West Nile virus is making an appearance in Morrow County for the first time since 2009, according to the North Morrow Vector Control District.

Two test sites have yielded positive West Nile results with one site south of Irrigon and the other in the city of Boardman, said Greg Barron, vector control district manager.

It was kind of surprising in a way, because we have been catching the disease-carrying mosquito species since we got the bout of heat after the Fourth of July, Barron said. That got them moving.

In the last outbreak, Barron said 110 test sites were positive for West Nile virus, most of which were on or near the Umatilla National Wildlife Refuge. There was one human case of West Nile and one horse case in 2009, he said.

Morrow County and state health officials say the best ways to avoid the disease are to eliminate sources of standing water, which serve as breeding grounds for mosquitoes, and use repellants containing DEET, oil of lemon eucalyptus or Picardin. Long-sleeved shirts and long pants are also recommended in mosquito-infested areas and ensuring screens on windows and doors are tight and in good repair will keep the insects out of homes.

Barron said any bird baths should be emptied and cleaned at least once per week, buckets full of water should be treated the same and if swimming pools are not being used they should be covered.

In some rural areas, sites might be drying up and the mosquitoes are looking for more sites to complete the breeding cycle, Barron said. Look around your yard and make sure youre not creating mosquito sources.

About 80 percent of people infected with the disease do not exhibit symptoms, but of the remaining 20 percent, most have mild flu-like symptoms, said Morrow County Public Health Administrator Sheree Smith. There are no symptoms differentiating West Nile from the flu, but providers can do a lab test to confirm or deny a case of the virus, Smith said.

Symptoms are typically a fever, headaches and nausea lasting three to six days, but more severe cases actually affect the central nervous system.

Emilio DeBess, Oregon Department of Human Services public health veterinarian, said brain infections can be mild or severe depending on the case.

People can develop a more severe case of West Nile and it affects the brain and ability to be cognizant of whats going on. … In very few cases people have died of the disease.

Barron said the treatment being carried out by the vector control district is working right now and encourages people to not go out after dark if they do not have to.

Thats when the disease-carrying species of mosquitoes are out, Barron said. They prefer to feed on birds and thats where they get the West Nile virus, but people have to remember they are opportunistic feeders. … Dont overexpose yourself unnecessarily.  

Contact Anna Willard at awillard@eastoregonian.com or 541-564-4536.