VACCINATION OF NEWBORN PIGS WITH AN ATTENUATED STRAIN OF TRANSMISSIBLE GASTROENTERITIS VIRUS

Abstract

Clinical signs of transmissible gastroenteritis were not observed in newborn pigs orally inoculated with the high-passaged vaccinal transmissible gastroenteritis virus (TO-163 strain). Vaccinal viral multiplication in digestive tract of newborn pigs fed colostrum before inoculation and kept at 21-22.degree. C was diminished, but was not diminished in those fed colostrum and kept at 10-11.degree. C. Other groups of newborn pigs inoculated with the attenuated vaccinal virus and kept at 18-22.degree. C or at 31-34.degree. C were challenge exposed with virulent intestinal virus on the 1st-6th postinoculation (PI) days. In the groups kept at 18-22.degree. C, 2 of 7 inoculated pigs challenge exposed with virulent virus on the 3rd PI day, 4 of 7 pigs exposed on the 4th PI day, and all of the pigs exposed on and after the 5th PI day survived the exposure. In the groups kept at 18-22.degree. C, the attenuated vaccinal virus was distributed mainly in the respiratory organs and lymphatic tissues. In the groups kept at 31-34.degree. C, all of the pigs died in 2-5 days after challenge exposure, and the attenuated vaccinal virus was scarcely detected in any of the pigs.