More than 700 people, mostly children and teenagers, are sickened by gastrointestinal illness, possibly stemming from a state-run water playground, says, the New York state Health Department says Thursday.

"The numbers are growing significantly," says department spokesman Rob Kenny to The Associated Press.

Seneca Lake Park's Sprayground was closed after tests showed the tank system that feeds the water jets was contaminated with a common waterborne disease called cryptosporidiosis.

The disease is highly contagious and can cause diarrhea, nausea and fever that can last for weeks. It usually goes away without treatment in healthy individuals, according to the Centers for Disease Control and Prevention.

Five of the illnesses from the Sprayground have so far been confirmed as cryptosporidiosis.

No deaths have been associated with the outbreak, and many of the people connected with the outbreak have already recovered, Kenny says.

The Sprayground averages more than a thousand visitors a day in August. It is in the Finger Lakes region, about 45 miles southwest of Syracuse.