2 cases of West Nile virus confirmed in Utah

West Nile virus has arrived in Utah.

Health officials on Thursday confirmed one human case each in Salt Lake and Box Elder counties, though whether either patient contracted the disease in Utah is not known. The virus also has been found in mosquitoes in Grand and Washington counties.

The virus, which is potentially serious, first appeared in the United States in 1999. Mosquitoes infect humans and horses, but someone who has been infected can't spread it.

The Box Elder County resident, described as between 45 and 64 years old, was apparently very ill with meningitis, one of the possible neurological complications of the virus. But because during the two-week incubation period when he or she must have been infected the individual divided time between Utah and Arizona, it's unlikely officials will learn where exposure occurred, state epidemiologist Dr. Robert Rolfs said.

Health officials learned about the case in Salt Lake County just minutes before the news conference to announce the virus' detection in Utah. Rolfs said the patient is a young adult, but no other details were available. And though state health officials believe the two have the virus, the results will be confirmed by the state lab and possibly the Centers for Disease Control and Prevention, he said.

Though Colorado was ravaged last year, Arizona is the hardest-hit state so far this year, with 161 of the 256 cases reported nationally by July 27. Six individuals have died nationally.

That's extremely rare, according to Dr. Scott Williams, executive director of the state health department, and Rolfs. The vast majority — 80 percent — of people who are infected will show no symptoms. The other 20 percent will generally have flulike symptoms such as fever, muscle aches and possibly a rash. Neurologic effects such as meningitis, encephalitis and even death involve only a few cases. The risk of a severe illness increases with age.

There is no treatment for West Nile virus, so prevention messages are a key part of the public health campaign.

Health officials were not surprised the virus reached Utah, since it has been found in several surrounding states. All along, they've said it was "when," not "if." But this is about the time you'd expect cases, Rolfs said. And they're likely to continue into September.

An early, hard frost would help, said Gary Hatch of the Davis Mosquito Abatement District.