South Korean Wind Surfer Wonwoo Cho was taken to the hospital by ambulance after becoming sick during the Olympic sailing test event in Rio De Janeiro's heavily polluted Guanabara Bay.
Cho was dehydrated, vomiting, dizzy and had a headache. He is one of four athletes to have officially fallen ill so far this week. Officials say the reporting is incomplete with many teams and some of the 300 athletes afraid to disclose any illnesses, according to The Star Tribune.
Cho, 20, was back to 50-60 percent strength on Wednesday and out racing just 24 hours after his hospital stay.
"It is probably from the water," said Danny Ok, Cho's coach and an exercise physiologist. Ok described the bay as smelly and added, "I can't imagine how they can have racing in this area."
An independent five-month analysis showed dangerously high levels of viruses from human sewage at all Rio Olympic water venues. Despite the findings, brown sewage continues to flow into the Marina da Gloria at several points, according to the Toronto Sun.
The International Olympic Committee has declined to endorse testing for viruses, which can cause stomach and respiratory ailments that could knock an athlete out of competition, according to FOX Sports.
Cho said he has not taken a swim in the bay and only gets in up to his knees in prep for a race.
The IOC has declined to move to cleaner venues for next year's first Olympics in South America, which open Aug. 5, 2016.
