Duration: 10/01/2006 to 09/30/2011

Administrative Advisor(s):

NIFA Reps:

Non-Technical Summary

Statement of Issues and Justification

Bovine respiratory disease (BRD) continues to be the most costly disease problem facing the cattle industry. In cattle, respiratory disease occurs as a complex caused by a variety of bacteria and viruses, and exacerbated by management practices. The BRD complex results in losses estimated as high as $3 billion to the US cattle economy annually(29,33,45). One specific example of the importance of this problem is that the Academy of Veterinary Consultants has called for a plan to eradicate bovine viral diarrhea virus (BVDV), a major contributor to BRD(34). The BRD complex has been identified by producers as the leading cause of morbidity and mortality in feedlot cattle(59), and the leading cause of death of weaned dairy heifers(60). A changing agriculture landscape driven by globalized agricultural markets and consumer demand is forcing a changing paradigm in how we manage cattle and their disease, as well as increasing the chances for emergence of new bovine respiratory disease pathogens. Thus research using cutting edge approaches to the identification, treatment, and prevention of disease is needed to allow U.S. cattle producers access to the most current strategies to attack BRD and allow them to maintain a competitive advantage in the global marketplace.

Continued research on the nature of factors that put cattle at risk for significant respiratory disease and on the pathogenesis of single agent and multi-agent respiratory diseases is needed. Currently available diagnostic tests and vaccines have limited effectiveness. This is of increasing importance with increased pressure to remove antibiotics from routine management and greatly restrict their use in cattle. Efficient and cost effective diagnostic methods for identification and control of pathogens in the production setting, and management tools that optimize the development of immunological responses to limit infection and disease, must be developed. Failure to develop new monitoring and prevention strategies will result in increasing economic losses to U.S. cattle producers, and increasing animal suffering due to morbidity and mortality associated with respiratory disease.

The committee will consist of a team of researchers with a broad range of experience with the techniques necessary to undertake the research. The scope and complexity of bovine respiratory disease is great. Participating researchers possess the necessary contemporary skills in molecular biology, immunology, virology, bacteriology, and animal management to develop integrated diagnostic and preventative strategies. For example: researchers from LA are part of a center that has developed methods to prepare viral strains optimized for expression of antigens as part of a large system-wide program. They are developing a DNA based bacterial artificial chromosome (BAC)to optimize expression of bovine coronavirus antigens in new vaccines. Others at LA have established models to test the efficacy of antibiotic treatment protocols and use of gene-engineered vaccines in control of BRD. The group from SD has conducted comparative assessment of several methods for diagnosis of bovine viral diarrhea virus and established a system for assessment of maternal vaccination for fetal protection, in conjunction with workers from AL, that has allowed vaccine manufactures to establish claims of fetal protection. These workers have also developed models to assess the interaction between BRD viral agents and the innate immune system of cattle. Researchers from OK have run collaborative trials with workers from several stations of management systems for birth to market reduction in BRD mediated losses. This group has established production level systems for assessment of impact on treatment cost and meat yield/quality as outcomes of their work. TX has provided leadership in the epidemiology of BRD to the committeee. They have also developed production level systems for assessment of vaccine and metaphylactic methods to control BRD, and have determined the effect of BVD persistently infected (PI) cattle on animal productivity in feedlots. GA has worked in the areas of neonatal immune development, vaccine assessment, retained ownership based production level studies of management programs and feedlot AIP/ARDS. They collaborate with SD and others in the assessment of inflammatory function as a pathogenic mechanism in BRD losses and are establishing systems for production scale assessment of inflammation control in management of BRD problems. The group from MI has provided leadership in the application of sensor technology to diagnostic monitoring of BRD agents. CA has provided leadership in the study of polymicrobial disease and the role of type 1 hypersensitivity in BRD. They have established systems that will allow development and production level implementation of new vaccines needed to control BRD in the emerging environment. MN, NADC, IA, MS, and WI have provided leadership in understanding the pathogenesis of bacterial agents involved in BRD. Their work is defining the basis for the next generation of vaccines and management programs to control BRD. KS and NE have established systems that will allow the production of marker vaccines for herpesviruses important to BRD and developed techniques necessary to characterize mechanisms of latency and reactivation by bovine herpesviruses, important to control of BRD. Members of the team have also demonstrated dedication to education of stakeholders, by presenting a Symposium on BRDC at the 2001 Winter Meeting of the Academy of Veterinary Consultants, and by contributing to a new reference on BVDV (Vet Clin N Am, Food Animal, 2004;20:1, "Bovine Viral Diarrhea Virus: Persistence is the Key"); this volume was edited by a member of the Technical Committee of the current project, and 6 of 12 chapters were authored by project members.

