Tiny gram negative coccobacillus. Includes B. avium, B. bronchiseptica (kennel cough in dawgs), B. hinzii, B. holmseii, B. pertussis (whooping cough), B. parapertussis, and B. trematum.
Being fool enough to not get the vaccine or coming from a place too poor and deprived to offer the vaccine. Like California. Complain at my e-mail. Like it will do any good.
PCR is the usual diagnostic test.
B. pertussis: whooping cough. The incubation period of pertussis is 7 to 10 days, but may be up to 42 days. Three stages.
1) Catarrhal stage: characterized by the insidious onset of coryza (runny nose), sneezing, low-grade fever, and a mild, occasional cough, similar to the common cold. The cough gradually becomes more severe.
2) Paroxysmal stage; the patient has paroxysms of numerous, rapid coughs. At the end of the paroxysm, a long inspiratory effort is usually accompanied by a characteristic high-pitched whoop. During such an attack, the patient may become cyanotic (turn blue). The cough becomes less paroxysmal and disappears over 2 to 3 weeks.
3) Convalescent stage: slow recovery; superinfection may occur.
Older persons and those partially protected by the vaccine may become infected with B. pertussis, but usually have milder disease. Pertussis in these persons may present as a persistent (>7 days) cough, and is indistinguishable from other upper respiratory infections. B. pertussis is estimated to account for up to 7% of coughing illnesses per year in older persons (CDC). The adult is now the reservoir of infection and there is a vaccine now adults (I got mine).
B. parapertussis can mimic pertussis and requires specific testing.
B. holmsii can also mimic pertussis especially in adolescents, and circulate at the same time as B. pertussis; it is very sensitive to azithromycin and has a shorter course (PubMed). The vaccine has no effect on B. holmsii and perhaps as a result it is moving into the ecological niche as cases of pertussis from this organism are increasing (PubMed)
Azithromycin is the preferred prophylaxis within 3 weeks of exposure should be given for 14 days to all household and other close contacts of persons with pertussis, regardless of age and vaccination status (CDC). TMP/Sulfa is an alternative.
Kills 300,000 children a year worldwide. I mention this for all the anti-vaccine nut cases out there (CDC).
The current vaccine is not that great at prevention but will lead to a milder illness (PubMed).