Skip to main contentSkip to main content
You have permission to edit this article.

Beating West Nile

Mosquito control begins early

  • 0

Fulfilling many boys' dream of getting paid to play in swampy ponds, John Leman walked to the edge of the still water north of Casper Wednesday and scooped a half cup into his plastic cup.

About 75 little black swimmers, each about 2 millimeters long, wriggled in the cup.

These are the enemy.

The little swimmers will grow into big mosquitoes who could carry the West Nile virus and spread it to humans, horses and birds. Leman is hoping to limit their numbers and stop them from carrying the virus.

"With the warm weather we've been having, it's just brought 'em on," said Leman, mosquito control supervisor for the Casper-Natrona County Health Department.

The number of West Nile virus cases this year will depend on what the spring is like, state health officials say. If it's a wet, warm spring, mosquito populations will be high and the virus will be a problem. If it's cool and dry, it likely won't be so bad.

According to Terry Creekmore, West Nile surveillance coordinator for the Wyoming Department of Health, mosquito control will be important in any case.

The West Nile virus first appeared in New York in 1999 and has made its way further west with every mosquito season. Last year, the second year of the virus in Wyoming, nine people died and a total of 393 people contracted the virus. Natrona County had 29 cases and no deaths.

It hit hard in eastern agricultural communities, particularly in Platte and Goshen counties. Those two counties saw five deaths and 150 confirmed cases. Goshen County had 727 cases per 100,000 people, said Creekmore. This rate may be second or third highest for all of the nation's counties, he said.

Leman started killing the immature mosquitos, or larviciding, last Monday. He and five other workers will soon be out from 7 a.m. to 5 p.m. at the 130 breeding sites they monitor around the county. They use a biological agent which is toxic to mosquitoes, but generally not to humans.

In the summer they will start killing mature mosquitos, or adulticiding, from about 10 p.m. to midnight.

"I get four or five hours of sleep (a night) from April through September," Leman says.

But he believes the mosquito control program is effective. He said one light trap by the Natrona County International Airport would catch 2,000 to 3,000 mosquitoes a night last spring. When they started treating the drainage in the area in June, the numbers went down to 200 to 300 a night.

Casper and Natrona County are slated to spend $65,000 this year, which could be matched by a grant from the Wyoming Department of Agricultural. The Agriculture Department appropriated $1.5 million in this budget year to give to mosquito control agencies. Leman said if Natrona County gets a grant, workers may do aerial spraying, as Albany and Laramie counties have done in previous years.

Torrington in Goshen County was identified early last year as a West Nile hot spot. Dennis Grubbs, who does mosquito control for the town, said he went from spraying two hours a night from Monday to Friday to spraying eight hours a night from Monday to Saturday.

Grubbs has applied for $59,000 from the Wyoming Agriculture Department to supplement the $10,000 he gets from the city. He has seen mosquitoes flying around already but will not start spraying until April 18 because there is little moisture in the city.

It's not clear how many years Wyoming counties will need to hunt mosquitoes.

Creekmore said there is speculation that eventually, outbreaks of the virus will become cyclical or sporadic. But it could be years before that happens.

State Health Officer Brent Sherard said people who have been infected already will probably have long-lasting immunity to the virus.

"If it's lifelong is still up in the air," Sherard said.

In any case, officials are recommending wearing insect repellant with DEET and wearing proper clothing this spring and summer.


* I understand and agree that registration on or use of this site constitutes agreement to its user agreement and privacy policy.

Related to this story

Most Popular

Jacob Black has been the city's interim fire chief for months. Now, he's getting the "interim" removed from his title.

Get up-to-the-minute news sent straight to your device.


News Alerts

Breaking News