Authors: OLCAY TÜRE, FETHİYE ÇÖVEN
Abstract: Infectious bursal disease (IBD) field viruses were isolated from the bursa Fabricius (BF) materials collected from the IBD infected or suspected flocks in different geographical regions of Turkey during 1992-1994. The field viruses were adapted to embryonated spesific-pathogen-free (SPF) eggs and chicken embryo fibroblast (CEF) cell cultures by serial blind passages and characterized by virus neutralization test (VN). In this study, out of 60 BF samples that were diagnosed positive for IBDV by agar gel precipitation (AGP) test, only 20 isolates adapted and grew in CEF cell cultures and showed cytopathic effect (CPE) typical to IBDV. During further characterization of the 20 isolates, it was noticed that these isolates were mixed with other viruses which have CPE characteristics similar to IBDV. A series of tests, such as hemaglutination (HA), chloroform susceptibility, IUDR (5'iododeoxyuridine) inhibition, adsorption with Reovirus antiserum were performed in order to sepearate IBDV from mixed viruses. As a result of this study, 10 field IBDV viruses were isolated. Characterization studies carried out by VN test using the reference antisera to serotype 1 group classic D78 strain, variant E (Ev) and serotype 2 group OH strain indicated that, 10 field viruses belonged to serotype 1 group. No antigenic relationship was detected between the serotype 2 group and the field viruses. This study provided information on the serotypes of the IBD viruses that caused great economic losses to the poultry industry in Turkey in recent years, and also provided 10 IBD Turkish isolates that can be used as reference viruses in later studies.
Keywords: Turkish IBDV, Very Virulent, Isolation, Serotyping, VN.
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