الفهرس 
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Abstract
Avian infectious bronchitis disease is one of the most common respiratory viral diseases of poultry. IBV is still epidemic in many countries in spite of extensive vaccination due to the continual emergence of new variants. For this reason, the characterization of virus isolates existing in the field is very important.
In this study virus isolation is made by passage the samples in 9-day-old embryonated specified-pathogen-free chicken eggs via the allantoic route. PCR gave ten positive IB samples. Four of the isolates were subjected for sequencing .We report isolation of an Egyptian IBV isolate; IBV/KFS/2016, IBV/KFS2/2016 ,IBV/KFS3/2016 and IBV/KFS4/2016 . S1 sequence analysis of IBV/KFS/2016 revealed its close relatedness to IB VAR2-06 while IBV/KFS2/2016, IBV/KFS3/2016 and IBV/KFS4/2016 may be emerged from the vaccination or the challenge virus was too virulent for the level of immunity produced by vaccination.