Summer—it’s the perfect time to hit up a trip to the beach or lake with the family or friends. But while you’re enjoying the water and having fun in the sun, you’re probably not thinking about all the germs hiding in the surf, many of which can leave you nauseated, cramping—or worse.
The germs that frequent the rivers, lakes, and oceans are what could turn a nice day at the beach into a not-so-nice trip to the hospital. “This danger is silent and invisible,” says Steve Fleischli, director of the National Resources Defense Council (NRDC). “The fact is too many of America’s beaches are sick, and they are spreading illnesses to our families.”
NDRC senior attorney John Devine says that pollution and stormwater runoff are to blame for the high bacteria counts in the water, even though the beaches are being routinely checked. “Many of our beach managers are being proactive, but unfortunately the problems do persist,” says Devine.
The good news? “Most water, whether it’s a pool or a beach, is safe for swimming,” says Michele Hlavsa, chief of the Healthy Swimming Program at the Centers for Disease Control (CDC). “However, you cannot know for sure unless the water is tested.” To be safe, Hlavsa recommends looking at EPA’s “Before You Go To The Beach” brochure and following the Triple A’s of Healthy Swimming.
Here is a breakdown of 11 diseases —or recreational water illnesses (RWIs), as the Centers for Disease Control call them—that you could catch at the shore, lake or river this summer, and how to swim safely.
- Shigellosis. Caused by the Shigella bacteria, this illness can cause diarrhea (often bloody), fever and stomach cramps that usually come on a day or two after exposure. The disease is typically transmitted when sewage runs into the water or swimmers (typically toddlers who aren’t fully potty trained) introduce the bacteria. Shigellosis usually goes away after 5 to 7 days without antibiotic treatment and is only rarely serious. In rare cases, joint pain, eye irritation and painful urination can develop. Shigellosis can be prevented by careful hand washing (as well as supervising hand washing of small children), and avoiding swallowing water from untreated water areas.
- Norovirus. This highly contagious virus is most common cause of acute gastroenteritis, an inflammation of the stomach and/or intestines that leads to nausea, stomach pain, diarrhea and vomiting. Like shigellosis, norovirus can be transmitted from sewage or infected swimmers. Since this is a viral infection, it is best to let it run it course, but drink plenty of fluids in order to prevent dehydration. Usually, people get better after 1 to 3 days. Showering before swimming to prevent germs from getting in the water and avoiding swimmming if you have a diarrheal illness can prevent Norovirus.
- E. coli. Here’s one good reason to keep your mouth shut when you’re doing the backstroke at the lake: A strain of E. coli, known as Shiga toxin-producing E. coli or STEC. STEC, which can cause symptoms like diarrhea, urinary tract infections, respiratory illnesses and even pneumonia, can infect swimmers who swallow contaminated water. STEC infections are usually mild and can cause diarrhea. Prevent STEC infections by washing your hands before and after swimming and avoid swallowing water while you’re taking a dip.
- Cryptosporidium. Most commonly known as Crypto, this parasitic illness is one of the top causes of RWIs and leads to diarrhea that can last 2 to 3 weeks. Other symptoms include nausea, vomiting, weight loss, stomach cramps, dehydration and fever. Pregnant women, young children and individuals with weakened immune systems are most likely to get infected. Even though Crypto can be found in lakes and rivers, you are more likely to find it in swimming pools.
- Giardia. Giardiasis is caused by swallowing water from freshwater lakes, rivers and streams where the giardia parasite may live. Symptoms include diarrhea, stomach cramps, nausea or upset stomach and dehydration. While there are prescription drugs to treat giardiasis, the best way to treat it is to drink plenty of fluids to prevent dehydration. The best way to prevent giardiasis is to shower before swimming to avoid introducing the bacteria into the water and wash your hands thoroughly. Also if you have small children, take them on frequent bathroom breaks and check their diapers often.
- Cercarial Dermatitis. Also known as swimmer’s itch, cercarial dermatitis is an allergic reaction to microscopic parasites that infect birds and mammals. Symptoms include tingling, burning and itching on exposed skin with small reddish pimples and/or blisters. Most cases of swimmer’s itch do not require medical attention, and the itching will gradually go away. Anti-itch lotion, corticosteroid cream, Epsom salts baths and colloidal oatmeal baths can provide some relief. Avoid marshy areas where snails are common. Shower immediately after swimming to wash off parasites that have not yet penetrated the skin.
- Leptospirosis. Caused by the bacteria Leptospira typically found in the urine of animals, leptospirosis can be a threat to people who frequent freshwater lakes and rivers. Symptoms can include high fever, jaundice, red eyes, headache, chills, diarrhea, vomiting, muscle aches and stomach pains, and rash. Leptospirosis symptoms can last up to three weeks or even longer. It can be treated with doxycycline or penicillin in the early stages of the disease, but intravenous antibiotics may be required for more serious cases. If left untreated, this illness can cause kidney damage, liver failure, meningitis, respiratory illnesses and even death. The best way to avoid leptospirosis is to avoid swimming after heavy rains, which can wash animal waste into the water.
- Campylobacteriosis. With up to 1.3 million cases each year, “campy,” as it’s known, is one of the more common conditions swimmers in fresh-water lakes, ponds and rivers will encounter this year. Campylobacter bacteria are easily spread from birds and other animals that come into contact with water sources. People exposed to the bacteria have diarrhea, cramping, abdominal pain and fever and typically recover without treatment within a week. The best way to prevent campylobacteriosis is to not swallow contaminated water and to wash hands thoroughly.
- Enterovirus. Enteroviruses top the list of diseases that plague summer swimmers. Most cases are mild, causing cold-like symptoms such as fever, runny nose, and cough and usually people don’t get sick. More serious cases can lead to paralysis and heart or brain infections, but these cases are very rare. Transmission occurs from swallowing contaminated water . Since there is no treatment for this viral illness, the best way to prevent it is to wash your hands often and avoiding those who are infected.
- Naegleria. While naegleria is super-rare, it’s super-serious, so awareness is key. Merely swimming or diving in a warm freshwater lake or river is enough to expose you to this potentially deadly amoeba, which causes primary amebic meningoencephalitis (PAM), similar to bacterial meningitis. Initial symptoms include headache, fever, nausea and vomiting, progressing to confusion, stiff neck, seizures and hallucinations. PAM can cause death within five days, and the fatality rate is over 99 percent. Because of this, people who are infected should seek medical attention as soon as possible. There are effective treatments for naegleria, but only if it’s caught early. The best way to prevent these infections is to avoid swimming in these waters altogether.
- Yersenia. This bacteria can cause a variety of symptoms: diarrhea, fever and abdominal pain in children; right-sided abdominal pain often confused with appendicitis in adults. While infection is rare, swimmers could be exposed by swallowing water in rivers, lakes or streams or hand-to-mouth transmission. Most cases are resolved without treatment, but antibiotics can be used to treat more severe cases. The best way to avoid yersiniosis is to avoid contaminated water and to wash your hands with soap and water before eating.
For more information on these diseases and how to stay safe while swimming, please go to www.cdc.gov/healthyswimming.