Improved vaccine strategies of infectious bronchitis disease to reduce shedding of virulent virus from infected birds

 

Inventors: Teacher Dr. Mushtaq Talib Bakr al-Zuhairi/Department of poultry diseases, College of veterinary medicine, University of Baghdad

Abstract

For the first time in Iraq prepare and evaluate multivalent inactivated infectious bronchitis (IB) Vaccine from the different local isolated strains. The aims of this study was to prevent and control IB and to reduce the economical losses due to this disease in broilers and layers. Prepared effective IB vaccines from any IBV strain stimulates the immunity widely against morbidity and mortality after challenge with virulent IBV strains. On the other hand, vaccinates with live IBV vaccines do not reduce infection or viral shedding after challenge. In order to compare the prepared IBV vaccines taken four different IBV genotypes all processes were conducted according to the world standard protocol of oil emulsified vaccine including, type of emulsion, viscosity, stability safety and potency to determine stimulating immunity and the amount of viral shedding after challenge, two hundred fifty one day broiler chicks divided into five groups and vaccinated with oil-adjuvant vaccines prepared of Iraqi isolates (I-I, I-II, I- III and I-IV). different inactivated IB viruses including strains QX, CH Baghdad M 2014, CH Baghdad F1 2013, CH Babylon F2 2013, and an allantoic fluid control. Using a hemagglutination inhibition test for serum analysis after challenge with virulent IBV (Variant2) to knowledge antibody content against each of the vaccine antigens, Monitored the vaccinated birds daily for of morbidity and mortality were recorded, and used PCR to determine the amount of viral copy of examined clinical samples in selected periods of viral shedding. All vaccines used in the study gave good protection against morbidity and mortality, except the control group. Homologous vaccines gave good protection and lowest viral shedding in the trachea, kidney and feces compared to the heterogeneous vaccines.