Aside from the recent Flint, Mich., water crisis, most towns and cities in the U.S. enjoy easy access to clean, purified water. The same goes, for the most part, for our recreational bodies of water.

It’s not often the Jersey Shore or Huntington Beach are closed or under a swim advisory due to contamination. And if they are, it’s usually because of a specific unfortunate event, such as the Gulf during the Deepwater Horizon Oil Spill in 2010.

U.S. waters are almost never shut down because they become so contaminated with human feces and raw sewage that exposure means almost certain illness. And yet, that’s the reality in Rio de Janeiro, Brazil, where hundreds of thousands of athletes and tourists will soon find themselves for the 2016 Summer Olympic Games beginning August 5.

Extreme water pollution is common in Brazil—and Latin America in general—where the majority of sewage is not treated. According to Fernando Spilki, a virologist at Feevale University in Southern Brazil, sewage treatment is less than 50 percent for 30 million people in the country. Therefore, all the water from the toilets, showers and sinks is released into bodies of water like Guanabara Bay, Rodrigo de Freitas lake and the water surrounding Fort Copacabana–all Olympic venues.

As a result, Olympic athletes are almost certain to come into contact with disease-causing viruses that in some tests measured up to 1.7 million times the level of what would be considered hazardous on a Southern California beach, according to a year-long investigation by the Associated Press (AP).

Testing and analysis
Spilki has been working with the AP to sample and analyze Olympic venue waters since March 2015. At first, he and his team collected water samples from the shore of Guanabara Bay. Then, they branched out to include other bodies of water, as well as points in the open ocean of the bay to see if the quality of water was any better further from shore.

The AP commissioned four rounds of testing in each of the three Olympic water venues, and also in the surf off Ipanema Beach, which is popular with tourists but where no events will be held. Thirty-seven samples were checked for three types of human adenovirus, as well as rotavirus, enterovirus and fecal coliforms. Viral testing, which will continue through the start of the Olympic Games the first week of August, found not one water venue safe for swimming or boating, according to Spilki and other AP global water experts. The concentrations of the viruses in all tests were roughly equivalent to that seen in raw sewage.

Spilki told Laboratory Equipment he and his team used quantitative PCR (qPCR) to analyze and detect viruses present in the water samples. They additionally used conventional PCR complimented with nuclear sequencing and genetic analysis for confirmation of the identity of the viruses.

Spilki said the test results found high counts of active and infectious human adenoviruses, as well as enterovirus depending on the point of sampling. Adenoviruses, which multiply in the intestinal and respiratory tracks of humans, are known to cause respiratory and digestive illnesses, including fevers, diarrhea, abdominal pain and vomiting.

Tests found the Rodrigo de Freitas lake waters to be among the most polluted for Olympic sites, with results ranging from 14 million adenoviruses per liter on the low end to 1.7 billion per liter at the high end. By comparison, water quality experts who monitor beaches in Southern California become alarmed if they see viral counts reaching 1,000 per liter.

“The fact is, the chance of being infected is very high. Researchers agree that almost everyone will get an infection, and some of them will fall ill,” said Spilki. “When we look at historical data from the team who has been training in the Bay in the last two years, they report something like 5 to 7 percent of athletes experience vomiting and diarrhea after contact with water. That is above expected. If you have clean water, no one will get ill. If you have not-so-heavily-contaminated water, some persons will get ill. But when you have something more than 5 percent, it shows you the water is really contaminated, and you shouldn’t come into contact with it.”

Fortunately, even if athletes do contract an infection and become ill, it would be unlikely for them to have any long-term symptoms, according to Amesh Adalja, Senior Associate and Instructor of Infectious Diseases at the University of Pittsburg School of Medicine.

“The concern is about the initial symptoms, but in rare cases, they can last longer,” said Adalja, who is not involved in the AP investigation. “It’s not the norm to encounter severe complications, but in certain individuals it can happen. Most will just have gastrointestinal illnesses.”

