West Nile Virus continues to be an issue for South Dakota. With the most recent year data findings, 2025 saw fewer cases than health officials anticipated.
The final update for the 2025 WNV season published by the state Department of Health found four deaths and 87 total cases. That’s short of the peaks seen in 2012, 2013, 2016, and 2018.
That total of 87 is significantly less than the 123 cases predicted by the DoH.
The virus, which can lead to fever, rash, and in some cases severe fever and seizures, is disproportionately impacting East River counties.
Seventeen total cases were found in Minnehaha County, and no West River counties tallied more than four cases in the last season.
Additionally, no mosquito pools tested positive for WNV West River. This could be for several reasons, including the sparser western South Dakota population and the semi-arid climate in the west spawning fewer mosquitos.
Populations most susceptible to WNV are over 40 years old. Just 19 of the 87 statewide cases were tallied in ages under 39.
Generally, WNV season correlates with the peak of summertime, and just a single case was found in South Dakota in the last month.
Common mitigation efforts for next summer include city-wide mosquito spraying, along with the use of bug sprays and insect-repellant candles.
A link to the West Nile Virus dashboard can be found on the Department of Health's website.
