About This Disease

Cryptosporidiosis is caused by a very small intestinal parasite, Cryptosporidium. It is a common cause of diarrhea worldwide and can be a severe problem for people with weak immune systems.



Signs and Symptoms

The symptoms usually start about 7 days after exposure to the parasite, but they can begin from 1 to 12 days after exposure. The major symptoms are stomach cramping and frequent, watery diarrhea. Less commonly, nausea, vomiting, and fever may also occur. Symptoms may last for several days to several weeks, but should resolve within one month for healthy individuals.


Cryptosporidiosis is spread via fecal-oral transmission; in other words, by ingesting a small amount of fecal matter containing the parasite. Cryptosporidiosis is spread by eating food or drinking water contaminated with stool from infected animals and humans. The parasite can survive even in properly chlorinated water and is commonly spread through swimming pools. The eggs of the parasite can stay alive outside the body for 2 to 6 months in moist settings. People who have recovered from infection can continue to shed the parasite in their stool for days or weeks.



Cryptosporidium cannot be detected with routine stool cultures. Your doctor must order a special stool test.


The illness usually passes in 3 to 7 days in most people; however, doctors can also prescribe anti-parasitic medications for severe illness or to shorten duration. Persons with this illness should drink plenty of fluids to replace what is lost in diarrhea. The infection can be serious, even life threatening, when it occurs in persons whose immune systems are weakened by certain medical treatments or diseases such as cancer or HIV/AIDS.


None known.

Risk in Hawaii

Cryptosporidiosis is present in Hawaii, but it is uncommonly reported. Many cases are linked to travel to other states or countries.


Any child with diarrhea should stay from day care until the diarrhea stops. Also, people with diarrhea who work in food-handling or take direct care of patients should stay home from work until well. Infected people with no symptoms who work as food handlers, child-care and health care workers, should get permission from their doctor or the Health Department before returning to work. A person with cryptosporidiosis may be able to spread the disease for several weeks after the symptoms have gone away. Therefore, careful hand washing is very important upon return to work.

  • There is no vaccine to prevent cryptosporidiosis.
  • Wash your hands carefully after using the toilet, after changing diapers, after handling animals, and before eating or making food. After changing diapers, wash the child’s hands as well.
  • Dispose of human and animal waste promptly and carefully.
  • Avoid drinking untreated water from ponds, lakes, streams, swimming pools, hot tubs or fountains. If you must drink untreated water, first bring it to a rolling boil for at least 1 minute.
  • Cryptosporidium can live for days in swimming pools even with proper chlorine levels. Always shower before entering a swimming pool and avoid swallowing pool water. Take young children for bathroom breaks every 30-60 minutes.
  • If you have been diagnosed with Cryptosporidiosis, refrain from swimming for at least 2 weeks following the resolution of your symptoms.

Additional Resources

Information for Clinicians

Cryptosporidiosis is a ROUTINE/ENTERIC (enteric prevention priority) notifiable condition and must be reported by phone if the individual is a food handler, direct care provider, or pre-school aged child. Otherwise routine reports may be used.

Disease Reporting Phone Numbers (24/7)
Oahu (Disease Investigation Branch): (808) 586-4586
Maui District Health Office: (808) 984-8213
Kauai District Health Office: (808) 241-3563
Big Island District Health Office (Hilo): (808) 933-0912
Big Island District Health Office (Kona): (808) 322-4877
After hours on Oahu: (808) 566-5049
After hours on neighbor islands: (800) 360-2575 (toll free)

For more information: Centers for Disease Control and Prevention (CDC)


Last reviewed August 2017