Diagnóstico da infecção pelo vírus da diarréia viral bovina em propriedades da microrregião de Viçosa

• Autor(a) principal: Nogueira, Flávia da Silva
• Data de Publicação: 2003
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5199
• topic: Diarréia viral bovina; Flavírus; Isolamento; Caracterização sorológica; Bovine diarrhea virus; Isolation; Neutralizing antibody; CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA::MEDICINA VETERINARIA PREVENTIVA

The Bovine Viral Diarrhea Virus (BVDV) belongs to the family Flaviviridae and it is a member of the genus Pestivirus. BVDV has a worldwide distribution and infection in cattle is common, which is evidenced by a high level of seropositive animal in the infected population. The major economical damage caused by BVDV in susceptible herds is still caused by intrauterine infections and it depends on the age of fetus. The infection during the first third of pregnancy could generate immunotolerant animals that would present a persistent infection (PI) condition. The impact of the infection of BVDV in the bovine population of Minas Gerais is unknown. The objective of this investigation is to characterize the occurrence of the BVDV infection by detection of the PI animals and the level of antibodies in herds. For PI detection, we tested 385 samples of serum, 214 of those from fetuses collected at slaughtering house and 171 from young (six to 10 month old) animals, by virus isolation in MDBK cells. Three blind passages were made before the MDBK cells were tested by indirect immunofluorescence (IFI) using a poll of monoclonal antibodies against BVDV. Additionally, sera of 315 unvaccinated adult animals were tested by serum neutralization test (SN). All the samples tested by passage in MDBK were negative when tested by IFI. The prevalence of antibodies found in the adult population was 14.3% (44/315) and titles were between 2 to 128. Current knowledge about BVDV indicates that herds with 40 to 80% of antibody prevalence could result in 1 to 3% of PI. Moreover, the titles of antibodies in population where the virus are present usually are higher than we found in the SN assay. The low antibody prevalence associated with low titles could explain the lack of BVDV isolation.