THE POSSIBLE ROLE OF MICROORGANISMS AND VIRUSES IN THE ETIOLOGY OF CHRONICDEGENERATIVE DISEASES OF MAN1

Abstract: Extramural Programs National Institute of Allergy and Infectious Diseases National Institutes of Health U. S. Department of Health Education and Welfare Bethesda Maryland 1 The survey of the literature pertaining to this review was concluded an January 15 1967. INTRODUCTION A lapse of 50 years followed Rous's observation that tumors of fowls could be induced by a filterable agent (1) before a full-scale investigation was initiated of a vital etiology of cancer in man. The Information to be presented here and recent publications from other sources (2 3) indicate that Information as compelling as that which has stimulated studies an viral oncology exists relative to other chronic and degenerative human diseases. The relationship of microbial agents to the induction of acute infectious diseases and even some of the mechanisms by which they produce their effects an the host are known and commonly accepted in medicine. However the thesis of an infectious etiology of the chronic and degenerative diseases introduces a whole new conceptual as well as technical approach to disease causation; one not so easily accepted within the framework of our present training and experience. Illustrative of such a conceptual approach is the pattern of disease causation outlined by Sigurdsson for "slow virus infections" (4). Sigurdsson and his colleagues had the unique opportunity of studying a group of diseases in Icelandic sheep; namely visna (5) maedi (4) Rida (scrapie) (4) and infectious adenomatosis (6) which were classified as "slow virus infections" because of the following distinguishing features: 1. Long incubation period-months to years. 2. Insidious onset of clinical disease. 3. Protracted clinical course. 4. Serious disease ending in death. 5. Pathologic changes unlike those of acute viral disease. The diseases to be described will involve other microbial agents as well as viruses; however while many do not exhibit the basic qualities of the "slow virus diseases they can be classified as being of a chronic or degenerative nature. ... ___MH

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