Four cases of whooping cough have come up in East Lyme High School and Flanders Elementary in East Lyme.
East Lyme school officials are warning parents after cases of whooping cough have been confirmed in students in two schools.
Superintendent James Lombardo sent a letter home to parents on Thursday, confirming cases of whooping cough at Flanders Elementary School and East Lyme High School.
The Connecticut Department of Public Health said it has received reports of four confirmed cases of whooping cough in East Lyme this year.
The illness, which is known as pertussis, is spread through the air and is highly contagious, according to the Centers for Disease Control and Prevention.
"If your child has symptoms or develops symptoms compatible with pertussis, it is important to contact your child's health care provider," Lombardo said in the letter to parents.
Symptoms include an uncontrollable, violent cough, which often makes it hard to breathe, according to the CDC. Whooping cough is most common among infants and can be fatal, especially in babies less than 1 year of age, according to the CDC.
A spokesperson for the Connecticut Department of Public Health said cases of pertussis are not rare in the state. So far in 2013, Connecticut has 39 reported cases of pertussis, according to William Gerrish, spokesperson for the Department of Public Health. Connecticut had 156 reported cases around this time last year, Gerrish said.
School officials are urging parents to make sure their children are up to date on their pertussis vaccinations.