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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Endemic Poultry Viral Diseases Research » Research » Research Project #443180

Research Project: Enhancing Genetic Resistance and Vaccinal Response to Control Marek’s Disease, Infectious Laryngotracheitis, and Infectious Bursal Disease in Chicken

Location: Endemic Poultry Viral Diseases Research

Project Number: 6040-31320-011-000-D
Project Type: In-House Appropriated

Start Date: Aug 2, 2022
End Date: Aug 1, 2027

Objective:
1. Enhance chicken genomic resources to support genetic selection, immunological efforts, and other strategies to reduce poultry diseases. 1.1. Enhance the chicken genetic map and its integration with the genome assembly. 1.2. Develop complete T cell receptor (TCR) sequences for various haplotypes. 2. Genetic and epigenetic characterization of Marek’s disease (MD) resistance and vaccine protective efficacy. 2.1. Identify specific alleles in cancer driver genes associated with MD genetic resistance. 2.2. Determine if MD genetic resistance contributes to Marek’s disease virus evolution to higher virulence. 2.3. Determine if DNA methylation of specific genes is associated with MD vaccination response and efficacy. 2.4. Define the role of specific viral miRNAs on Marek’s disease virus (MDV) transmission and vaccinal protection. 3. Identify specific immune response genes that confer resistance to Marek’s disease (MD) or improves vaccinal response. 3.1. Determine the role of interleukin-10 (IL-10) on MD genetic resistance. 3.2. Determine the role of TCR diversity in the MD vaccinal response. 3.3. Validate viral genome polymorphisms associated with the ability of the virus to escape immune surveillance. 4. Determine if there is a host component for resistance to infectious bursal disease (IBD) or infectious laryngotracheitis (ILT). 4.1. Determine if lines that vary for MD genetic resistance or major histocompatibility complex (MHC) haplotype influence IBD or ILT disease incidence. 4.2. Determine if host genetics differentiates IBD vaccinal protection. 4.3. Determine if host genetics contributes to ILT vaccinal protection efficacy.

Approach:
Poultry is the fastest growing and most consumed meat both in the U.S. and globally. To achieve economic efficiency, birds are raised at very high densities. Since these conditions promote the spread of infectious diseases, the industry relies heavily on biosecurity and vaccines, if available, for disease prevention and control. Marek’s disease (MD), infectious laryngotracheitis (ILT), and infectious bursal disease (IBD) are three poultry viral diseases of high relevance. A common theme to all these diseases is that while current control measures are able to control disease incidence for the most part, the increasing recurrence of outbreaks in vaccinated flocks and the emergence of new field strains strongly suggest that improved or alternative control strategies are needed for long-term and sustainable disease prevention. This project focuses on host genetics for achieving long-term disease control. Herein we have identified four objectives to help achieve this goal, and to provide basic and applied knowledge to reduce diseases incidence as well as improving overall animal health and welfare. First, we continue to provide critical genomic resources. Second, using various genomic and molecular approaches, we identify specific genes or epigenetic modifications that are associated with MD genetic resistance. Third, we identify specific immune response genes that confer resistance to MD or improve vaccinal protection. And fourth, we will advance our knowledge of vaccine efficacy against infectious diseases that is attributable to genetics and epigenetics, which will greatly empower science-based vaccine design and development. If successful, this project will provide (1) a more complete genetic map that will aid in improving the chicken genome assembly, (2) candidate genes and pathways conferring MD resistance or vaccinal response for evaluation in commercial breeding lines, and (3) knowledge on how to reduce ILT and/or IBD disease incidence. Ultimately, both the poultry industry and US consumers will benefit from the production of safe and economical poultry-based products.