Evolution of Canine Parvovirus in Argentina

GALLO CALDERON, MARINA; DANILO BUCAFUSCO; FOGEL, FERNANDO; IGLESIAS, MARCELA; PERIOLO, OSVALDO; MATTION, NORA; LA TORRE, JOSE

Punta del Este: Maldonado : Uruguay (Barradas Hotel)

Conferencia; 150 years of Darwin's Evolutionary Theory: a South American celebration; 2009

Canine Parvovirus (CPV) is a 26 nm diameter, non-enveloped virus, carrying a single stranded DNA genome of approximately 5200 nucleotides.CPV is responsible for a severe, highly contagious gastroenteric disease in pups and was first identified in the late 1970s, when outbreaks of fatal myocarditis and hemorrhagic gastroenteritis were observed in young puppies worldwide.A few years after its emergence, two new antigenic variants, named CPV2a and CPV2b, were characterized. At present, the original CPV2 is not circulating in dog populations, although it is still present in vaccine formulations, whereas the variants are distributed worldwide. A new antigenic variant, carrying the aa substitution Asp426Glu, was reported in Italy in the year 2001. This new mutant, designated CPV2c, has been detected later in Vietnam, Spain, USA, Portugal, Germany, the United Kingdom and Uruguay.The aim of this study was to apply a rapid, sensitive and specific PCR method for the detection of CPV DNA in clinical specimens from Argentine dogs showing symptoms compatible with CPV disease.A total of 38 rectal swabs samples were obtained from domestic dogs from Buenos Aires city and other cities. Clinical specimens were submitted to the laboratory for diagnostic purposes between the years 2002 and 2008.CPV genomic DNA was extracted directly from rectal swabs. Three different sets of primers, were used. The amplified DNA fragments obtained with the Pb primer pair from 18 clinical samples were cloned into the pGEM-T Easy vector and sequenced. Sequence analysis was performed using ClustalW.Twenty-seven, out of 38 samples analyzed were CPV positive. The classical CPV2 strain was not detected in any of the samples, but nine samples were identified as CPV2a variant and 18 samples as CPV2b variant. Further sequence analysis revealed a mutation at aa 426 of the VP2 gene (Asp426Glu), characteristic of the CPV2c variant, in 14 out of 18 of the samples identified initially by PCR as CPV2b. The appearanceof CPV2c variant in Argentina might be dated at least to the year 2003. Three different pathogenic CPV variants circulating currently in the Argentine domestic dog population were identified.