Just days ahead of the Olympic Games the waterways of Rio de Janeiro are as filthy as ever, contaminated with raw human sewage teeming with dangerous viruses and bacteria, according to a 16-monthlong study commissioned by the Associated Press.
Not only are some 1,400 athletes at risk of getting violently ill in water competitions, but tourists also face potentially serious health risks on the beaches of Ipanema and Copacabana.
The AP's survey of the aquatic Olympic and Paralympic venues has revealed dangerously high levels of viruses from the pollution, a major black eye on Rio's Olympic project that set off alarm bells among sailors, rowers and open-water swimmers.
Since the AP released the initial results in July 2015, athletes have been taking elaborate precautions, including preventatively taking antibiotics, bleaching oars and donning plastic suits and gloves to limit contact with the water.
But antibiotics combat bacterial infections, not viruses. And the AP investigation found that infectious adenovirus readings — tested with cell cultures and verified with molecular biology protocols — turned up at nearly 90 percent of the test sites over 16 months of testing.
"That's a very, very, very high percentage," said Dr. Valerie Harwood, chair of the Department of Integrative Biology at the University of South Florida. "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."
While athletes take precautions, what about the 300,000-500,000 foreigners expected to descend on Rio for the Olympics? Testing at several of the Brazilian city's beaches has shown that in addition to persistently high viral loads, the beaches often have levels of bacterial markers for sewage pollution that would be cause for concern abroad — and sometimes even exceed Rio state's lax water safety standards.
Harwood had one piece of advice for travelers to Rio: "Don't put your head under water."
Danger is lurking even in the sand. Samples from the beaches at Copacabana and Ipanema revealed high levels of viruses, which studies have suggested can pose health risks — particularly to babies and small children.
While local authorities including Rio Mayor Eduardo Paes have acknowledged the failure of the city's water cleanup efforts, calling it a "lost chance" and a "shame," Olympic officials say Rio's waterways will be safe for athletes and visitors.
"We would never, ever risk the health or the condition of any athlete for a competition," said Mario Andrada, chief spokesman for the local organizing committee. "So the health of the athletes is our first priority. And the athletes don't run a risk sailing in Guanabara Bay."
The committee has previously said bacterial testing conducted by Rio state authorities has shown the aquatic venues within state guidelines.
Promises to clean up Rio's waterways stretch back decades, with a succession of governors setting firm dates for a cleanup and repeatedly pushing them back. In the city's 2009 Olympic bid document, authorities pledged the Games would "regenerate Rio's magnificent waterways."
Just over a month before the Games, biologist Mario Moscatelli spent more than two hours flying over Rio in a helicopter. "The Guanabara Bay has been transformed into a latrine," said Moscatelli, an activist who's the most visible face of the fight to clean up Rio's waterways. "Unfortunately Rio de Janeiro missed the opportunity, maybe the last big opportunity" to clean it up.