The South Dakota Department of Health confirmed South Dakota’s first two human West Nile virus (WNV) detections of the 2022 season, in residents of Minnehaha and Spink Counties. South Dakota has reported more than 2,681 human cases and 47 deaths since WNV was first reported in 2002.

“West Nile Virus is an infection most commonly spread through mosquito bites,” said Dr. Joshua Clayton, state epidemiologist. “The rate of severe infection that includes swelling of the brain and spinal cord with symptoms of stiff neck, confusion, and muscle weakness is highest in South Dakota and other Midwest states. Raising awareness of human cases can ensure residents and visitors alike take action to reduce their risk.”

Individuals and families can reduce their risk by taking the following actions:

– Apply mosquito repellents (DEET, picaridin, oil of lemon eucalyptus, 2-undecanone, param-menthane-diol, or IR3535) to clothes and exposed skin. Limit exposure by wearing pants and long sleeves in the evening;

– Limit time outdoors from dusk to midnight when mosquitoes are most active. Culex tarsalis are the primary carrier of WNV in South Dakota;

– Remove standing water that gives mosquitoes a place to breed. Regularly change the water in birdbaths, outside pet dishes, and drain water from other flowerpots and garden containers and stay away from areas near standing water; and

– Support local mosquito control efforts.

These precautions are especially important for people at high risk for WNV, including individuals over 50, pregnant women, organ transplant patients, individuals with cancer, diabetes, high blood pressure or kidney disease, and those with a history of alcohol abuse. People with severe or unusual headaches should see their physicians.

“Nearly 200 South Dakota cities, counties, and tribes received grant funding from the department in May to control mosquitoes and prevent this virus,” added Dr. Clayton.