PHOENIX - Maricopa County Department of Public Health officials are investigating an outbreak of Cryptosporidium, a diarrheal illness caused by a parasite Cryptosporidium parvum, and are advising the public to take precautions to further prevent the spread of this disease.

Public health officials said 19 cases were reported in July. Five of those initial cases have been linked to recreational water facilities.

While officials said some people with Crytosporidium show no symptoms, the most common symptom to be on the lookout for is watery diarrhea usually beginning 2-10 days from infection.

Some other symptoms include stomach cramps, dehydration, nausea, vomiting, fever and weight loss.

"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."

Typically, people with healthy immune systems recover in one or two weeks without treatment.

Officials warned that although Cryptosprodidium 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.

"If you have diarrhea lasting longer than 10 days, blood in your stool, or have trouble staying hydrated, see a healthcare provider," Sunenshine said.

The disease is typically spread in swimming pools and other recreational water areas when an infected person swims or plays in the water, contaminating it with fecal matter.

While chlorine typically kills most germs in swimming pools, this disease can survive even in properly chlorinated waters for long periods of time.