Flu, traffic accidents, and traveler’s diarrhea are the real public health threats that tourists face at Brazil’s Olympics. Also: Look out for floating garbage.

Mario Tama / Getty Images People cool off beneath a water fountain beneath the Olympic rings in Madureira Park in Rio de Janeiro, Brazil.

Zika gets all the headlines, but visitors of the 2016 Olympic and Paralympics Games face bigger worries from the relative mundanities of upset stomachs, traffic accidents, and muggings, public health experts warn. As many as 500,000 tourists from 206 countries will travel to Rio for the games, which begin with opening ceremonies on the evening of August 5. Brazil is the epicenter of the Zika outbreak that has spread to 50 nations or territories in the last year. But in reality, Zika should be low on the list of tourists’ anxieties. “During the Games, mosquito-borne Zika virus transmission is expected to be low,” a CDC analysis has concluded. That’s largely because the Olympics and Paralympics will be held in August and September, winter months in Brazil when cool and dry weather typically reduces mosquito populations. A Yale School of Public Health study released this week, for example, found that even if Olympic tourists lived under the same conditions as local Rio residents, without air conditioners and screened hotel windows, only about 80 would catch Zika, and just 16 would feel any symptoms. Once the Games are over, only four countries — Chad, Djibouti, Eritrea, and Yemen, which are sending about 60 people in all — face a higher-than-normal risk of Zika spreading to their country because of the Olympics, the CDC said. That’s because hardly anyone from those four countries travels to Brazil, so the Games will slightly increase the odds that an infected traveler returns home with the disease to spread to heretofore uninfected mosquitoes. For everyone else, it’s a wash. In February the World Health Organization declared a public health emergency over the spread of Zika in Brazil. Health authorities were particularly worried about the thousands of severe brain birth defects linked to the mosquito-borne virus, and the rarer cases in adults of post-infection paralysis caused by Guillain-Barre syndrome. After the WHO’s declaration, Brazil’s sports minister George Hilton issued a statement saying that cancelling the Olympics because of Zika was “not in discussion.” Yet calls for the cancellation of the Games have continued, for example from the Harvard Public Health Review and a May letter signed by 238 health experts. A few athletes, mainly golfers, have dropped out of the Games because of Zika worries. But they’re not being very rational, experts say. “The bigger drama is over water quality,” Neil Silverman, an obstetrician at the Ronald Reagan UCLA Medical Center, told BuzzFeed News, who now regularly advises patients on travel to Brazil. “That doesn’t mean the risk of Zika isn’t there. But from a public health perspective, it doesn’t look like there is a big risk of more people being infected because of the Olympics.” “Rio thy sea, endless beaches. Rio you were made for me,” sang Brazilian musician Tom Jobim in Samba do Avião, celebrating the “marvelous city.” If you’re headed to the Olympics, in all likelihood, you’ll have a wonderful, healthy time in Rio de Janeiro, reveling in the city’s beautiful beaches, stunning mountains, and carnival atmosphere. But if you’re intent on worrying about something, here’s what’s more concerning than Zika.

Mario Tama / Getty Images

1. The water Rio’s Guanabara Bay is so polluted that Olympics organizers plan to have helicopters scanning the water for floating garbage. Raw sewage spilling into the bay means “some athletes, using these sites at times of poor water quality, may suffer from illnesses such as stomach upsets and respiratory tract infections,” according to the WHO. Even for tourists who never go into the water, traveler's illness has that name for a reason, Silverman said. “Diarrhea is so common in travel that I just always tell people to prepare for it.” Hepatitis A is also something people can catch from tainted food or water, and Brazil “is prone to outbreaks,” according to the WHO. Although it is too late to get the vaccine (which comes as two shots, spaced three months apart) in time for the Games, Silverman said, even the first shot can give some protection a few weeks ahead of time.

Adalberto Roque / AFP / Getty Images A woman on Ipanema beach in Rio de Janeiro.

