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Jul 21, 2023

Cheyenne, Laramie County continue pest control against West Nile

Mosquitoes carrying the West Nile virus were first found in Laramie County in mid-June. CHEYENNE — Abnormally high amounts of rainfall and warmer-than-average temperatures have led to a greater influx

Mosquitoes carrying the West Nile virus were first found in Laramie County in mid-June.

CHEYENNE — Abnormally high amounts of rainfall and warmer-than-average temperatures have led to a greater influx of mosquitoes than Cheyenne and Laramie County have seen in recent years, according to pest control and public health officials in the region.

“We definitely have a mosquito population, but it’s not at this level,” said Jennifer Escobedo, environmental health specialist with the Cheyenne-Laramie County Public Health Department. “The Culex tarsalis is the one that carries West Nile (virus). So (our pest control specialists) are specifically trained to identify that.”

City-County Health has been running the county’s West Nile virus prevention program to help trap, test and eliminate adult and larval mosquitoes and keep the population of mosquitoes to a minimum. In the city, Cheyenne’s Weed and Pest Division, which uses the same company as the county to set traps, spray problem areas and address constituent complaints, handles mosquito prevention for the city.

“We have full-time crews that are continually doing local mosquito control every summer,” said Steven Trowbridge, Cheyenne’s Weed and Pest manager.

“We have around 500 sites that we continually check, and we’re constantly checking for more, as far as the adult mosquito spraying, which would be the spray trucks that some people may see at night in the neighborhoods. We basically do that any night that the weather allows us to in areas where we see elevated numbers in our mosquito traps, which is what we use to monitor the population.”

This year, mosquitoes carrying West Nile virus were first found in Laramie County in mid-June. The Wyoming Department of Health has kept an online data table that tracks how many cases of West Nile virus have been confirmed among people and mosquitoes in the state.

As of Thursday, one case of West Nile virus involving a human has been confirmed in Wyoming, according to the chart. The person tested positive for a neuroinvasive form of the virus (as opposed to exhibiting fever-like symptoms) in Goshen County.

According to the chart, 427 mosquito pools in the state have been tested to date and, so far, 23 have come back positive. In Laramie County, 162 mosquito pools have been tested, and eight have tested positive for the virus.

“The standing water is probably our single biggest factor this year that’s leading to such a large number of mosquitoes,” Trowbridge said. “It’s just one of the biggest things that’s going to contribute to that in any year. Having lots of rain, then followed by some pretty warm temperatures over the last few weeks, are kind of the perfect storm. Those are going to be the things that are most likely to contribute to not only more mosquitoes, but also more virus-like environments.”

Both the city and county urge residents to practice a “Five D” approach: Dawn, Dusk, Dress, Drain and Deet.

The Culex tarsalis mosquito, Escobedo said, is most active during dawn and dusk. Avoiding going outside at this time can reduce someone’s exposure to potential disease-carrying bugs. The third D, dress, urges Laramie County residents to dress in a way that keeps mosquitoes away from their skin.

Trowbridge also said that, to him, one of the most important ways you can reduce potentially harmful mosquito populations is the fourth D, draining.

“The single most effective form of mosquito control is removing those sources for them to breed in,” he said. “So that’s what we really would like people to do is to pay attention to those sources that might be on their property or nearby or if they spot things that they don’t think are being addressed.”

The final D, Deet, informs residents to use a protective insect repellant, like ones that contain Deet. While this can be effective, Escobedo warned people to use these with caution, especially around children. She said always following manufacturers’ guidelines to keep children safe from both toxicity and mosquitoes.

“Deet shouldn’t be above 10%, if going on a kiddo,” she said.

Although the West Nile virus is on the rise in insects in Laramie County, that doesn’t mean there is no end in sight or that Wyoming is the only state with insect-related illnesses.

“Mosquitoes are one of those things that can carry different diseases, depending on which region of the country you’re in,” Escobedo said. “In this region, it primarily is West Nile virus, but in other parts of the country ... it’s things like St. Louis Encephalitis and Eastern Equine Encephalitis. Malaria made a comeback in the Florida area, so it’s always a good idea to protect yourself against mosquitoes, no matter where you are.

“Winter will be helpful, because it will freeze and kill those mosquitoes — at least for a few months, before we start again, right?”

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Samir Knox is the Wyoming Tribune Eagle’s criminal justice and public safety reporter. He can be reached by email at [email protected] or by phone at 307-633-3152. Follow him on Twitter at @bySamirKnox.