Committee members also have relationships with stakeholders in veterinary practitioner groups and cattle producer organizations that will allow communication of new strategies developed by the committee to individuals on the front line of the battle against bovine respiratory disease.
The advantage of doing the work as a multistate effort is that we have a documented capacity to interact productively to address the issues critical to minimizing the impact of bovine respiratory disease. We have a history of extending collaborative research outside the bounds of the current and past NC projects into other research and application programs, including proof of concept studies to drive the adoptions of methods to reduce the impact of BRD. Moreover, the impact of bovine respiratory disease crosses state lines. Factors that predispose animals to respiratory disease in one state impact producers who receive the animals after shipment to another state. The ability of scientists from various states to bring their perspectives to a coordinated group attack on the problem of bovine respiratory disease will result in a more balanced and effective approach than would be possible by any state working in isolation.

Likely impacts from successfully completing this work:

• Scientific tools for undertaking a BVDV eradication program as proposed by the Academy of Veterinary Consultants will be put into place; these tools will allow producers to identify and remove persistently infected (PI ) cattle more efficiently and with less expense, minimizing production losses due to BVDV and the associated financial impact.
  
• A greater understanding of the major virulence mechanisms of Mannhemia haemolytica, Mycoplasma bovis, Pasterurella multocida and Histophilus somni will be developed, allowing distribution of novel therapeutic and intervention strategies to veterinarians and cattle producers, improving efforts to minimize morbidity, mortality, and financial loss due to these agents.
  
• The characteristics of a safe and effective immune response to bovine respiratory syncytial virus (BRSV) and BVDV will be determined, allowing the development of vaccines that prevent, but do not enhance, disease due to these agents. This will provide producers with tools to decrease disease without the concern of inducing unwanted harmful side effects.
  
• Improved understanding of the molecular pathogenesis of bovine herpes virus (BHV-10, bovine coronavirus (BC), BVDV, and BRSV will be established, leading to the development of strategies to mitigate the effects of infection by these agents. Because these pathogens are widespread contributors to BRD in U.S. cattle, improved animal health and attendant financial gains will be recognized by producers and veterinarians who utilize updated approaches to control of these agents.
  
• Knowledge of how current management practices contribute to the development of bovine respiratory disease will be disseminated to veterinarians and cattle producers so that effective management changes can be put into place to decrease the morbidity, mortality, and financial loss that accompanies BRD.

Related, Current and Previous Work

Bovine respiratory disease (BRD) is a preeminent among disorders causing morbidity, mortality, and financial loss to the U.S. cattle industry. In cattle, respiratory disease occurs as a complex caused by a variety of bacteria and viruses, and exacerbated by certain management practices. Recent NAHMS surveys confirmed that BRD is the leading cause of morbidity and mortality in U.S. feedlots(59), and that BRD is the most common cause of weaned dairy heifer mortality(60). Current estimates indicate that the BRD complex results in losses of up to $3 billion to the US cattle economy annually(29,33,45). BRD has been confirmed to decrease productivity of cattle of a variety of production classes(43,54,62); other costs are related to animal death, loss of valuable seedstock, and cost of medications(22,54). One example of the importance of BRD is that the Academy of Veterinary Consultants has called for a plan to eradicate bovine viral diarrhea virus (BVDV), a major contributor to the BRD complex(34).

