The rugged Cryptosporidium parasite is spreading around American pools and hot tubs, making people sick and becoming immune to standard chlorine treatment. The toxic parasite can survive on its own for ten days or more in water, even if its been treated to kill germs.
The Centers for Disease Control and Prevention (CDC) recently reported 90 outbreaks of illness in 32 states and Puerto Rico from 2011-2012 linked to the parasite. These illnesses affected over 1700 people, sending 95 to hospital and resulting in one death.
Lead author of a CDC report, Michele Hlavsa, warned that "this parasite is extremely chlorine-resistant. Swimmers bring it into the water when they are sick with diarrhea."
The parasite’s resistance to chlorine even seems to be getting stronger. The CDC's report goes on to say that "since 1988, the year that the first U.S. treated recreational water-associated outbreak of Cryptosporidium was detected, the number of these outbreaks reported annually has significantly increased."
Part of the increase may be a result of inconsistencies in regulating codes of treating public recreational pools and spas, according to the CDC. These codes are established by state or local agencies.
"There are different standards and people are responding differently," Hlavsa suggested. "We need a certain set of standards and it should be the same across the country."
A key element in improving consistency between agencies may include the CDC’s Model Aquatic Health Code (MAHC.) Issued in 2014, the MAHC contains scientifically backed guidelines for how to improve water quality, including recommendations for water venues that have experienced many outbreaks of Cryptosporidium to install secondary disinfection like ultraviolet light or ozone to kill the parasite.
The CDC picks up where motherly advice leaves off, recommending not relieving yourself in the water, not swimming while afflicted with diarrhea, and showering before and after swimming.