Detection of of porcine parvovirus (PPV) in swine fetal tissues / Pesquisa da presença de parvovirus suino (PVS) em tecidos de fetos de suinos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Swine female reproductive quality is mainly measured by return to estrus, litter size, abortion, stillbirth and mummies. Porcine parvovirus (PPV) transplacental infection is associated to fetal death at different gestacional age, and mostly with fetal mummification due to abscence of fetal immunecompetence in early pregnancy. In late gestational age, immunecompetent fetuses can survive the PPV infection and the virus may be isolated from stillbirth and aborted animals. From commercial vaccinated swine herds, thirty nine fetuses over 70 days of gestational age, so immunocompetent, were separated for analysis. The application of hemagglutination inhibition test confirm fetal immunecompetence in 93,4% of the samples. Viral antigen was detected in isolated individual cells of the lung (alveolar macrophage), in multiple miocardial cells and in stromal cells of the timus (epithelial-reticular), by immuneperoxidase staining using an anti-VP2 monoclonal antibody. These results were observed in stillbirth and aborted fetuses. There was no statistically significant difference for PPV infection in stillbirth and aborted fetuses, but lung and thymus were significantly more positive that the heart. The presence of virus in fetal tissues was analyzed by nested-PCR assay for the NS-1 gene of PPV in stillbirth, aborted fetuses and mummies. The viral DNA was detected in 82.4% of the samples, with no significant difference in the type of fetus, determining that the porcine parvovirosis should not be characterized only as a disease of fetal mummification. Using nested-PCR assay, the frequency of identification of PPV was higher in the lung (96,99%) and hearth (93,33%) than in the spleen (54,91%), thymus (66,0%) and kidney (69,5%). Fetuses which death estimated age more than 100 days old were less positive to PPV and a significant difference in PVS detection was detected in tissues from fetuses from sows with lower (92.28%) and highest (65.43%) number of parturitions. This suggests for a higher susceptibility of transmission in younger sows, submitted to a fewer vaccinations. PPV DNA were detection was independent of antibody presence in fetuses. Fetus immunecompetence did not prevent the infection by PPV and these viruses are associated with abortion, stillbirth and mummies.

ASSUNTO(S)

aborto tecnicas imunoenzimaticas polymerase chain reaction mortalidade fetal reação em cadeia de polimerase fetus abortion immunoenzyme technique feto fetal mortality

ACESSO AO ARTIGO

Documentos Relacionados