Resumo

Chicken astrovirus (CAstV), avian nephritis virus (ANV) and chicken parvovirus (ChPV) have been related with enteric disease. These viruses are very difficult to be isolated and there are a few strains isolated around the world. There are no reports about their isolation in cell lines of common use. The aim of the present work was isolate and propagate in VERO cell line CAstV, ANV and ChPV. Many samples of these viruses isolated in chicken embryos were inoculated in triplicate into the monolayer of VERO cells of 11 days old with cell culture medium with 5% of fetal bovine serum. Cytopathic effect (CPE) was observed 24 hours post infection in the monolayer for each virus. The stronger CPE was observed in the first passage, effect that decreased in the successive passages. The infected cell line was maintained in incubation for 4 to 7 days, depending of the integrity of the monolayer. The cell monolayer appeared torn and many cells changed their features become more rounded, these characteristics was increased in the following days. The viral confirmation was carried out through PCR and RT-PCR. In the present work was amplified and identified the inoculated viral agents, confirming the isolation of the three viruses used in this study. Each sample was tested for all of three viruses in order to avoid mixture strains. In many samples inoculated was not identified any of the three viruses, however CPE was observed, evidencing that there is no relation with the CPE and virus isolation. The CPE was not different between the three viruses, being difficult to identify which virus was isolated and determining the presence of only one of these viruses based uniquely on the occurrence of CPE. In case of these experiment was used samples with the virus isolated in chicken embryonated eggs where the presence of yolk, blood and fat may be influencing in the presentation of abnormal effects in the cells. The results showed in the present work demonstrate the isolation and propagation of CAstV, ANV and ChPV in the VERO cell line, being the first isolation of these viruses in this kind of cell line and in Brazil. These findings suggest also that the VERO cell line provide a novel host system for the isolation of these enteric viruses.