Bordetella pertussis is an aerobic, non-spore forming, Gram negative coccobacillus (Shumilla et al., 2004). It has no known reservoir other than humans and is thought to be unable to survive in the environment for prolonged periods of time (Merkel, 1998). The Bordetella genus of the Alcaligenaceae family is comprised of seven different species, four of which cause upper respiratory tract infections in different host organisms (Babu et al., 2001). Bordetella parapertussis is the most closely related to Bordetella pertussis . It can cause a milder pertussis-like disease in humans, but Bordetella pertussis is the most serious human pathogen in this genus (Babu et al., 2001). B. pertussis invades its human host through entry into the respiratory tract where it colonizes to cause whooping cough, also known as pertussis, which was at one time a very common and potentially life threatening infection for children (Steele, 2004). Today, whooping cough still effects 20-40 million people worldwide each year and causes between 200,000-400,000 fatalities (Shumilla et al., 2004). The image on this slide shows the B. pertussis after Gram staining.

1. Pertussis

2. Introduction
 Acute respiratory infection caused by
B.pertussis
 Etymology
 From per- (“thorough”) + tussis (“cough”)
 Whooping cough
 The 100-day cough
 Whooping cough
 Inspiratory sound made at the end of
paroxysmal cough
 Prominent feature of illness
 Uncommon among infants ≤ 6 months
 Frequently absent in older children and

3. Microbiology
 Bordetella genus comprised ten species
 Significant medical species
 B.pertussis (infects only humans)
 B.parapertussis
 B.bronchiseptica
 Two additional species
 B.hinzii Unusual causes of bacteremia
 B.holmesii

4. Microbiology cont’
 B.pertussis
 Gram-negative aerobic bacillus
 Slow-growing fastidious organism
 Forms small glistening bifurcated colonies
 Produces wide array of toxins and biologically active
products
 Important in its pathogenesis and in immunity
 Regulated by single genetic locus
 Pertussis toxin
 Most important virulent factor
 Affects the circulation of lymphocytes
 serves as an adhesin

5. Microbiology cont’
 Other important adhesins and virulent factor
 Filamentous hemagglutinin
 Pertactin
 Fimbriae
 Tracheal cytotoxin
 Adenylate cyclase toxin
 Dermonecrotic toxin

6. Epidemiology
 Highly communicable disease
 Unimmunized household contact (80-100%)
 Immunized household contact (20%)
 Worldwide distribution
 Cyclical outbreak every 3-5 year
 Important cause of morbidity and death in developing
country
 Estimated >300,000 deaths annually worldwide

8. Epidemiology cont’
 Common cause of morbidity before EPI in
developed countries
 Peak during preschool years in developing
countries
 High mortality rate in infants
 Sex-related demographic
 Race-related demographic

9. Pathogenesis
 Organism attachment to the ciliated
epithelial cell of nasopharynx
 Attachment mediation by surface adhesins (e.g.,
pertactin)
 Fimbriae role has not been fully delineated .
 Proliferation and toxin production in
attachment site
 Pathogenesis of clinical manifestations
 paroxysmal cough
 Neurological events
 pneumonia in pertussis patients

11. Immunity
 Both humoral and cell mediated immunity are
important
 Protective role of antibodies against toxin and
adhesin
 Immunologic role of pertussis agglutinin in wP
vaccines.
 Duration of immunity after wP vaccines
 Duration of immunity afte natural infection

12. Clinical Features
 Prolonged coughing illness
 Clinical manifestations vary by age
 Incubation period is 4-21 days
 Clinical stages
 Catarrhal Stage
 Paroxysmal Stage
 Convalescent Stage

13. Clinical Features cont’
 Catarrhal phase
 Coryza
 Lacrimiation
 Mild cough
 Low grade fever
 Malaise
 Paroxysmal phase
 More frequent spasmodic cough
 Frequent posttussive vomiting
 Audible whoop
 Weight lost is not uncommon

14. Clinical Features cont’
 Convalescence phase
 Can last 1-3 months
 Characterized by gradual resolution of coughing
episodes
 recrudescence of paroxysmal cough with viral
infection
 Atypical clinical manifestation in adults.