Tuberculosis in Man, Dog and Cat: An Investigation into the Inter-Relation of Tuberculosis between Humans and Their Domestic Pets

Hawthorne, V. M (1962) Tuberculosis in Man, Dog and Cat: An Investigation into the Inter-Relation of Tuberculosis between Humans and Their Domestic Pets. PhD thesis, University of Glasgow.

Abstract

1. An account is given of an investigation, extending over eight years, into the inter-relation of tuberculosis between man, and his domestic pets, the dog and cat; with particular reference to the ecological aspects of the infection, whether or not it was a zoonosis, and if so, its epidemiological significance. 2. The method of investigation was by a combined medical and veterinary approach, aimed at ascertaining the incidence of tuberculosis among apparently healthy animals in contact with active tuberculosis in humans, and among humans -in contact with animals dying of tuberculosis. 3. The investigation included an attempt to refine existing methods of diagnosis of tuberculosis in dogs and cats, by the development of B.C.G. as a test of immunity, in place of P.P.D. tuberculin, which was found to be both ineffective and unreliable. 4. A questionnaire was devised to elicit the required ecological details; and then distributed by the Feline Advisory Bureau to 750 individuals in the British Isles, Western Europe and the United States of America. 5. M. tuberculosis of human origin, was recovered from 4 dogs and 3 cats in a group of 48 animals, exposed to active tuberculosis in their owners, and from one cat in a further, similar group of 22 animals. The presence of these bacilli, which were of normal virulence, was not accompanied by pathological changes typical of tuberculosis; and it was concluded that the bacilli were probably present as commensals in highly resistant animals. 6. The atypical pathological changes, described as sinus catarrh, in isolated glands of the animals producing growths of M. tuberculosis, suggested further studies to determine if these changes might be related to sarcoidosis or an early, latent, phase of a tuberculous infection in a highly resistant animal. 7. The dangers of the apparently healthy domestic pet, excreting viable and virulent tubercle bacilli, indicated the advisability of proscribing the animal for a period of several months, following the detection of an active case among the human members of the household. 8. Three quarters of the human contacts of 31 dogs dying of tuberculosis were traced, half of them to the owner, or a member of his family, but in seven cases to a neighbour or a previous owner. Of the total of 354 human contacts, 41 (11.86%) were found to have had active tuberculosis at a material time in their association with the sick animal. 9. While the definition of the exact hazard of the tuberculous animal to its owner needed a more comprehensive, and inflexibly applied study of the human contacts, including Mantoux testing, and a new method of identifying identical growths obtained from owner and pet, the present investigation made it clear that the diagnosis of tuberculosis in a domestic animal, should be subject to the same statutory notification to the Public Health Authority, as was required in the case of a tuberculous human. 10. The intradermal injection of 0.1 ml. of B.C.G., producing a papule which ulcerated before 14 days (average interval from injection to ulceration, 9 days for cats and 11 days for dogs), was interpreted as the early, immune, 'positive' reaction of the infected animal; whereas a papule ulcerating after 14 days (average interval from injection to ulceration, 22 days for cats and 24 days for dogs), was taken as the late, non-immune, 'negative' reaction of the un-infected animal. The earlier the appearance of the ulcer, i.e., an accelerated, early, immune, 'positive' reaction, the more likely the animal to be suffering from an active tuberculosis infection. (Abstract shortened by ProQuest.).

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Medicine, Epidemiology, Pathology
• Date of Award: 1962
• Depositing User: Enlighten Team
• Unique ID: glathesis:1962-79424
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 05 Mar 2020 09:58
• Last Modified: 05 Mar 2020 09:58
• URI: https://theses.gla.ac.uk/id/eprint/79424