South Dakota health officials say the West Nile virus season is nearing its peak. The state Health Department reported Thursday that West Nile virus has been detected in humans or mosquitoes in 11 counties across South Dakota. State epidemiologist Dr. Joshua Clayton says the West Nile season typically peaks during the first part of August, so people are being exposed to the virus now. Clayton says people exposed today can take up to one to two weeks to develop symptoms. Human cases have been identified in Buffalo and Minnehaha Counties. The virus was detected in blood donors in Faulk, Hand, Minnehaha, Potter, Spink and Todd Counties. There are been positive mosquito detections in Beadle, Brookings, Brown, Minnehaha and Stanley Counties.