School officials on Monday sent out a letter informing parents of a new case of pertussis, also known as whooping cough, in the Three Village Central School District: a student at Setauket Elementary School was diagnosed with the highly contagious illness.
A school spokeswoman said Wednesday that the student has recovered and is back in school.
This case of pertussis is the third to be confirmed within the 2012-2013 academic year. In September, a student at Murphy Junior High was diagnosed with pertussis. In November, a student at Nassakeag Elementary was diagnosed with it.
Dr. Gregson H. Pigott of the Suffolk County Division of Public Health said in the letter that the county has seen an increase in cases of pertussis.
"The disease is a highly contagious bacterial disease that is spread through the air by cough from an infected individual," Pigott said. "Children and adults may still develop pertussis even if they are up to date with their vaccinations as immunity to pertussis wanes over the years."
The letter, posted on the district website, provides information about the disease and directs parents and staff to call the county Department of Health Services at 631-853-3055 with questions about the disease or its vaccine.
Editor's note: This article has been updated to reflect the student's recovery status.