Health officials say the number of whooping cough cases in Montana has passed 200 this year and they're encouraging people to get vaccinated against the contagious bacterial infection that can lead to uncontrollable coughing fits.
The Department of Public Health and Human Services reported Friday that it's the biggest outbreak in the state since 2005, when there were nearly 600 cases.
Most of the cases have involved children ages 5 to 18. Five people have been hospitalized and none have died.
Pertussis starts out like the ordinary cold, but can turn more serious, especially among infants. It is spread by coughing and sneezing.
Pertussis vaccination begins at age two months, but protection can fade over time, so booster shots are recommended.