Relationship between growth behavior in vero cells and the molecular characteristics of recent isolated classified in the Asia 1 and 2 groups of canine distemper virus.

Ten recent isolates of canine distemper virus (CDV) strains were classified according to the growth ability and development of syncytial cytopathic effects (CPE) in Vero cells. Strains P94S, Ac96I, S124C, MD231, MS232, MSA5 and 095Cr were classified as Type 1 and exhibited hardly and did not develop CPE in Vero cells. Strains 007Lm, 009L and 011C were classified as Type 2 as grew well but failed to develop a syncytial CPE in Vero cells. A comparison of the phylogenetic trees of the H and P genes showed that all Type 1 strains belonged to the Asia 1 group and all Type 2 strains belonged to the Asia 2 group. Our findings suggest that the recent Asia 2 isolated of CDV in Japan, but not Asia 1 may grow in Vero cells, and their growth ability may be related with their molecular characteristics.