While ingesting contaminated water is an obvious pathway to infection—which doesn’t bode well for the Olympic swimmers–there are additional ways. For example, Adalja told Laboratory Equipment that some infections can take hold if an athlete gets water in his/her eyes because it’s a mucus membrane. Additionally, while the skin usually serves as an appropriate barrier, any athlete who has a cut or abrasion and comes into contact with the water is at a higher risk for skin and gastrointestinal infections.

This not only puts the swimmers at risk, but also those athletes participating in canoeing, rowing, sailing, and the triathlon–which totals just about 1,400 Olympians. (See box)

Location Event Number of Athletes

Aquatic sports impacted by polluted water.

Guanabara Bay Sailing (10 events) 380
Rodrigo de Freitas Lake -Canoeing
Copacabana -Swimming
(open-water marathon)

Training in Guanabara Bay, some athletes have already reported to the AP that they have fallen ill with vomiting and diarrhea. An Australian sailor told the news organization that he and his teammates wash their faces immediately with bottled water when they get splashed by waves and shower the minute they return to shore–however, it’s not helping.

Adalja is not surprised to hear that, and he cautions other athletes against going to Rio early in an attempt to “build up” an immunity to the contaminated waters.

“I don’t think it’s advisable to try to build up your immunity by swallowing the water and making yourself sick,” Adalja said. “There is no way to build up immunity. [This situation] is not akin to an athlete going to train in Denver to build up endurance to low oxygen. It’s not like it’s just a couple bacteria. There is clearly a breadth of different infections one could attract from being exposed to sewage in the water. Even if you do go there and get yourself sick, you’re only immune to what you got, not necessarily what you could get. It doesn’t make scientific or biological sense to do such a thing in this type of setting.”

Bacteria vs. viruses
The AP says its testing was the first independent, comprehensive testing for both viruses and bacteria at the Olympic sites. Neither the government nor the International Olympic Committee tests for viruses, relying on bacteria testing only. However, this is common practice as most of the standards for contamination are based on bacterial counts, given how easy and cheap bacteria markers are to detect and analyze.

“Viruses aren’t that easy to work with because you have to do a complete analysis, which comprises molecular biology and classical virology,” Spilki explained. “You have to cultivate the virus first. After cultivation and molecular detections, you have to sequence the samples to confirm results. It’s
much easier and less intensive to detect and read bacteria markers.”

In Rio, the bacteria, or fecal coliform levels, were not as egregious as the viral numbers the AP testing found. This gap is at the heart of a debate between governments and global water experts, many of whom are pushing governments to adopt viral as well as bacterial testing to determine if recreational waters are safe.

According to Spilki and the AP, the number of fecal coliforms exceeded Brazil’s legal limit for “secondary contact,”—such as boating or rowing—in 75 percent of the samples taken and analyzed from Rodrigo de Freitas lake. Two samples spiked to more than 10 times the accepted level.

The Bay exceeded the limit only once, while at Rio’s most popular tourist beach, Ipanema, fecal coliforms tested at three times the acceptable level in a single sample. No violations of fecal coliform counts were found at Copacabana.

“But you have to test for viruses,” Spilki said. “Sometimes, there are very low counts or even negative results for bacteria, but the water still has viruses, and lots of them. It’s very common, especially in the conditions of Latin America where the water is not safe. The same goes for protozoa and other pathogens that are more resistant underwater.”

The problem is, there is no standard for the quantity of virus in water. Almost all countries standardize water quality based on bacterial tests.
As an infectious disease doctor, Adalja said he doesn’t think it’s as important to draw differences between bacteria and virus, but rather recognize both of them as markers for sewage and contamination.

“They are both going to give you similar information,” he said. “If the water is already contaminated with fecal coliform bacteria, a virus testing will give you a little more flavor of that water. You know there are viruses there too. Bacterial counts are just a much more standardized way of doing this.”
Either way, Adalja said contamination does not discriminate.

