As many as 900 exposed to whooping cough at MSU

As many as 900 people may have been exposed to an whooping cough by someone with an undiagnosed case of the infection at Michigan State University's Grandparents University from June 29 to July 1.

Twenty individuals have been identified by the Michigan Department of Community Health as being at high risk for contracting pertussis, also known as whooping cough, StateNews.com reports.

The majority of the 20 people diagnosed have been immunized, Marcus Cheatham, the assistant deputy health officer for the Ingham County Health Department, told StateNews.com. Those who have not yet been immunized were told to see a doctor immediately.

Cheatham also said that pertussis outbreaks are becoming common and can happen anywhere. Pertussis infections may include a strong, hacking cough lasting several weeks. In infants, the infection can be fatal.

Michigan State has done a "tremendous" job handling the mass exposure, Bob Swanson, director of the Division of Immunization for MDCH, told StateNews.com. Swanson also praised the university's work with MDCH to limit the spread of the illness.

“They cooperated with us very closely and they were able to provide us with a list of individuals,” Swanson told StateNews.com.

This recent mass exposure follows reports that California is facing its worst whooping cough outbreak in 50 years. As of June 15, the state had recorded 910 cases of the infection, including the deaths of five children under three months old.