Genetic diversity of Brazilian strains of porcine circovirus type 2 (PCV-2) revealed by analysis of the cap gene (ORF-2)

Abstract

Porcine circovirus 2 (PCV-2) is associated with a broad range of syndromes. In this study, 19 of 870 samples from pigs from different Brazilian states were found to be positive for PCV-2 by polymerase chain reaction (PCR). A fragment of 700 nt of the cap gene (ORF-2) from the 19 PCV-2-positive samples were sequenced using three pairs of primers (Fa/Ra, Fb/Rb and Fc/Rc). Maximum parsimony genealogy with a heuristic algorithm using the 19 field strain studied here, 21 sequences from GenBank and PCV-1 as an out-group showed the existence of two major clusters (A and B) and the Brazilian strains segregating in both of them. PCV-2 was found in pigs with various clinical signs. No association between clusters of PCV-2 and different states or clinical signs were observed, demonstrating that the exact role of PCV-2 in porcine circovirus diseases (PCVD) in Brazil still needs to be clarified. These results contribute to the molecular characterization of PCV-2, which serve as a basis for the epimiology of PCV-2 infection.