Infectious diseases and social conditions

The brilliant successes of bacteriology at the end of the 19th century and at the beginning of the current century so overshadowed the purely epidemiological study of infectious diseases that the focus began to be mainly on the bacteriological resolution of questions of an essentially epidemiological nature (the question of transmission, spread and course of infectious diseases). Koch's triad was a purely deductive principle, and the emergence of infectious diseases was postulated by the existence of those or other, but necessarily specific pathogens-discovered, or, due to the imperfection of our technology, not yet discovered. But already in the first decade of the present century individual voices of infectious disease specialists who express doubt as to the correctness of a purely bacteriological approach to the solution of epidemiological questions began to be heard, and the time after the war, which gave a great number of observations of an almost experimental character and precision, made it think that epidemiology could have its own method and experience.