Although BRD continues to be a serious problem for cattle producers, past research, much of it carried out by members of previous NC-107 projects or their collaborators, solved important components of the problem and led to strategies that lessen losses due to BRD in some settings. Early research established that simultaneous infection with multiple agents is the rule in BRD(4,14,48). Studies of individual agents revealed many of their individual mechanisms of pathogenesis. For example, bovine herpesvirus-1 (BHV-1) impairs host defense mechanisms such as the mucociliary clearance apparatus and function of lymphocytes and macrophages(7), BHV-1 thus renders cattle unable to clear bacteria such as annheimia haemolytica and Pasteurella multocida that advance from their normal location in the upper airways to the lower lung, where they proliferate and cause severe fatal pneumonia(19,20). M. haemolytica produces many pathogenic factors; pre-eminent of these is the leukotoxin (Lkt), which specifically destroys bovine white blood cells(5,37). Other bacteria that participate in BRD include Histophilus somni (formerly Haemophilus somnus) and Mycoplasma bovis. M. bovis is associated with chronic pneumonia that responds poorly to antibiotics typically effective against BRD(1,49); this syndrome is costly to producers because of expense of repeated treatments and the loss of chronically sick cattle. Co-infection of cattle with BRSV and H. somni leads to enhanced disease characterized by a mechanism similar to that induced by allergic sensitization(13). BRSV can also cause severe disease when acting alone(16), and certain vaccines for BRSV and M. haemolytica have been found to enhance disease in vaccinated cattle(23,52,63). H. somni vaccines have been associated with adverse reactions, possibly due to induction of IgE(50). BVDV can cause mild respiratory disease alone(44), but contributes more significantly to BRD by impairing the immune response in a variety of ways, including suppression of bacterial killing and the induction of lymphocyte suicide (apoptosis)(2). This immune suppression causes BVDV-infected cattle to have more severe disease when co-infected with other pathogens(9,15,44); Perhaps the most devastating activity of BVDV is the ability of the virus to cause permanent, life-long infection of cattle when they are infected in utero; such persistently infected (PI) cattle can appear normal but shed great numbers of virus and thus serve as perhaps the leading source of infection of other cattle(25). In addition to the pathogens mentioned, parainfluenza type 3 (PI3), coronavirus, adenoviruses, and others were also found to contribute to the BRD complex(18,38,55).

Other research showed that management practices contribute to BRD. An early finding was that shipment and mixing of cattle increased the occurrence of BRD(29,24). Prophylactic antimicrobial treatment of cattle at arrival to feedlots was found to decrease disease61, and is often considered cost effective in "high risk" cattle(53). The concept of "metaphylaxis" became established, wherein treatment of cattle at arrival is utilized and considered to be either therapeutic or prophylactic(26). This concept is logical because the actual disease status of animals immediately following shipment is not always obvious. "Dual prophylaxis", wherein high risk cattle are vaccinated and treated simultaneously prior to shipment, was shown to be more effective than metaphylactic treatment at arrival(36). The recent finding that calves can be primed for a protective immune response by vaccination in the face of maternal antibody(47,51) was a major finding that contradicted a longstanding paradigm, and indicates that more research is necessary to determine how producers can exploit the opportunity to vaccinate young calves as a means of preventing later disease.

The impact of BVDV PI cattle on morbidity, mortality, and financial loss is the focus of ongoing research. In spite of the long recognition of the importance of PI cattle, the financial impact of PI cattle has only recently been characterized. More research is necessary; the small amount of data to date indicates PI cattle have decreased performance and, contact with PI cattle can increase disease and decrease productivity of non-PI cattle(37,58), but not all studies agree(40). If BVDV is to be eradicated, as some have suggested(34), it will be necessary to confirm the extent of financial loss attributable to this agent, as eradication will be costly. Methods to rapidly and inexpensively identify BVD PI cattle have been developed by NC-107 members and their collaborators. Currently identification of virus in a skin biopsy taken by ear notch is a convenient method widely used(10,34). Efforts continue to further simplify and improve the accuracy of tests for BVDV. A new finding is that white tailed deer can be infected with BVDV, and may become PI; studies are ongoing to confirm whether PI deer exist(12). If so, this also would have significant impact on efforts to control or eradicate BVDV.

