[Infection with species of the genus Bordetella in adults, a factor in maintaining morbidity for whooping cough. Serological studies].

A number of 1021 serological investigations were performed to identify agglutinating antibodies against B. pertussis and B. parapertussis in adults. The investigations were initiated to study the presence of agglutinins in serum, in response to a previous infection with Bordetella species. The serological tests revealed the presence of agglutinating antibodies at titres considered to be positive (> or = 1/320) in 136 (13.3%) sera. The results obtained suggest that pertussis is relatively frequent in adults, and must be considered as a factor of maintaining morbidity.