Utah health officials call the absence of an outbreak of the diarrhea-inducing parasite a public-health success story. They credit new ultraviolet filtration systems, better-maintained pools and swimmers who stayed away when they were sick.
"I consider it a success," said state epidemiologist Robert Rolfs, who had feared a repeat of 2007, when there were 1,900 reported state cases of crypto - the nation's largest outbreak last year.
Still, Rolfs said it doesn't mean the parasite won't attack again in force. "This still does remain a threat as long as it's a chlorine-resistant germ," he said.
Still, swimmers and pool operators are relieved that the parasite apparently remained under control this year. Labor Day signaled the end of the traditional swimming season.
To date, there have been 30 crypto cases, with just eight associated with recreational-water exposure. Besides being spread by swallowing infected pool water, the parasite is passed through animal contact and agricultural water.
Rolfs said the state will continue to track crypto for a couple more weeks, in case swimmers were infected early in the month and don't become sick and get tested until later.
The Centers for Disease Control and Prevention warned Utah it would have more cases than the average 15 a year that occurred before the outbreak.
Instead, "Utah beat the odds and has had no pool-related crypto outbreak," said Pam Davenport, spokeswoman for the Salt Lake Valley Health Department.
Several pools in Salt Lake County installed UV filtration systems, which are better than chlorine at killing crypto. New state rules made pools more sanitary. And TV stations ran public-service announcements aimed at swimmers.
Other states have taken notice. Rolfs will present Utah's experience to state and local health officers at national meetings in California this week.