LONDONDERRY, N.H. — School officials say a staff member at New Hampshire’s Londonderry Middle School has been diagnosed with whooping cough, the third such case at the same school.

A letter sent from the district superintendent to parents Tuesday said that the New Hampshire Department of Health and Human Services qualifies three cases of whooping cough in the same school as an outbreak.

Whooping cough, also known as pertussis, is a highly contagious respiratory disease. It’s known to cause uncontrollable, violent coughing that can make it hard to breathe, and is sometimes fatal to young children or infants.

School officials cautioned that it is possible for more whooping cough cases to occur over the next few weeks.

They said they are taking every available precaution to ensure students and staff are not at risk.