Antigenic and genomic variabilities among recently prevalent parvoviruses of canine and feline origin in Japan.

Canine parvovirus type 2 (CPV-2) and feline panleukopenia (FLP) virus (FPLV) are well known and ubiquitous diarrhea-causing pantropic viruses. A "new" antigenic variant of CPV-2 (designated as CPV-2a) has been also prevalent among dogs in Japan. In the present study, 24 canine and 8 feline isolates collected during 1987-1991 were compared with 17 CPV-2 or CPV-2a and 7 FPLV strains that had been characterized previously. Genomic properties were determined by the restriction cleavage patterns of amplified genes encoding the capsid proteins VP1 and VP2 by the polymerase chain reaction. Antigenic properties were determined by hemagglutination-inhibition assay with monoclonal antibodies against an FPLV strain. Growth characteristics in feline CRFK and canine MDCK cells were also examined. Genomic and antigenic properties of the canine isolates were relatively invariable with one exceptional isolate, C27, which was recovered from a typical clinical case of parvovirus infection but possessed properties similar to FPLV rather than CPV-2 and CPV-2a. All isolates from FPL cases possessed the same genomic and antigenic properties as those of reference FPLVs isolated in the 1970s, but three of five strains isolated from the feces of clinically healthy cats were likely to be of canine origin because they possessed very similar properties to CPV-2a. Although species-specificity of these novel isolates could not be determined definitely, the results indicate a possibility that transmission of parvovirus has occurred between these two animal species.