West Nile virus has again been found in a mosquito sample in Laramie, the city announced Tuesday morning.
Despite finding a second positive sample, Laramie stays rated at “Level 1 – Low Risk” based on the guidelines from the Centers for Disease Control. Currently, the risk is categorized as “limited to sporadic activity in local mosquitoes and birds,” according to a city news release.
The first positive sample for WNv was found about a month ago in a trap within city limits.
The adult mosquito trap with the second positive sample was located approximately 6 miles southwest of city limits. The news release said city mosquito technicians so far this year have tested 22 samples of the WNv vector mosquito, Culex tarsalis, with two samples testing positive for the virus.
Low to moderate numbers of vector mosquitoes have been collected at trap locations near the Big Laramie River and other rural locations.
“Residential surveillance sites within city limits report low vector numbers,” the release said. “Overall, nuisance mosquito numbers have been decreasing and vector mosquito numbers have been slowly increasing.”
Tyler Shevling, Mosquito Control crew supervisor, said the city always sees higher nuisance mosquito numbers than vector mosquitoes, which is why they’re measured in two different thresholds on the city’s adult surveillance traps.
“We’ll keep monitoring for both, but I expect the nuisance mosquitoes to continue to go downward,” he told the Laramie Boomerang on Tuesday afternoon. “Our vector mosquitoes, they actually particularly like the hotter, drier days of summer. So, we’ll see an increase in vector mosquitoes, but it won’t be anything like our nuisance mosquitoes.”
Shevling added the “vector mosquitoes particularly like semi-permanent or permanent water,” and one great way to help the city’s efforts is to dump standing water out of old tires, pet water bowls, birdbaths and other areas where the mosquitoes can lay their eggs.
Mosquito Control has continued its fogging efforts in residential areas where “both vector and nuisance mosquitoes are being found,” the release said. Additionally, crews are targeting areas with higher vector number densities as well as areas popular for outdoor recreation, including city parks and the Laramie River Greenbelt Trail.
Shevling said fogging conditions have improved since the first WNv-positive sample was found last month.
“We’ve been able to get the fog trucks out a little more frequently, especially this last week or so,” he said. “We still keep running into some afternoon/evening thunderstorms, but overall our mosquito numbers are on a downward trend, which is good.”
Currently, the fogging routes still avoid all designated “No Spray” zones in the city, the news release said.
The Wyoming Department of Health has confirmed one case of WNv in a human so far in 2019 — a woman in Campbell County. No human, equine or avian cases have been reported in Albany County at this time.