Expert: Small amounts of Rio water could make swimmers ‘violently ill’

“Don’t put your head under water.”

With the 2016 Olympics set to begin on Friday, the water in Rio de Janeiro remains highly contaminated, leading a biology expert to issue a warning to Rio travelers.

“Don’t put your head under water,” said Dr. Valerie Harwood, chair of the Department of Integrative Biology at the University of South Florida, according to the Associated Press.

An AP study published last year revealed viral levels in Rio’s water that were up to 1.7 million times greater than levels that would be considered troubling in the U.S. or Europe. With such a great concentration of viruses in the water, ingesting just three teaspoons of water could cause a swimmer to become infected with viruses that could cause stomach problems, respiratory illness or even heart and brain inflammation. 

Simply by putting their heads beneath the water, swimmers would likely ingest enough water to become “violently ill,” Harwood said.

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Over 16 months of testing, nearly 90% of water testing sites showed the presence of infectious adenovirus, which can be especially harmful to children.

“That’s a very, very, very high percentage,” Valerie Harwood said. “Seeing that level of human pathogenic virus is pretty much unheard of in surface waters in the U.S. You would never, ever see these levels because we treat our waste water. You just would not see this.”

Dr. Fernando Spilki, the virologist and coordinator of the molecular microbiology laboratory at Feevale University in southern Brazil who studied the water for the AP, said there has been little improvement in the water conditions since the study was first released.