Genetic characterization and predominance of the new CPV-2a variant in clinical cases of canine parvovirus in the western region of Rio Grande do Sul, Brazil

Abstract

Canine parvovirus 2 (CPV-2) is an important causative agent of segmental enteritis in young dogs and has globally distributed variants and subtypes. Viral mutations can alter the pathogenesis and clinical signs, making identifying the samples circulating in a given region relevant. This study described the epidemiological and clinical findings and the molecular characterization of CPV-2 samples circulating in the canine population of Uruguaiana, Rio Grande doSul (RS), Brazil. We analyzed 27 cases with a complete clinical history and at least one confirmatory etiologic diagnosis. In addition to clinical and epidemiological data, whole blood samples or tissues were tested by PCR for viral DNA detection. Amplified products were sequenced and analyzed, and phylogeny was generated with reference sequences. The disease was diagnosed especially in the summer months, and the most common clinical findings were diarrhea, anorexia, listlessness, and vomiting. Infection was predominant in young (< 6 months) unvaccinated or partially immunized dogs, with mortality exceeding 93%. It was possible to identify 15 CPV-2 samples, four of which were CPV-2a and 11 were new CPV-2a. It can be concluded that canine parvovirus is a disease with high mortality rates, with young unvaccinated dogs being more susceptible, with a predominance of the new CPV-2a variant in the western region of Rio Grande do Sul.