Health officials in Arizona and North Carolina have recently reported outbreaks of diarrheal illnesses caused by the parasite cryptosporidium that have spread in recreational water facilities.

On Thursday, the Maricopa County (Ariz.) Department of Public Health announced it is investigating a “crypto” outbreak that has led to 19 reported cases in the Phoenix area in the month of July. Five of the initial interviews of those cases have been linked to water parks, according to the department.

Last week, the Wake County Public Health Division in North Carolina confirmed 29 crypto cases and is investigating other potential cases, the News & Observer in Raleigh reported.

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, the Maricopa County department said in a press release. Crypto can survive in normal levels of chlorinated water.

From ABSeven Steps to Ensure Proper Pool Water Quality

“Most healthy people infected with cryptosporidium may experience some unpleasant symptoms but will recover without treatment,” said Dr. Rebecca Sunenshine, medical director for the 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.”

“Although Crypto can infect all people,” Sunenshine added, “individuals with weakened immune systems can have more prolonged or severe symptoms and should contact their healthcare provider for additional guidance.”

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According to a Phoenix TV report, the Wet ’n’ Wild Phoenix water park is among the areas under investigation. One 15-year-old with down syndrome, a genetic condition susceptible to a weakened immune system, reportedly became ill with crypto.

The park said it is treating its waters with high levels of chlorine as a precaution.

“Ensuring the public safety of our guests is our single greatest priority,” park spokesperson Heather Austin said in a statement. “Our pools, slides and attractions are inspected hourly, and we exceed county, state and national industry water safety standards.”

At least two cases, and possibly more, have been reported at Raleigh’s North Hills Club, which initially notified members in June of reports of illness. However, North Hills Club did not report the pool-related illnesses within two working days to the local health department, which is in violation of a state law, the News & Observer reported. The health department did not learn of the crypto cases linked to the North Hills pool until two weeks after the first report of illness, according to the newspaper.

“The procedure is if there is a report of illness, the pool should be closed,” Dr. Joseph Threadcraft, the county’s environmental services director, told the newspaper.

The general manager of North Hills Club declined to comment, but the club did reportedly close its pools and continues to hyper-chlorinate them as a preventative measure.