Mosquito counts drop
Fogging operations have helped to reduce the number of active mosquitoes in Jamestown and especially in the northeast neighborhoods, said Dawn DeVillers, city vector control officer.
There are currently an average of seven mosquitoes in the eight traps around Jamestown, she said. The average daily count would need to exceed 124 mosquitoes to prompt fogging operations again, she said.
"Last week our count was down considerably," DeVillers said. "The cooler temperatures as well helped this weekend's count."
There are 74 cases of hospital reported West Nile virus in North Dakota so far since Memorial Day weekend, according to the North Dakota Department of Health. Twenty-four cases required hospitalization.
This compares to 62 cases of West Nile virus and one related death reported in the state from June through November 2017.
The peak week for West Nile virus in 2018 was July 29 through Aug. 4, when 17 cases were reported, according to the Department of Health. The number of reported cases dropped to 12 for the week ending Aug. 11 and then four cases on Aug. 18.
The decreasing numbers are not yet a telltale sign that the season is winding down, said Jenny Galbraith, an epidemiologist with the Division of Disease Control of the North Dakota Department of Health.
"I would like to see how things change over the next week or so to truly be able to say if the season is winding down," Galbraith said.
There are now four cases reported in Stutsman County this season. Stutsman County has reported to have one mosquito pool test positive for the presence of West Nile virus. There are no reported animal or birds testing positive, the Health Department said.
The cases by county include Burleigh, 27, Cass, 10, Morton, six, Stutsman, four, with two cases each in LaMoure, Mercer, Mountrail, Ramsey, Ward and Williams, and one case each in Barnes, Bowman, Dunn, Foster, Grand Forks, McHenry, McKenzie, McLean, Ransom, Richland, Sargent, Sheridan, Sioux, Stark and Wells.
The mosquito species present in North Dakota that carry West Nile virus are the Culex tarsalis, along with Aedes vexan, which is known to carry canine heartworm and encephalitis. These varieties were not discovered in the traps this summer since Memorial Day, the Health Department said.
Residents can help eliminate mosquito breeding grounds in the yards, DeVillers said. Mosquito eggs take just a few days to hatch in warm, wet places and eliminating high grass, cleaning gutters and removing tires or items that collect from yards will reduce the available breeding grounds, she said.