High frequency of bovine viral diarrhea virus type 2 in Southern Brazil

M.N.Webera, S.Silveiraa, G.Machadob, F.H.S.Groffc, A.C.S.Mósenaa, R.F.Budaszewskia, P.M.Duponta, L.G.Corbellinib, C.W.Canala

  • a Laboratório de Virologia, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9090, CEP 91-540-000 Porto Alegre, RS, Brazil

    b Laboratório de Epidemiologia Veterinária (Epilab), Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9090, CEP 91-540-000 Porto Alegre, RS, Brazil

    c Secretaria da Agricultura, Pecuária e Agronegócio do Rio Grande do Sul (SEAPA-RS), Av. Praia de Belas 1768, CEP 90-110-000 Porto Alegre, RS, Brazil

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Ruminant pestiviruses can infect cattle populations worldwide and cause significant economic losses due to their impact on productivity and health. Knowledge of pestivirus diversity is important for control programs and vaccine development and for determining probable sources of infection. In this paper, we describe a search for ruminant pestiviruses with RT-PCR in sera of 9078 calves from 6 to 12 months of age. The calves were first analyzed in pools and then analyzed individually. Thirty-three RT-PCR positive animals were detected (0.36%) from 6.9% (24) of the 346 herds. The sequencing analysis of the 5' non-coding region and N terminal autoprotease showed the presence of BVDV-1a (15 isolates), -1b (3), -1d (1) and -2b (14), with a higher frequency (42.4%) of BVDV-2 in comparison with other countries. The presence of sheep was significantly associated with BVDV infection. Our results also suggested that a BVDV control program based only on the investigation of cattle would not be successful, especially in regions with farms harboring multiple animal species. This study may also serve as a reference for future control programs in Southern Brazil because it reports the prevalence of cattle with active infections and the genetic background of the circulating strains.