National Academy of Agricultural Sciences (NAAS)
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PRINT ISSN : 2319-7692
Online ISSN : 2319-7706 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcmas@gmail.com / submit@ijcmas.com Editor-in-chief: Dr.M.Prakash Index Copernicus ICV 2018: 95.39 NAAS RATING 2020: 5.38 |
The Erns gene (681 bases) of a live attenuated classical swine fever (CSF) cell culture Indian vaccine virus (IVRI-CSF-BS)was sequenced and had only three nucleotide changes compared to its parental virulent virus at passage 6 in cell culture. The vaccine virus had Thymine at 151 and Guanine at 184 and 638 positions instead of Cytosine and Adenine at respective places in p6 virus. Out of these three mutations, nucleotide changes at 184 and 638 positions resulted in amino acid changes from Lysine to Glutamic acid and Arginine, respectively. The Erns sequences of the vaccine virus were same as in the back passages up to passage 20. Further down at passage 15, the sequences were same except for Adenine at the 638 position, like it was in the p6 virus. Overall p15 had one amino acid change (Glutamic acid) and from p20 onwards, the viruses had two amino acid changes (Glutamic acid and Arginine). These changes were however not linked to virus attenuation, as the p20 virus produced fatal CSF infection in susceptible piglets. Additionally, the vaccine virus was phylogenetically more related to other CSF cell culture vaccine viruses derived from virulent CSF viruses than the lapinized vaccine viruses.
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