The Maricopa County Department of Public Health is investigating an outbreak of a diarrheal illnesses caused by the parasite, Cryptosporidium parvum, and is advising the public to take precautions to prevent further spread of the disease. Nineteen cases were reported to public health officials in July, and five of the initial interviews have been linked to recreational water facilities. The investigation is ongoing.


“Most healthy people infected with Cryptosporidium may experience some unpleasant symptoms, but will recover without treatment,” said Dr. Rebecca Sunenshine, medical director for Maricopa County Department of Public Health. “It is critical, however, that anyone with diarrhea avoids swimming and preparing food for two weeks after symptoms resolve to keep it from spreading to others.”

While some people with Cryptosporidium, or Crypto, will have no symptoms, the most common symptom is watery diarrhea that generally begins one week (ranging from 2-10 days) after infection. Other symptoms include stomach cramps, dehydration, nausea, vomiting, fever, and weight loss. Persons with healthy immune systems usually recover in one to two weeks without treatment.

“Although Crypto can infect all people, individuals with weakened immune systems can have more prolonged or severe symptoms and should contact their healthcare provider for additional guidance,” advises Dr. Sunenshine. “If you have diarrhea lasting longer than 10 days, blood in your stool, or have trouble staying hydrated, see a healthcare provider.” Healthcare providers should report Cryptosporidium cases to public health.

Crypto is typically spread in swimming pools or other recreational water when an infected person swims or plays in the water, contaminating the water with fecal matter. Although chlorine kills most germs in swimming pools, Crypto can even survive in properly chlorinated water for long periods of time. Outbreaks have also been associated with petting zoos that include contaminated livestock.

Crypto can be highly contagious. Public health strongly recommends that infected individuals follow these guidelines to avoid spreading the disease to others:

  • Do not swim or play in recreational water (pools, hot tubs, splash pads, lakes, rivers, etc.) if you have diarrhea and for at least 2 weeks after the diarrhea stops.
  • Wash hands with soap and water thoroughly before preparing food and after toileting or diapering. Alcohol based hand sanitizer is not effective against Crypto.
  • Avoid food preparation while symptoms last.
  • Children with diarrhea should be excluded from child care settings until the diarrhea has stopped.