Other recent research carried out by members of previous NC-107 projects took advantage of advances in microbiology and cellular and molecular biology to determine the exact mechanisms by which the pathogens described above cause disease in cattle. A brief summary of selected findings: the first step in killing of leukocytes by M. haemolytica leukotoxin (Lkt) is attachment to the cell surface molecule leukocyte function antigen-1 (LFA-1), also known as CD18/CD11a(31). Exposure of cells to BHV-1 increases expression of LFA-135. Binding of Lkt to LFA-1 activates cellular pathways that lead to apoptosis (cell suicide)(3). The death of cells following binding of Lkt to LFA-1 is unexpected, because ligation of LFA-1 usually causes cells to grow. Further research is necessary to determine if molecules that block or impair binding of Lkt to LFA-1 can prevent disease in cattle; this approach has promise because mutant M. haemolytica that cannot produce Lkt cause little or no disease in cattle(27). Enhancement of disease by BRSV vaccination is related to development of an inappropriate T helper type 2 cell response which leads to increased production of IgE and bronchiolar constriction and inflammation in a manner similar to that induced in allergic hypersensitization(32,64). This research confirmed that the components of a vaccine can induce an immune response that is harmful. The cloning and expression of the BRSV G protein(8), which is most often linked to induction of the inappropriate T helper type 2 response(41), should allow further characterization of the aspects of the virus that induce immunopathology. Genetic sequencing of BVDV isolates from naturally affected cattle confirms a high level of genetic variability among field isolates(46,57). This variability can allow the virus to escape the immune response; in fact, in some cases the majority of field isolates vary significantly from strains in currently available BVDV vaccines(21). H. somni, which characteristically induces thrombus formation as part of the pathology in the lung and central nervous system, was shown to induce apoptosis of endothelial cells and production of procoagulent factors via direct interaction with endothelial cells(6,56). Studies of BHV-1 latency (a "quiescent" state that allows the virus to persist undetected until it is reactivated and shed by a previously infected animal during times of stress)(17,30 showed that a novel gene is expressed by the virus in trigeminal ganglia (nerve tissue) of latently infected calves(28). The gene encodes multiple functions that together regulate latency, including interference with apoptosis, which promotes neuronal survival during the transition from acute infection to latency. Other research showed that the BHV-1 gE and US9 genes are necessary for the virus to be reactivated from latency(11). Currently available modified live BHV-1 vaccines can establish a latent infection; thus an animal can be considered permanently infected once it has been vaccinated, and unwanted side effect of an otherwise useful practice(42). The research will help the development of vaccines that induce protective immunity but do not establish latency and thus permanent infection in the vaccinated animal.

As described above, many discoveries have been made by NC-107 team members and their collaborators that have helped scientists, veterinarians and producers understand why cattle develop BRD, and undertake practices that decrease disease. However, the nature of cattle production in the United States provides an exceptional challenge to efforts to curtail BRD. Young cattle are typically reared in one area and transported in groups to other areas, often over long distances and across many states. This situation optimizes the potential for BRD development, as young animals from different management backgrounds carrying different viruses and bacteria are mixed together and placed under the stresses of transport, weather changes, new social groups, and other pressures. Producers struggling with often narrow profit margins constantly change management or treatment schemes in order to find a combination that works. However, this inconsistency frustrates efforts by veterinarians and researchers to gather adequate data to confirm or refute the efficacy of various practices and interventions. Much research has focused on single organisms that cause BRD, but more time and money is needed so that the practical application of laboratory findings to the field setting can be made. Moreover, very little is known about the ways that multiple pathogens interact to cause BRD.
While local and regional practices challenge veterinarians and researchers working to stop BRD, factors also must be addressed on a larger scale. The ever-increasing rate of national and international movement of cattle and cattle products requires the development of new diagnostic tests that will yield accurate results in minutes to hours, rather than the days to weeks typically required for currently utilized tests. Management and preventative strategies must be developed that reflect the state of the art in biomedical science, allowing U.S. cattle producers to maintain an economic advantage over their global competitors while producing beef that is wholesome and safe. The expertise and skill of the scientists engaged in the project proposed here will be focused on addressing these issues. Some specific issues that require further study and will be addressed in the new project are as follows (see Methods for more detail): tests used to identify BVDV PI cattle need to be more rapid and accurate; project researchers will test new approaches and work to refine existing strategies to solve this problem. Management practices that minimize disease and financial loss due to BVDV PI cattle will be evaluated so that veterinarians and producers can be taught the best practices to circumvent this pathogen. The ability of BHV-1 to undergo latency allows this pathogen to infect cattle permanently and be shed intermittently when the cattle are stressed. This characteristic is relevant to both natural infection and the widely used modified-live vaccines; project researchers will determine molecular steps in the latency pathway that are amenable to interference in order to develop mechanisms to block latency. M. bovis causes pneumonia that responds poorly to antibiotic treatment, but the reason for this is unknown; impairment of the host immune response, which is necessary to complement the effect of antibiotics, is one possible cause. Project researchers will study cellular and molecular mechanisms of immune impairment caused by M. bovis. BRSV appears to enhance disease due to coinfecting agents or allergens, but the reason this happens is imperfectly characterized; project researchers will test whether mechanisms operative in enhanced disease due to the closely related human RSV are active in cattle. The interaction of Lkt-LFA-1 may be amenable to interference in order to prevent disease due to M. haemolytica infection, but methods must be developed to apply laboratory-based methods of interference to the "whole animal" setting. Project researchers will determine what aspects of the Lkt-LFA-1 interaction are vulnerable to disruption by methods safe and effective in vivo. There is no overlap between the proposed replacement project and existing multistate research projects. A search of the NIMSS database using the terms "bovine", "cattle", or "respiratory" revealed only the previous NC-107 project and this proposed project that will replace NC-107.

