Efficacy of vaccination of sows with serologically related coronaviruses for control of transmissible gastroenteritis in nursing pigs.

Three groups of pregnant sows were vaccinated at 8 and 2 weeks before parturition with tissue culture-adapted feline infectious peritonitis (FIP) virus, porcine transmissible gastroenteritis (TGE) small-plaque (SP) virus from a persistently infected cell line, or noninfected cell culture fluids (controls). Pigs nursing vaccinated sows were orally challenge exposed with virulent TGE virus when they were 1 to 3 days old. The morbidity of the nursing pigs was 48% in the SP-TGE group, 82% in the FIP group, and 93% in the controls. The survival rate among the nursing pigs was 77% in the SP-TGE groups, 48% in the FIP group, and 14% in the controls. Virus-neutralizing antibodies of immunoglobulin A were detected in colostrum and milk of the SP-TGE group, but not in the FIP or control groups.