Cryptosporidiosis (or “Crypto” for short) is a disease that causes watery diarrhea. It is caused by microscopic germs—parasites called Cryptosporidium. Although Crypto can affect all people, some groups are likely to develop more serious illness. For people with weakened immune systems, symptoms can be severe and could lead to severe or life-threatening illness. Examples of people with weakened immune systems include those with HIV/AIDS; those with inherited diseases that affect the immune system; and cancer and transplant patients who are taking certain immunosuppressive drugs.

Crypto lives in the gut of infected humans or animals. An infected person or animal sheds Crypto parasites in their poop. An infected person can shed 10,000,000 to 100,000,000 Crypto germs in a single bowel movement. Shedding of Crypto in poop begins when symptoms like diarrhea begin and can last for weeks after symptoms stop. Swallowing as few as 10 Crypto germs can cause infection.

Crypto can be spread by:

• Swallowing recreational water (for example, the water in swimming pools, fountains, lakes, rivers) contaminated with Crypto
  • Crypto’s high tolerance to chlorine enables the parasite to survive for long periods of time in chlorinated drinking and swimming pool water
• Drinking untreated water from a lake or river that is contaminated with Crypto
• Swallowing water, ice, or beverages contaminated with poop from infected humans or animals
• Eating undercooked food or drinking unpasteurized/raw apple cider or milk that gets contaminated with Crypto
• Touching your mouth with contaminated hands
  • Hands can become contaminated through a variety of activities, such as touching surfaces or objects (e.g., toys, bathroom fixtures, changing tables, diaper pails) that have been contaminated by poop from an infected person, changing diapers, caring for an infected person, and touching an infected animal
• Exposure to poop from an infected person through oral-anal sexual contact

Crypto is not spread through contact with blood.