RABBIT POX I I I . REPORT ox~ AN EPIDEMIC WITH ESPECIAL REFERENCE TO EPIDEMIOLOGICAL FACTORS BY HARRY

Descriptions of an epidemic disease in rabbits comparable with small pox in man were given in a previous paper (1). Pearce, Rosahn and Hu (2) found that the disease was caused by a filterable virus of the pox group which was closely related to vaccine virus but not identical with either the neurotropic or dermotropic form. From their investigations, it may be inferred that the causative agent is either a variant of one or the other or a distinct virus. The infection produced by this virus is capable of spreading among rabbits and may produce an epidemic much like small pox in man. As was pointed out in previous papers, the epidemic occurred in an animal population which had been under close observation for a period of years and contained a variety of racial types and groups which were known to differ radically in their constitutional potentialities. An unusual opportunity was thus offered for the study of epidemiological factors. The object of the present paper is to record the essential facts conceruing the origin of the epidemic, the source of infection and its spread through the colony and eventual disappearance, together with crude mortality data for different periods of the epidemic. Particular attention will be given to events of epidemiological significance preceding the outbreak. Consideration of selective variations in susceptibility which were disclosed by the epidemic will be reserved for another paper. Compos#ion of the Population