Objectives

1. To evaluate the prevalence of viral and bacterial agents of respiratory disease by developing, validating and disseminating new state-of-the-art molecular diagnostics for rapid identification of these agents
   
2. To investigate the basic biology, molecular pathogenesis, and immunopathogenesis of polymicrobial infections including important viral and bacterial agents
   
3. To develop management and prevention strategies that incorporate new vaccines and treatment protocols to combat bovine respiratory disease and reduce economic loss
   

Methods

Objective 1: This objective has two components: 1) identifying emerging and re-emerging agents and 2) developing diagnostic methods for BRD. MN and SD will collect and summarize BRD pathogen data from all diagnostic laboratories represented in the project. In addition, MN will tabulate yearly the antibiotic susceptibility spectrum of P. multocida, M. haemolytica, and H. somni to determine whether there is an increased trend of resistance to certain groups of antibiotics. IA will expand its Mycoplasma spp. surveys, collaborating with GA, OK, NE, and MI to look at the prevalence of this emerging pathogen in different production settings. In cooperation with OK, NADC will survey feedlot cattle to determine the prevalence of adenovirus and its effect on disease and performance. GA will work with IA to evaluate associations between PCR and culture, and the significance of isolation of M. bovis from various respiratory sites. LA will continue to develop real-time PCR (TaqMan) assays for the detection and differentiation of respiratory and enteric coronaviruses. These assays can be performed from material retrieved from nasal swabs as well as from tissues of infected animals. In addition LA will develop low-density microarrays for diagnostic purposes and targeting major respiratory pathogens such as BHV-1, M, haemolytica, BVDV and coronavirus. IA will evaluate ELISA serology systems as well as molecular detection techniques for Mycoplasma bovis. MI will continue the development of real time biosensors for detection of BVDV and other pathogens; AL and SD also cooperate in this effort. NADC will develop RT-PCR to detect bovine adenovirus. SD will work with NADC on BVDV proficiency testing for other diagnostic laboratories. Project members will work with Academy of Veterinary Consultants (AVC), American Association of Bovine Practitioners (AABP), and the American Association of Veterinary Laboratory Diagnosticians (AAVLD) on the development an implementation of diagnostic techniques for BVDV voluntary eradiation programs Objective 2: Using genomic and proteomic techniques, SD will study the interaction of BVDV and BHV-1 with macrophages to elucidate molecular mechanisms of immunosuppression. A focus will be on downregulation of cell receptors such as MHC 1 & II, CD14, Toll-like receptors. This is a collaborative study with MI and NADC. SD will also investigate the effect of BVDV and BHV-1 on cytoskeletal rearrangement and signaling. In collaboration with NADC, SD will study immune responses of PI animals to learn what cellular and/or molecular events result in the death of the animal. SD, NADC, MI and Colorado are also determining if BVDV infection of whitetail deer can result in persistently infected deer. KS will study the molecular basis of differential pathogenesis in bovine herpesvirus types 1 and 5 infections, and identify factors crucial for transport within the neuron to aid in the development of vaccine virus that is defective in retrograde and anterograde transport (and thus latency). NADC, in cooperation with Moredun Research Institute (Penicuik, UK), will characterize bovine P. multocida from field specimens by RFLP and compare their virulence in a small animal model. MS will identify proteins present in professional antigen presenting cells and evaluate the mechanisms involved in the function of monocytes/macrophages and dendritic cells (DC). MS will investigate the role of in vitro BVDV infection in the phenotypic and functional maturation of DC in dairy cattle. Phenotypic measures will include expression of MHC II, CD80/86, CD1, CD11c and MR; functional measures will include active endocytosis, capacity to directly stimulate B cells, and promotion of DC-dependent cytokine polarization in PBMC cultures. Comparative membrane and cytosolic protein profiling will be used to elucidate the mechanisms of innate and adaptive immune responses in CP and NCP BVDV infection in monocytes and monocyte-derived DC. Using in vivo and in vitro studies, CA will look at the synergistic effects of dual infection with BRSV and H. somni. In vitro studies will examine alterations in cytokine and adhesion molecules on bronchial epithelial cells that may predispose H. somnus attachment and