GOSHEN COUNTY – The mosquito is the No. 1 animal killer of humans in the world. It carries a wide range of diseases, depending on the genus and region, including West Nile virus, Zika virus, Malaria, Yellow fever, Dengue fever and Chikungunya virus.
In Goshen County and throughout Wyoming, residents’ main concern is West Nile virus, which not only affects humans, but can cause encephalitis in horses and heartworms in dogs.
Mosquitoes spread WNV when they feed on infected birds and then bite people, animals and other birds, Wyoming Department of Health epidemiologist Katie Bryan said in a press release.
“Most people infected with WNV do not realize it’s happened,” she explained. For those who become ill, symptoms include fever, headache, body aches, skin rash and swollen lymph nodes. Additionally, the WDH release states a very small percentage of those infected develop West Nile neuro-invasive disease with symptoms including severe headache, fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions and paralysis.
Since WNV first appeared in Wyoming in 2002, reports of infections in humans have ranged from two with no deaths in one year to 393 and nine deaths in another. In 2016, 10 WNV cases were reported to WDH. The list of cases reported included seven people diagnosed with neuro-invasive disease.
“Overall, West Nile virus could be underreported,” Bryan said. “We’ve learned testing and reporting is more likely when people are seriously ill.”
Fortunately, the state funds local programs and equips qualified individuals with the right tools to keep dangerous mosquitoes at bay.
One of Goshen County Weed and Pest’s (GCWP) goals is to “monitor and treat densely (mosquito) populated areas with a high-risk factor of contracting WNV,” according to its website (goshenweedandpest.com). The department’s mosquito control program is funded annually through an emergency insect management grant, administered by the Wyoming Department of Agriculture.
For the last two years, Goshen County has received significantly less funding (from more than $90,000 to approximately $78,000) due to the state’s current economic downturn – however, GCWP is making the money it does have count.
At a recent Lingle Town Council meeting, GCWP Supervisor Bob Baumgartner said his department stretches dollars using an intense trapping and monitoring schedule to identify the type of mosquitoes present and to what extent before treating.
The GCWP’s focus is on human health hazards, specifically Culex mosquitoes, which carry WNV. On other hand, Aedes or nuisance mosquitoes are insects that do not pose health threats to humans.
The GCWP site explains the department monitors mosquitoes in Goshen County through the collection of specimens from areas known to have large mosquito and, specifically, Culex populations. Workers set traps on a weekly basis to determine the presence of WNV and the effectiveness of treatment. Once mosquitoes are trapped, they are sorted by genus and Culex mosquitoes are tested for WNV.
GCWP generally waits to treat mosquitoes until late summer when temperatures are hot and Culex populations are peaking – this helps conserve grant funds by making treatment more effective. GCWP will spray densely populated areas with an insecticide, often using an “ultra-low volume machine known as a fogger, mounted in the back of a pickup which emits a mist of product to kill adult mosquitoes,” per its website. Spraying occurs on a weekly schedule throughout Goshen County.
Yoder, LaGrange, and the city of Torrington spray their own towns, while GCWP covers Jay Em, Lingle, Fort Laramie, Veteran, Hawk Springs, Huntley, South Torrington, West Torrington, Badger Town and McKenna addition.
An airplane is used for spraying rural areas where adult Culex species have been found. Larva control in wet areas is also completed countywide.
According to mosquito population data collected by GCWP from 2004 to 2016, North Torrington has the most Culex mosquitoes with more than 400 on average per trap, followed by Huntley with more than 300 and Veteran with more than 200. Areas with the highest concentrations of non-Culex mosquitoes are Table Mountain with more than 900 on average per trap, followed by Huntley with more than 400 and the state line with approximately 400.
Ahead of Mosquito Control Awareness Week June 25 through July 1, the WDH and GCWP suggest following the five Ds to avoid bites:
1) Dawn and 2) Dusk: Mosquitoes that spread WNV prefer to feed at dawn or dusk, so avoid spending time outside during these times.
3) Dress: Wear shoes, socks, long pants and a long-sleeved shirt outdoors. Clothing should be light-colored and made of tightly woven materials.
4) Drain: Mosquitoes breed in shallow, stagnant water. Reduce the amount of standing water by draining and/or removing.
5) Defend or DEET: Use an insect repellent containing DEET (N, N-diethyl-m-toluamide). When using DEET, be sure to read and follow label instructions. Other insect repellents such as Picaridin (KBR 3023) or oil of lemon eucalyptus can also be effective.
More information about WNV in Wyoming is available online at https://health.wyo.gov/publichealth/infectious-disease-epidemiology-unit/west-nile-virus/.
