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 approximately 3 miles west of Irrigon on the Umatilla National Wildlife Refuge McCormick Slough, are the first to test positive for the disease in Morrow County in 2024.
Health officials are advising people in Morrow County to take precautions against mosquitoes to avoid the risk of infection, including preventing mosquito bites. Most infected people will show little or no signs of disease. People who are infected may 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 and get tested for West Nile virus. Testing is available in most private laboratories.
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.
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 virus also affects wildlife and domesticated and farm animals. Horses are a risk of developing West Nile virus. Consult your veterinarian about vaccinating your horses against WNv.
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.
“Although mosquitoes are an inevitable part of summer, mosquito bites don’t have to be — they are preventable,” said Emilio DeBess, public health veterinarian. “You can take simple steps to protect yourself and reduce the risk of contracting West Nile disease.”
DeBess offers these tips for protecting yourself against mosquitoes:
- Eliminate sources of standing water that are a breeding ground for mosquitoes, including watering troughs, bird baths, ornamental ponds, buckets, wading and swimming pools not in use, 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.
Additional information about West Nile virus can be found on the Oregon Health Authority website or the U.S. Centers for Disease Control and Prevention website.
