Outbreaks of swine vesicular disease in japan: virus isolation and epizootiological survey.

Outbreaks of a vesicular disease occurred among pigs in Kanagawa and Ibaraki Prefectures in Japan in November, 1973. Another outbreak was observed in Aichi Prefecture in December. The clinical signs of the disease observed included fever and vesicular lesions on the coronary bands, bulbs of the heel and in the interdigital spaces. In some pigs, vesicular lesions were observed on the snout, tongue and skin overlying the legs and abdomen. All the vesicular samples produced cytopathic changes on cultures of primary swine kidney cells of PK-15 cells. Three isolates of cytopathic agents tested were identified as swine vesicular disease virus from their physicochemical properties and antigenicity. The virus strains isolated from vesicular epithelial samples obtained from Ibaraki, Kanagawa and Aichi Prefectures were designated as Japan/Ibaraki/1/73, Japan/Kanagawa/1/73 and Japan/Aichi/1/73 strain, respectively. An outbreak of the disease among pigs due to swine vesicular disease virus was confirmed by the serum neutralization test with serum samples collected from pigs on affected farms. Approximately 80% of the pigs housed in affected shed showed high levels of neutralizing antibody titers. This is the first to report an occurrence of swine vesicular disease among pigs in Japan.