West Nile virus, which is spread by mosquitoes, has been detected in mosquitoes at a testing site in Morrow County, according to Oregon Public Health officials.
The mosquitoes, found in a rural area near the city of Boardman, are the first to test positive for the disease in Morrow County in 2021.
Health officials are advising people in Morrow County to take precautions against mosquitoes to avoid the risk of infection, including preventing mosquito bites. West Nile virus is spread to humans through the bite of an infected mosquito. Most infected people will show little or no signs of disease.
The incubation period is usually two to 14 days. Rarely, infected individuals may develop neuro-invasive disease (infection of the brain or spinal cord) that can be severe or may cause death. This is especially of concern to people 50 and older, people with immune-compromising conditions, and people with diabetes or high blood pressure.
About one in five people who are infected develop a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea, or rash. Most people with febrile illness due to West Nile virus recover completely, but fatigue and weakness can last for weeks or months. It is important that you contact your health care provider if you experience any of these symptoms.
Communities and individuals living in or spending significant time outdoors, particularly near irrigated land, waterways, standing water, and used tires — including those working in agriculture, such as migrant and seasonal farm workers — may be at increased risk of mosquito bites and related diseases.
The number of mosquito pools — samples of 10-50 mosquitoes — that test positive in any area may indicate the risk of human exposure and infection, said Greg Barron, manager of North Morrow Vector Control District. He 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.
While risk of West Nile disease is low, a handful of people get it each year in Oregon. The virus also affects wildlife and domesticated and farm animals.
In 2019, nine human cases of West Nile virus infection were reported in Oregon, with 85 mosquito pools and seven horses also found to be positive for the virus. In 2018, there were two human cases, with 57 mosquito pools and two horses testing positive. Last year was relatively mild for West Nile, with only three mosquito pools and one bird found to be positive for the virus.