2. Sunburn WHO’s William Perea said sunburn or sunstroke is the number one health risk for tourists at the Games, speaking at a July briefing. “Particularly for people standing outside for long periods of time,” he added, you’ll want SPF 15 or higher sunscreen applied every two hours to ward off the sun, and a water bottle to ward off dehydration. 3. Flu (and other vaccine-preventable diseases) Summer in the northern hemisphere is winter flu season in Brazil, Lin Chen of Harvard Medical School told BuzzFeed News. “That means people should be washing their hands a lot.” In a helpful round-up of health risks to Olympics visitors released this month, WHO starts by suggesting travelers have vaccinations for diphtheria, Haemophilus influenzae type b, hepatitis B, measles, mumps, pertussis, polio, rubella and tetanus.

SECRETARIA DE ESTADO DE SAÚDE DO RIO DE JANEIRO Rio cases of dengue (red), chikungunya (blue), and Zika (purple) have plunged as of June 6 (Week 23).

4. Dengue and chikungunya viruses, both carried by mosquitoes The WHO listed dengue and chikungunya viruses ahead of Zika in its warning, just a few of the viruses that afflict travelers to Brazil. “There are many others that are much more important than Zika,” said the WHO’s Perea. Dengue, carried by the same mosquito as Zika, is often seen as a proxy for how the latter virus would spread, which is slowly: The winter plunge in dengue cases started in Rio in the last month, dropping from 8,700 cases in April to less than 700 in June. Few Dengue cases have been identified in the city lately — just 15 people out of a city of millions, in the last week of June. And Zika cases are reported with similar frequency, according to the latest report from the state government.

Wikipedia / Via en.wikipedia.org Hookworms attached to the intestinal mucosa.

5. Parasites and fleas A 2014 study of nearly 1,600 ill travelers found that hookworms, fly, and flea infestation was the leading health complaint of travelers to Brazil from 1997 to 2013, followed by diarrhea, and then fevers from dengue or malaria. The CDC also advises skipping swimming in freshwater lakes in Brazil for this reason, due to the threat of schistosomiasis. It’s caused by parasitic worms, found in freshwater snails, that infect some 200 million people worldwide. 6. Sexually transmitted infections That same 2014 study found 28 cases of HIV acquired by travelers to Brazil, which points to the risks of sexually transmitted infections (including Zika), Chen noted. The CDC advises travelers to Brazil to abstain from sex or to use condoms during vaginal, oral, or anal sex, something that should continue for eight weeks after getting home, even without any symptoms.

Christophe Simon / AFP / Getty Images Police carry a motorcycle stolen by traffickers at Jacarezinho shantytown in Rio de Janeiro.

7. Crime Leaving illness aside, crime is also a worry in Rio: “Assaults are common on beaches or in parks after dark,” according to the US Department of State. “Even while driving, motorists can be vulnerable to armed bandits on motorcycles who prey on potential victims waiting at traffic lights or in traffic.” Rather than driving yourself, the State Department suggests people take a licensed taxi or Uber driver. Or maybe stick to walking. “Traffic accidents and injuries, mostly caused by motor vehicle crashes, are the leading causes of death among travelers under the age of 55 years,” according to the WHO. Pedestrians need to be wary of Brazilian drivers at crosswalks. 8. The germs you bring with you Travelers themselves are a worry for Brazil, and for other tourists. The Pan American Health Organization this week reminded Olympics visitors to get their vaccinations for measles, mumps, and rubella, concerned they might carry those diseases to Brazil. The mass gathering that looks most similar to the Olympics, Chen said, with large international collections of tourists coming together, is the Hajj, the religious pilgrimage to Mecca, in Saudi Arabia. Coughing and flu regularly crops up among the two million people who make the pilgrimage there every year. She also advises a lot of handwashing, particularly before eating. “Illness goes both ways,” Chen said. “Travelers can bring diseases, and travelers can bring back diseases home. People need to be careful.”