Cryptosporidiosis: How the Crypto Parasite Spreads and How to Avoid It

Cryptosporidiosis is a contagious disease that causes watery diarrhea. It is caused by Cryptosporidium parasites, often called Crypto for short, which live in soil, food and water in every region of the United States and around the world. Crypto can also be on surfaces or on hands contaminated with the stool of people or animals that are infected.

How it spreads

People catch Crypto by swallowing the parasite in food, drinking water or water they swim in. It can also be picked up by touching something contaminated and then touching the eyes, nose or mouth, and it can spread through sexual contact.

Who is more likely to get it

• children, and people who work in child care centers
• adults aged 75 and older
• people caring for someone who has Crypto
• international travelers
• backpackers, hikers and campers who drink water that has not been filtered or treated
• swimmers and others who swallow water from contaminated sources
• people who handle infected animals, often cows or sheep

Symptoms

Watery diarrhea is the most common symptom. Others include dehydration, weight loss, stomach cramps or pain, fever, nausea and vomiting. Symptoms usually start 2 to 10 days after infection and, in people with healthy immune systems, last about 1 to 2 weeks, though they occasionally last longer or come and go for up to 30 days. Some people have no symptoms at all.

People with weakened immune systems can develop a serious, long-lasting illness. The immune system can be weakened by HIV, cancer, a genetic condition affecting immunity, or medicines such as chemotherapy and the drugs taken after an organ transplant. Anyone with watery diarrhea lasting more than a few days should contact a health care provider, especially if their immune system is weak.

Diagnosis

Crypto is diagnosed by examining stool, usually under a microscope. The number of parasites in stool can vary a lot from one day to the next, so a lab may ask for three samples collected on three different days to be sure of the result.

Treatment

Most people recover without treatment, usually in about one to two weeks. Drinking plenty of fluids to prevent dehydration is important; the guidance singles out pregnant people, and infants and young children should also get extra fluids. Pregnant people, and anyone who thinks they or their child is severely dehydrated, should ask a provider how to get enough fluids. Some dehydrated patients need intravenous (IV) fluids in a hospital.

Over-the-counter anti-diarrheal medicine may slow diarrhea, but should not be taken without asking a provider first. A medicine is available to treat Crypto diarrhea in people with healthy immune systems, and a provider can discuss whether it is suitable.

Prevention

• Wash hands often with soap and water, especially after using the toilet, changing diapers or touching animals, and before eating or preparing food. Alcohol-based hand sanitizers do not work against Crypto.
• Drink only water known to be safe.
• Drink only pasteurized milk and apple cider.
• When traveling where the food supply may be unsafe, avoid uncooked foods.
• Never swim while you have diarrhea, and avoid swallowing water when swimming.
• Use condoms or dental dams every time you have sex, which also helps prevent other sexually transmitted infections.

Sources

• MedlinePlus (National Library of Medicine), "Cryptosporidiosis," based on information from the Centers for Disease Control and Prevention. https://medlineplus.gov/cryptosporidiosis.html
• The source's sentence on fluids is garbled ("drink plenty of fluids to prevent dehydration if you are pregnant"); this page keeps its emphasis on pregnant people without adding to it.