High mosquito counts in northeast Jamestown have prompted city vector control efforts to deter continued growth from recent rain and hot weather.
“July and August are the two worst months for mosquitoes, obviously because they are the hottest,” said Dawn DeVillers, city vector control officer.
The eight mosquito traps around Jamestown are checked daily. When a trap has at least 124 female mosquitoes the city Street Department will conduct nighttime fogging of pesticides in that neighborhood and will fog citywide when the average of all traps exceeds 124 mosquitos.
In the past week the Eastwood pond mosquito trap at 5th Street and Eastwood Drive Northeast has had from 200 to 364 mosquitoes, DeVillers said. The increase is the result of water pooling on saturated ground from recent steady rain and warmer temperatures, she said.
“It’s not going down at all,” DeVillers said of the pooling water. “The wet and the heat absolutely does not help. We don’t want to wait until it gets to be 500.”
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Two days of larvicide operations in northeast Jamestown have depleted the remaining 30-day supply, she said. More larvicide was ordered and 180-day briquettes are available for areas where it is efficient to use them, she said.
“We also have the fogging chemical and we did fog the northeast on Thursday and Saturday nights,” she said. “That makes three times the northeast has been fogged so far.”
Fogging operations are typically carried out from 1 a.m. to 5 a.m., she said. The fogging truck will spray along every street, avenue and alley in the neighborhoods involved, she said.
“It’s unrealistic for people to think they are not going to have any mosquitoes,” she said. “We’re just trying very hard and doing the best we can to keep it under control.”
The cooler weather helped as the Thursday morning mosquito count was just 36 in the same northeast Jamestown traps with the higher counts earlier this week. But there is a lot of summer left, she said.
Residents can help by removing items that collect water from yards, cleaning gutters and cutting overgrown grass and vegetation to eliminate mosquito breeding grounds, she said. Mosquito eggs take only one to three days to hatch, and it takes just a bottle cap with some water to hold up to 400 mosquito eggs, she said.
“Driving down the alleys I see the high grass, tires and junk laying there and I know that is going to add to the problem,” DeVillers said.
Jenny Galbraith, an epidemiologist with the Division of Disease Control of the North Dakota Department of Health, said there is an increase in mosquitoes testing positive as West Nile virus carriers around the state. There was an increase from five to 10 positive pools between July 1 and July 14, she said.
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“It’s difficult to predict what the mosquitoes will be like in the upcoming weeks, which is why it is important to mindful of those personal precautions,” Galbraith said. “Historically, we see our peak onset for West Nile virus cases in August, and again, that is why it is so important to protect yourself from mosquito bites.”
There are three cases of hospital reported West Nile virus in North Dakota so far since Memorial Day weekend. The cases were reported in Cass, Ramsey and Ransom counties.
There were 62 cases of West Nile virus and one related death reported in North Dakota from June through November 2017.
The mosquito species present in North Dakota that carry West Nile virus us the Culex tarsalis, along with testing for the presence of Aedes vexan, a species that carries canine heartworm and encephalitis.
