A second Utah County person has died of complications from West Nile virus, and health officials are readying for an unusually severe season.

The central Utah County person, who is older than 65 years old, died within the past few days, said Lance Madigan, spokesman for the Utah County Health Department. The test results came in Wednesday afternoon, two days after the first death, that of an elderly southern Utah County man, was reported.

"It's throughout the county," Madigan said. "People can't think that it's just down by the lake or in the south side of the county or by the mountains."

As of Wednesday, 21 human cases were confirmed with the Utah Department of Health, according to the weekly West Nile report; 12 of those were in Utah County. That doesn't include this death, which was confirmed Wednesday afternoon, nor does it include all of the cases that weren't severe enough to require a doctor's visit and never got tested.

Utah County, however, says the number of confirmed cases here is 18.

"We do know that's the tip of the iceberg," said Dr. Lisa Wyman, an epidemiologist with the Utah Department of Health, adding plenty more cases are anticipated this season. "We are pretty much way ahead of our curve. It's not of epidemic proportions, but we're definitely having a very strong, intense season."

She estimated that a few hundred people have already been infected, but because only about 20 percent exhibit any symptoms, most people don't know when they get it. Those who do, however, are most likely severe.

"For a fever case to be reported it probably means that somebody was very sick and went to their doctor looking for an answer, basically," Wyman said.

West Nile, which is spread by mosquitoes, made its first appearance in Utah three years ago. Last year one person in Uintah County died from complications of the neuroinvasive form the disease, which can cause meningitis and encephalitis; 12 of the confirmed cases this year have fallen into that category.

The population centers in the state have been hardest hit this year, with Utah, Salt Lake and Davis counties reporting the most outbreaks in mosquitoes, horses and birds in addition to people. That's a change from last year, Wyman said.

"The biggest difference this year is that the Wasatch Front is really getting hammered," she said.

County mosquito abatement programs are actively spraying; Madigan said Utah County's program is only trapping half the number of mosquitoes it was last year. The problem is the concentration of infected bugs is higher, and "they're biting people with a will."

Wyman said health officials are anticipating that a couple hundred people will have confirmed West Nile before the end of the season.