Public pools and other recreational bodies of water can still carry a parasite that may ruin a week or even a summer, but the cases are decreasing and so are the restrictions.

Cryptosporidium, a parasite that can be picked up from fecal matter in swimming pools, can cause severe diarrhea, and has been causing pain across the state since July. However, the number of cases of cryptosporidiosis, the illness resulting from cryptosporidium, has decreased enough for the state Department of Health to lift more pool restrictions.

There have been about 2,000 reported cases in the state this year, 450 of which were in Utah County. At it's peak in August, there were more than 80 test-confirmed cases in a week in the county. During the first week in October, there were three test-confirmed cases in the county.

The health department announced Thursday that public pool owners won't be required to hyperchlorinate and maintain higher chlorine levels in public pools to help kill the parasite. Last month it lifted restrictions banning children younger than 5 from public pools.

Typical chlorine levels in a pool are 1-5 parts per million. About once a month, pools will "superchlorinate" up to 10 ppm. The health department had asked pools to "hyperchlorinate" up to 20 ppm once a week.

People in diapers are still out of luck -- restrictions keeping diaper-clad swimmers out of the water are still in place. The state health department also warns parents not to take a diaper off to take a child swimming.

Charla Haley, spokeswoman for the state department of health, said the diaper restriction could be re-evaluated in two weeks, based on the number of cases the state is still seeing. It doesn't say anything about next year, but the worst may be over.

"We're thinking that we're on the downside," Haley said.

Normal levels of chlorine can't take care of cryptosporidium. According to The Centers for Disease Control and Prevention, the parasite can survive for days in chlorine. Higher levels of chlorine only help marginally and can be annoying for swimmers because it increases exposure to the chemical.

"We all know that you should not drink bleach, which is essentially what chlorine is," said Lance Madigan, spokesman for the Utah County Health Department.

The pool at 24 Hour Fitness in Provo has been hyperchlorinating due to the restrictions. The system at the gym uses salt, so the higher levels of chlorine aren't as noticeable, but patrons can still tell. Keeley Egbert, who manages the gym, is glad that she won't have to come in on the weekends to hyperchlorinate the pool.

In past years the state has seen an average of about 30 cases of the disease a year. This summer there were nearly 2,000 confirmed cases of cryptosporidiosis state wide. There could be substantially more cases that are unreported because the disease spreads easily from person to person and within families where not every infected member goes to the doctor.

Haley said the state health department, in conjunction with local health departments and the CDC, will conduct a study once the outbreak has slowed to determine what caused the large number of cases and how they can be prevented.

Utah had a bad case of crypto this year, but it wasn't the worst ever recorded. In 1993, Dane County, Wis., had an outbreak that affected more than 400,000 people.

The state health department is asking people to take a part in preventing the spread of the disease by not swimming for two weeks after having diarrhea. Officials also ask that people shower before entering pools, wash their hands after using the bathroom, and let pool staff know if there is fecal matter in the pool, so they can handle it.

"If people aren't policing themselves, we'll just be back in the same place we were before," Madigan said.

• Brittani Lusk can be reached at 344-2549 or at blusk@heraldextra.com.