The North Dakota Department of Health reports 13 new human cases of West Nile virus since reporting the first case last week, bringing the statewide total to 14. 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 the past week since 2007 when there were 369 human cases reported. Of the 14 confirmed cases, five have been hospitalized.
“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 North Dakota Department of Health. “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.
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 – 14
• Positive horses – 8
• Positive birds – 1
• 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. West Nile virus activity will be updated Wednesday mornings each week throughout the West Nile virus season on the Department of Health’s West Nile virus website at www.ndhealth.gov/wnv.