The Summer 2016 Olympics are here, and while some athletes are wondering what shining medal they'll get, others are worrying about what devastating disease they'll contract.

For months, scientists and public officials have issued dire safety warnings about Rio's water supply. The city's water is home to a beautifully diverse array of rotaviruses and drug-resistant super bacteria -- and shockingly, it's dangerous for humans to swim in the feces of strangers.

Who knew?

SEE ALSO:Would I know by now if I'm going to the Olympics?

To celebrate the Rio Olympics, below is a short list of some of the diseases athletes could contract by swimming in Rio waters, or simply walking around the city. An investigation conducted by The Associated Press last year found that Rio waters were home to disease-causing bacteria at 1.7 million times the level of what would be considered hazardous at a Southern California beach. Even athletes who manage to stay above ground are at elevated risk for becoming a victim of a crime.

Let the games (and the gas) begin!

1. Adenoviruses

Waterborne adenoviruses can cause gastroenteritis, an infection which irritates the stomach and intestine and causes truly magical amounts of diarrhea amongst sufferers.

Australia's polo team actually contracted gastroenteritis even before they made it to Rio while training in Rome. Upon arriving in Brazil, they were quarantined in the Olympics' media village, not the athletes villages, so that they wouldn't get anyone important sick (just dorky journalists, who probably deserved it anyway).

Once the team is back in Rio's waters, they will be at increased risk for contracting the popular illness yet again.

2. The flu

Via Giphy

It's peak flu season in Brazil -- and some scientists are predicting that the common illness will affect more people than its popular alternative, Zika. While most athletes who are in good health will survive the illness, the disease can have terrifying complications for people whose immune systems are already compromised.

Let's hope Rio's public bathrooms are prepared to handle all of the (potential) excess sewage.

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Hooray!

3. Food poisoning

According to the WHO, gastrointestinal infections are common in Brazil -- and travelers should always make sure their food has been "thoroughly cooked" and remains "steaming hot." Travelers are further advised to only drink bottled water, assuming that they don't want to stink up the hotel bathroom and spend their entire trip lying and crying on a cold tile floor.

4. Zika

The seasonal flu appears to be more likely to affect Olympians than the Zika virus, but athletes should still take caution. Brazil was the country hit hardest by the epidemic. And while the number of new cases has sharply declined, WHO is still advising athletes to take caution in mosquito-infested areas and practice safe sex.

5. Dengue fever

Dengue fever may not have malaria's brand recognition, but this mosquito-borne illness is still terrifying. Symptoms include a high fever and diarrhea, and in a rare number of cases, hemorrhagic fever -- causing blood to appear in little dots on the skin and under the skin in large patches.

There have been over 1.2 million cases of dengue in Brazil this year -- six times what it was last year at this time. Still, it's winter in Rio, which means that chances are low that many people will contract the fever.

6. Vibrio infections

Vibrio bacteria live in warm coastal waters, and causes extensive diarrhea, nausea and vomiting. Vibrio contaminates some of your favorite undercooked shellfish, including delicious raw oysters. For people whose immune systems are compromised, the consequences can be fatal.

7. Astrovirus

While not as well known as some of the other viruses, astrovirus, which can be contracted from warm Rio waters, can cause outbreaks of violent diarrhea.

Key theme here at Rio: terrible diarrhea.

8. Rotavirus

The magic of Rio's waters.Credit: renata brito/ap

One of the best known viruses on this list, athletes who compete in the water may come into contact with Rotavirus -- the main cause of gastroentertis globally.

9. Norovirus

If you've ever been on a cruise, there's a decent chance you've been exposed to norovirus, a highly contagious virus spread through food, water and humans. The virus can cause vomiting and guess what -- diarrhea.

10. Hepatitis A

The CDC recommends travelers get a Hepatitis A vaccine before traveling to Brazil.

While many Americans have had the vaccine (except for our precious contigent of anti-vaxxers), Hepatitis A is one the most common waterborne illnesses found in human feces -- and therefore in Rio's waters.

11. Enterovirus

September tests at the Naval School race course in Rio were positive for enterovirus, which most commonly causes respiratory illness, obviously causes diarrhea and, less often, inflammations of the brain.

Best of luck to our athletes! We wish you health, success and lots and lots of toilet paper.

TopicsOlympics