Project Number: 3040-32000-034-00-D
Project Type: In-House Appropriated
Start Date: Jan 3, 2017
End Date: Jan 2, 2022
Objective 1. Elucidate host response associated with the bovine respiratory disease complex (BRDC) and protective immunity, including discovering genetic and biological determinants associated with bovine respiratory disease susceptibility, tolerance, or resistance, and discovering genetic and biologic determinants associated with good responders to bovine respiratory disease vaccines. Sub-objective 1.A: BVD viral infections play an integral and complicated role in BRDC. Current available technology for preventing BVD virus infection includes vaccination, biosecurity, and the elimination of persistently infected cattle. However, if available, genetic selection for animals less likely to become persistently infected would facilitate control and eradication of BVD. The proposed research will test for genetic risk factors associated with BVD virus infection. Sub-objective 1.B: Ovine progressive pneumonia is one of the most economically important diseases in sheep. A major gene TMEM154 was recently discovered that influences susceptibility to OPP in sheep. However, there are no ovine cell lines with defined TMEM154 diplotypes available to study OPP virus infection in vitro. The proposed research will develop cell lines to enable the study of TMEM154 variants in OPP virus infection.S Objective 2. Develop genomics-based strategies to control respiratory diseases of ruminants, including identifying antibiotic-resistance genes and other virulence determinants of bacteria that associate with increased BRDC severity, and developing intervention strategies to reduce antibiotic use and BRDC severity based on genetic typing of bacteria and cattle. Sub-objective 2.A: M. haemolytica of North America place into two major genotypes (1 and 2). Genotype 2 associates with BRDC and genotype 1 does not. The proposed research will identify genomic determinants specific to genotype 2 that may lead to intervention strategies that reduce the incidence of BRDC caused by genotype 2 M. haemolytica. Sub-objective 2.B: Current interventions for BRDC in beef calves include vaccination and metaphylactic use of antibiotics. However, if we had knowledge of the disease-causing potential of nasopharyngeal bacteria in calves, alternative interventions could be designed to reduce the impact of BRDC outbreaks. The proposed research is designed to identify genetic and biological determinants that may influence the disease-causing potential of nasopharyngeal bacteria. Sub-objective 2.C: BCV is involved in the etiology of three distinct clinical syndromes: calf diarrhea, winter dysentery with hemorrhagic diarrhea in adults, and respiratory infections in cattle of all ages. The biological mechanisms underlying disease presentation and variation in their severity are not well understood. The proposed research will determine the influence of serum antibodies, virus strain, and co-infection with other respiratory pathogens on BCV disease presentation and severity of disease.
Infectious respiratory diseases of ruminants are a serious health and economic problem for U.S. agriculture. In cattle alone, the costs of bovine respiratory disease complex (BRDC) exceed one billion dollars annually. Therefore, this research focuses primarily on BRDC with an additional component targeting ovine respiratory disease. Our project vision is to reduce the prevalence and severity of respiratory diseases, thereby promoting livestock welfare, enhancing producer efficiency, and reducing antibiotic use. BRDC is a multi-component disease caused by complex interactions among viral and bacterial pathogens, stress and environmental factors, and host genetics. Consequently, we have developed a multi-component approach focused on the host-pathogen interface to study respiratory disease. On the host side, a genome-wide association study will test for genetic risk factors for bovine viral diarrhea (BVD) virus susceptibility. On the bacterial pathogen side, genomics combined with phenomics will identify the spectrum of genetic determinants of M. haemolytica and other bacteria that associate with BRDC. On the viral pathogen side, genomics combined with serology, and microbial diagnostic testing will determine the contribution of bovine coronavirus (BCV) to BRDC. Lastly, novel ovine cell lines will be developed to test host and virus genetic risk factors for ovine progressive pneumonia (OPP). The knowledge gained from this research will be valuable for developing new intervention strategies for controlling BRDC and producing healthier livestock, and could ultimately benefit animals, producers, veterinarians, diagnostic laboratories, pharmaceutical companies, genetic testing laboratories, and regulatory agencies.