Over the past two summers, about 65 people fell ill from a chlorine-resistant parasite they most likely caught while swimming in Wyoming pools.

The Wyoming Department of Health reported outbreaks of Cryptosporidium - or "Crypto" - associated with treated swimming pools affecting at least 30 people in 2007 and 34 people in 2006. The parasite is commonly transmitted through small amounts of fecal material in swimming pools.

The outbreaks were concentrated in Campbell and Crook counties, said Kelly Weidenbach, surveillance epidemiologist for the health department.

Over the past few years, reported cases of "Crypto" have increased significantly. Utah reported thousands of cases in 2007, Weidenbach said.

"Very few people die from 'Crypto,'" Weidenbach said. "It causes diarrhea and the most common complication is dehydration."

Other symptoms include nausea and vomiting. Without treatment, most people recover from the illness in less than 30 days with it lasting about 10 to 14 days in the average person.

Weidenbach said the increase in cases could be due to an increase in testing for the disease. The U.S. Food and Drug Administration approved the first drug to treat "Crypto" just a few years ago.

The parasite is transmitted after a person accidentally ingests contaminated water or food, Weidenbach said. The parasite gets in the water through very small amounts of feces.

"Even a small amount of fecal material on you can make a problem like right after you go to the bathroom," Weidenbach said. "We recommend not swallowing water, especially when in natural bodies of water because you know for sure there is 'Crypto' and other germs in there."

Chlorine kills most germs in pools, but parasites like "Crypto" can live for days in a pool with normal levels of chlorine.

Contact health reporter Allison Rupp at (307) 266-0534 or allison.rupp@trib.com.

Swim safe

The health department wants to reduce the number of people who get sick from 'Crypto' this summer. Here are some actions swimmers can take:

* Do not swim with diarrhea. This is especially important for children in diapers. Wait a few days after diarrhea symptoms subside before swimming.

* Do not swallow the water to allow water in the mouth.

* Practice good hygiene by showering before entering the pool and washing hands after using the restroom or changing diapers.

* Take children on bathroom breaks or change diapers often.

* Change children's diapers in the restroom, not close to the pool.