Time-course of infection and responses in a coughing rat model of pertussis

Adult female Sprague-Dawley rats were challenged intrabronchially with Bordetella pertussis strain 18-323 embedded in fine agarose beads and the time-course of infection and other events was determined. There was a steady decline in the numbers of B. pertussis recovered from the rat lungs, with clearance of the infection in most animals by day 12. Leucocytosis, lung inflammation and an increase in total serum IgE in the rats as a result of the challenge were highest around day 10, which was coincident with the highest incidence of coughing in such animals. IgG and IgA antibodies to the B. pertussis antigens pertussis toxin and filamentous haemagglutinin were not detected until after this period. The coughing rat model of pertussis resembles the human disease in the relationship between the time course of infection and cough production.