A new report highlights how danger lurks in even the most innocuous and fun activities. The Centers for Disease Control has published statistics regarding the illnesses associated with public water parks and swimming pools. The numbers are harrowing; 27,219 cases of sickness, 493 outbreaks, and eight deaths in the years from 2000 to 2014 in the US. Among the bacterial afflictions that run rampant in public pools are Cryptosporidium, Legionella (which causes Legionnaires’ disease), and Pseudomonas. These hardy strains of microbes are resistant to disinfectants, making them especially persistent in causing human illness.

The CDC defines outbreak in this context as "the occurrence of similar illnesses in two or more persons, epidemiologically linked by location and time of exposure to recreational water or to pathogens or chemicals aerosolized or volatilized from recreational water into the surrounding air."

Don't be a party pooper, feces in water is a major cause of sickness

One method for harmful bacteria to infiltrate an otherwise clean pool is diarrhea. If a diarrheal incident occurs, the CDC recommends hyperchlorination of the pool, to combat the spread of active Cryptosporidium that would typically result. Ultraviolet light or ozone systems can also be used to render Cryptosporidium cells inactive. Infants and toddlers in the water are considered to be high-risk factors for contamination, due to their limited toileting skills.

High levels of urine content in swimming pools that are not properly chlorinated can also cause outbreaks of sickness.

Setting, time and places of occurrences

In the months of June, July, and August, the sum total of outbreaks surpasses those of all the other months of the year combined. Of the years studied, 2007 contained the greatest numbers of illnesses reported.

Hotel swimming pools seem to be the most common source of infections, accounting for roughly half of the known outbreaks. Other sources include water parks, hot tubs, communal showering spaces, and saunas. Most outbreaks are caused by bacterial parasites, but a few are caused by viruses such as norovirus, Bacillus, nontuberculous mycobacterium, and Staphylococcus.

Symptoms of these infections range from mild gastrointestinal distress, earaches and, flu-like symptoms to death in the case of the worst Legionnella afflictions. The CDC advises to check chemical levels of pools and avoid swallowing pool water. With wary precautions, we can keep swimming the safe activity that is should be.