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Abstract

Objective: This study was carried out to find the progressive
cellular changes developed in cell culture with cytopathic (cp) and
noncytopathic (ncp) pestiviruses isolated from cow and sheep. Design: Observational study. Procedure: Following inoculating the R-BK cell cultures in Lighton tube with NADL strain of BVD, a cp strain of Border disease virus
and a nocytopathic BVD, the cells were stained with FA and
observed with IF microscope. In inoculated cultures with cp and
ncp pestivirus obvious changes were present at the first day and multiple focal expression of viral antigens were seen. Results: In the second day in cp inoculated cultures, the
morphological changes began and antigenic spread were more
intensive. In the 3rd day the CPE foci were seen in different parts
of the cultured cells with high concentration of antigen around the CPE sites. The cells started to detach and became rounds and finally in the 4th and 5th day, almost all cells were antigen positive and
developed CPE. However, those cultures inoculated with noncytopathic
strain of BVD, in daily observation the antigenic spread was too
slow and up to 6 days post inoculation no CPE were observed.

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