RABBIT POX : III. REPORT OF AN EPIDEMIC WITH ESPECIAL REFERENCE TO EPIDEMIOLOGICAL FACTORS.

A devastating epidemic of rabbit pox in a breeding colony was studied with especial reference to factors of epidemiological significance. The evidence obtained indicated that the epidemic originated among animals inoculated with vaccine virus and that the infection was spread to the breeding colony by caretakers. The epidemic began insidiously with atypical cases of visceral disease followed by typical cases of pox and terminated as a mild cutaneous disease with scattering monosymptomatic affections of various kinds, difficult to recognize as cases of pox infection. An analysis of data concerning the health and functional efficiency of the population and the immunity of exposed animals showed that the epidemic of rabbit pox was the terminal event in a series of progressive disorders which began fully a month before the first case of pox occurred. In like manner, the terminal decrease in the severity of the disease and the eventual termination of the epidemic appeared to be referable to an improvement in the condition of the population rather than to a specific immunity acquired by exposure to infection.