The Reaction of the Nursling Rabbit to Vaccination with Vaccine Virus

The results of the vaccination with vaccine virus of 1185 nurslings in a rabbit breeding colony are reported. Failure to develop a local reaction to vaccination was of frequent occurrence, especially in very young rabbits. A characteristic finding in many animals was the occurrence of generalized manifestations, the most striking of which was a cutaneous papular eruption. Vaccination was carried out in three successive experiments on December 19, 1933, January 24, and March 21, 1934. The general character of the resulting vaccinia underwent a progressive decline in severity, and in the last experiment there was little clinical evidence of infection. The results are discussed from the standpoint of the reaction of the host and particularly with reference to such factors as the nature of the local response to vaccination, the age of the animal, the condition of fostering, and the immune or susceptible state of the nursing female.