been widely used since the second half of the 20th century. The first vaccines were whole-cell vaccines, composed of chemically inactivated bacteria. They are being replaced by acellular vaccines, composed of purified surface antigens, mainly fimbriae, filamentous haemaglutinin, pertactin and pertussis toxin. It is part of the diphtheria, tetanus, and acellular pertussis (DTaP) immunization. As a zoonotic disease Uncertainties of B. pertussis and whooping cough as a zoonotic disease have existed since around 1910, but in the 1930s, the bacteria were found to have lost their virulent power when repeatedly spread on agar media. This explained the difficulties in reproducing results from different studies, as the preinoculation handling of the bacteria was not standardized among scientists. At least some primate species are highly sensitive to B. pertussis, and develop a clinical whooping cough in high incidence when exposed to low inoculation doses. Whether the bacteria spread naturally in wild animal populations has not been confirmed satisfactorily by laboratory diagnosis, but whooping cough has been found among wild gorillas. Several zoos have learned to vaccinate their primates against whooping cough. Diagnosis A nasopharyngeal or an oropharynx swab is sent to the bacteriology laboratory for Gram stain (Gram-negative, coccobacilli, diplococci arrangement), growth on Bordet–Gengou agar or BCYE plate with added cephalosporin to select for the organism, which shows mercury drop-like colonies. B. pertussis can also be detected by PCR, which is more sensitive than culture. The primers used for PCR usually target the transposable elements IS481 and IS1001. Several diagnostic tests are available, especially ELISA kits. These are designed to detect FHA and/or PT antibodies of IgG, IgA, or IgM. Some kits use a combination of antigens which lead to a higher sensitivity, but might also make the interpretation of the results harder, since one cannot know which antibody has been detected. The organism is oxidase positive, but urease, nitrate reductase, and citrate negative. It is also motile. Treatment Whooping cough is treated by macrolides, for example erythromycin. The therapy is most effective when started during the incubation period or the catarrhal period. When applied during the paroxysmal cough phase, the time of reconvalescence is not affected, only further transmission is prevented. References External links Type strain of Bordetella pertussis at BacDive—the Bacterial Diversity Metadatabase Burkholderiales Whooping cough Bacteria described in 1952