HELENA, Mont. -

Health officials say seven cases of whooping cough have been confirmed in and around Helena.
    
Karen Wandel of the Lewis and Clark City-County Health Department says that two or three more cases would have to be reported to consider it an outbreak.
    
Wandel says the cases began appearing this month and have affected children from preschool to high school ages. Four of the seven cases have been reported at Capital High School.
    
Whooping cough, or pertussis, is a contagious respiratory disease that can cause severe coughing. The illness can be potentially deadly to infants or small children who are too young to be vaccinated.
    
Wandel advises parents to have their pre-teen children vaccinated and adults to make sure they have had pertussis booster shots.