Response of pigs to recent isolates of Coxsackievirus B5

Abstract Coxsackievirus B5 (CB5) was serially passaged five times in pigs in an attempt to establish clinical disease. No clinical signs were seen although some pigs had a transient rise in rectal temperature. Viremia was not detected although virus was isolated from nasal swabs and fecal samples. No CB5 specific fluorescence or virus was detected in any tissues of five passages by immunofluorescent test and tissue culture methods, respectively. Brain lesions were noted in all passages; extensiveness of lesions increased slightly up to the third passage although no evidence of increasing viral replication was found. No increase in brain lesions was found in the fourth and fifth passages. The development and progress of brain lesions were similar to but less extensive than those caused by swine vesicular disease virus (SVDV) in most pigs examined. Contact pigs also showed more brain lesions than inoculated pigs. In some passages, microscopic changes also were found in the heart. All pigs exposed to CB5 had positive neutralizing antibody titres against CB5 and SVDV but became ill after challenge with SVDV. There was an anamnestic response to both viruses following challenge.