Pertussis, or whooping cough, is a highly contagious disease involving the respiratory tract. It is caused by a bacterium that is found in the mouth, nose and throat of an infected person. Approximately 100 to 500 cases are reported annually in Washington. In 1999, there were 739 cases. The 826 cases in 1996 gave the highest incidence since 1963 when 517 cases were reported.
Pertussis can occur at any age.
Severe illness is more common in young children who have not been immunized. Older immunized children or adults with pertussis have milder symptoms. The diagnosis of pertussis should be considered for older children or adults with persistent coughs to ensure they do not pass the infection on to young children. Pertussis is primarily spread when infected people cough or sneeze, expelling droplets that contain Bordetella pertussis bacteria. Older siblings or adults who may be harboring the bacteria in their nose and throat can infect an infant.