Identification of a novel nephropathogenic infectious bronchitis virus in Israel

A novel infectious bronchitis variant, designated as IS/885/00, associated with nephritis, was isolated from outbreaks in 23 broiler farms in Israel. The virus was first identified by reverse tran scriptase-polymerase chain reaction and showed a distinct restriction fragment length polymorphism pattern from previously described Israeli isolates. Sequence analysis of the S1 gene and the deduced amino acid sequence revealed 97.2% protein similarity to genotype IS/720/99 and 71.6% similarity to the vaccine strain HI 20, the only strain permitted for use in this country. A database search in GenBank revealed a closely related isolate from Egypt, Egypt/Beni-Seug/01, with 96.6% similarity. Other published nephropatbogenic infectious bronchitis virus strains/isolates shared less than 77% similarity with IS/885/00. A vaccine protection test ill specific-pathogen-free chicks indicated 91% protection to the trachea and only 25% protection to the kidneys in vaccinated birds challenged with IS/885/00.