It's community pool season and while urban moms think that a chlorinated municipal pool is cleaner than a rural pond, microbiologists know that isn't really true.

Bacteria and parasites can lurk in all kinds of water and put a real damper on summertime fun.

At biggest risk are the youngest kids, for a variety of reasons.

“One of the worst offenders is the kiddie wading pool,” said Christopher Ohl, M.D., professor of infectious diseases at Wake Forest Baptist Medical Center and medical director of communicable diseases for the Forsyth County (N.C.) Health Department. “Warm, shallow water and kids in swim diapers (which don’t do a good job of containing feces) can create a perfect breeding ground for water-borne infections even though the water is chlorinated. The best way to prevent young children from getting sick is to keep them from swallowing that water.”

And that's the most important tip - don't swallow the water. Kids with any type of GI illness should be kept them away from pools or water parks for several days to prevent contamination of the water but telling kids to never swallow water is the smartest tip of all. 

Salt water presents less of a problem regarding infections from bacteria and parasites, but swimmers should stay out of the water if they have a cut or wound that could become infected. Also, it is a good idea to stay away from jellyfish floating on top of the water in the ocean. 

Natural water sources carry risk also. Freshwater lakes and streams can harbor leptospirosis, a bacterium excreted in the urine of mammals that drink from the water. The infection can cause fever with headache or muscle aches in people, but can usually be treated,

To prevent, just don’t swallow the water, Ohl reminds.

Never drink untreated water in springs or streams even if it looks ‘fresh and pure.’ Remember, wild animals drink from springs and streams and then relieve themselves in it. 

For the truly paranoid parent, if you are worried about your child contracting Naegleria, a rare but deadly brain-eating amoeba that is almost impossible to treat, tell them not to jump feet first into a warm, stagnant pond. According to Ohl, jumping feet first into a pond can forcefully push water up into the top of the nose where there is a bone plate with tiny holes that the amoeba can crawl through to get into the brain.

 Brain-eating amoeba? Maybe that urine-filled community pool isn't so bad after all.