9 - Pertussis Flashcards
What are the characteristics of bordetella pertussis?
Gram-negative coccobacillus
Strict aerobe
What are the three species of bordetella? What is each type associated with?
B. pertussis: whooping couch, only one that produces pertussis toxin
B. parapertussis: mild infection
B. bronchoseptica: respiratory disease in animals
How easy/difficult is it to contract pertussis?
Easy, it’s HIGHLY infectious.
> 90% of unimmunized contacts will become infected
Humans are the only reservoir
Pertussis is an _______ disease in the US with periodic endemics every ______ years and frequent outbreaks with no known causes.
Endemic
3-5 years
What does pertussis colonize? When do symptoms begin?
Ciliated cells only.
Symptoms 10 days after exposure.
What are the three stages of infection associated with B. Pertussis?
Catarrhal: 1-2 wks, mild symptoms, uncomplicated URI
Paroxysmal: 1-6 wks, hacking cough over 15-20 sec, terminating in mucus or vomiting. Characteristic whooop.
Convalescence: several months, persistent cough may lead to morbidity.
What are the molecular properties of the pertussis toxin?
ADP-ribosylates Gi, causing an increase in adenylyate cyclase and an increase in cAMP.
Gi is a heterotrimeric G protein that modulates cAMP inside the cell and is important for immune cells.
What is the structure of the pertussis toxin?
It’s an A-5B toxin.
A is the catalytic subunit
B are the 5 binding subunits
How would you treat B. pertussis?
Erythromycin eliminated oragnism within 3-4 days.
Also given to siblings and close contacts of the infected individual.
What do the lower and upper case letters in the names of the vaccines mean?
Lower case letters “d” and “p” are the reduced doses of diphtheria and pertussis, and “a” stands for “acellular” meaning the pertussis component contains only part of the organism.
Upper case letters means the dose is full strength.
