The Beaver Area School District is alerting parents about two cases of whooping cough, also known as pertussis. The district said two children who attend College Square and Dutch Ridge elementary schools are being treated by doctors for the illness. The district is asking parents to watch for symptoms in their children and to seek immediate medical attention if their children develop symptoms. Pertussis begins with a cold and an irritating cough, which worsens at night. Characteristic “whooping” develops in one to two weeks. It is spread by direct contact with airborne droplets of respiratory secretions of an infected person. The district told parents that children with a positive diagnosis are to be kept at home for five days from the start of an appropriate antibiotic treatment.