Three Rock Hill elementary school students have been diagnosed with staph infections, district spokeswoman Elaine Baker said.
One student attends Mount Gallant Elementary, one is at York Road and one at Ebinport.
Principals notified parents at all three schools, Baker said.
"The students are being treated with antibiotics and will not be allowed to return to school until they are not contagious," she said. "It is not an outbreak of any kind."
Staph is a type of bacteria that can cause serious skin infections. This type, Methicillin-Resistant Staphylococcus Aureus, or MSRA, is resistant to certain antibiotics, which makes it more difficult to treat.
Constance Marin, a disease surveillance and response coordinator at the York County Health Department, said school nurses are not required to report individual cases of staph infections.
More than 20 Charlotte-Mecklenburg students and faculty members were diagnosed with MSRA last fall.
To prevent staph from spreading, wash hands frequently, keep cuts clean and covered and don't share personal items such as towels or razors.