German sailor Erik Heil has undergone surgery for skin infections which he says were caused by polluted water at the Olympic test regatta in Rio de Janeiro.
The 26-year-old had an operation on the largest of the five areas infected on his legs and hips and is receiving daily treatment in a Berlin hospital.
Heil finished third with team-mate Thomas Ploessel in the 49er class at the regatta behind the winners from New Zealand, Peter Burling and Blair Tuke.
They were competing in August at Rio's Guanabara Bay where garbage, discarded furniture and dead animals float.
"I have never in my life had a leg infection," he wrote in a Sailing Team Germany blog.
"I assume that I got it from the test regatta."
Heil was treated with strong antibiotics after contracting a highly resistant germ and was unable to train.
The inflammations started on the plane trip from Rio and, soon after getting off the plane, he sought treatment from Berlin's Charite hospital, which specialises in tropical diseases.
"The cause was probably from the port at Marina de Gloria, where the waste water flows unabated from the municipal hospital," added Heil.
The German sailor said he learned his lesson and would take extra precautions for next year's Olympics.
"In future, we will see to it that we arrive relatively late in Rio so that any outbreak of disease happens at the end of the race or back at home," he added.
"In addition, Thomas and I are considering wearing plastic covers over our normal neoprene shoes."
The sports governing body ISAF has repeatedly expressed serious concerns about the water quality for Rio's Olympic regatta and Heil said he hoped the site was moved.
The organising committee for Rio 2016 did not immediately respond to requests for comment on Heil's case, but spokesman Mario Andrada insisted at a news conference that the sailing will not be moved.
The pressure is mounting, however.
Buzios, a beach resort and popular watersports destination a few hours out of Rio, is campaigning to replace Guanabara Bay for next year's Olympic sailing and has organised a press visit this weekend to show it has the infrastructure and water quality necessary to host the event.
Biologists last year said rivers leading into the bay contained a superbacteria resistant to antibiotics that cure urinary, gastrointestinal and pulmonary infections.
South Korean windsurfer Wonwoo Cho, 20, had to be hospitalised with headaches, dehydration and vomiting during the test regatta while numerous other athletes also complained of feeling unwell after competing, according to reports.