South Dakota has its first confirmed human case of West Nile virus this season.
Health officials say the virus was detected in a Beadle County blood donor who was not ill. The person is between 20 and 29 years old.
State Epidemiologist Lon Kightlinger urges South Dakota residents to protect themselves against the virus through such measures as limiting exposure to mosquitoes and using insect repellents.
The peak West Nile virus period in South Dakota is July through early September. The state has had nearly 1,800 cases including 26 deaths in the past decade.