<prompt> The usual incubation period of peusis is ?7-14 days3-5 days21-25 daysLess than 3 days  <response>: Ans. is a i.e., 7-14 days Whooping cough peussis After an incubation period of about 1-2 weeks, the disease takes a protracted course comprising three stages-- the catarrhal, paroxysmal and convalescent - each lasting approximately two weeks. 