Swimming-Related Illness Fact sheet

Swimming in contaminated pools, rivers, lakes, bays, and oceans can cause infections of the stomach and intestines (gastroenteritis) and skin (infectious dermatitis)

Swimmers usually get gastroenteritis from water contaminated by Shigella, Escherichia coli, Giardia, or Cryptosporidium

Gastroenteritis can be spread from the feces of an infected person. It can be spread through water when someone with gastroenteritis gets into a swimming pool or a wading pool.
Shigella is a bacteria that can cause diarrhea, stomach cramps, fever, nausea and vomiting.
E. coli O157:H7 is a strain of Escherichia coli bacteria that can cause severe illness in people. Symptoms can include severe bloody diarrhea and stomach cramps.
Giardia is a parasite that can cause diarrhea, abdominal cramps, bloating and gas.
Cryptosporidium is also a parasite that can cause diarrhea, stomach cramps, fever, and nausea.

See fact sheets on shigellosis, E. coli O157:H7, giardiasis, and cryptosporidiosis for more information about these diseases. Swimmers can also get gastroenteritis from other bacteria, viruses, and parasites.

Dermatitis can be caused by chemicals such as too much chlorine in the water (chemical dermatitis) or by germs such as bacteria, viruses and fungi. A bacteria called Pseudomonas often causes infections in hot tubs, spas, and whirlpools

Pseudomonas causes an itchy rash over most of the body with bumps or blisters
It can also cause a sore throat, nose, eyes or ears
The rash will go away on its own

Swimming-related illnesses can be prevented:

Do not swim if you have diarrhea or an upset stomach
Do not let children with diarrhea enter a pool or wading pool
Do not change diapers at poolside
Take your child to the bathroom often to prevent accidents
Wash hands with soap and water after changing diapers or using the bathroom
Make sure young children are wearing rubber pants over diapers designed to prevent leaks
Shower with warm water and soap before entering the water
Rinse off before getting into a swimming pool, wading pool, or hot tub
Rinse off after leaving the "kiddie pool" before going into another pool
Avoid swimming in pools with cloudy looking water
Do not drink or swallow pool water
Notify lifeguards or pool management of any feces in a pool

Pools stay clean by proper filtration and chlorine levels, but chlorine does not kill all of the organisms that can cause infections.

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Maryland Department of Health & Mental Hygiene
— Epidemiology & Disease Control Program
May 2002