Emergence of CPV Types 2a and 2b (CPV-2a and CPV-2b)
Since the emergence of CPV-2, two new antigenic types of CPV, designated CPV-2a and CPV-2b, have arisen consecutively. These new virus types have now almost completely replaced CPV-2 viruses as the dominant infectious agents  (Figure 3). At least four conserved nonsynonymous substitutions have been observed between CPV-2 and CPV-2a isolates in the VP2 gene ( Table 1 ). CPV-2b isolates have another two nonsynonymous changes from CPV-2a ( Table 1 ). Although the exact mechanisms of these evolutions are not clear, the emergence of these new antigenic types of CPV can likely be ascribed to the adaptation of CPV-2-type viruses in dogs. Of interest, each new antigenic type has lost at least one neutralizing epitope compared with the former serotype .
Emerging Infectious Diseases. 2002;8(4) © 2002 Centers for Disease Control and Prevention (CDC)
Cite this: Feline Host Range of Canine parvovirus: Recent Emergence of New Antigenic Types in Cats - Medscape - Apr 01, 2002.