Within the past 10 days the Central District Health Department has seen 19 cases of cryptosporidiosis. During a normal year the health district might see 10 cases.

The Idaho Statesman reports the health department has advised area swimming pool operators of the situation and many responded by hyper-chlorinating the pools, a technique that kills the parasite. Still, those efforts can be rendered ineffective when people carrying the disease use recreational waters.

“We know the hot weather is driving people to seek relief in area pools, lakes and rivers,” Kimberly Link, Program Manager for Communicable Disease Control at CDHD, said in a press release. “If you’ve been ill with diarrhea we can’t emphasize enough how important it is to stay out of recreational waters for at least two weeks after your symptoms resolve.”