Outbreaks caused by a potentially fatal fecal parasite which lives in pools is increasing at alarming rates.

Outbreaks of Cryptosporidium, Crypto, in the United States has increased on average by 13% each year from 2009-2017, the CDC announced in a report released on Thursday.

“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. But we as parents can take steps to help keep our kids healthy in the water, around animals, and in childcare," Michele Hlavsa, R.N., M.P.H., chief of CDC’s Healthy Swimming Program said.

Crypto, a parasite, is spread through the poop of infected humans or animals. People can get sick after they swallow the parasite in contaminated water or food or after contact with infected people or animals. Crypto is the leading cause of disease outbreaks in the United States linked to water, specifically outbreaks linked to pools or water playgrounds, according to the CDC.

From 2009 through 2017 there have been 444 Crypto outbreaks, resulting in 7,465 people becoming sick, 287 hospitalizations and one death, the CDC reports.

Around 35% of the outbreaks were linked to treated swimming water in places like pools and water playgrounds. 15% were linked to contact with cattle; 13% were linked to contact with infected people in childcare settings; 3% were linked to drinking raw milk or apple cider.

The CDC classifies Crypto as a "challenging parasite." It's protected by an outer shell that makes it tough to kill. It can survive for days in chlorinated water in pools and water playgrounds or on surfaces disinfected with chlorine bleach, officials say.

Crypto can easily cause outbreaks because it only takes a few germs to make someone sick and there can be millions of Crypto germs in poop, the CDC reports. Someone sick with Crypto can have diarrhea for up to three weeks.

The CDC recommends following these steps to protect yourself and others:

  • Do not swim or let kids swim if they have diarrhea.
  • If diagnosed with cryptosporidiosis, do not swim until two weeks after diarrhea completely stops.
  • Do not swallow the water you swim in.
  • Keep kids sick with diarrhea at home and away from childcare.
  • Wash your hands with soap and water after coming in contact with animals or anything in their environment, especially animal poop. Alcohol-based hand sanitizers do not work effectively on Crypto.
  • Remove shoes worn in the animal environments (for example, in barns) before going inside your home.
  • If you drink milk or apple cider, only buy if it has been pasteurized.

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