Excited to hit the pool this summer? A new report by the U.S. Centers for Disease Control and Prevention may make you think twice before you dive in.
Outbreaks of Cryptosporidium, a parasite spread through the feces of infected humans or animals, increased an average 13% a year from 2009 to 2017, the CDC announced in a report published Friday.
Crypto is the leading cause of disease outbreaks in the U.S. linked to water, specifically recreational water, like swimming pools and water parks, that have been contaminated with diarrhea, according to the CDC.
From 2009 to 2017, public health officials in 40 states and Puerto Rico reported 444 outbreaks linked to Crypto, resulting in 7,465 people becoming sick, 287 hospitalizations, and one death, according to the CDC.
The findings, published in the CDC's Morbidity and Mortality Weekly Report, revealed that 35% of the outbreaks, or about 156, occurred in treated recreational water and resulted in 4,232 cases of illnesses and 183 hospitalizations.
Crypto can spread through the feces of another person who is infected, including through pool water that's been contaminated with diarrhea, according to the CDC. Chlorine can't easily kill the parasite, meaning it can last for up to 10 days in water that is otherwise properly treated.
One mouthful of contaminated water can leave a healthy person sick with diarrhea, cramps and vomiting for up to three weeks.
"Young children can get seriously sick and easily spread Crypto. They don’t know how to use the toilet and wash their hands, or are just learning how," said Michele Hlavsa, chief of CDC's Healthy Swimming program, in a statement.
The CDC recommends avoiding the swimming pool if you or your kids have diarrhea. If diagnosed with cryptosporidiosis, do not swim until two weeks after diarrhea completely stops. The agency also warned against swallowing water you swim in.
It is not clear whether the number of outbreaks has increased or whether better surveillance and laboratory methods are leading to better outbreak detection. The CDC also noted that the reported number of cases "likely underestimate" the actual magnitude of an individual outbreaks since most people don't report their illnesses to the agency.
The CDC provides more information here.