West Nile Virus (WNV) a mild flu-like disease spread by mosquitoes, has been detected for the first time in Malheur County in 2020 in mosquitoes at a testing site in Malheur County, according to Oregon Public Health officials.
Health officials are advising people in Malheur County to take precautions against mosquitoes to avoid the risk of infection, including preventing mosquito bites. West Nile is spread to humans through the bite of an infected mosquito.
WNV was found on the corner of Butte and Onion in between the cities of Vale and Ontario close to the Vale golf course. The Malheur County Vector Control District fogged extra in that area on Saturday, August 29th and Wednesday, September 3rd, to mitigate the spread of the virus. The Vector Control District also plans on larviciding new sites in the area with drones and will increase trapping in the affected area.
This is what we are planning on doing extra for the area that WNV was found until our test come back negative.
About one in five infected people may show signs of West Nile virus. People at risk of serious illness include individuals 50 and older, and people with immune-compromising conditions, such as diabetes and high blood pressure.
West Nile symptoms may include fever above 100 degrees and severe headache, stiff neck, mental confusion, muscle weakness, shaking, paralysis or rash. People should contact their health care provider if experiencing any of these symptoms.
The incubation period is usually two to 14 days. Rarely, infected individuals may develop an infection of the brain or spinal column that can be severe or may cause death. This is especially of concern to those who have a compromised immune system, or the elderly.
The number of mosquito pools – samples of about 50 mosquitoes – testing positive in any area could lead to infection. Dr. Emilio DeBess, veterinarian at the Oregon Health Authority’s Public Health Division, recommends people and animals be protected against mosquito bites.
“It’s very easy for people to prevent bites from mosquitoes that may carry West Nile virus,” DeBess says. “Although the risk of contracting West Nile virus is low, people can take simple precautions to keep these insects at bay if they’re headed outdoors.”
DeBess offers these tips:
- Eliminate sources of standing water that are a breeding ground for mosquitoes. This includes watering troughs, bird baths, clogged gutters and old tires.
- When engaged in outdoor activities at dusk and dawn when mosquitoes are most active, protect yourself by using mosquito repellants containing DEET, oil of lemon eucalyptus or Picardin, and follow the directions on the container.
- Wear long-sleeved shirts and long pants in mosquito-infested areas.
- Make sure screen doors and windows are in good repair and fit tightly.
Malheur County Vector Control monitors the presence of the West Nile Virus in thee Culex mosquitoes. Once the virus is detected, then the Malheur Vector Control will apply pesticides to the proven affected areas as well as continue to monitor for the virus. However until the virus is detected, we will focus our effort on applying larvacides and testing the culex population for the West Nile Virus.
Climate change effects such as increased temperature and changes in rainfall have led to longer mosquito seasons and are contributing to the spread of West Nile virus, health officials say. They agree these, and other climate change indicators must be considered to help people better prepare for future transmission of the disease.
Contact the Malheur County Health Department at 541-889-7279 or the Malheur County Vector Control at 541-473-5102 with any questions or concerns.
Additional information about West Nile virus is available at:
- Oregon Health Authority:
- U.S. Centers for Disease Control and Prevention:
Malheur County Health Department 
Where in the county was it found?
Ken, thank you for your question. I’ve updated the post with the following information: WNV was found on the corner of Butte and Onion in between the cities of Vale and Ontario close to the Vale golf course. The Malheur County Vector Control District fogged extra in that area on Saturday, August 29th and Wednesday, September 3rd, to mitigate the spread of the virus. The Vector Control District also plans on larviciding new sites in the area with drones and will increase trapping in the affected area.