Genetic and Pathological Characterizations of Gumboro (IBD) in Chickens

Gumboro, or infectious bursal disease (IBD), represents a significant threat to poultry worldwide due to its genetic and pathogenic variations. Viruses can mutate and produce new variants, which can have an impact on the epidemiological situation. The study will determine and assess the genetics, protein sequence, and pathogenicity of IBDV present in broiler flocks in different locations within Ismalia and Dakahlia Governorates, Egypt, in 2022. A total of 150 bursa samples were collected from 15 broiler flocks exhibiting symptoms indicative of IBDV infection. The VP2 (viral protein2) gene was partially detected and then subjected to complete gene sequencing in order to summarize the key genetic mutations found and histopathological examination. The results demonstrated that 12 out of 15 farms were infected with IBDV. Genetic analysis revealed that 10 of the 12 identified strains belonged to genogroup 3, which was similar to previous Egyptian strains. The remaining two strains were of genus 1. The VP2 gene's hypervariable region displayed amino acid alterations at several positions. Classic IBDV strains (genogroup 2) showed similar amino acid profiles. Amino acid alterations were identified in the VP2 gene, indicating that classic IBDV strains may cause damage to the bursa of Fabricius, leading to immunosuppression. In Egypt, vvIBDV (very virulent infectious bursal disease virus) strains have led to recurring outbreaks and high chick mortality rates. These findings are anticipated to contribute to the latest features of IBDV in the examined regions. Therefore, it is recommended that IBDV immunization programs in Egypt, where live attenuated virus vaccinations are common, be reevaluated. It is also recommended that the evaluation of clinical signs in broiler chicken flocks over time be monitored for diagnosis.