"The intent of that is to knock down the first wave of mosquitoes in the county," said Lee Griffen, who heads up the West Nile program at the El Paso County Department of Health and Environment. Mosquitoes breed in standing water and can lay hundreds of eggs at a time.

A human case of West Nile has been confirmed in Weld County. But it's possible it was contracted from an infected mosquito that lived through the winter, because no mosquito pools there have tested positive for the virus.

The 59-year-old man fell ill in mid-April and is recovering at home, said Marian Ruge, spokesman for the Weld County Department of Public Health and Environment.

No Indication How This Season Will Unfold

Mosquitoes are being seen in El Paso County, but not yet in great numbers, Griffen said. The bugs carry the virus to people after feeding on infected birds.

Most people will suffer minor symptoms if infected, but the virus can cause permanent disability or death. Symptoms range from aches and rashes to convulsions and paralysis.

West Nile hit Colorado with a vengeance in 2003, when 63 people died and nearly 3,000 cases were confirmed.

In the 2004 mosquito season, 291 cases were reported statewide; last year, the number of human cases totaled 106, according to the Colorado Department of Public Health and Environment.

There's no indication of what this season might hold, Griffen said.

"This could be the year where it pops back up," he said.

People who have gotten sick say it's not a disease to be taken lightly.

Just ask Margaret Radford, city councilwoman and now a spokeswoman for the county Health Department. She was wiped out by the virus in August 2003.

For two weeks, she was in bed round-the-clock, she said.

"I had the chills, the neck pain, the muscle pain, but the most enduring symptom for me was the fatigue, and that went on for another eight weeks. I had never experienced anything like that, including major surgeries and childbirth.

"I have to admit that of all the important things we do at the Health Department that West Nile is really close to my heart because I had it."

Some Tips for Repelling Mosquitoes

Empty water from wheelbarrows, tires, plant saucers, garden equipment and anything else that could be a potential breeding site.

Change water in birdbaths and wading pools weekly.

Wear long-sleeved shirts and long pants while outdoors, especially at dawn and dusk, when mosquitoes are most active.

Stock ornamental ponds with fish that eat mosquito larvae.

Use insect repellent.

For more information, visit www.fightthebitecolorado.com.