Bordetella pertussis
- epidemiology
- classification and characteristics
- virulence factors
- transmission and infection
- clinical manifestations
- diagnosis
- treatment
Epidemiology
Bordetella is the cause of whooping cough, or 100 day cough.
Classification and Characteristics
- small, gram negative cocci-bacilli
- strictly aerobic, fastidious
- grequires growth on media containing charcoal, blood, or starch
- grown on BG or RL medium
Virulence Factors
Transmission and Infection
Pertussis is highly contagious. It is spread via droplets following coughing fits.
Clinical Manifesations
causative agent of pertussis.
Greatest incidence is in children <1 and in adolescents.
incubation period generally lasts 7-10 days (range of 4-21)
classical course of disease:
catarrhal stage - 1-2 weeks
- symptoms non-specific
- low grade fever, mild cough, coryza
paroxysmal stage - 1-6 weeks
- paroxysmal cough, inspiratory whoop
- often posttussive vomiting
- infants may develop apnea
- attacks can be preciptated by exercise, eating, yawning
- severe symptoms may last for 6 weeks, but cough can continue for up to 6 months
- cough can result in subconjunctival hemorrhae, hernias, rectal prolapse, epistaxis
convalescent stage - 2-4 weeks
- gradual decrease in symptoms
Children under 6 months of age are at highest risk.
COmplications
Otitis media
respiratory complications (sinusitis, pneumonia, atelectasis, pneumomediastinum, pneumothorax, subcutaneous emphysema
seizures, ncephalopathy (rare), intracranial hemorrhage
Diagnosis
clinical diagnosis of URTI, paroxysms, and afebrile
increased WBC count
best diagnosed with naso-pharyngeal specimens
- can be cultured
- RT-PCR
- DFA (direct fluorescent antibody)
Treatment
Treatment is primarily supportive.
macrolides (ie erythromycin) are first choice for prevention of infection, not to change course of illness.
Prevention via erythromycin for household contacts
Acellular pertussis vaccine and booster used to prevent infection