A south Utah County man died of West Nile virus Sunday, marking the first death from the disease this season and the first casualty of the virus in the county ever.

The man, who was older than 65 years old, was taken to Utah Valley Regional Medical Center for encephalitis or brain inflammation. He was tested for West Nile, but the results didn't come in until Monday afternoon. He was the 15th confirmed case in Utah County; 23 individuals throughout the state have tested positive for the virus.

Lance Madigan, spokesman for the Utah County health department, said finding out the man's diagnosis earlier wouldn't have made a difference since West Nile cannot be treated; doctors only provide supportive care and hope the person's immune system can battle the virus. In this case, most likely because of the man's age, it couldn't.

"It can cause all sorts of severe complications," Madigan said of the virus, which is spread by mosquitoes. He couldn't comment on the specifics of this case but said because the disease had progressed to the neuroinvasive stage, which attacks the nervous system, the man's case was severe.

The health department cannot release any additional identifying information because of privacy laws, and the Daily Herald was unable to find the man's family.

Health officials are still tracking the incidence of West Nile throughout the state with some concern; the season started several weeks earlier than last season, although there was an unusually lengthy period between when the virus was found in mosquitoes and when it spread to horses and humans. Since it hit humans, though, many cases have been confirmed, with about half in Utah County. The blame there most likely falls on Utah Lake, which is a perfect breeding ground for the insects.

Madigan said he anticipates the human cases will continue showing up at a similar rate, most likely until early September at the earliest, although what the season will do is difficult to predict.

"If we had a freeze tomorrow, that would change the rules," he said.

If Utah County had an Indian summer and the warm temperatures lasted into late September or October, that would also change the situation and present a greater danger.

According to the state health department, 52 cases of West Nile virus were confirmed in Utah in 2005; 16 of those were in Utah County. An elderly man from Uintah County was the only reported West Nile death in 2005.

The disease is transmitted only by mosquitoes, so Madigan said it is unlikely the victim's family is at greater risk because he had the virus. However, they could be at risk if they were in the same area and were bitten by mosquitoes. Four out of five infected people don't have any symptoms; those who do have flu-like symptoms such as fever, nausea, lethargy and body aches. A few have severe neurological symptoms; most of those with severe symptoms are old or young, but potentially anyone could be affected.

The best way for people to protect themselves, health officials have and will continue to emphasize, is wearing bug repellent with DEET, wearing long sleeves and pants when outside between dusk and dawn and ridding yards of standing water, which can act as mosquito breeding places. A recent report estimated about one in five mosquitoes in Utah County is carrying the West Nile virus.

The county's mosquito abatement program is doing aerial spraying and sending out vehicles to spray the worst mosquito areas, according to the county, and the number of mosquitoes is down from previous years. But that's no reason to stop taking precautions.

"Wear your DEET," Madigan encouraged.

Heidi Toth can be reached at 344-2543 or htoth@heraldextra.com.

This story appeared in The Daily Herald on page A1.