Molecular epidemiologic survey of infectious bursal disease viruses in broiler farms raised under different vaccination programs

Abstract

SUMMARYOver a span of nearly 4 yr, 246 bursal tissue samples were collected from Brazilian commercial broiler flocks (Gallus gallus) throughout the country and imprinted to sample collection cards (Flinders Technology Associates (FTA) cards). A total of 75 infectious bursal disease virus (IBDV) strains was successfully detected from the FTA card imprints and were submitted for further identification and molecular characterization. Nucleotide and predicted amino acid sequences of the IBDV surface protein VP2 were used to identify strains of the virus and place them into phylogenetic groups. The amino acids across the hypervariable region of VP2 in this study varied, but around half of all positive samples were classified as vaccine virus. The IBD viruses fell into 3 categories: variant IBDV, classic IBDV (vaccine), and very virulent (vv) IBDV. The samples were collected according to the 3 different vaccination strategies used in broilers: vectored vaccine, antigen-antibody complex vaccine, and conventional live vaccine. The genetic profile and frequency of the strains recovered from the flocks were highly dependent on the vaccination program. This information helps us gain a better understanding of the current landscape of IBD in Brazil and provides additional scientific data to support selection of the most effective vaccination strategies, products, and practices to prevent disease.

Genetic Diversity of Recent Infectious Bursal Disease Viruses Isolated From Vaccinated Poultry Flocks in Malaysia

“…Virus identification is usually achievable by sampling, detecting, and sequencing the immunodominant region of the virus. Several studies have reported the evolution of IBDV in some geographical locations around the world with the emergence of an antigenic variant (20,21) and recombinant (22), reassortant (23,24), and distinct (25,26) strains of the virus. These isolated strains of IBDV with diverse antigenicity have made vaccination programmes against IBDV more complex due to vaccine failure.…”

Histopathology and Serology Reaction to an Immune Complex Infectious Bursal Disease Vaccine (V877 Strain) in SPF and Commercial Birds

“…The analysis of the histopathological scores between the two experiments, SPF vs commercial birds, showed that commercial birds exhibited more severe lesions in lymphoid follicles than SPF birds in final weeks of the trial. These findings are expected because, in addition to the effect of the vaccine stimulating seroconversion, there is also an ever-present field challenge from the birds' environment (MUNIZ et al, 2017). Generally, in both experiments, bursal lesions indicative of vaccine virus replication was slightly detected from day 14 to 28 onward, reaching a peak at 28 days, for both the s.c. or in ovo schedule.…”

“…Based on the degree of attenuation, these vaccines can be classified as mild, intermediate, intermediate plus or hot, which are the closest to field viruses (OIE, 2011). Nowadays, immune complex and vector vaccines, as well as conventional vaccines, are currently used in Brazil to control Gumboro disease (MUNIZ et al, 2017).…”

Ensuring the labor safety of workers at sanitary checkpoints of agricultural enterprises

“…The sanitary checkpoint and the disinfection complex as a whole are in a non-working condition (Figure 1). Before installing the disinfectant complex, it is necessary to carry out a number of measures to improve the internal state of the sanitary checkpoint -clean the room from clutter (food, rubble, garbage), carry out repairs, insulate the wires [5][6][7].…”