As of Wednesday, the North Dakota Department of Health reported five new human cases of West Nile virus since reporting the first case two weeks ago, bringing the statewide total to 19. This compares to only four cases confirmed in 2011. The North Dakota Department of Health has not detected increases in West Nile virus activity similar to what has been reported in recent weeks since 2007 when there were 369 human cases reported. Of the 19 confirmed cases, five have been hospitalized.
Kirby Kruger, director of the disease control division of the North Dakota Department of Health, said Friday two of the human cases so far have been reported in Barnes County. In addition, there was one Barnes County rreport of what Kruger described as an “asymptomatic blood donor – it’s related to West Nile, but not referred to as a case.”
Along with the human cases, there were 13 confirmed cases in horse and two confirmed cases of the virus in birds, Kruger said.
Theresa Will, director of City-County Health, said Friday along with the confirmed cases in Barnes County, “I have been getting occasional calls from citizens saying someone has West Nile virus” that is not counted as confirmed cases. Will said she spoke with the State Health Department and discovered state rules for defining confirmed cases eliminate some exposure of the virus to humans. “I think it is more than reported.”
“The cases are geographically wide-spread, except in the west. There have been confirmed cases in almost all southeastern North Dakota counties,” Kruger said.
“We are starting to see significant West Nile virus activity in North Dakota and many parts of the country are seeing large numbers of cases,” said Alicia Lepp, epidemiologist with the State Health Department.
“People need to be aware that there are mosquitoes out there spreading disease even though the mosquitoes are not as visible as in past years. People need to take the proper precautions to protect themselves from this serious disease.”
People in North Dakota may not notice significant numbers of mosquitoes this year, as indicated by the low number of mosquitoes collected in the state mosquito trap network. Many of the mosquitoes normally collected in the mosquito traps are “nuisance” mosquitoes and typically do not carry West Nile virus, meaning the number of mosquitoes collected in the traps does not necessarily indicate the number of mosquitoes carrying West Nile virus. The Culex tarsalis mosquito, the mosquito that transmits West Nile virus in North Dakota, is most active between dusk and dawn and people may not recognize that they are being bitten. Those spending time outdoors, especially between dusk and dawn, need to make sure they are protecting themselves from mosquito bites.
Will said people outdoors a lot, such as hunters and others in the fall, should take precautions to use mosquito repellant “and cover up.”
To reduce the risk of being bitten by mosquitoes, the state health department recommends the following protective measures:
• Use insect repellent that contains DEET, picaridin, IR 3535, oil of lemon eucalyptus or permethrin when outdoors. Always follow the directions on the manufacturer’s label.
• Limit outdoor activities between dusk and dawn when mosquitoes are most likely to bite.
• When possible, wear long pants and long-sleeved shirts while outside.
• Eliminate stagnant water and leaf debris in containers around homes where mosquitoes can lay their eggs (e.g., buckets, flowerpots, old tires, wading pools and birdbaths).
• Keep mosquitoes from entering your home by repairing screens in windows and doors.
• Keep the grass around your home trimmed.
The following is a summary of West Nile virus activity in North Dakota to date:
• Human cases – 19
• Positive horses – 13
• Positive birds – two
• Positive asymptomatic blood donors – 14 (not counted as cases)
• Statewide, activity has been detected in 16 out of 53 counties in North Dakota: Barnes, Benson, Burleigh, Cass, Grand Forks, Grant, Dickey, LaMoure, McIntosh, Ramsey, Ransom, Richland, Sargent, Stark, Stutsman and Walsh.