Although it has been cooler than normal this summer, the city says that hasn't reduced the intensity of its fight against West Nile virus.
Grand Forks scheduled mosquito spraying between 8 p.m. and midnight Thursday, weather permitting, though the morning's average mosquito trap count was only 14. Mosquito control supervisor Todd Hanson said the concentration of West Nile carrying Culex tarsalis mosquitoes has varied.
"One day, 50 percent in trap are Culex tarsalis, then the next day that number drops down," Hanson said. "We want to make sure we reduce that risk of West Nile virus."
The Grand Forks Public Health Department said people should protect themselves from being bitten because it's the peak season for human West Nile virus cases.
People older than 50 years old are most at risk. Hanson said that risk does not decrease in the transition from summer to fall.
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"September has been a challenging month," Hanson said. "We get artificially low trap count numbers because mosquito activity at night goes down as the temperature drops. For example, we can't spray until school kids are through with outdoor sports practice, so we don't get an accurate concentration in the traps."
Hanson said crews sprayed as late as Sept. 25 last year. He said larvicide crews will continue the ground attack until the end of September.
Reach Johnson at (701) 780-1262; (800) 477-6572, ext. 262; or send e-mail to jjohnson2@gfherald.com .
