West Nile Virus surveillance activities begin in North Dakota

Staff reports

On June 1, 2011, the North Dakota Department of Health – in conjunction with several local, state, federal and private agencies – began coordination of West Nile virus surveillance activities, according to Michelle Feist, epidemiologist with the Department of Health.

Surveillance activities include reporting and testing sick horses, trapping and testing mosquitoes, monitoring illness in humans, and reporting and testing dead birds.

West Nile virus is transmitted through the bite of an infected mosquito. In North Dakota, the greatest risk for West Nile virus transmission occurs during the months of July and August when the Culex tarsalis mosquitoes, the mosquito that transmits the disease, is more abundant.

“Many people have been asking if flooding in the state is going to increase the risk for West Nile virus this summer,” Feist said. “The truth is that we can’t predict if there will be more cases, but because mosquitoes need water as a part of their life cycle, statewide flooding and above normal moisture increases the potential for more mosquitoes.”

In 2010, nine West Nile virus cases in humans were reported to the Department of Health, with no deaths.

Additionally, West Nile infection was identified in two horses, one dog and one reindeer. It’s also important to note that since surveillance started in 2002, a human case has been reported in every county in the state.

“Anyone who comes into contact with mosquitoes is at risk for West Nile virus, no matter where you live in the state,” Feist said. “It is important for people to take precautions now and throughout the summer months to protect themselves.” 

The best protection against West Nile virus infection is to avoid being bitten by mosquitoes. People are encouraged to take the following protective measures:

• Use insect repellents containing ingredients registered with the U.S. Environmental Protection Agency – such as DEET, picaridin, IR3535, oil of lemon eucalyptus (or PMD) or permethrin – and apply according to manufacturer’s instructions.

• Wear protective clothing, such as long-sleeved shirts and pants.

• Limit outdoor activities between dusk and dawn when mosquitoes are most likely to bite.

• Eliminate stagnant water in containers around homes where mosquitoes can lay their eggs (such as buckets, flowerpots, old tires, wading pools and birdbaths).

• Keep the grass around your home trimmed.

Most people infected with West Nile virus experience no symptoms or have only mild symptoms such as fever and headaches. More severe infection may result in high fever, severe headache, stiff neck, altered mental state and death.

The elderly are more likely to have severe infections, but anyone who develops severe symptoms should consult a physician.

For more information about West Nile virus, contact Michelle Feist, North Dakota Department of Health, at 701.328.2378 or visit www.ndhealth.gov/wnv.