[A pertussis outbreak in a ward for severely retarded].

In June 2000, many cases with persistent cough were observed among inpatients and the staff of a ward for severely retarded. Some of them had symptoms suggestive of pertussis, such as whooping, post-tussive apnea. We performed a retrospective investigation to assess symptoms and serological findings suspicious of pertussis. There were a total of 14 cases of persistent cough over 3 weeks (4 to 9 weeks). 6 cases were inpatients and 8 were hospital staff. Of those, serological test for pertussis infection was performed in 10 cases and 6 cases were diagnosed as serologically confirmed pertussis. The other cases with persistent cough were also considered to be probable pertussis as they have had intensive contact with serologically confirmed cases. 12 cases were treated by antibiotics, but they all failed to respond. It was suggested that Bordetella pertussis must be considered as a causal organism of persistent cough even in adults. To prevent nosocomial transmission of pertussis, droplet precautions and macrolide treatment should be provided for patients with symptoms highly suggestive of pertussis.