“…More recently this definition for a disease nidus has come to recognize the importance of the various ecological requirements for the pathogen's survival, both naturally and due to specific human geographic features (Pavlovsky 1966, 249, Meade, Florin andGesler 1988, 62 Thomas (1931), Trewartha (1940), Meyer (1954Meyer ( , 1956Meyer ( , 1959, Gentilcore (1957, Meyer andStrietelmeier (1963, 778-795) and Peplies (1965). In…”