retention. In vivo studies will examine the role of H. somnus specific IgE in disease by examining dual infection with immunomodulation to down-regulate IgE production. In collaboration with NADC, IA, and WI, MN will continue to define the molecular interactions between M. haemolytica Lkt and its receptor in bovine leukocytes and how this interaction generates inflammatory mediators that leads to lung injury. Using a combination of gene swapping and site-directed mutagenesis, the precise amino acid residues within the region of the bovine CD18 which constitute the binding motif that imparts ruminant cell specificity of M. haemolytica Lkt effects will be mapped. MN will also begin the generation of peptides corresponding to the binding motif of Lkt that will inhibit the binding of the toxin to its receptor on alveolar leukocytes in vitro, and abrogate its biological consequences. LA will undertake pathogenesis studies to assess the role of the bovine coronavirus spike glycoprotein in respiratory disease in cattle. Work planned includes the generation of viral mutants and investigations of their host tropism and pathogenicity in cattle. In collaboration with MN, MI and GA, IA will focus on polymicrobial infections involving BVDV and M. bovis, with emphasis on immune response modulation, and expression of phase-variant virulence determinants of M. bovis during BVDV/M. bovis combined infections. MI will develop BVDV/M. bovis dual infection models to study the interaction between these pathogens. GA will work with NE and IA to characterize the cellular and molecular inflammatory pathways associated with co-infection with BRSV and BVDV, BRSV and M. bovis, and BVDV and M. bovis. NE will provide plasmids expressing various aspects of the immunomodulating BRSV G protein, and strains of BVDV for use in the research. Expression of chemokines, cytokines, and cell surface molecules will be assessed in primary bovine respiratory epithelial cells in vitro and by lymphocytes and antigen presenting cells ex vivo. In addition GA will continue assessing the effects of M. bovis on the phenotype and function of granulocytes. WI will continue study of BHV-1, M. haemolytica and H. somnus. These investigations will identify both individual virulence strategies of each agent, as well as evaluate the integration of these strategies in dual viral/bacterial infection of bovine pulmonary epithelial cells and leukocytes in vitro. By so doing, we expect to identify cellular and molecular mechanisms that amplify the severity of respiratory disease following co-infection with viral and bacterial agents. These efforts will include identifying regulation of gene products of BHV-1, identifying the intracellular transport of the M. hemolytica Lkt and how this affects the physiology and survival of viral infected cells, and how prior exposure to BHV-1 alters the adherence and cytotoxic properties of H. somnus for bovine pulmonary epithelial and endothelial cells. Objective 3: MS will investigate the effects of sub-minimum inhibitory concentrations of three classes of antibiotics on protein and gene expression of P. multocida. Data will be used to help design new potential drug therapies for treatment of bovine respiratory disease. GA will assess the use of small inhibiting RNA (siRNA) to limit BRSV infection. siRNAs specific for the BRSV P, F, and G proteins will be assessed in vitro for their ability to limit BRSV replication. SD will investigate the role of feed additives (yeast and colostral fractions) and dried distillers grains on the immune response. WI will continue its translational research investigations on how air quality affects the pulmonary health and susceptibility to respiratory pathogens of dairy cattle. IA will develop MLV vaccines for Mycoplasma bovis. These will be tested in collaborative field trials in CA, MI, OK, TX, NE. LA will continue to work on the generation of attenuated and viral vectored vaccines for bovine coronavirus. Recombinant adenoviruses have been constructed capable of expressing codon-optimized bovine coronavirus genes. These vaccines will be tested in experimental infections in cattle. GA will collaborate with Diversa, Inc., to develop prime-boost neonatal vaccine systems for BRD agents based on Diversa's gene discovery/assessment and protein production technology and GA's experience in development of adjuvant-delivery systems. SD will work with NADC on the development of new generation BHV-1 and BVDV vaccines. NADC, with OK, will evaluate an experimental M. haemolytica / P. multocida vaccine in field trials to determine influence on performance through slaughter. In collaboration with SD, AL will conduct an evaluation of the ability of BVDV vaccines to prevent bovine respiratory tract disease using pneumopathic strains of BVDV.

