The mosquito-borne West Nile virus has landed in Douglas County.

A blue jay found dead this week in Douglas County tested positive for the disease that has killed seven people in Louisiana and sickened others in 36 states, health officials announced Thursday.

The discovery brings to 12 the number of Kansas counties with confirmed West Nile cases, found either in infected birds or horses. Infected birds also have been found in nearby Shawnee, Johnson and Wyandotte counties.

So far, no cases of human West Nile infection have been confirmed in the state.

Infected mosquitoes carry the virus and transmit it to birds, horses or people, but that doesn’t mean every bite will make someone or something sick, said Kay Kent, administrator for the Lawrence-Douglas County Health Department.

Most people who get infected with West Nile virus never know it. Some get flulike symptoms, such as headache, fever, body aches and swollen lymph glands. More severe infections can lead to encephalitis, or inflammation of the brain, which is marked by headache, high fever, neck stiffness, disorientation, coma and seizures.

It’s estimated that about one in 1,000 people who get infected will die. Those most at risk for severe disease are more than 50 years old and have weakened immune systems.

“Anytime you have a disease that could cause severe complications and death, of course we’re concerned. But we need to keep it in perspective,” Kent said. “The majority of people who are exposed don’t develop symptoms, and in those that do develop symptoms, they are very mild.”

The virus has been spreading across the United States since its confirmed arrival three years ago in New York. Kansas’ first confirmed case came a week ago, with the death of an infected horse in Cowley County.

State and local health officials declined to identify where the infected blue jay was found in Douglas County. Such information is immaterial, they said, because of the high mobility of birds.

“Once West Nile has been identified in a given area, it’s generally acknowledged in that area,” said Mike Heideman, spokesman for the Kansas Department of Health and Environment.

Prevention remains the best defense against contracting the disease, said Kim Ens, communicable diseases coordinator for the health department. People should limit their exposure to mosquitoes by:

 Wearing long sleeves and long pants, particularly at dusk and at night when mosquitoes are most active.

 Using insect repellent that contains DEET.

 Getting rid of stagnant, standing water at home, such as in wading pools, bird baths or discarded tires. Such pools can be breeding grounds for mosquitoes.

City and county officials have no immediate plans to spray pesticides in area fields or neighborhoods to kill mosquitoes.

That’s because the dangers of spraying chemicals around people can be more dangerous than a bite from an infected mosquito, said Craig Weinaug, county administrator.

“This is not something that’s going to go away,” Weinaug said. “As I understand it, this is going to be with us from now on. You don’t eradicate mosquitoes. You can’t go out and kill all the birds. People just need to learn to take reasonable precautions.”

State officials will continue encouraging people who find dead birds to contact the state’s toll-free West Nile hot line, (866) 452-7810, for possible testing, Heideman said. People should not call local law enforcement agencies.

Either way, he said, people should wear gloves when handling dead birds.

“There’s really no evidence of West Nile virus being transmitted from birds to humans, but it’s just good sanitation,” Heideman said.

Officials at Kansas State University have been screening for the disease since May, testing animals across the state.

Of the more than 400 tests conducted so far on horses, five have turned up positive, said Dr. Sanjay Kapil, a professor of veterinary virology at Kansas State. Tests on Douglas County horses thus far have come up clean.

“Most of the horses remain normal, but we do see some (that are infected) with weakness in the legs, head pressing and nose twitch,” he said. “In general, they will be showing nervous signs.”

Vaccinations are available for horses. People with questions or wishing to order a West Nile test for a horse may contact Kansas State’s veterinary diagnostic lab at (785) 532-5650.