Now, at least 10 high school swim team members in Durham and Orange Counties have tested positive for Cryptosporidiosis, more commonly known as Crypto.
A health official said there five confirmed cases in Durham, another five in Orange County, and four other likely cases.
"It's a water-borne illness. It is generally a diarrheal illness of short duration," said Susan Thompson, of the Durham County Department of Public Health. "Symptoms are generally diarrhea but you can also have abdominal cramps and vomiting."
The parasite can survive in properly chlorinated pools for a couple days. The only real way to stop the spread of the disease is to stay out of the water.
Several pools were shut down after swimmers started contracting the illness, but doors have since reopened. The state urges weekly hyperchlorination to stop the spread of the parasite.
"Diarrhea and swimming just don't mix at any time. So if you're ever symptomatic, you really shouldn't go swimming and the best way to prevent most disease is good old fashioned hand washing," Thompson said.
Health officials cannot pinpoint a specific pool because the students who fell ill were on competitive swim teams and were in multiple pools for meets and practices.
Health departments sent out a letter to area athletes and coaches advising them to stay out of the pool for two weeks after becoming sick.
Anyone with additional questions is asked to contact either the Durham County communicable disease nurse at (919) 560-7635 or the Orange County nurse at (919) 245-2340.