Causes and Symptoms of Waterborne Illness - Minnesota Dept. of Health

Recreational Water Illnesses (RWIs)

Minnesota Department of Health
Revised 6/2015

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Recreational Water Illnesses (PDF)

What are recreational water illnesses?

Recreational water illnesses (RWIs) are illnesses spread by swallowing or having contact with contaminated water from lakes, swimming pools, hot tubs, oceans, or rivers.

Where can you get RWIs?

RWIs can be spread through use of swimming pools, water parks, hot tubs, splash pads, decorative fountains, lakes, rivers, and oceans.

What are possible causes of RWIs?

Possible causes of RWIs include:

How are RWIs spread?

When people are ill with diarrhea, even a speck of their stool can contain millions of germs. Swimming while ill can easily contaminate the water – even if you don’t have an accident. Also, lakes and rivers can be contaminated by animal waste, sewage spills, and water runoff following rainfall. If someone swallows water that has been contaminated, he/she may become sick.

Other non-diarrheal RWIs are caused by germs that live naturally in the environment (water, soil). If disinfectant is not adequately maintained at the appropriate levels in a pool or hot tub, these germs can increase to the point where they cause illness when swimmers breathe or have contact with the water.

A very rare but fatal brain infection can be caused by Naegleria fowleri. This ameba infects people by entering the body through the nose. This usually occurs when people use warm freshwater for swimming or diving.

What are the symptoms?

The most common symptoms of RWIs include diarrhea (sometimes bloody), vomiting, stomach cramps, loss of appetite, weight loss, and fever. Other RWIs can cause skin, ear, eye, respiratory, or neurologic symptoms.

What should I do if I have symptoms?

  • Contact your health care provider.
  • Do not swim while you have diarrhea. If you are diagnosed with Cryptosporidium, you should not swim for 2 weeks after your diarrhea has stopped.

Healthy Swimming Tips:

  • Do not swim while you have diarrhea. You can spread germs in the water and make other people sick.
  • Take a shower before and after swimming. Germs on your body end up in the water.
  • Wash your child thoroughly before swimming (especially the rear end).
  • Do not swallow water or get water in your mouth while swimming.
  • When swimming, take kids on frequent bathroom breaks – waiting to hear “I have to go” may mean that it’s already too late.
  • Change diapers in changing rooms, not poolside or on the beach. Wash your hands after changing diapers.

The only certain way to prevent Naegleria fowleri infection is to avoid water-related activities in warm freshwater. If you choose to swim, the following measures might lower risk:

  • Avoid water-related activities in warm freshwater during periods of high water temperatures and low water levels.
  • Avoid putting your head under the water in hot springs and other untreated thermal waters.
  • Avoid digging in, or stirring up, the sediment while taking part in water-related activities in shallow, warm freshwater.
  • Hold your nose shut or use nose clips when taking part in water-related activities in bodies of warm freshwater.

To report a suspected waterborne illness, call the Minnesota Department of Health at 1-877-366-3455 (or 651-201-5655 from the Twin Cities).


Updated Wednesday, March 22, 2017 at 07:03AM