Study of the bacterial flora of the upper respiratory tract of the dog and cat

The scarcity of information concerning the normal bacterial flora of the mouth and upper respiratory tract of the various domesticated animals has been the subject of recent comment by Veterinary Surgeons, arising out of ;queries regarding the possible carrier rate amongst animals of organisms pathogenic to those animals and also, in the case of pet animals, as to the possibility of their carrying and transmitting infections to their owners. In 1941, Francis, While summarising the Public Health Report on the study of the bacterial flora of the nasopharynx of individuals of the population in London and South-East England (Straker , Bedford, Lovell and Rosher, 1939) , drew the attention of veterinary research workers to the fact that there had been no adequate investigation of the bacteria normally present in the nasopharynx of any species of domestic animals, or of the factors which affected the carrier rate. He pointed out that a study of such a nature would be of obvious value in several of the respiratory diseases of domestic animals, particularly of those affecting young animals kept under intensive conditions. Bosworth (1947) Quoted the need for an adequate survey of staphylococci in dogs in normal health and sickness, Levi (1946) thought that a detailed study of the normal inhabitants of the nasopharynx of the cat would be of value in interpreting bacteriological findings in cases of "snuffies". much has been said in recent years about the incidence of haemolytic streptococci. in dogs and their pathogenicity (pilot, Bïiick, Davis and Eastman, 1936; Hare and = ry, 1935; Stafseth, 1940; Hare, 1946,; and Carside , 1947) , but the frequencies of these organisms in relation to other possible pathos, ens have not been studied. Taking these factors into consideration, it was decided to make a general survey of the various organisms present in the upper respiratory tracts of dog's and cats. These animals were chosen because of the facilities available for the collection of material (Clinical Department attached to the Royal (Dick) Veterinary College, Edinburgh) , but an important factor which weighed too in selecting these two species of animals, was the Public Health aspect. It was thought that the results of this investigation would provide information as to whether or not these animals were frequent carriers of human pathogens. In modern society the dog and cat have become such household pets that they are fairly considered as members of the family, having free access practically to everything and to every piece in their masters' homes, so that if these animals harbour any of the human pathogens, transmission to Human beings may be easily accomplished Several reports regarding the high f'requency of haemolytic streptococci in the throats of dogs, stated above, repeated reports in the medical literature of Pasteurella infection in man following cat bites and, -in one instance, dog bite (napel and Holm, 1930; Schenk, 1938; Allin, 1942; Allott et al, 1944; and Hansman and Tully, 1945), and the cases recorded of tularaemia following cat bites (Smiles, 1931; Collins, 1933 -34) specially influenced this aspect of the study.