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
