The peak season for West Nile Virus isn't until August, but state public health officials want residents to start taking precautions now.
The best way to avoid catching West Nile later this summer is to keep the mosquito population down now, officials say.
"This is the time of year to start making sure you're not a mosquito breeder," said John Pape, Colorado Department of Public Health and Environment epidemiologist.
Culex mosquitoes are the primary carriers of West Nile. The mosquitoes have been found in Colorado this year already, but none have tested positive for the virus.
In Moffat County, roughly 100 mosquitoes have been tested; all were negative for West Nile.
Last year, Colorado had 291 human cases of West Nile, four of them fatal.
Moffat County didn't have any West Nile cases, but Rio Blanco County had one.
Culex mosquitoes are not common above 9,000 feet, but Pape said that doesn't mean people in higher elevations are safe from West Nile.
"Based on some of the testing in (Northwest Colorado) you've got the right kind of mosquitoes," Pape said, which means the disease is a possibility.
Although the number of human West Nile cases in Colorado was far greater than in neighboring states, such as Utah, with 11, and Wyoming, with 10, it was a major drop-off from 2003, when Colorado had 2,947 cases of the disease.
Pape said weather is always an important factor for determining the severity of the mosquito season, but it's impossible to predict how severe the West Nile season will be.
"There's no way to predict the severity," Pape said. But, "we know we're going to have virus activity."
Pape said weather on the Front Range suggest "a much quieter" West Nile season than last year.
Pape said people who spend time outdoors should follow the "four D's." Dress in long pants and shirts, avoid dusk and dawn when mosquitoes are out, drain standing water and use insect repellent with DEET.
Jacque Malley, a public health nurse with the Visiting Nurse Association of Craig, said parents should take the proper precautions when using DEET on their children. That means avoiding open cuts and sores and washing the repellent off when children come back inside.
The Centers for Disease Control and Prevention also endorse using repellents with picaridin and oil of lemon eucalyptus.
Malley said it is important for people to follow the "four D's" even if they are in their own yard.
"Your back yard is not a safe zone," Malley said. "You can get bit anywhere."