Overview

Cryptosporidium infection (cryptosporidiosis) is an illness caused by tiny, one-celled cryptosporidium parasites. When cryptosporidia (krip-toe-spoe-RID-e-uh) enter your body, they travel to your small intestine and then burrow into the walls of your intestines. Later, cryptosporidia are shed in your feces.

In most healthy people, a cryptosporidium infection produces a bout of watery diarrhea and the infection usually goes away within a week or two. If you have a compromised immune system, a cryptosporidium infection can become life-threatening without proper treatment. You can help prevent a cryptosporidium infection by practicing good hygiene and avoiding swallowing water from pools, recreational water parks, lakes and streams.

Symptoms

The first signs and symptoms of cryptosporidium infection usually appear within a week after infection and may include:

  • Watery diarrhea
  • Dehydration
  • Lack of appetite
  • Weight loss
  • Stomach cramps or pain
  • Fever
  • Nausea
  • Vomiting

Symptoms may last for up to two weeks, though they may come and go sporadically for up to a month, even in people with healthy immune systems. Some people with cryptosporidium infection may have no symptoms.

When to see a doctor

Seek medical attention if you develop watery diarrhea that does not get better within a few days.

Causes

Cryptosporidium infection begins when you ingest the one-celled cryptosporidium parasite. Some strains of cryptosporidium may cause more serious disease.

These parasites then travel to your intestinal tract, where they settle into the walls of your intestines. Eventually, more cells are produced and shed in massive quantities into your feces, where they are highly contagious.

You can become infected with cryptosporidia by touching anything that has come in contact with contaminated feces. Methods of infection include:

  • Drinking contaminated water that contains cryptosporidium parasites
  • Swimming in contaminated water that contains cryptosporidium parasites and accidentally swallowing some of it
  • Eating uncooked, contaminated food that contains cryptosporidia
  • Touching your hand to your mouth if your hand has been in contact with a contaminated surface or object
  • Having close contact with other infected people or animals — especially their feces — which can allow the parasite to be transmitted from your hands to your mouth

If you have a compromised immune system from HIV/AIDS, you're more susceptible to illness from cryptosporidium parasites than is a person with a healthy immune system. People with HIV/AIDS can develop severe symptoms and a chronic, persistent form of disease that may be difficult to treat.

Hardy parasites

Cryptosporidium parasites are one of the more common causes of infectious diarrhea in humans. This parasite is difficult to eradicate because it's resistant to many chlorine-based disinfectants and can't be effectively removed by many filters. Cryptosporidia can also survive in the environment for many months at varying temperatures, though the parasite can be destroyed by freezing or boiling.

Risk factors

People who are at increased risk of developing cryptosporidiosis include:

  • Those who are exposed to contaminated water
  • Children, particularly those wearing diapers, who attend child care centers
  • Parents of infected children
  • Child care workers
  • Animal handlers
  • Those who engage in oral-to-anal sexual activity
  • International travelers, especially those traveling to developing countries
  • Backpackers, hikers and campers who drink untreated, unfiltered water
  • Swimmers who swallow water in pools, lakes and rivers
  • People who drink water from shallow, unprotected wells

Complications

Complications of cryptosporidium infection include:

  • Malnutrition resulting from poor absorption of nutrients from your intestinal tract (malabsorption)
  • Severe dehydration
  • Significant weight loss (wasting)
  • Inflammation of a bile duct — the passage between your liver, gallbladder and small intestine
  • Inflammation of your gallbladder, liver or pancreas

Cryptosporidium infection itself isn't life-threatening. However, if you've had a transplant or if you have a weakened immune system, developing complications can be dangerous.

Prevention

Cryptosporidium infection is contagious, so take precautions to avoid spreading the parasite to other people. There's no vaccine that can prevent a cryptosporidium infection.

All preventive methods aim to reduce or prevent the transmission of the cryptosporidium germs that are shed in human and animal feces. Precautions are especially important for people with compromised immune systems. Follow these suggestions:

  • Practice good hygiene. Wash your hands for at least 20 seconds with soap and water after using the toilet and changing diapers, and before and after eating. Alcohol-based hand sanitizers do not effectively kill the germs that cause cryptosporidium infection.
  • Thoroughly wash with uncontaminated water all fruits and vegetables that you will eat raw, and avoid eating any food you suspect might be contaminated. If you're traveling in a developing country, avoid uncooked foods.
  • Purify drinking water if you have a weakened immune system or are traveling in an area with a high risk of infection. Methods include boiling — at least one minute at a rolling boil — or filtering, although filtering may not be as effective as boiling. Be sure to use a filter that meets the National Safety Foundation Standard/American National Standards Institute (NSF/ANSI) standard 53 or 58 requirements for cyst and oocyst reduction. You'll need a separate water filter for bacteria and viruses.
  • Limit swimming activities in lakes, streams and public swimming pools, especially if the water is likely to be contaminated or if you have a compromised immune system.
  • Avoid fecal exposure during sexual activity.
  • Handle newborn farm and domestic animals with care. Be sure to wash your hands after handling the animals.

Always refrain from swimming anytime you're experiencing diarrhea. If you know you've had a cryptosporidium infection, don't go swimming for at least two weeks after your symptoms subside because you may still be contagious.

Nov. 30, 2016
References
  1. Ray CG, et al. Apicomplexa and microsporidia. In: Sherris Medical Microbiology. 6th ed. New York, N.Y.: The McGraw-Hill Companies; 2014. http://www.accessmedicine.com. Accessed Sept. 19, 2016.
  2. Longo DL, et al., eds. Protozoal intestinal infections and trichomoniasis. In: Harrison's Principles of Internal Medicine. 19th ed. New York, N.Y.: McGraw-Hill Education; 2015. http://accessmedicine.com. Accessed Sept. 19, 2016.
  3. Leder K, et al. Epidemiology, clinical manifestations, and diagnosis of cryptosporidiosis. http://www.uptodate.com/home. Accessed Sept. 19, 2016.
  4. Parasites — Cryptosporidium: Prevention & control. Centers for Disease Control and Prevention. http://www.cdc.gov/parasites/crypto/prevention-control.html. Accessed Sept. 19, 2016.
  5. Levinson W. Intestinal and urogenital — protozoa. In: Review of Medical Microbiology and Immunology. 14th ed. New York, N.Y.: McGraw-Hill Education; 2016. http://www.accessmedicine.com. Accessed Sept. 19, 2016.
  6. Leder K, et al. Treatment and prevention of cryptosporidiosis. http://www.uptodate.com/home. Accessed Sept. 19, 2016.

Cryptosporidium infection