SIOUX FALLS, S.D. (AP) - South Dakota saw a jump in West Nile activity with six more human cases in the past week, plus an infected horse and more pools of infected mosquitoes.

The Health Department reports nine human infections so far this summer, plus one that was detected through a blood donation. They're found in nine counties around the state.

Lon Kightlinger in the Health Department says the caseload is well below the August numbers of the past two years. He attributes that to a cool summer that reduced activity by a species of mosquito that transmits West Nile from birds to humans.

South Dakota had 39 human cases last summer and 208 the year before. The peak transmission season is mid-July to mid-September.