Advances in biomedical leprosy research

Abstract

The book by Harry L. Arnold and Paul Fasal, 'Leprosy, Diagnosis and Management', published in 1973, commences with the sentence 'We are at the beginning of a new era in leprosy'. This is certainly true as far as understanding the disease and the bacterium are concerned. Inability to grow the bacterium and therefore being unable to learn anything about it and failure to have on hand a valid animal model for the study of leprosy as it occurs in man were the main retarding factors in gaining a better understanding of the disease and of the germ. There were no answers to the following fundamental questions: How and how frequently is the leprosy bacillus transmitted in endemic areas? Why do most persons living in poverty, in stable communities ion highly endemic surroundings escape leprosy? Why are there such dissimilar clinical diseases as tuberculoid and lepromatous leprosy? Do the severe, disseminated forms of leprosy result from higher infectious doses, or more virulent bacilli, or greater host susceptibility? The advances in biomedical leprosy research can be summarized with the following statements: We have learned to identify the leprosy bacillus, determine its viability, screen the efficacy of antileprosy drugs, and monitor a patient's bacilli for sensitivity to the drug being received. There is now evidence that subclinical infections occur frequently among contacts of patients with leprosy and that its different manifestations in man reflect individual differences in resistance to Mycobacterium leprae. The nine-banded armadillo provides the amounts of leprosy bacilli which furnish the materials for bacteriologic, metabolic, epidemiologic, immunologic and immunotherapeutic studies. In addition, the nine-banded armadillo might help to solve such fundamental questions as the cellular basis of resistance and susceptibility and shed light on the possibility that the latter rests on a genetically determined defect.