Athletes who swam in the Seine during the Olympic games in Paris had higher rates of gastroenteritis than those in games past, a U.S. Olympic official told Ƶ.
About 10% of athletes who competed in the triathlon or open water swimming events developed gastroenteritis, compared with about 1% to 3% of athletes in the same events in Rio de Janeiro and Tokyo, Jonathan Finnoff, DO, chief medical officer of the U.S. Olympic & Paralympic Committee (USOPC), told Ƶ editor-in-chief Jeremy Faust, MD, MS, in an interview.
The figures come from the International Olympic Committee's injury and illness surveillance data, Finnoff said.
Finnoff cautioned that it's "hard to compare apples to apples" because in past games, these events occurred in salt water, "which is very different than fresh water in a river in a city."
Still, the rate of infection is "substantially higher" than in the past, he said.
During the games, athletes who participated in events in the Seine reported they were coming down with gastroenteritis. Belgian triathlete Claire Michel that she experienced "three days of vomiting and diarrhea." Tests revealed her symptoms were due to a virus, not E. coli, which had been a key concern heading into the games.
Finnoff added that the rate of gastroenteritis was "lower than 10%" for U.S. athletes who participated in the Seine events. The U.S. teams used rapid PCR tests to identify the pathogens that caused their illnesses to help decide whether to use antibiotics.
Some athletes received antibiotics while others did not, Finnoff said, though he noted that the "severity of their symptoms and whether they have another competition or not comes into play" when deciding on treatment.
While he did not give further details about specific pathogens, he noted that at least one was "a pathogen that one would commonly think of in a dirty urban river."
While some Olympic teams participating in events in the Seine took antibiotics prophylactically, Finnoff said, the U.S. did not.
"If there are a lot of different pathogens, which antibiotic do you use?" Finnoff said. "Is it going to be broad-spectrum enough to eliminate the risk of all of these, which it won't, and you also have your own risks associated with antibiotic use, which can cause photosensitivity, gastrointestinal discomfort, and distress just from changing your flora."
Overall, he said there were "really minimal problems with gastroenteritis."
For the upcoming Paris Paralympic games, the triathlon is scheduled to take place in the Seine.