County looks at West Nile virus |

County looks at West Nile virus

SILVERTHORNE – Summit County’s mosquitos are every bit as annoying as their cousins elsewhere in the world, but they’re less likely to carry the West Nile virus. Nevertheless, the county’s environmental health director plans to educate local residents about the disease.

The disease killed 277 people in the United States last year, and began showing up in Colorado in late summer. Front Range cities are already bracing for the potential of more infections this summer, and while the chances of a case showing up here are less likely, Jim Rada says it can’t be ruled out.

“There has been no mosquito trapping or monitoring of mosquito populations in the county for at least the last 14 or 15 years, so we really don’t know what kind of mosquitos we have, or the relative numbers of mosquitos we have,” said Rada, Summit County’s environmental health director.

The culex species of mosquito is the primary carrier of West Nile, “and those species can survive at elevations of 9,000 feet,” Rada said.

However, because the water temperatures in mountain communities are so cold, that likely discourages mosquitos from breeding. It’s also likely to extend the life cycle, meaning the mosquitos need more time to hatch and for the larvae to develop into adults.

“So, it’s likely that in our county, we have smaller populations of these particular mosquitos,” Rada said.

The culex is more prevalent along the Front Range, which means business is booming for Marhsall Lipps, operations manger of Colorado Mosquito Control. The Broomfield-based company contracts with towns and counties to map mosquito breeding sites, look for larvae and then treat those sites.

But he doesn’t expect to do an overwhelming amount of business in Summit County.

“The culex is more of a Front Range mosquito,” Lipps said. “You don’t typically find them in the higher elevations. I’m not going to say never, but their numbers are much lower than we find here. There’s a much larger threat down here.”

The culex species has one bothersome trait, Rada said. They can survive the winter by tucking themselves into drainage culverts and mines, areas not exposed to extreme cold, then emerge in the spring. Some of those mosquitos may have gone into hibernation in the fall already carrying the West Nile virus.

The county does not now plan to spray for mosquitos, Rada said, “but we are looking at promoting the idea of larva siting.”

During that process, water that is a likely host for the culex mosquito can be treated to stop the mosquito larvae from developing.

“We’ll start out with public education, and some general monitoring of disease patterns around us,” Rada said. “If we see that perhaps we have a heightened risk of West Nile occurring here, then maybe we look at trying to trap mosquitos, to do more intensified monitoring and treat them with larvicide.

“Because of the county’s financial situation, I’m not recommending the county get into the mosquito abatement business. But if it elevates and we’ve got significant disease occurring in our community, we would want to step in and take some stronger action.”

So far, Colorado’s incidences of animal and human West Nile have been centered around river basins in counties including Weld, El Paso, Adams, Denver, Jefferson and Morgan. In Colorado, 13 people contracted it in 2002, but none of them died. It poses the greatest danger to those age 50 and older.


To avoid mosquito bites:

– Apply insect repellent containing DEET.

– When possible, wear long sleeves and long pants treated with repellent. Mosquitos can bite through thin clothing.

– Repair holes in windowscreens.

– Eliminate standing water sources around your home.

– Limit outdoor activity at dawn and dusk. The West Nile-carrying culex mosquito species – along with other mosquito species – feeds primarily at those times.

Jane Reuter can be reached at (970) 668-3998, ext. 229, or by e-mail at

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