Students returned to Deerfield Park Elementary School where a case of bacterial meningitis was reported Tuesday.
Parents on Wednesday warned their children about sharing drinking glasses and touching their classmates' belongings.
The school will be disinfected, said Broward County Public Schools spokeswoman Nadine Drew.
Thirty students were absent Wednesday, said Drew, who added that about 15 students are typically absent.
Health department officials didn't say whether the patient was a student or staff member. A letter was sent home to parents on Tuesday.
Bacterial meningitis is highly contagious and affects the lining of the brain and spinal cord. It spreads by coughing, sneezing, and kissing.
"I would be concerned but I would only be concerned if my child developed any of the symptoms," said Dr. Micheyle Goldman, a pediatrician at Memorial Regional Hospital.
Symptoms include high fever, chills, tiredness, severe headaches, nausea, vomiting, rashes, and stiffness in the neck and spine.
Anyone with questions is asked to call the Coordinated Student Health Services Department at 754-321-1575.