Measurement of Progress and Results

Outputs

• In years 1-5, a scientific presentation will be given at the American Association of Veterinary Laboratory Diagnsoticians-United States Animal Health Association (AAVLD-USAHA) summarizing the BRDC diagnostic and antibiotic sensitivity data from the previous years. Individual stations will present information on new approaches for the diagnosis of BRDC. At the end of year 5, a peer-reviewed article will be published summarizing the results of the incidence of bovine respiratory disease complex organisms and discussing any new or reemerging disease patterns.
• By year 3, a peer-reviewed publication on improved diagnostic techniques and incidence of bovine adenovirus will be published.
• By year 4, a peer-reviewed publication on improved diagnostic techniques for Mycoplasma bovis will be published.
• In year 2 begin discussions for a new edition of the BRD review in The Veterinary Clinics of North America (VCNA): Food Animal Practice with the plan for a new edition by yr 5.
• By year 5, a peer-reviewed publication on improved diagnostic techniques for bovine coronaviruses will be published.
• At the end of year 5, a peer-reviewed publication on improved diagnostic techniques for BVDV will be published.
• At the end of year 5 a peer reviewed publication on use of microarrays for BRDC pathogen diagnosis will be published.
• In year 3 or 4 a one day BRDC symposium will be organized with either the American Association of Bovine Practitioners and/or the Academy of Veterinary Consultants (AVC).
• By year 4, experiments will be completed on the immunosuppression mechanisms of NCP and CP BVDV infection of macrophages and dendritic cells.
• By year 4, experiments will be completed for identifying viral factors critical for neuronal transmission of BHV-1 and 5.
• By year 4, experiments will be completed for identifying viral factors critical for neuronal transmission of BHV-1 and 5.
• By year 4, experiments defining the interaction of BHV-1, M. haemolytica and H. somnus in BRDC will be completed.
• By year 5, experiments defining the molecular interactions between M. haemolytica leukotoxin, bovine leukocytes and inflammatory mediators in the lung will be completed.
• By year 5, experiments defining the interaction of BRSV and H. somnus in BRDC will be completed. Additional experiments with BRSV in vitro infection systems will also be completed.
• At the end of year 5, experiments defining the role of M. bovis in polymicrobial infections with BVDV and BRSV will be completed. At the end of year 5, experiments to differentiate P. multicida and measure virulence will be completed.
• At the end of year 5, experiments to determine the role of whitetail deer in BVDV epidemiology will be completed.
• By project end, develop a comprehensive USDA BVDV targeted research grant program similar to rograms for PRRS and Johnes Disease.
• In year one, vaccine trials will be completed evaluating BVDV vaccines to prevent BRDC caused by pneumopathic strains of BVDV.
• In year one, field trial will be completed on the use of modified live M. bovis vaccine.
• In year two, experiments determining the antibiotic inhibitory concentrations against P. multicida will be completed.
• In year two, experiments determining the effect of siRNA in preventing BRSV infections will be completed.
• In year two, experiments using attenuated and adenovirus vectored coronavirus vaccines will be completed.
• In year three, experiments investigating the immune modulation of feed additives on bovine immune response will be completed.
• In year three, field trials to evaluate an M. haemolytica/ P. multicida vaccine in beef cattle will be completed.
• In year three, experiments measuring the effect of air quality on respiratory health in dairy cattle will be completed.
• In year four, experiments developing a new generation of BVDV vaccines will be completed.
• In year five, experiments with a novel adjuvant-delivery system for neonatal BRD vaccines will be