“If the water is at a level that is likely to cause an infection, an athlete will get the infection,” he said. “Bacteria does not care if you are an Olympic athlete. They are just seeing a new host to infect. Bacteria don’t make exceptions.”

Another problem: Zika
As if contaminated water isn’t enough of a problem, Brazil will see the Olympic Games bring an influx of about 500,000 people to the country–in the middle of a Zika epidemic. In fact, researchers believe the mosquito-borne virus originally came to the country during another major sporting event—the 2014 World Cup. Since then, more than 1.5 million people in Brazil have contracted the disease, which has officially been linked to the birth defect microcephaly and brain disorders Guillain-Barré syndrome (GBS) and acute disseminated encephalomyelitis (ADEM).

By itself, Zika is not considered life-threatening. In fact, most people, about 80 percent, are asymptomatic, showing no symptoms at all. But, if 80 percent don’t show symptoms, then 80 percent of people also do not know they are carriers of the virus.

Researchers know Zika stays in the blood for seven days, in urine slightly longer and in semen for 62 days. So, the virus can be carried in a person’s blood from Brazil to a new country, then passed to others via mosquito bites. The same can be said of sexually transmitting the virus to one or multiple partners, where it can, again, be subsequently spread by U.S. mosquitos.

Zika is carried by the Aedes aegypti mosquito, a tiny mosquito that prefers warm weather, the indoors and small amounts of standing water.
According to Diana Weber, who is part of the Ecology and Evolution of Infectious Diseases program at the National Science Foundation, Aedes aegypti can be found in the southern U.S., mostly in Florida, Texas and California. But, as summer weighs heavy in the U.S. post-Olympics, it is likely the species will move up the Eastern seaboard—creating a larger possible infection area.

Using worldwide temperature profiles and air travel routes, Oxford University researcher Moritz Kraemer found that more than 60 percent of the population of the U.S. lives in areas where Zika can be transmitted during the Northern Hemisphere’s summer. A much smaller number, about 23 million people, live in parts of the U.S. where Zika can be transmitted year-round, like Florida and Texas.

However, due to the limitations of vectors and other extenuating circumstances, Kraemer told Laboratory Equipment he doesn’t see the likelihood of a Zika epidemic in the U.S.

“[In our paper] we do acknowledge the possibility of travelers from the U.S. coming back to regions where local transmission can occur,” he said.

“However, past experiences with related viruses such as dengue and chikungunya have shown that the risk posed to the continental U.S. is relatively low as people spend more time indoors and generally have better living conditions. In addition, the U.S. government is aware of a potential outbreak and is likely to be able to control it with rapid response.”

The Aedes albopictus is the other mosquito species present in the U.S. While lab studies have shown that it is capable of passing on the Zika virus in controlled conditions, researchers are not sure if it’s a constant vector in the wild.

A positive element of the situation is that August—when the Olympics are set to occur—is the winter season in Brazil. That means the temperatures range in the low 60s to low 70s, and the country experiences very little rain—a climate that is not conducive to the heat-loving Aedes aegypti.
Still, precautions must be taken. Brazil officials have said inspections of Olympic facilities began in April to eliminate mosquito breeding grounds, and daily sweeps will continue to take place during the Games.

Since the Aedes aegypti mosquito likes to “live” indoors with humans, “the most effective thing for Brazil to do is everything they can to protect the perimeter of people’s houses,” Weber told Laboratory Equipment.

The mosquito only needs a teaspoon of water to lay and hatch eggs, which makes it vitally important to eliminate any and all stagnant water outside, especially that found in close proximity to the home. Screens on windows and doors would also be helpful, although that is hard for a developing country.

The CDC is recommending any travelers to Brazil use a DEET formula that is 30 percent, compared with the normal 15 percent, which is considered insufficient in this case. The agency also advises wearing long sleeves and long pants, and staying in the air conditioning.