ROCHESTER  — Health officials in southeastern Minnesota are working to contain an outbreak of whooping cough.

Since January, Olmsted County has recorded 127 cases of pertussis — the highest number since an outbreak four years ago.

The bacterial infection, which causes uncontrollable, violent coughing, originated in teenagers. Schools posed the highest risk for spreading the disease.

Officials hoped cases would decline after the school year ended. According to a press release,  the illness has spread, affecting a range of people but still mostly teenagers.

Epidemiologist Stacy Sundve of Olmsted County Public Health said the disease is spreading at daycares, summer schools and youth athletics programs.

To combat pertussis, officials are urging people to check their vaccination history. Immunizations become outdated and adults may need to get a booster vaccination.