Wednesday, February 03, 2010

Another red flag for public swimming areas

A dip in the public pool or local lake may boost people's odds of catching a case of "stomach flu." Australian researchers found that among more than 2,800 adults and children they followed for 15 months, participants were somewhat more likely to develop gastroenteritis in the week or two after a public swim.

Gastroenteritis refers to inflammation in the gastrointestinal tract caused by viral, bacterial or parasitic infection. The symptoms -- what people commonly identify as "stomach flu" -- include abdominal pain, vomiting, diarrhea and fever. Contaminated food and drinking water are common sources of infection, and recreational swimming has been linked to outbreaks of gastrointestinal illness. But the extent to which swimming, in different types of venues, raises the odds of gastroenteritis has been less clear.

In the current study, participants' gastroenteritis risk was about one-quarter higher in the one to two weeks after a visit to a public pool or spa, versus other weeks. The odds went up 77 percent, on average, in the week after a swim in a river or lake, while a similar increase was seen among adults who had taken an ocean dip in the past two weeks. The findings, the researchers write in the American Journal of Epidemiology, confirm that swimming in fresh, salt or treated waters can pose a risk of gastroenteritis.

Still, the investigators are not advising people to retire their swimming trunks. The increases in gastroenteritis risk were "relatively small," and swimming, as a form of aerobic exercise, can also have health benefits. There is, however, a need for better preventive measures, the researchers write. In Melbourne, they note, health authorities recommend that to prevent disease transmission, people with diarrheal illnesses not get into a public pool for at least one week after their symptoms have cleared. That window extends to two weeks for people with confirmed cases of giardiasis or cryptosporidiosis -- two parasitic waterborne infections. However, no one knows how well people follow that advice. In addition, Dale's team notes, there are no specific guidelines regarding swimming in lakes, rivers or oceans.

Steve - do you trust your fellow man to adhere to proper public swimming etiquette that would go a long way to preventing this issue?


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