Outcomes or Projected Impacts

• The integrated approach of surveillance and diagnostic development described for Objective 1 will have wide impact on the US cattle industry. The analysis and presentation of diagnostic data from the major cattle production areas of the US will aid veterinarians and diagnosticians in their awareness of new and reemerging bovine respiratory diseases, helping them to correctly determine the cause of BRD outbreaks and choose appropriate therapies more rapidly, minimizing cost of treatment and loss of animals due to chronic disease or death.
• A major component of this proposal is the continuous distribution of information to veterinarians and cattle producers coupled with technology transfer of the latest validated diagnostic methods to US veterinary diagnostic laboratory network.
• Publication of a new edition of VCNA dedicated to BRD will have great impact by providing a convenient source of the most up-to-date information regarding pathogenesis, diagnosis, treatment, and prevention of BRD to veterinarians and veterinary students in the US and worldwide.
• The basic pathogenesis research will allow improved understanding of new targets for intervention in both treating and preventing BRDC. This multi-faceted approach aimed at all major BRDC pathogens is one of the true strengths of this committee.
• The basic information generated will be disseminated through both peer-reviewed and producer-based publications. Thus the work of the committee will benefit specialists and researchers by providing updated information regarding molecular mechanisms of pathogenesis that will form the basis for future research to prevent and treat BRD.
• The work proposed will also benefit field veterinarians and producers by providing them with management recommendations based on the latest understanding of how viruses, bacteria, and management practices lead to BRD.
• This research should also allow the development of more multi-investigator research grants, leveraging time and funds invested into this project.
• The more applied portion of the proposal (Objective 3) will result in the development of new and effective therapeutics and biological agents that can readily be applied in the field to allow more efficient and cost effective intervention. Most of these approaches involve multiple investigators to aid in the field-testing of many of these vaccines in a variety of states and in different classes of cattle, ensuring that the results will have broad application. Several of these approaches involve animal health company participation to increase the speed that these products are brought to market, as well as allowing project support to leverage further research support from industry.
• Overall this proposal strikes at many areas of economic impact of BRDC and the implementation of this project will increase the economic returns to US cattle producers.

Milestones

(1):VLD-USAHA BRDC presentation

(2):VLD-USAHA BRDC presentation, planning of new issue of VCNA-Bovine Respiratory Disease

(3):VLD-USAHA BRDC presentation; BRDC Symposium; M. bovis publication

(4):VLD-USAHA BRDC presentation; Bovine coronavirus publication

(5):VLD-USAHA BRDC presentation; Diagnostic Pathogen summary publication; BVDV publication; Microarray publication

Projected Participation

View Appendix E: Participation

Outreach Plan

As described in the "Outputs" and "Outcomes or Projected Impacts" sections, the project will result in the publication of articles in producer magazines, and peer-reviewed manuscripts in the scientific literature, that will help producers and veterinarians use the most up-to-date information available to diagnose, treat, and prevent BRD. Scientific publications by team members will form the basis of future research that will extend the findings of the proposed project. Annual presentations by team members at the AAVLD-USAHA meeting, the AABP meeting, and the AVC meetings will provide additional venues for the dissemination of information to veterinarians, cattle producers, and researchers, as well as technology transfer of the latest validated diagnostic methods to US veterinary diagnostic laboratory network.

Organization/Governance

The Technical Committee will consist of one voting member from each cooperating station as appointed or otherwise designated by that station, with an Administrative Advisor and representative of CSREES. A President and Secretary of the Technical Committee will be elected by a majority vote of the committee, with Secretary serving as President-Elect; each will serve a one-year term. Annual meetings will be held at a time and site agreed on by the Technical Committee, with the majority of meetings held in conjunction with a national meeting of an organization related to bovine health (such as the American Association of Bovine Practitioners or the Academy of Veterinary Consultants). At the annual meeting, the Secretary will record the minutes and, following approval by the Technical Committee, will submit them to the Administrative Advisor for dissemination. The President will prepare the annual report summarizing material supplied by the voting member from each participating station and, following approval of the report by the Technical Committee, will submit the report to the Administrative Advisor for dissemination to the appropriate parties.

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Attachments

Land Grant Participating States/Institutions

CA, FL, GA, IA, KS, KY, LA, MI, MN, MS, NE, OK, SD, TX, WI

Non Land Grant Participating States/Institutions