With the onset of warmer weather, the US Centers for Disease Control and Prevention (CDC) said today that reports of Cryptosporidium outbreaks linked to pools and waterparks are increasing.
There were twice as many outbreaks reported to CDC in 2016 compared with 2014, researchers from the CDC and from health department in Alabama, Arizona, and Ohio reported today in the latest issue of Morbidity and Mortality Weekly Report (MMWR).
Unique risks, unclear reasons
Crypto parasites, the most common cause of diarrhea and outbreaks linked to swimming pools or waterparks, aren't easily killed by chlorine. Ingestion of pool water contaminated with feces from a symptomatic person can sicken healthy people with diarrhea, stomach cramps, nausea, or vomiting for as long as 3 weeks, according to the CDC.
In 2016, at least 32 Cryptosporidium outbreaks were reported to the CDC, compared with 16 in 2014. The CDC said it's not clear if the number of outbreaks has increased or if better surveillance and lab testing has helped better detect outbreaks.
Michele Hlavsa, RN, MPH, said in the CDC press release, "To help protect your family and friends from Crypto and other diarrhea-causing germs, do not swim or let your kids swim if sick with diarrhea." She also urged people to protect themselves by avoiding swallowing pool water.
State experiences, molecular tests help
In their report today the authors also detailed examples of recent large Crypto outbreaks in Alabama, Arizona, and Ohio. Arizona and Ohio reported steep increases for 2016.
In Arizona, an outbreak involving a Little League team and family members was traced to a July visit to an aquatic center, and Ohio's report involved members of a college sports team who were part of a waterpark-related outbreak.
Alabama's outbreak last year was tied to an aquatic facility that was in compliance with local standards, which the authors said shows how vulnerable facilities can be, even when properly operated.
The team also detailed how a relatively new molecular testing network, CryptoNet, is helping states detect and track outbreaks, as well as identify the types that are sickening people. For example, the researchers said Arizona health officials used the system last year to confirm a specific type of Cryptosporidium that spread to multiple swimming pools around Phoenix.
May 18 MMWR report
May 18 CDC press release