Methods for control of economically important viral diseases of poultry
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The U.S. poultry industry is the world's largest producer and the second largest exporter of broiler meat and a major egg producer. U.S. consumption of poultry meat is considerably higher than beef or pork. The poultry industry is also a major user of feed grain produced in U.S. and 18% of total poultry production is exported. The combined value of production from broilers, egg, turkeys and the value of sales from chicken in 2014 was 44.4 billion in 2013 (USDA, ERS data, 2015).Per capita consumption data from 2017 show that Americans consume 108.6 pounds of poultry per annum (National Chicken Council), but the beef consumption that peaked in the 1970s is currently at 56.9 pounds per annum. U.S. egg operation produced 105.6 billion eggs in 2017, and per capita consumption was 274 eggs per annum. Broiler, turkey and eggs are an important source of high-quality dietary protein.The total value of poultry and eggs produced in the state of Texas was estimated to be $2.6 billion in 2012. Nationally, Texas is ranked 6th in poultry production. Control of disease is vital to maintaining Texas as a leader in animal production. Like all other livestock, poultry are susceptible to various diseases caused by bacteria, viruses, mycoplasma and protozoa. But the viral diseases are the most important and have a major economic impact.The major focus of my research is on Marek's Disease (MD) and the development of novel vaccines to control economically important diseases of poultry. Diseases continue be a major threat to the poultry industry. Various pathogens that cause immune-suppression, cancer and respiratory diseases lead to high losses if not controlled successfully. The overarching goal of my research is to use the knowledge generated from the biology of MD virus, to develop novel vaccines that are capable of protecting poultry against economically important diseases. Marek's disease is a cancer-like disease in chicken leading to immunosuppression (15). The causative agent is a herpesvirus that is ubiquitous in the environment (7). This virus spreads through feather dust, so eradication of this disease is not practical in commercial flocks (14). Marek's disease is effectively controlled by vaccination, but the causative agent continues to mutate to greater virulence, resulting in reduced efficacy of the available vaccines (2, 13). My laboratory is focused on understanding how MD virus causes leukemia in chickens. By studying the genes involved in T-lymphocyte transformation, we will be able to genetically engineer viruses that are able to protect against highly virulent field strains of the virus.We are interested in using knowledge generated on MD biology to develop recombinant vaccines to control economically important diseases of chicken. More specifically, we are targeting economically important respiratory and immune suppressive diseases of chicken. We are using MD virus as a vector to develop next generation vaccine capable of protecting against highly virulent field viruses that are emerging (13). We are also exploiting this virus to develop a vaccine vector for delivery of protective antigens from other pathogens so that a single vaccine can confer protection against multiple diseases.Specific problems to be addressed over the next 5 years include: 1) How MD-infected chickens develop cancer-like disease of the lymphocytes; and 2) Improved vaccines and novel vectors for the control of economically important poultry diseases.