Properties

Pathogenesis

Clinical findings

Laboratory diagnosis

Treatment & Prevention

Encapsulated gram-negative rod

Pathogen only for humans.

Transmitted by airborne droplets.

Attach to ciliated epithelium of upper respiratory tract but do not involve underlying tissue.

Decreased cilia activity & epithelial cell death occur.

Pertussis toxin stimulates adenylate cyclase by catalyzing addition of ADP-ribose to G_i with consequent increase in cAMP.

Highly contagious disease occurring primarily in infants & young children.

Disease: whooping cough

Whooping cough:

- acute tracheobronchitis

- begins with mild upper respiratory tract symptoms.

- followed by typical paroxysmal cough, which lasts from 1 to 4 weeks.

- characterized by a series of hacking coughs, accompanied by production of copious amounts of mucus.

Organism is restricted to upper respiratory tract; blood cultures are negative.

Pronounced leukocytosis with 70% lymphocytes seen.

CNS anoxia & exhaustion can occur.

Death due mainly to pneumonia.

Organism is isolated from nasopharyngeal swabs taken during the paroxysmal stage.

Plated out at bedside, on a special selective medium & incubated for at least 7 days.

Erythromycin reduces number of organisms in throat & decreases risk of secondary complications but has little influence on course of disease.

Supportive care, e.g. oxygen therapy & suction of mucus, during paroxysmal stage is important in infants.

Active immunization with:

- killed B pertussis organism.

- acellular vaccine containing purified proteins from organism.

Vaccination:

- pertussis vaccine is given combined with diphtheria & tetanus toxoids in 3 doses beginning at 2 months of age.

- a booster at 12-15 months of age & another at time of entering school are recommended.