Summary and Conclusions
A summary of the results of these anaphylactic tests with a polyvalent antigen of washed and heat-killed cultures of B. bronchisepticus (Ferry-McGowan) is shown in table 6.
As shown in this summary the highest percentage of positive reactions occurred among dogs suffering with distemper at the time these tests were made and among those known to have had distemper while under our direct observation.
Whether or not the reactions occurring among those dogs that were normal at the time of these tests, but of whose previous medical history we were ignorant and totally unable to ascertain whether or not they had distemper prior to admission to the University animal house, were true anaphylactic reactions due to sensitization with bronchisepticus protein as a result of infection, we are unable to say definitely. Owing, however, to the widespread dissemination of canine distemper and the large number of young dogs known to contract this disease, it is highly probable that some of these animals had been infected with B. bronchisepticus and that the reactions were an expression of cutaneous hypersensitiveness to the protein of this microörganism.
While we wish to record in another communication the results of our experiments bearing upon the etiological character of B. bronchisepticus in canine distemper either as the direct cause of this disease or as a mircoörganism closely associated with it in a manner analogous to the relation of streptococci to scarlet fever, we may state here that B. bronchisepticus is found in a large proportion of dogs suffering with distemper and that these anaphylactic tests indicate this relationship by the large proportion of infected animals displaying a condition of cutaneous hypersensitiveness to its protein.
While the bronchisepticin skin test may prove of practical value in the diagnosis of canine distemper and particularly as an index of a previous infection in an apparently normal animal, it is probable that it has no value as an index of immunity and that an animal presenting a positive reaction is still susceptible to relapses or recurrences of the disease (7).