- There are some germs that can survive in the ocean and cause infection.
- Some of the infections that you could contract from swallowing contaminated ocean water include cryptosporidiosis, shigellosis, and E. Coli.
- If you swim with an open wound, you could also get infections from staphylococcus aureus and vibrio vulnificus.
- This article was reviewed by Jason R. McKnight, MD, MS, a family medicine physician and clinical assistant professor at Texas A&M College of Medicine.
- This story is part of Insider’s guide on How to Kill Germs.
Germs aren’t only in doctors’ offices and grocery stores, they’re everywhere – even in the ocean. While you have the added bonus of being out in the fresh air instead of in an enclosed area when you’re at the beach, there are still risks of getting sick in ocean water and the beach environment.
How ocean water affects bacteria and viruses
Viruses need a host to survive and replicate, says Rachel Noble, PhD, distinguished professor at UNC Institute of Marine Sciences. So, you should be more concerned about catching infectious germs from other people, or beach facilities, than from being infected by ocean water.
Plus, contagious diseases, such as the common cold, are often airborne. That means you’re more likely to catch a contagious disease from respiratory droplets in the air – not in the water.
However, some germs, particularly bacteria, are better suited for living in the ocean compared to viruses. Noble says this means that they can survive and even replicate on their own in a new environment.
In ocean water, you’re more likely to get infections if pathogens get into open wounds or are swallowed, says Manisha Juthani, MD, an infectious disease specialist and associate professor of medicine and epidemiology at Yale School of Medicine.
Most common ways to get sick from ocean water
According to Juthani, there are a few common infections you can get from contaminated ocean water.
If you swallow contaminated ocean water, this can include:
- Cryptosporidiosis:This is caused by a parasite called cryptosporidium. The most common symptom of this parasitic infection is watery diarrhoea. According to the CDC, it’s the most common water-borne disease for humans.
- Shigellosis: This is a bacterial infection caused by shigella bacteria, also resulting most commonly in diarrhoea.
- Escherichia coli (E.coli)infection: This is another bacterial infection that causes diarrhoea.
If you have an open wound in contaminated ocean water, this can include:
- Vibrio vulnificus infections: Infections caused by Vibrio bacteria can be very serious, but are rare. If your wound is infected with this bacteria, you may experience fluid leaking from the wound, swelling, redness, and fever. If the infection is bad enough it can lead to necrotizing fasciitis, which many refer to as the “flesh-eating disease.” The bacteria is most common in warm coastal water during May through October.
- Staphylococcus aureus infections: Staph infections, specifically MRSA, can be caught from ocean water, Juthani says. MRSA is a type of antibiotic-resistant bacteria that can cause severe infection. Symptoms are painful red bumps that can turn into abscesses.
As for how these bacteria live in the water, Juthani says that some of these bacteria naturally exist in the ocean, such as Vibrio. However, other bacteria like Cryptosporidium, E.coli, and Shigella are introduced into the water when human or animal faeces contaminate it. Another possible way for germs to enter the ocean is through a sewage spill, Noble says.
On top of these infections, Juthani says it’s common to pick up respiratory infections like coughs or colds from close exposure to other people. Just because it isn’t cold and flu season, doesn’t mean you can’t get infected, even at the beach.
How to stay germ-free at the beach
To avoid getting sick at the beach, the most crucial thing to do is to keep your distance from others. Juthani says it’s important to stay at least six feet away from other parties. Try to park your beach chair away from crowds. The more secluded, the better.
If you go in the ocean, make sure you keep your distance there, too, especially because people are unlikely to be wearing masks. If the designated swimming area is too crowded for you to have a six-foot bubble, it’s not worth the risk.
Don’t play sports like beach volleyball or anything else that requires you to get in close proximity with people outside your household. The CDC advises against sharing equipment and toys, such as footballs, frisbees, and volleyballs, since these become high-touch surfaces when you’re playing with them.
You should also pack hand sanitizer or hand sanitizing wipes to keep your hands clean if you aren’t going to have access to soap and water. Be sure to clean your hands before eating, and avoid touching your face.
To avoid germs in the water, don’t drink the ocean water and avoid going in the ocean if you have open wounds. Juthani says if you get a cut at the beach, clean it off and seek medical attention if you start to notice it swelling or becoming infected.
As long as you can follow these precautions, you can have a safe and fun beach day. If you notice any new symptoms after the beach, don’t hesitate to see your doctor in case you have contracted an infection. It’s better to be safe than sorry.