Washington state can hang onto its claim as one of the few West Nile virus-free states in the country – at least for now.
Lab results have concluded that a north Spokane woman who initially tested positive for West Nile virus does not have the mosquito-borne illness, the Spokane Regional Health District announced Monday.
“No test is perfect, even though these are very good tests,” said Dr. Kim Thorburn, county health officer.
The woman, who has not been identified, checked into Holy Family Hospital late last month complaining of a headache and fever. She also reported having received mosquito bites.
An initial test for West Nile virus came back positive on July 1, after the woman had already been discharged from the hospital.
The health district sent those results to the lab at the state Department of Health for verification. Had those results been positive, the sample would have been forwarded to the Centers for Disease Control and Prevention in Atlanta for further corroboration.
“When there’s not a lot of disease in the population, and right now, of course, there’s no West Nile virus, it’s more likely a positive test will be a false positive,” Thorburn said. “There needed to be confirmation testing.”
Thorburn does not know what caused the woman’s symptoms, but, she said, “I understand she’s well now.”
Since 1999, there have been nearly 17,000 West Nile cases and almost 700 deaths reported around the country, according to Christine Pearson, a spokeswoman for the Centers for Disease Control and Prevention in Atlanta. Mosquitoes that draw blood from infected birds can transmit the infection to humans.
Only Washington, Maine, Alaska and Hawaii have yet to log any human cases of the disease, Pearson said.
But it’s unlikely any state will remain untouched by West Nile virus for long, she said.
The virus made its first appearance in New York in the late 1990s and exploded around the country in 2002.
“Since then, it has just continued to move westward,” Pearson said. “We do believe West Nile activity will continue.”
The virus can cause swelling of the brain and inflammation of the spinal cord and brain lining, as well as paralysis and death.
However, there is some good news.
Almost everyone infected with West Nile will suffer no symptoms at all. Just two out of 10 people who get the virus will experience fever, headache, nausea, weakness and fatigue. And less than 1 percent of those people will contract the most serious form of the virus. People over 50 are at greatest risk of becoming ill from the virus.
The illness comes on anywhere from a couple of days to two weeks after being bitten by an infected mosquito.
Just because Washington has yet to post a human case of West Nile doesn’t mean residents should forget about taking precautions against mosquitoes, Thorburn said.
“We don’t want people to get complacent,” she said. “This is still fairly early in the season. We still need to be vigilant about mosquito bites.”
Local journalism is essential.
Give directly to The Spokesman-Review's Northwest Passages community forums series -- which helps to offset the costs of several reporter and editor positions at the newspaper -- by using the easy options below. Gifts processed in this system are not tax deductible, but are predominately used to help meet the local financial requirements needed to receive national matching-grant funds.
Subscribe now to get breaking news alerts in your email inbox
Get breaking news delivered to your inbox as it happens.