Phylogenetic analysis comparing partial S1 gene of avian infectious bronchitis virus to commercial vaccine strains in Iran
2015
Hashemzadeh, Masood | Masoudi, Shahin | karimi, vahid | Shoshtari, Abdol Hamid | Ghalyanchi-Langeroudi, Arash | Mahmoodzadeh, Mohsen
BACKGROUND: Infectious bronchitis is a highly contagious disease which may cause poor weight gain and low feed efficiency in infected chickens. There are a large number of reported serotypes/genotypes, which makes the control of the disease more difficult through vaccination. However, there are only a few amino acid differences in the S1 protein of vaccine and wild type strains which are responsible for protection. OBJECTIVES: The purpose of this study is to compare IBV variants isolated from commercial chicken flocks in Iran with currently used vaccine strains. METHODES: The partial S1 gene of the spike protein, covering a hypervariable and constant regions, was amplified and sequenced using conventional RT-PCR. RESULTS: Phylogenetic analysis of amino acid sequences revealed that eight of total nine isolates were divergence at least 21.8% from vaccinal Massachusetts serotypes, and six of nine isolates were divergence at least 22.7% from 4/91, and none of the nine isolates were similar to Dutch-type, D274,vaccine serotypes. CONCLUSIONS: These findings are essential for continuous surveillance disease control strategies and monitoring of variants, and thus emphasize on the importance of improving the vaccination program in Iran.
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