Porcine parvovirus 5 (PPV5) is an unclassified member of the family Parvoviridae with no reported pathogenicity, although it is associated with multisystemic, reproductive, and respiratory diseases. Its open reading frame 1 (ORF1) encodes non-structural protein 1 (NS1), which is predicted to have helicase activity that is essential for viral replication. This protein contains a C-motif with an invariant asparagine residue that forms the core of the enzyme's active site, in conjunction with the Walker A and B motifs. The aim of this study was the phylogenetic and molecular characterization of the NS1 of PPV5 through nested PCR and sequencing of three Mexican PPV5-positive samples. Subsequently, a phylogenetic tree, identity matrices of nucleotide and amino acid sequences, and a three-dimensional model of NS1 were constructed. The amplified sequences, which represented 96.9% of the PPV5 ORF1, occupied the same branch in the phylogenetic tree and exhibited the most nucleotide sequence similarity to the corresponding region of PPV4 and the most amino acid sequence similarity to the NS1 proteins of PPV4 and PPV6. A three-dimensional model of NS1 displayed a C-motif characteristic of superfamily 3 (SF3) helicases. The phylogenetic proximity of PPV5 to PPV4 and PPV6 suggests that it may belong to the genus Copiparvovirus. Further studies on helicases from viruses infecting domestic animals may be useful in developing antiviral drugs for both human and veterinary medicine.

Las especies de Circovirus porcinos (Porcine circovirus, PCV por sus siglas en inglés) son ubicuos en la población porcina doméstica y silvestre. Hasta el momento, se han descrito cuatro especies (PCV1 al PCV4), siendo el PCV2 la especie más documentada por su participación en la Enfermedad Asociada a Circovirus Porcino cuya patología compleja conduce al desarrollo de diferentes presentaciones clínicas que causan pérdidas económicas importantes en la industria porcina. En el presente trabajo, se revisan los conceptos recabados con relación en los PCVs, incluyendo genotipos, interacción y replicación en las células del huésped, patogenia e inmunidad, así como la posible asociación del PCV3 y PCV4 con la enfermedad, enfatizando sobre la problemática de establecer dicho potencial debido a la alta tasa de coinfección entre los PCVs y otros virus patógenos y emergentes.