Mosquitoes are out and about
The insect’s population starts to increase in June
June 16, 2017
Bryan Stephens says the county's Mosquito Abatement District uses biology to fight biology when eradicating blood-sucking insects that act as vectors for viruses such as West Nile.
"We use BTI (bacillus thuringiensis israelensisa), a natural occurring bacteria found in soil, to kill mosquitoes," said Stephens, who is the district's director. "We concentrate it and then we use that material to put in the water as a treatment. It's a very target specific material for mosquitoes, so it doesn't affect other organisms or insects."
While the district's employees are out on the field working to kill the annoying assailants, people should take precautions such as using insect repellent to avoid bites during mosquito season, Stephens advises.
This year's season began in mid-April, but the months of June, July and August are when the mosquito population in Summit County is at its height.
"The population starts growing during the hotter parts of June and into August, then we start to see things temper down in October when the area gets its first freeze," Stephens said.
The director added that elevation, temperature and water are factors that determine the mosquito population during summer. Higher elevations tend to be cooler, he said, so mosquito season in Salt Lake City lasts longer than in Park City.
"The amount of water also has an influence," Stephens said. "This year, we have a lot of water, so there may be more mosquitoes this year."
Late June is when Stephens and his team start to be concerned about West Nile.
"Later into the end of June, July and August is when the county starts seeing the mosquito that carries the West Nile virus," Stephens said. "We haven't started testing for it yet in the county, because we haven't been able to collect that type of mosquito yet."
According to the Centers for Disease Control and Prevention's website, most people infected with West Nile show no symptoms, but one in five "will develop a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea or rash."
Stephens said the Culex tarsalis is one type of mosquito that carries the virus.
"Salt Lake has that mosquito, which carries West Nile down there," Stephens said. "We have that same mosquito up here, so we have the potential to have West Nile, just as they do in the valley."
Stephens said Salt Lake County reported cases of West Nile last year.
"When I say that, I mean they have reported cases when they test mosquito pools and find the virus in mosquitoes," he said. "They also have had human cases in the past."
According to the Utah Department of Health's website, zero cases of West Nile were found in Summit County's mosquito population last year, while hundreds of mosquitoes tested positive for the virus in Salt Lake County in 2016.
The website also reported Salt Lake County saw five human cases in 2015.
Stephens said the Culext tarsalis is a mosquito that tends to come out at night.
"If people are getting bitten in the day, it's not much of a concern," Stephens said.
In addition to using insect repellent, people should wear long-sleeved shirts and pants at night, the district director suggests.