The continuous emergence of new strains of canine parvovirus (CPV), poorly protected by current vaccination, is a concern among breeders, veterinarians, and dog owners around the world. Therefore, the understanding of the genetic variation in emerging CPV strains is crucial for the design of disease control strategies, including vaccines. In this paper, we obtained the sequences of the full-length gene encoding for the main capsid protein (VP2) of 11 canine parvovirus type 2 (CPV-2) Argentine representative field strains, selected from a total of 75 positive samples studied in our laboratory in the last 9 years. A comparative sequence analysis was performed on 9 CPV-2c, one CPV-2a, and one CPV-2b Argentine strains with respect to international strains reported in the GenBank database. In agreement with previous reports, a high degree of identity was found among CPV-2c Argentine strains (99.6-100% and 99.7-100% at nucleotide and amino acid levels, respectively). However, the appearance of a new substitution in the 440 position (T440A) in four CPV-2c Argentine strains obtained after the year 2009 gives support to the variability observed for this position located within the VP2, three-fold spike. This is the first report on the genetic characterization of the full-length VP2 gene of emerging CPV strains in South America and shows that all the Argentine CPV-2c isolates cluster together with European and North American CPV-2c strains.

A type A avian influenza (AI) virus was isolated from dead or severely ill red-winged tinamous (Rhynchotus rufescens) found in a hunting ground in April 2008 in Argentina. The subtype of A/red-winged tinamou/Argentina/MP1/2008 was determined as H1N1 by sequence analysis. The cleavage site of the viral hemagglutinin corresponded to a low pathogenic influenza virus, although the clinical presentation and pathological studies suggest that the virus was pathogenic for red-winged tinamous. Phylogenetic analysis of the viral genome suggested that while the hemagglutinin and neuraminidase genes were related to AIV from North America, the internal genes were most closely related to other South American isolates. These findings support the postulated South American phylogenetic lineage for AIV PB2, PB1, PA, M and NS genes, and suggest that the evolutionary pathways of HA and NA genes involve exchanges between the Northern and Southern hemispheres.

No abstract