Transplacental Hog Cholera Infection in Susceptible Sows

Abstract

SUMMARY Susceptible sows in various stages of pregnancy were vaccinated simultaneously with attenuated or virulent (Ames) hog cholera ( hc ) virus and anti- hc serum. Tissue specimens from offspring of the sows were examined for hc virus by the fluorescent antibody cell culture technique ( facct ). Isolates from the newborn pigs and composite suspensions of tissues that gave negative results by the facct were inoculated in susceptible pigs for confirmation. Transplacental infection occurred in 4 sows vaccinated with Ames virus and either 35 or 75 ml. of anti- hc serum. The dose of antiserum and stages of gestation in which the vaccination was performed were factors that were considered to affect the results of the experiment. These 4 sows were in the first month of pregnancy and 3 of the 4 sows had been given the smaller dose (35 ml.) of antiserum. Transplacental infection was not confirmed in 12 sows vaccinated with attenuated vims and 20 ml. of anti- hc serum nor in 8 sows vaccinated with Ames virus and either 35 or 75 ml. of antiserum.