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Chapter 44 : Robert Koch and His Postulates
Specific etiology was one of the most powerful and productive ideas in the entire history of medicine. Robert Koch outlined the postulates according to which an organism could be conclusively implicated as the agent of a specific disease. The now-familiar form of the four postulates closely followed Koch's own work on anthrax. Half a century later, there are additional grounds for asking whether the tenets of specific etiology can be considered realistic any more. As well as more sophisticated comprehension of the ecological context explored by Dubos, our understanding of pathogenesis is being continually modified by insights from disciplines such as microbial population genetics and molecular ecology. Among several attempts over the years to brush up Koch's postulates to take account of new knowledge, Stanley Falkow's paper was an elegant restatement in light of modern molecular genetics. This chapter talks about a new research which aims to assess the presence of Helicobacter DNA in the gastric mucosa of 20 Thoroughbred horses in Caracas, Venezuela.The results of PCR tests on squamous and glandular mucosa samples showed that seven of the horses had gastric ulceration, five had gastritis, and six had both conditions. Helicobacter-like DNA was evident in two of the horses with gastric ulceration, in three of those with gastritis, in five of those with both pathologies, and in one with normal gastric mucosa. 10 of the 11 infected animals showed gastric lesions, with just 1 of them having normal mucosa.