title: Characterization of Egyptian field strains of infectious bursal disease virus.
abstract: The reverse transcriptase-polymerase chain reaction/restriction fragment length polymorphism (RT-PCR/RFLP) technique was used for identification and characterization of Egyptian field strains of infectious bursal disease viruses (IBDVs) that caused severe outbreaks with (30%-60%) mortality rate. Twenty-four bursal samples collected from 24 field outbreaks in commercially reared chicken flocks experiencing signs typical of infectious bursal disease (IBD) were used. Ten of the bursal samples examined were determined to contain IBDV as evidenced by amplification of a 743-bp region of the VP2 gene of IBDV by RT-PCR. The RT-PCR products of the detected viruses were characterized by digestion with three restriction enzymes, BstN, MboI, and SpI. Three different RT-PCR/RFLP profiles were observed. Seven of the detected viruses had RFLP profiles identical to the very virulent European strains of IBDV (vvIBDVs). One virus had a RFLP profile identical to the U.S. classic vaccine strain, and one virus had a unique RFLP profile. The clinical history of the outbreaks and the presence of the SspI site in the 743-bp RT-PCR fragment were the criteria for designating the viruses as belonging to the very virulent (vv) phenotype.
authors.affiliation: Department of Poultry Diseases, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt 12211.
authors.forename: Gomaa
authors.initials: G
authors.lastname: Abdel-Alim
authors.forename: M H H
authors.initials: MH
authors.lastname: Awaad
authors.forename: Y M
authors.initials: YM
authors.lastname: Saif
mesh_terms: D001483:Base Sequence; D018175:Birnaviridae Infections / Q000453:epidemiology / Q000401:mortality / Q000662:veterinary*; D004196:Disease Outbreaks / Q000662:veterinary; D004534:Egypt / Q000453:epidemiology; D007243:Infectious bursal disease virus / Q000145:classification* / Q000302:isolation & purification; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012150:Polymorphism, Restriction Fragment Length; D011201:Poultry Diseases / Q000453:epidemiology / Q000401:mortality / Q000821:virology*; D015183:Restriction Mapping; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary