First West Nile Virus Case Found in Washington State Since 2010

Tacoma/Pierce County, WA — For the first time since 2006, a Pierce County resident has been diagnosed with . The person had traveled and was probably exposed out of Washington State.

Today, the Washington State Health Department announced that a resident of Yakima County has also been diagnosed with the virus; this person had not traveled.

“Although we have yet to see signs of West Nile activity in Pierce County , the case in Yakima and increased activity across the nation reminds us that the risk is real and the need to raise awareness and avoid mosquito bites”, says Anthony Chen, Director of Health for Tacoma-Pierce County Health Department.

West Nile Virus is transmitted by mosquitoes and although it is primarily a bird disease, humans and horses can become infected when bitten by an infected mosquito.

While no mosquito samples have been reported testing positive in Pierce, or any other county of the west side of Washington State, several mosquito samples have tested positive for West Nile virus and one horse (which was euthanized) was also identified with the virus in central Washington.

At this time, there are no indications that Pierce County is likely to see high levels of human disease; however, the Tacoma-Pierce County Health Department is conducting surveillance with medical providers to identify any potential cases and arranging testing of dead birds.

Most people who are infected show no symptoms or may have a mild to moderate illness with fever, headache and body aches. A small number of people infected can develop more severe illness like meningitis (inflammation of the covering of the brain and spinal cord) or encephalitis (inflammation of the brain).

People can protect themselves from West Nile virus by using mosquito repellants and wearing long pants and long sleeves. This is especially important if you are traveling to areas where West Nile Virus activity has been identified. Mosquitoes thrive in standing water, so it is important to not let water collect and stand in containers, old tires, and puddles around the home. 

In Washington State, West Nile virus activity has historically been very low. Since surveillance began, the highest level of West Nile virus activity occurred in 2009 when there were 38 human cases (36 were acquired in Washington State), 73 cases in horses or other mammals, and 273 birds tested positive. There were two human cases of West Nile virus in 2010 and none in 2011.

Additional Information Resources:

• Washington State Department of Health (DOH) Website: www.doh.wa.gov/DataandStatisticalReports/DiseasesandChronicConditions/WestNileVirus/2005WestNileVirusActivity.aspx
• Centers of Disease Control and Prevention (CDC) Website:  http://www.cdc.gov/ncidod/dvbid/westnile/index.htm

Information courtesy of Tacoma Pierce County Health Department.