Sabini L, Zanon S, Lara L, Torres C, Sutil S, Rovera M, Ramos B

Language: English
References: 22
Page: 111-116
PDF size: 158.35 Kb.

ABSTRACT

There are no antigenic differences between known strains of Aujeszky’s Disease virus or the Pseudorabies virus (PV). The characterization of these viruses has been based on pathological and/or pathogenic aspects of the host. In this study, PV (RC/79 strain) virulence markers have been characterized based on their capacity to produce changes in monolayer cell cultures and by effects generated in experimentally infected rabbits. By analyzing the cytopathic effect induced on Vero cells by the virus, it was possible to visualize the formation of rounded-up cells at the beginning of the infection and later on the appearance of multinuclear or syncytial cells. Lysis plaques (4-5 mm) under agar had rounded, well defined borders. Studies carried out in cell cultures and experimental infections in rabbits showed the virulent nature of the RC/79 strain, for all cases studied. In this animal model intense pruritus was seen at the site of inoculation, with the appearance of a lesion exuding serum and blood from 6-24 h before death. For all cases, the mortality rate was 100%, even when smaller viral doses (102 PFU/ml) were used, which indicates that there was an absence of dose response. The rabbit marker was used to characterize the RC/79 strain of the PV as strongly virulent. This model could also be used in epidemiological studies to diagnose AD, differentiating between virulent and atte nuated strains. It represents a useful tool that can be used to assess naturally attenuated virulent isolates that are potential vaccine candidates. Furthermore, the rabbit model may be useful to determine the degree of attenuation in viral strains that have been submitted to laboratory modifications.

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