Four cases of Shigella were reported this week at a Grovetown elementary school.

The incidents took place at Cedar Ridge Elementary School, but system officials do not believe the infectious bacteria originated there, according to statement released Thursday.

"The coincidence is that they're all students of this school," said schools Assistant Superintendent Robert Jarrell.

Mr. Jarrell did not know when the first Shigella incident was discovered. He said he believed it was this week.

System officials sent a letter to parents Thursday warning of the outbreak and the measures the school is taking to prevent the spread of the illness.

"It's not a serious situation in terms of an epidemic," Mr. Jarrell said. "But we wanted parents to be aware of the symptoms."

Shigella symptoms include diarrhea, cramping, vomiting and nausea. It is highly contagious, according to the Kids Health Web site.

Cedar Ridge Elementary custodial staff are sanitizing the school, but the school will remain open, Mr. Jarrell said.

System officials also are emphasizing hand-washing procedures with pupils and staff at the school, according to the release.

The Columbia County Health Department is working with the school to contain the outbreak, Mr. Jarrell said.

A phone message left for Cedar Ridge Principal Sarah Wells was not immediately returned Thursday.