In a statement on August 10, the German Olympic Sports Federation said: "Two German female swimmers were treated as outpatients (on August 9) for nausea, vomiting and diarrhea. They have been feeling much better since this morning. Another swimmer with similar symptoms is currently being treated by the German team doctors."

The identities of the swimmers were not mentioned in the statement, but swimmer Leonie Beck revealed her condition on social media: "Yesterday threw up 9 times and had diarrhea," she wrote.

Another German swimmer in the women's open water race was Leonie Maertens, who finished 22nd out of 24. Germany also had two swimmers in the men's event: silver medalist Oliver Klemet and eighth-place finisher Florian Wellbrock.

Although Beck is convinced her symptoms were caused by the river, the German Olympic Committee said water tests showed it was "feasible" to go ahead with the two races.

Many athletes also said water quality was not an issue. Women's gold medalist Sharon van Rouwendaal of the Netherlands said she took sips of river water when she felt thirsty during her race.

The Paris Olympic organising committee said they had "heard reports on the athletes' health and wished them a speedy recovery".

"At this stage, we are not aware of any link between the illness and the water quality of the Seine," the statement said. "The water quality on the day of the marathon swim was considered 'very good' or 'excellent' at all four testing sites and was within the thresholds set by World Aquatics."

Ngoc Anh (according to AP)