First Case Of West Nile Virus Confirmed In South Dakota

A wet spring combined with recent summer-like temperatures have led to South Dakota's first confirmed arrival of West Nile virus for 2026.

According to the Department of Health, the virus has been detected in mosquito pools in Brown County, prompting state officials to remind the public to take steps to protect themselves:

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.
Support local mosquito control efforts.

Personal precautions are especially important for those at high risk for severe illness from West Nile – people over 60 years of age, pregnant women, transplant patients, individuals with cancer, diabetes, hypertension, and kidney disease. People with symptoms like severe or unusual headaches should see their physicians.

South Dakota has reported more than 2,952 human cases and 58 deaths since West Nile was first reported in 2002. Last year was especially active in the state with more than 100 confirmed cases (108) for the first time since 2018.