West Nile: Dewey County has second highest incidence rate in US

A South Dakota county with the second-highest national rate of lethal West Nile virus in humans shares a border with a county that has never reported a single case.

Between 1999 and 2023, Dewey County recorded 13.74 West Nile neuroinvasive cases per 100,000 people, just behind King County in Texas, according to the U.S. Centers for Disease Control and Prevention. Neuroinvasive refers to those more …