Species Affected and Geographical Distribution

Abstract

The concept of host specificity was first enunciated c. 400 bc allegedly by Hippocrates: “...some one may ask, why these diseases do not affect all animals in the same manner, but confine themselves to some particular sort? This is the reason; because in their bodies, their nature, and their food, they differ from each other....” During the Great Plague of London, the physician Hodges wrote in 1672: “And the Conjecture that sickness amongst Cattle is transferable to the humane Species, hath not yet appeared on any good Foundation... I cannot be induced to believe that the Pestilence amongst Cattle from a private Cause, can ever obtain any Dominion over Mankind” (Hodges, 1720). Another English physician, Richard Mead, in 1720 wrote that he was well aware “that there are plagues among animals, which do not indifferently affect all kinds of them, some being confined to a particular species like the disease of the black cattle here, a few years since, which neither proved infectious to other brutes, nor to men.” (Mead, 1720). Layard (1757) was of the opinion that rinderpest affected only horned cattle, but although a disease of all cloven-hoofed ungulates, not all species may be affected by particular strains.