Mosquitoes in Benton County test positive for West Nile virus

KENNEWICK, WA - Mosquitoes recently collected in Benton County have tested positive for West Nile virus. 

According to Dr. Amy Person with the Benton-Franklin Health District, "Reports of West Nile virus activity in mosquitoes are a reminder that each of us needs to take steps to prevent mosquito bites. This mosquito activity is a warning that we will have a long season to prevent illness from the virus this year."

No human cases have been identified in Benton and Franklin Counties so far this year. "The virus is currently active in our region and the risk of human illness is here. With planning and careful effort, West Nile infection can often be prevented," said Rick Dawson, Senior Manager of Surveillance and Investigation.

Primarily causing infections in birds, West Nile virus can spread to people and other animals through mosquito bites. While a vaccine is available for horses, there is no current vaccine to prevent illness in people. Instead, people must "fight the bite" to help prevent infection.

Safety steps include:

  • Drain sources of standing water around your home each week so mosquitoes don't grow. The mosquitoes most likely to spread West Nile virus prefer to breed in water found in containers, tires, buckets, and other small sources of stagnant water.
  • If possible, stay indoors during prime mosquito biting times: dusk and dawn.
  • If going outside, use an EPA-approved insect repellent. Approved mosquito repellents have ingredients that include DEET, picaridin, PMD, IR3535, or oil of lemon eucalyptus. Be sure to read and follow the label directions.
  • Make sure doors and windows have tight-fitting screens. Windows and doors without screens should be kept shut, especially at night.
  • Dress with long sleeves, pants, and a hat when mosquitoes are present.

The risk of West Nile virus infection will be high until mosquitoes go away after the first hard frost. To track the virus in the Pacific Northwest or get additional information, visit the DOH website at

The Benton-Franklin Heath District works with local mosquito control districts and other partners to help monitor for the virus. Due to the known activity of West Nile virus in the area, birds will no longer be collected for testing for the virus by the Benton-Franklin Health District.


West Nile virus is spread through the bite of an infected mosquito. Most people with the virus have no symptoms, but an estimated two people out of 10 infected with the virus with have symptoms 3-14 days after the mosquito bite.

Illness from West Nile virus is usually mild and includes fever, head and body aches, and possibly a rash. However, serious illness that involves the nervous system, such as encephalitis and meningitis, and death are also possible. Serious illness can occur in people of any age; however, people over age 50 or people with weakened immune systems (for example, transplant patients) are at the highest risk for getting severely ill when infected with West Nile virus. Anyone with symptoms is encouraged to contact their health care provider.

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