Detection and Identification of Infectious Bursal Disease Virus in Broiler Farms in Sulaimani Province

Abstract

The bursal Infectious disease (IBD) is an acute and highly contagious viral infection of immature chickens. A total of 76 poultry farms in areas around Sulaimania region was sampled to investigate the infection with the infectious bursal disease in broiler chickens. Out of 76 poultry farms, 28 (36.8 %) were infected with IBD during the period from October 2012 to March 2013. The significant clinical symptoms were a sudden drop in feed and water consumption, severe depression, watery white droppings and high mortality, at necropsy, there are hemorrhages in leg muscles, degeneration of the pectoral muscle, white mass (urate deposit) in the kidneys and cloaca are frequently observe during a post-mortem examination. Also, hemorrhagic & swollen bursa filled with strawcolored fluid was identified in few cases. Histopathology revealed hyperplasia of the reticuloendothelial cells and expansion of interfollicular connective tissue with edema of the affected bursa of Fabricius. The nucleotide sequence of Sulaimani IBDV isolates showed %99 homology and they also showed %96-%99 similarity with other IBDV strains. Regarding phylogenetic tree, construction based on the VP2 hypervariable region of IBDV nucleotide sequence alignment of the 16 genomes. IBD virus was divided into two general groups, namely Very virulent 1 (VVI) and Very virulent two (VVII). The topology of the tree indicated that the field isolates Sulaimania 01, 2012 and Sulaimania 02 2012 belong to very virulent IBDV strains that contain Indian and Egyptian Isolate. An outbreak of infectious bursal disease affecting 20-45 days old broiler chickens was investigated for the first time in Sulaimani region. This research is the first occurrence of infectious bursal disease in Sulaimania region/Iraq by RT-PCR.