"Live IBD vaccine exacerbates disease and pathological effects of Asian lineage H9N2 LPAIV in chickens."

Avian Pathol. 2023 Jul 13:1-25. doi: 10.1080/03079457.2023.2236994. Online ahead of print.ABSTRACTAvian influenza H9N2 is one of the most circulating viruses in numerous Egyptian poultry farms. The Asian lineage H9N2 exhibits an immunosuppressive effect, and its pathogenicity is amplified when it co-infects with other pathogens, especially with the immunosuppressive infectious bursal disease virus (IBDV), resulting in increased mortality rates. Both vaccines and field infection can exacerbate the pathogenicity of H9N2, particularly in the bursa of Fabricius (B.F), causing more significant lymphoid depletion. To comprehend the impact of the IBD vaccine on the viral and pathogenic effect of H9N2 infection in specific pathogen-free chicks (SPF), the experiment was designed as four groups; group-1 served as the control negative, group-2 received (228E) IBD vaccine, group-3 was challenged with H9N2, and group-4 was vaccinated by the IBD vaccine then challenged with H9N2. The clinical signs, relative immune organs' weights and histopathological lesion scores were recorded. The tracheal and cloacal H9N2 viral shedding were also measured. Group-4 exhibited a significant decrease (P≤0.05) in the relative bursal weight and an increase in the bursal lesion score when compared with groups (1&3) at 4, 8th day post challenge (DPC). The tracheal lesion score of group-4 recorded a significant increase when compared with groups (1&3). The renal lesion score of group-4 achieved a sig...

Source: Avian Pathology - July 13, 2023 Category: Pathology Authors: N W Khalil M A Elshorbagy E M Elboraay A M Helal Source Type: research