv. That site also contains more information about the virus and how to avoid it.