Evaluation Of Bivalent Inactivated Infectious Bronchitis Viral Vaccine Prepared From Local Isolates

Infectious Bronchitis (IB) is currently one of the most important diseases in poultry flocks all over the world causes huge economic losses in poultry industry. Many IBV outbreaks associated with respiratory distress, nephropathy, and high mortalities were attributed to the circulation of new nephropathogenic IBV variant 2 strains. This study was conducted to development of  bivalent inactivated IBV vaccine by using the local classical and variant isolates (KP279995/2014 and KP279998/2014 respectively) which isolated from poultry farms in Egypt as previous surveillance study during IBV outbreak from Al-Sharkia and Al-Qalubia governorates. The locally prepared vaccine formulated by using formalin for inactivation and MontanideTM  ISA71 RVG as oil adjuvant. The prepared bivalent inactivated (IBV) vaccine was tested for sterility, safety and potency, the efficacy of the prepared vaccine was applied in specific pathogen free chicks (SPF) for monitoring the antibody titers by using of Enzyme Linked Immuno Sorbent Assay (ELISA) post vaccination with estimation of shedding parameters by Real-Time RT-PCR in challenging birds with 104.5EID50/dose challenge IBV strains (classical and/or variant). The results revealed that the prepared vaccine free from any bacterial or mycotic contamination also safe after double dose inoculation in SPF chicks. The efficacy of inactivated vaccine showed from 92% to 96% protection against homologous challenge based on assessment parameters. This confirms that poultry industry can be protected from IB disease if using locally isolates in preparing of inactivated vaccine which reduce the economic losses caused by IB infection viruses in Egypt.