Relaxing near the water at Stockton's Weber Point, J.C. Ruiz had no clue about Crypto.

“If it is really spreading out. It’s something we might be supposed to be hearing about. I haven’t heard anything about it," says Ruiz.

But the tiny worm like creature is making it’s presence known, causing a spike in reported cases in San Joaquin County.

“Our investigations have not pointed to any particular source for this infection. It looks like people are getting exposed in multiple different places," said Karen Furst, Assistant County Public Health Officer for San Joaquin County.

The microscopic worm can cause severe watery diarrhea and stomach cramps that can last one to two weeks or more.

The symptoms generally begin in two to 10 days. Symptoms can come and go for up to 30 days.

Already this year, 17 cases have been reported in San Joaquin County. 41 cases are experiencing symptoms.

On average, only one case of Crypto is reported per year.

Most cases happen by swallowing water.

The health department says the parasite is spread in swimming pools, splash parks, water parks and even waterways like the Delta.

“It’s also spread very easily person to person especially in close settings such as families and schools," says Dr. Furst.

Doctor Furst says one way to prevent it from infecting you is quite basic.

“In order to prevent person to person spread, it’s important that people wash their hands frequently, wash their hands before they prepare food for anybody," added the doctor.

And if you plan on going in the water, be clean before you go in.