West Nile Virus, which is transmitted by mosquitoes, causes paralysis, encephalitis and meningitis in about 1 percent of cases. Death occurs only rarely.

Health officials are investigating a case in an adult in south Utah County, where three horses and two chickens have also tested positive for the disease; an adult case in Uintah County, and another adult case in Duchesne County.

All three tests showed positive in preliminary testing, but Joseph Shaffer, director of the TriCounty Health Department serving Daggett, Duchesne and Uintah counties, said he isn't calling it West Nile virus until final testing.

Utah County Health Department spokesman Lance Madigan said positive confirmation is expected Wednesday.

Death from West Nile Virus Is Rare

The cases were likely contracted in the area where the people live, Madigan said. Health officials refused to identify home towns or the gender of the victims

In a statement, Utah County Health Department director Dr. Joseph Miner said the suspected infections are not cause for panic.

"But it is another reminder to us to protect ourselves and our families when outdoors by wearing insect repellents containing DEET or Picaridin."

Most folks the disease infects don't show symptoms, but about 20 percent do. Those symptoms may include fever, body aches, headache, skin rash and occasionally swollen lymph nodes.

In about 1 percent of cases, victims exhibit paralysis, encephalitis (inflammation of the brain) and meningitis (inflammation of the brain's lining). Death occurs only rarely, according to the Utah County Health Department.

Avoid Mosquito Bites

Mosquito abatement teams increased their activity in Utah County when the presence of West Nile became known, Miner said.

He cautioned people to stay indoors and repair window and door screens. When venturing outside during the hours between dusk to dawn cover up with a long-sleeved shirt and long pants and use repellent, he said.

"The best way to keep from being infected with the disease is to avoid mosquito bites," he said.

Last week mosquito abatement teams captured about 4,000 mosquitos in one trap near a southwest Provo ballpark, he said.

The virus can be spread by infected birds over long distances, although only infected mosquitoes can transmit it to birds, horses and humans.

West Nile virus first entered the United States in 1999 and was first discovered in Utah in 2003. Utah health officials have had no reported fatalities, Madigan said.