Watch Out For Bacteria, Parasites In Pools, Hot Tubs, CDC Says

Nearly 500 disease outbreaks caused by pathogens found in pools, hot tubs, spas and water parks were reported between 2000 and 2014 and a majority of these outbreaks happened in hotel pools, according to The Centers for Disease Control and Prevention. The CDC said that as result of these outbreaks, more than 27,000 disease cases were reported and at least eight people died.

Among the outbreaks for which there was a confirmed cause, a majority (58 percent) were caused by cryptosporidium, a parasite which causes gastrointestinal illnesses. About 16 percent of the outbreaks were cause by legionella, which causes Legionnaires' disease and 13 percent were caused by pseudomonas, which causes conditions like "hot tub rash" and "swimmers' ear."

While most of the disease cases were caused by cryptosporidium, the CDC said six of the eight deaths were reported to be people affected by outbreaks caused by legionella. Pathogens that have become resistant to chlorine are the leading cause of the outbreaks, the CDC says.

For the outbreaks that started at hotels that had an identifiable cause, the CDC says most were caused by pseudomonas, followed by legionella and cryptosporidium. A majority of the hotel outbreaks were associated with hot tubs and spas.

The CDC says extremely chlorine-tolerant cryptosporidium can survive in water for over seven days.

"The parasite’s extreme chlorine tolerance enables it to persist in water, cause outbreaks that sicken thousands, and spread to multiple recreational water venues and other settings (e.g., child care settings)," the CDC writes. "Rates of individual cases caused by Cryptosporidium peak in the summer, coinciding with the summer swim season."

Legionella and pseudomonas can be controlled by substances like chlorine and bromine but because they can persist in biofilm, they are amplified when disinfectant concentrations are not properly maintained, according to the CDC.

The CDC notes that the outbreak counts likely underestimate the actual incidence and because reporting and review procedures changed over time, it's hard to compare data for different years.

“Don’t swim or let your kids swim if sick with diarrhea," is the CDC's key message to the public, particularly to parents. The CDC also said people should check the inspection scores of public treated water facilities.

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