Restriction Fragment Length Polymorphism Analysis of Highly Virulent Strains of Infectious Bursal Disease Viruses from Holland, Turkey, and Taiwan

Abstract

Strains of highly virulent infectious bursal disease virus (HVIBDV) from Turkey (OA, OE), Holland (HOL), and Taiwan (PT, IL) were characterized by reverse transcriptase/polymerase chain reaction-restriction fragment length polymorphism (RT/PCR-RFLP) analysis and compared with the United States of America (USA) classic (STC) and variant (MD, IN) serotype 1 viruses and serotype 2 OH strain. A primer pair that amplified a 743-bp fragment of the VP2 gene was used. The RFLP profiles of the RT/PCR products were determined with four restriction enzymes (SspI, BstNI, MboI, and StyI). The SspI enzyme distinguished the HVIBDVs from the USA classic and variant viruses and the serotype 2 virus. The USA serotype 1 viruses used in this study did not have restriction sites for SspI in the 743-bp VP2 fragment. The RFLP profiles of the five HVIBDVs when digested with BstNI were different from the USA classic STC virus but were similar to the variant viruses (MD, IN). The RFLP profiles for isolates from Turkey and Holland were similar to the classic STC strain when digested with MboI but were different from the variant USA viruses (MD, IN). The RFLP profiles of the two Taiwan isolates were different from the Holland, Turkey, and USA classic and variant viruses when digested with MboI. When the five HVIBDVs were digested with StyI enzyme, their RFLP patterns were similar to those of the USA classic STC strain but were different from the USA variant viruses. None of the strains tested had patterns similar to serotype 2 OH virus.