A Pandemic of Rabbit-Pox

Abstract

A recent outbreak of a highly contagious disease in our breeding colony produced such serious consequences that it seems desirable to direct attention to the infection. This report concerns the disease produced by natural transmission. The experimental infection and the causative agent have been studied by Pearce, Rosahn, and Hu. 1

The first cases of the disease appeared in December, 1932, and within a month every animal in a colony of 1500 rabbits had been infected.

Clinically, the disease resembled small-pox in man. It was characterized by an elevation of temperature with a pock-like eruption of variable extent in the skin and mucous membranes and an incubation period of from 5 to 10 days. In typical cases, the first sign of infection was the appearance of erythematous spots; papules were then formed in these areas and later became umbilicated and covered by crusts. These lesions varied in size from minute points to nodules a centimeter in diameter; they occurred singly, in groups, or as confluent masses with extensive edema and in some cases were hemorrhagic. The papules occurred over the entire body but were most numerous in the ears, the eyelids and brows, the lips, the nape of the neck, the skin of the trunk, and the scrotum.

The mouth, nose, and pharynx were frequently the seat of large nodules, diffuse infiltrations, and ulcerative lesions which, in extreme cases, obstructed respiration and prevented eating. Such animals usually showed a mucopurulent discharge with the formation of brownish crusts about the nose and lips suggestive of snuffles or a clear blood stained secretion from the nose.

Eye lesions were of frequent occurrence and in some animals were the only visible manifestation of infection. The lymphoid system was invariably affected and one of the earliest signs of infection was enlargement and induration of the popliteal nodes.