STUDIES ON BACILLUS CALMETTE-GUÉRIN (B.C.G.) AND VACCINATION AGAINST TUBERCULOSIS

作者：Edmund Watson · 发表于：Canadian Journal of Research/Canadian journal of research · 年份：1933 · DOI：10.1139/cjr33-073 · 被引用次数：9 · 研究领域：vaccines and immunoinformatics approaches、Tuberculosis Research and Epidemiology、Microbial infections and disease research

Vaccination trials and biological studies of B.C.G. have been carried on for a period of over eight years and are still continuing. Under conditions of continuous exposure to natural infection through cohabitation with tuberculous animals, trials varying in duration from two months to four and one-half years have been completed on 44 vaccinated cattle and 28 unvaccinated controls. In trials of short duration the percentage of cattle free from tuberculosis is slightly in favor of the vaccinated. In all cattle over two years of age tuberculosis was present to a greater or lesser degree. Judged by slight, moderate and extensive tuberculous involvement, there is some evidence of a greater resistance in the vaccinated cattle up to two and a half years of age, 26% of which showed extensive generalized tuberculosis, as compared with 53% of the unvaccinated. But in the age group ranging from two and a half to four and a half years no greater resistance is found in the vaccinated than in the unvaccinated cattle. It has not been possible to demonstrate a true lasting immunity by this method of vaccination, and such increased relative resistance as B.C.G. may confer during the early months of life declines and soon disappears, and fails to protect cattle exposed for two years to natural sources of infection from developing typical tuberculosis.The attenuated virulence and potential pathogenicity of B.C.G. have been studied for a period of over eight years in three original strains recei...