A Gwinnett County elementary school will be closed Friday for cleaning after an outbreak of a stomach illness.

Public health officials recommended Knight Elementary School, in Lilburn, close due to the number of students with symptoms of gastroenteritis, Principal Toni Ferguson said in a letter posted on the school's website. More than 10 percent of students were absent Thursday due to illness, the school system said.

Gastroenteritis, or stomach flu, often causes diarrhea and vomiting and symptoms can develop within one or two days of exposure, according to the health department.

“Please be assured that we are working very closely with the Gwinnett County Health Department as we follow their recommendations for cleaning the school and for monitoring our students who have become ill,” Ferguson wrote in the letter.

The school plans to re-open Monday. But students still exhibiting symptoms are asked to stay home until they are symptom-free for 24 hours, Ferguson said.