Origin and genetic diversity of canine parvovirus 2c circulating in Mexico.

Canine parvovirus type 2 (CPV-2) emerged in the late 1970 s as a pathogen that is capable of causing high rates of morbidity and mortality in dogs. Currently, three genetic variants circulate worldwide (CPV 2a, 2b, and 2c); however, epidemiological studies have not been conducted in all countries to identify its variants. The objectives of this work were to determine which genotypes of CPV-2 circulate in Mexico and to identify the genetic relationships between CPV-2 sequences from Mexico and those from other parts of the world. Samples from five geographical regions of Mexico were analysed by PCR for identification of CPV-2. Here, 1638 bp of the VP2 gene were amplified and sequenced from 50 CPV-2-positive samples, and a phylogenetic network was assembled using these 50 sequences and 150 others obtained from GenBank, representing different countries around the world. The network showed that the most common genotype circulating in the geographic zones of Mexico was CPV-2c. In the network, the 50 samples were organised into two clusters: cluster I, derived from a group of samples of European origin, which belong to genotype 2c, and cluster II, derived from samples belonging to genotype 2b from the USA. Our data suggest that the CPV-2 strains circulating in Mexico originated from two possible virus introduction events. In addition, high genetic diversity was observed among the CPV-2c-derived sequences, which correspond exclusively to the presence of Mexican CPV-2c haplotypes.