More Mosquitoes with West Nile Virus Found in Morrow County


For the second time this summer, West Nile virus, a mild flu-like disease spread by mosquitoes, has been detected in mosquitoes at a testing site in Morrow County, according to Oregon Public Health officials.

The mosquitoes, found near the city of Irrigon, are the second to test positive for the disease in Oregon in 2019.

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 is spread to humans through the bite of an infected mosquito.

“The risk of contracting West Nile virus may be low, but we do encourage people to take appropriate precautions to protect themselves against mosquito bites,” said Greg Barron, Manager of North Morrow Vector Control District. “We will continue to increase our mosquito control operations utilizing our Ultra Low Volume (ULV) truck mounted sprayers and possibly some spraying aerially to reduce adult mosquito populations,” Barron said.

About one in five infected people may show signs of West Nile virus, said Shelley Wight, Communicable Disease coordinator for Morrow County Health Department.

“People at risk of serious illness include individuals 50 and older, and people with immune-compromising conditions, such as diabetes and high blood pressure,” said Wight, adding that West Nile virus testing is available for both humans and animals. Contact the local health department for further information on lab testing instructions.

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.

Last week, in Morrow County, four mosquito pools tested positive for WNV. In 2018, there were two human cases of West Nile virus Harney and Clackamas counties. The virus was found in one bird, 58 mosquito pools — samples of about 50 mosquitoes each — and two horses. In 2017, seven humans, 92 mosquito pools, five horses and one bird tested positive for West Nile. The virus also can be found in chickens, squirrels and dogs