Summer: when people and parasites head for the water

Pamela Egan Practical Practitioner


By: Pamela Egan, FNP-C CDE



Summer: when people and parasites head for the water



After treating several bacterial skin infections, ear infections, gastroenteritis and eye infections in patients who have gone tubing, swimming and skiing, there is a need to discuss the other side of swimming. My children often tell me that I know too much about microbiology. The more you know about epidemiology, the harder it is to go swimming. The Gulf not only has jellyfish and sharks but various sorts of bacteria, flagellates and viruses.

Dr. Michael Beach, an epidemiologist in the parasitic disease section of the Centers for Disease Control and Prevention in Atlanta, is involved in the healthy swimming campaign for the agency. The seashore and rivers, ponds and lakes are part of its concern, because they can certainly contain health hazards, even if they are not polluted. But the current focus is on pools and a parasite called cryptosporidium.

The CDC has come out with brochures that discuss the way that infections are spread in swimming pools and other bodies of water. One of their brochures states, “Think about it!” the big type blurts. “You share the water with everyone in the pool. If someone with diarrhea contaminates the water, swallowing the water can make you sick.”

Most of us love swimming. We swim in pools, in the ocean, in rivers, streams, ponds and swamps. We swim under water and scuba dive. We even swim where we know there are leeches in the water.

Most of us don’t think about parasites when we’re swimming – until now.

Swimming anywhere can result in ear, eye, skin and respiratory infections, as well as gastrointestinal diseases. The ocean has one major advantage – there’s a lot of it. So the bad things are diluted, which does not help much if you’re near a place where someone is dumping raw sewage. In the cleanest ocean water, there are still a lot of bacteria that love an open wound.

Lakes, rivers and ponds have their own problems. After a heavy rain, runoff can carry all sorts of stuff into them, and not just from people. Some parasites like cryptosporidium are spread in animal feces. If you’re in a farm country lake, you’re more likely to have a problem.

Pools have chorine, which kills almost everything, but not immediately. It takes the chlorine in a pool six or seven days to kill cryptosporidium. The CDC suggests increased vigilance by pool staffs and swimmers to combat the parasite. The agency’s brochure “Fecal Accident Response Recommendations for Pool Staff: What Do You Do When You Find Poop in the Pool?” and its poster that poses the question, “Can you read this:” The letters of the chart say: “Have diarrhea? Don’t swim.”

Diarrhea outbreaks caused by Cryptosporidum are 10 times as common as they were 15 years ago. There have been some outbreaks in drinking water. And now epidemiologists are seeing outbreaks in pools, because of the parasite’s resistance to chlorine. Ultraviolet light will kill it, but it’s a one-time treatment.

Any pool can become infected. And there have been outbreaks at big water parks, although some of the biggest offenders are the little kiddie pools.

Swimming is a very good exercise. The point here is not to scare people off. On the other hand, it’s important to be careful. Be wary of people who are all crowded into a pool. Think about their hygiene. Don’t go near kiddie pools if you have a cut and wherever you swim keep your mouth closed.

This article was originally published June 14, 2004 in The St. Tammany News. > Health Articles > Health and Wellness