Diseases and Conditions


What is cryptosporidiosis?

Cryptosporidiosis is an infection that causes diarrhea. It is sometimes called Crypto. It is caused by a parasite found in stool. You can get this infection after eating food or drinking water that is contaminated with stool. This includes swallowing water while swimming. You can also get infected if you touch things or surfaces contaminated with stool. You can also get the infection from another person.

The parasite has an outer shell. Because of this, using chlorine to clean water may not kill the parasite. Crypto is one of the most common causes of waterborne disease in the U.S.

What causes cryptosporidiosis?

Cryptosporidiosis is caused by the parasite Cryptosporidium. Once inside your body, the parasite passes through your digestive tract and infects your stool. Anything contaminated with the infected stool can pass the infection on to other people.

Who is at risk for cryptosporidiosis?

The parasite is found throughout the world. But you are more likely to get the infection if you travel to rural areas in developing countries. Or if you often eat or drink in areas where sanitation is poor. Outbreaks have also occurred in the U.S. when water supplies or swimming pools become infected.

The disease is spread by accidentally swallowing anything that has come into contact with the stool of a person or animal with the infection. This includes:

  • Swallowing water contaminated with the parasite. The parasite can be found in swimming pools, hot tubs, jacuzzis, lakes, rivers, springs, ponds, or streams contaminated with sewage or stool.
  • Eating uncooked foods tainted with the parasite.
  • Swallowing the parasite picked up from surfaces contaminated with the stool of an infected person. This includes bathroom fixtures, changing tables, and diaper pails.

Cryptosporidiosis is normally not a serious disease in healthy people. But it can lead to a life-threatening illness for people with a weak immune system. Those at risk are:

  • People with HIV/AIDS
  • Cancer and transplant patients who are taking certain medicines that suppress the immune system
  • People with inherited diseases that affect the immune system

What are the symptoms of cryptosporidiosis?

Each person may have slightly different symptoms. These are the most common symptoms:

  • Diarrhea
  • Loose or watery stools
  • Vomiting
  • Weight loss
  • Stomach cramps
  • Fever

You may not have any symptoms. If symptoms do develop, they often last about 2 weeks and sometimes longer. But even if you have no symptoms, the parasite is passed in your stool for up to 2 months. During this time you are at risk of spreading the infection to others.

How is cryptosporidiosis diagnosed?

Your health care provider will look at a stool sample. You will need special testing because tests for this disease are not routinely done in labs.

How is cryptosporidiosis treated?

Your health care provider will figure out the best treatment for you based on:

  • How old you are
  • Your overall health and past health
  • How sick you are
  • How well you can handle specific medicines, procedures, or therapies
  • How long the condition is expected to last
  • Your opinion or preference

No treatment works fully against the infection. If you have a healthy immune system, you will likely recover on your own. People who are in poor health or have a weak immune system may get a more serious infection. In some cases, you may need to take medicine for diarrhea. It’s important to drink plenty of fluids to stay hydrated.

Can cryptosporidiosis be prevented?

You can’t prevent cryptosporidiosis with a vaccine or medicine. The best way to protect yourself is with good personal hygiene. You should also:

  • Wash your hands thoroughly with soap and water after using the toilet or changing diapers.
  • Wash your hands thoroughly before eating or making food.
  • Wash and peel all raw fruits and vegetables before eating.
  • Do not drink water from lakes, rivers, springs, ponds, or streams, unless they have been filtered and chemically treated.
  • Do not drink any water or eat any food that may be tainted.
  • When traveling to countries where the water supply may be unsafe, do not drink unboiled tap water. Also do not eat any raw foods washed with tap water. Choose steaming hot drinks, such as coffee and tea, and pasteurized fruit drinks. Make sure bottled water is safe to drink.
  • Many home water filters can remove Cryptosporidium. Read the label for details.

When should I call my health care provider?

Call your health care provider right away if your symptoms return or get worse, or you have new ones.

Key points

  • Cryptosporidiosis is an infection that causes diarrhea. It is caused by a parasite.
  • Most people get the parasite after swallowing food or water tainted with stool. This includes swallowing water while swimming.
  • Diarrhea, vomiting, and weight loss are the most common symptoms.
  • Dehydration is the main complication.
  • Good personal hygiene can help prevent it. You should also stay away from unclean water sources.

Next steps

Tips to help you get the most from a visit to your health care provider:

  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your provider tells you.
  • At the visit, write down the names of new medicines, treatments, or tests, and any new instructions your provider gives you.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your provider if you have questions.

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