Evolution of canine parvovirus in Argentina between years 2003 and 2010: CPV2c has become the predominant variant affecting the domestic dog population

Abstract

The current frequency of Canine Parvovirus variants (CPV2a, CPV2b and CPV2c) in the Argentine dog population was investigated by PCR amplification of a 583 bp fragment in the VP2 gene. From a total of 79 rectal swab samples that have been submitted to our laboratory since 2008, 55 (69.6%) resulted positive and were further analyzed by direct DNA sequencing. Fifty positives samples (91%) were characterized as CPV2c variant, which appeared in Argentina in the year 2003 and has been the prevalent type since 2008, whereas CPV2a and CPV2b, still found in Argentine dogs, were represented in 3.6% and 5.4% of the population, respectively. Considering that CPV2c is spreading worldwide, and that this variant is also affecting vaccinated dogs, efforts should be made towards the development of new matched CPV vaccines.

Fig. 1

Alignment of the deduced amino acid sequences of a fragment of the 583 bp amplicon of the VP2 gene amplified by PCR from clinical samples (aa 407–456). The aligned sequences correspond to a vaccine strain (CPV2, M38245), a CPV2a reference strain (CPV2a, M24003), a CPV2b reference strain (CPV2b M74849), an Italian CPV2c strain (FJ222821.1), and Argentine CPV2a, CPV2b and CPV2c variants. The positions 426 and 440 are highlighted.

Fig. 2

Updating of the evolution of CPV variants in Argentina. The number of cases detected in the years 2002–2010 belonging to each CPV variant are shown on top of the bars (previous study, Calderon et al., 2009). *Up to October 2010. White bars, CPV2a variants; black bars, CPV2b variants; grey bars, CPV2c variants.

Fig. 3

Distribution of the CPV2c variants in Argentine dogs, according to age.