Prevalence of avian infectious bronchitis virus in broiler chicken farms in south of Iraq, 2014 - 2015

Abstract

Avian infectious bronchitis (IB), caused by a gammacoronavirus, is an OIE-listed (List B) disease and characterized by respiratory and renal involvements, causing high mortality, and economic loss in both layers and broilers. In comparison with other diagnostic methods, real-time polymerase chain reaction (RT-PCR) and conventional RT-PCR are potent, more sensitive and faster techniques for infectious bronchitis virus (IBV) detection. This research was conducted to detect IBV using specific primers of IB in three governorates (Basra, Thi-Qar and Muthana) in the south of Iraq. Tracheal specimens were collected from 46 IB suspected commercial broiler flocks. XCE2+ and XCE2- Primers, which amplify all IBV serotypes, were used. Primers MCE1+, BCE1+ and DCE1+ were used to amplify the specific nucleotide sequences of Massachusetts, 793/B and D274 genotypes, respectively. The results of real-time RT-PCR of this study showed that 34 (74.00%) out of 46 infected flocks were positive to IBV. The results of nested PCR showed that 50.00% and 5.89% of positive samples were belonged to genotypes 793/B and Massachusetts, respectively, and the remaining positive (44.11%) were unknown. The results indicate presence of Massachusetts and 793/B IBV strains in commercial broilers in southern Iraq.

Keywords: Avian infectious bronchitis; Broiler; Iraq; Real-time RT-PCR.

Fig. 1

Distribution of positive IBV samples including 793/B, Massachusetts and unknown strains in the broiler farms of three governorates in the south of Iraq

Fig. 2

Electrophoresis (2% agarose gel) for infectious bronchitis virus (IBV). Lane M: 100 bp – 1000 kbp DNA ladder marker; Lane 1: Massachusetts (positive control; band at 295 bp); Lane 2: Positive control (793/B; band at 154 bp); Lanes 3: Negative control; Lane 6, 7, 8: 793/B (positive samples); Lanes 4 and 9: Massachusetts (positive samples); Lanes 5 and 10: Negative samples