Mc Keon, in nineteenth century studied the decline in the incidence of the infectious diseases like tuberculosis and he explained the co-relation between the declinein the incidence of infectious disease and told that the relation is better understood in terms of -
Increased awareness and knowledge
Social and economic factors
Behavioral interventions
Medical interventions
Thomas McKeown attributed the modern rise in the world population, AND DECLINE OF TB from the 1700's to the present to Broad economic and social changes (especially diet and nutrition- "Nutritional Determinism") rather than to targeted public health or medical interventions Ref: Internet
Communicable diseases