Topeka ? The first five human cases of West Nile virus have been confirmed in Kansas, but state health officials say cooler weather will reduce the risk of the mosquito-borne disease.

“We are getting very close to the time of the year when mosquitoes aren’t a problem in Kansas. Without mosquitoes, the virus doesn’t spread,” Dr. Gail Hansen, state public health veterinarian, said Thursday.

The Kansas Department of Health and Environment said three cases were in Rice County, with one each in Shawnee and Wyandotte counties. The cases were confirmed by the federal Centers for Disease Control in Atlanta.

In Rice County, the three were a 29-year-old with onset of symptoms Aug. 16; a 58-year-old with symptoms on Aug. 15; and a 72-year-old with symptoms on Aug. 28.

The Shawnee County case involved a 28-year-old with symptoms on Aug. 30. In Wyandotte County, a 52-year-old showed symptoms on Aug. 12.

Dr. Gianfranco Pezzino, state epidemiologist, said the five were men and women, but declined to provide specific genders, citing privacy concerns.

Pezzino said another four CDC tests came back negative, and KDHE is awaiting results in seven cases he called “suspect” but not certain to be West Nile. He said those people exhibited symptoms last month.

Only one person remained hospitalized, although health officials would not say where. Normally, symptoms in seriously ill West Nile patients last about a week.

Pezzino said there was no cause for alarm because “even if you are bitten, your chances of becoming seriously ill are small.”

He said of those who contract West Nile, only 1 percent become seriously ill. Of that 1 percent, no more than 15 percent die amounting to 15 out of 10,000.

Most people infected with West Nile show no symptoms. Some may have a fever, or aches of the head or body.

But others particularly those who are older or have weakened immune systems may contract encephalitis, a brain swelling that sometimes can be fatal.

Hansen said while cooler weather will reduce the mosquito population, that’s no guarantee that the virus won’t return with warm weather next year.

“I would be expecting to see more cases next year. I don’t expect to see it go away in Kansas,” she said.

The disease is transmitted when a mosquito bites an infected bird and then bites another animal or person. It cannot be transmitted from one person to another. disease when they return in the spring.

People should wear mosquito repellent with DEET and cover exposed skin while avoiding the outdoors at dusk, early evening and dawn, health official say.