SPRING VALLEY, N.Y. (CBSNewYork) — An infectious outbreak of the shigella bacterium has already been seen in Brooklyn, and now, the outbreak has spread to the suburbs.

CBS2 was the first to break the story earlier this week of the shigella outbreak in Williamsburg and Borough Park sections of Brooklyn. As CBS2’s Weijia Jiang reported exclusively, a new outbreak has stricken residents miles away in Rockland County.

“We began to see it spreading in other counties, not only Rockland, as well,” said Dr. Oscar Alleyne, director of public health planning for the Rockland County Health Department.

Alleyne has been tracking shigella infections – or shigellosis – a highly contagious disease that can cause severe intestinal distress. So far this month, there have been 17 confirmed cases in Rockland County, and from November through December, there were 49.

Alleyne believes patients may have contracted the shigella infections from Brooklyn, where 80 cases have been reported since November.

“A lot of the times, there’s a direct pipeline with families,” Alleyne said. “To be honest, our boundaries are never really boundaries. People travel back and forth all the time.”

And just like in Borough Park and Williamsburg, most of the shigella patients in Monsey and Spring Valley are young children.

Shigella spreads through person-to-person contact, and direct contact with feces, or contaminated food or water.

Symptoms include severe diarrhea, stomach cramps and fever, and the most severe cases involve convulsions and kidney failure.

Children between the ages of 2 and 4 are at the highest risk.

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In Brooklyn, Dr. Olitsa Roth told CBS2’s Ilana Gold she has treated several cases in recent weeks. She said most cases are very mild and might just involve a bellyache, but some may be more severe.

“The message is for parents — if the child isn’t feeling good, be on high alert and check their bowel movement,” Roth said.

In the wake of the Rockland County outbreak, parents were on high alert.

“Now I’m going to be wiping stuff down more,” said Christine DeMasi of Spring Valley. “Hopefully, the parents will be careful about keeping their kids home and not spreading it around.”

Alleyne said it is nearly impossible to identify the original source of an outbreak, but he said once shigella is in a community, it spreads quickly.

“What concerns me is maybe that my child might catch it, get sick, end up in the hospital,” said parent Debbie Griffith. “You know, you don’t want this thing to spread through schools.”

Doctors said the best tip for prevention is washing hands often.