The people in charge of keeping virus-carrying mosquitoes at bay are surprised they haven't seen West Nile virus appear in much of Utah yet.
But Sam Dixon, manager of the Salt Lake City Mosquito Abatement District, predicts it will show up this month.
"We're glad, but we're baffled that we haven't seen it here yet," he said. "The hotter the weather the better the chances of West Nile virus."
Managers thought that Utah's mild winter and warm spring would have set up conditions ripe for the virus to appear earlier than usual this summer.
Just one mosquito pool, in southern Utah, has turned up signs of the virus, which can cause disorientation, muscle weakness and a stiff neck or rarely seizures and death. But nearly all of the mosquitoes showing up in traps in Salt Lake City and Utah County are species that can carry the virus.
More than 300 human infections have been reported across the country this year, with 145 in Texas.
"The season is warming up for the virus," Dixon said. "If we're going to see it in Utah in humans or mosquitoes in the north, we should see it within the next couple of weeks."
He said mosquitoes that breed in the Great Salt Lake wetlands and feed on the birds usually seek out human blood around July 24, when the birds have left the drying beds. But wetland managers have put out more water than usual because of the drought, attracting birds and mosquitoes longer.
That won't last, Dixon said. He noted that homeowners are creating breeding grounds for the pests when they overwater their lawns and allow water to pool in containers at home as well as in catch basins in intersections.
In late summer, the older mosquitoes have an increased chance of picking up the virus.
"This is the time [people] need to be vigilant," said Bob Mower, director of mosquito abatement for Utah County.
West Nile virus season technically ends at the first hard frost, though the mosquitoes that carry the virus usually start feeding on nectar and not blood in September to fatten up. Shorter days cause them to switch from a reproductive to hibernation mode.
"Much like a bear, but only much smaller," Dixon said.
More than 80 percent of people who contract the virus don't show any symptoms, but the other 20 percent who do get sick with flulike symptoms may wait weeks before going to the doctor delaying the reporting rate.
In light of the high percentage of people who don't get sick, one theory is that many people have been affected by the disease already.
"So it could be we've all been essentially inoculated against it," said Lance Madigan, a Utah County Health Department spokesman. But he cautioned against people disregarding the seriousness of the virus.
"We don't want to create a sense of false security in people," he said. "It can be a very debilitating disease that can affect people for years."
To protect yourself from the virus:
Use repellent with DEET.
Wear long-sleeved shirts and long pants for additional protection.
Consider staying indoors at dawn, dusk and in the early evening, which are peak mosquito biting times.
Drain sources of standing water.