Grand Forks area approaching peak season for West Nile
Mosquitoes may not seem especially bothersome right now, but this is no time to let your guard down against the insects that could carry the West Nile virus, said Todd Hanson, head of the mosquito control program of the Grand Forks Public Health ...
Mosquitoes may not seem especially bothersome right now, but this is no time to let your guard down against the insects that could carry the West Nile virus, said Todd Hanson, head of the mosquito control program of the Grand Forks Public Health Department.
Hanson and his colleagues are taking "aggressive" action to counter what "we consider to be an elevated threat of West Nile virus," he said.
"We are finding mosquitoes and birds that are positive for West Nile virus on a weekly basis," Hanson said. "That's why we're out spraying even with low trap counts.
"We'll continue on that aggressive basis until we see that population of Culex tarsalis diminish. It will be the end of August or early September when we see that population reduce. After that, we'll fall back to nuisance control."
About half of the mosquitoes, 26 of 55, collected from traps around town this week were Culex tarsalis, which can carry and transmit West Nile, he said.
"The rest were nuisance mosquitoes," he said.
Don't be lulled by the apparent lack of mosquito activity, Hanson cautioned.
"We don't have a lot of nuisance mosquitoes right now, so people tend to think that mosquitoes are not that bad," he said. But "we are reaching peak season for West Nile virus, which is pretty much all of August. That's generally when the highest number of human cases is reported."
Two human cases of West Nile have been reported in North Dakota this summer-one each in Ramsey and Ransom counties.
"I'm surprised that there's only been two cases, based on the numbers of the Culex tarsalis population," he said.
The North Dakota Health Department has been urging people to take precautions to protect themselves from the virus, said Jenny Galbraith, surveillance epidemiologist in the department's Division of Disease Control.
In 2017, the state Health Department reported 62 cases of human infection with West Nile, about one-third of those resulted in hospitalization, Galbraith said.
Two people died after contracting the virus, she said.
In Grand Forks area, "West Nile virus is not isolated to one part of the city," Hanson said. "It's throughout the city. We picked up a bird the other day in East Grand Forks that tested positive for West Nile."
The virus also has been identified in throughout the Dakotas, he said.
"Grand Forks is better off than most of the region because of the type of program we have," he said. "We put out traps early, and we're looking for it earlier than other parts of the state."
Weather conditions here have been "ideal for Culex tarsalis-really hot and on the dry side," he said.
"Even though we've had some timely rains, we're a little on the dry side," he said.
The mosquito thrives in standing water, such as "a stock pond or a bucket in the backyard," Hanson said.
"In any permanent body of water, (the female) is going to lay the eggs and she will stay close to where the eggs are hatched," he said. "That's why it's so important for people to inspect their properties. Even the smallest containers can breed out thousands of mosquitoes."
Because they're not bothered too much by mosquitoes in daytime, residents "think they don't have to take precautions, but now is the time they need to be vigilant about this," Hanson said.
"The Culex tarsalis is more of a nocturnal mosquito," he said. "It comes out at dusk or twilight, when people are in their gardens. People really need to be cautious about wearing insect repellent and protective clothing.
"Personal responsibility is the most important part. Apply mosquito repellent and wear protective clothing. Don't rely on us," he said.
"All it takes is one mosquito to bite you and transmit that virus to you."