SIOUX FALLS - South Dakota added 32 human cases of West Nile virus in the past week, boosting the state count for the summer to 161.

Lon Kightlinger in the state Department of Health said the number of new cases will taper off as autumn approaches. But he says the threat isn't over until the first hard freeze kills mosquitoes, which transmit the disease.

The state had 113 human infections and three deaths last year. There have been three West Nile virus deaths this summer.

The Aberdeen area continues to be a hotbed for the virus. Almost 20 percent of the state's cases are in Brown County, where 32 people have been infected.