Bordetella pertussis whooping cough bacterial respiratory childhood infections

Bordetella (pertussis) (whooping cough) bacterial respiratory childhood infections B. Pertussis B. parapertussis

B. pertussis � Small gram-negative bacilli � Most fastidious � Culture media containing charcoal ◦ bordet-Gengou medium ◦ Charcoal blood agar � Strict aerobe � Slow growth (3 days) � 3 major agglutinogens ◦ ◦ ( attachment ) (1, 2 and 3) detected by specific antiserum Role in immunity Three serotypes �Type 1, 2 �Type 1, 3 �Type 1, 2, 3

pathogenesis � Non invasive infection of respiratory mucosa ◦ Ciliated epithelium of bronchi , trachea � Human is the only natural host � IP : 1 – 2 weeks � Tracheal cytotoxin ( TC ) � Pertussis toxin (PT) ◦ Lymphocytosis � Filamentous haemagglutnin (FHA)

clinical � Catarrhal phase ( preventable )-most infectious � Paroxysmal phase ( sever cough) � Convalescent phase � Atypical cases � Complications ◦ ◦ Bronchopneumonia Secondary infection Lung collapse Anoxia , convulsions

EPIDEMIOLOGY �SOURSE ◦ Patients ( droplets ) – child or adults ◦ Atypical cases �Cmunicable �Epidemics �Antibiotics reduce transmission �Incidence and mortality ◦ All ages ◦ Cause of death ( < 2 years , infants )

Immunity �One attack confers long lasting immunity ◦ (herd immunity) �Infection with different serotype �Passive protection from mother is incomplete � 3 – injections of vaccine – effective active immunity

Diagnosis �Clinical �lymphocytosis �Laboratory ◦ Nasopharynx (postnasal swab ) ◦ Pernasal swab ◦ Selective media ◦ Slid agglutinations ( antiserum)

Treatment �No effect in well established infection �Erythromycin ◦ Reduce severity if given before paroxysmal phase ◦ For 14 - days ◦ Reduces transmission ◦ Prophylaxis of contacts

Control �Vaccination is safe - > 90% effective ◦ Whole bacterial cell ( killed) – deep IM inj. ◦ Contain 3 – agglutinogens ◦ 3 – doses ◦ SE : neurological sequelae , crying , fever �Acellular pertussis vaccine ◦ PT , FHA + agglutinogens