Montana health authorities are investigating an outbreak of whooping cough in the Missoula area where six cases have been confirmed, including one that required hospitalization.
In addition, the Missoula City-County Health Department says in a news release that it has identified more than 300 close contacts who may have been exposed to the highly contagious disease.
Ages for the confirmed cases range from preschool through teenager. Additional suspected cases are pending laboratory results.
The department reports there is a mix of unvaccinated and vaccinated children among the cases.
The agency is working directly with the affected families and the schools the ill children attended to identify close contacts.