Antigenic Relatedness of Highly Virulent Infectious Bursal Disease Viruses Isolated From Different Regions of Turkey

Authors: Olcay TÜRE, Fethiye ÇÖVEN, Sabahattin İÇiN

Abstract: Antigenic relatedness of 4 highly virulent infectious bursal disease viruses (Agean: G34, G35; Marmara: G41; Central Anatolia: ETL3) isolated from infectious bursal disease outbreaks that occured during 1990's in Turkey were investigated compara-tively with the reference serotype 1 classic D78 strain, variant E (Ev) and serotype 2 OH viruses by cross virus neutralization (VN). Antigeanic relatedness values (R) for all the viruses were calculated from geometric mean antibody titers of minimum of three tests. Cross-neutralization studies indicated that there are 2 antigenic sub-groups exist among the regional highly virulent viruses. G34, G41 and ETL3 strains that were isolated from clinical cases were found to be antigenically very similar to standard D78 strain and classified as one sub-group. These same isolates were found to be antigenically distinct from Ev. The G35 which was isolated from a subclinical infection was classified in another sub-group, because it was different antigenically from D78, G34 and ETL3, but on the other hand closely related to G41. No neutralization was detected between the serotype 2 OH virus and the very virulent field viruses or the reference serotype 1 viruses. According to the results of this study, the majority of the highly virulent viruses causing acute disease outbreaks in Turkey were found to belong to classic antigenic group and no real antigenic variant infectious bursal disease virus was detected.

Keywords: Highly Virulent IBDV, Cross-VN, Antigenic Relatedness, Subtypes.

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