Dr. Carol Cardona receives $1,025,000 in funding from USDA NIFA’s Agriculture and Food Research Initiative (AFRI) as part of the USDA-NSF-NIH-BBSRC-BSF-NNSFC Ecology and Evolution of Infectious Diseases program.
Infectious bursal disease virus (IBDV) is a major cause of immunosuppression in chickens that exacerbates influenza A virus (IAV) pathogenicity, prolongs shedding, reduces vaccine efficacy, and facilitates the adaptation of waterbird IAV to poultry. Moreover, IBDV has been found in waterbird species that are the natural hosts for IAVs. However, there has been neither a quantitative study of how IBDV affects IAV transmission and evolution in poultry, nor on the contribution IBDV makes to the shedding of other viral infections in waterbird populations. Work in this proposal plans to define how IBDV affects transmission parameters in chickens such as the IAV: latent and infectious periods, peak shedding titre, mean 50% bird infectious dose, transmission probability, adequate contact rate, and R0.
These data will then be used in transmission and surveillance simulation models to determine the impact of IBDV exposure on an IAV outbreak in poultry and the time to detection. IBDV may also alter the evolution of IAV, and work in this proposal plans to deep sequence IAVs shed from inoculated and contact chickens to evaluate how IBDV exposure influences the IAV population. Moreover, a wild waterbird population in which IBDV has been detected will be used to determine the prevalence of the virus in wild waterbirds in the UK, the extent to which the waterbird IBDV causes disease and immunosuppression, and the contribution it makes to the transmission of other viruses by determining if there is a correlation with the presence of IBDV and the diversity and titer of viruses shed.
A major advantage of this project is the combination of studies in both poultry and aquatic waterfowl populations, permitting a more holistic, integrated approach combining field studies and metagenomic sequencing with experimental challenge studies in order to answer fundamental questions regarding the ecology and evolution of IBDV and IAV, both economically important pathogens for the poultry
industry. Moreover, this project will provide new information that will have real-world applications for disease control, and the data could influence policy on the management of IAV, for example, by increased surveillance for IBDV in chicken flocks, or by screening the immune status of chicken flocks to help identify at-risk flocks earlier. Furthermore, this project could set a precedent for investigating the impact of other causes of immunosuppression on the spread of infectious diseases in poultry and the results could have broader implications for agriculture as, to date, there is a lack of research into how the immune status of a wild animal reservoir or a flock or herd affects the transmission and evolution of infectious diseases. Immunosuppression in wildlife could facilitate the transmission of infectious diseases between across species in nature, and immunosuppression in livestock could make it more likely for infectious diseases to traverse the species barriers from wild populations into domesticated animals, making it more likely for the pathogen to adapt and become established in the population.
The results from this project will be of relevance to those responsible for detecting and controlling avian influenza outbreaks in wild birds and farmed poultry and will have a direct benefit to poultry producers and the communities in which they live. In addition, the data can be used to raise awareness of the need to maintain good immune status in a flock, benefiting animal welfare. The results will also benefit the health of wild birds, and will be of interest to the general public. The research team is deeply committed to promoting diversity and, to this end, offer summer research experiences through the Multicultural Summer Research Opportunities Program at UMN. In addition, this project will provide a unique opportunity for researchers to be trained in techniques relevant to studying the ecology and evolution of infectious diseases, and will drive innovation through international collaboration between world-class institutions in the USA and the UK, thereby strengthening the infrastructure for research and education in both countries. In addition to the traditional academic channels, the science in this proposal will be communicated to a wider audience by leveraging contacts the research team has to maximize outreach efforts. For example, by reaching out to with poultry producers through Cooperative Extension appointments, and by presenting data at the Midwest poultry federation meeting, at workgroups at the interface of industry, government and academia, and annual meetings attended by industry veterinarians. In addition, the team will make use of existing outreach programs directed at addressing national anima disease emergency preparedness.
The Research Team
The UMN College of Veterinary Medicine, Poultry Health Researchers:
Dr. Carol Cardona, DVM, PhD., Principal Investigator
Dr. Sasidhar Malladi, PhD., Co-Investigator
Mr. Peter Bonney, Research Assistant
Dr. Marie Culhane, Co- Investigator
The Pirbright Institute Researchers:
Dr. Andrew Broadbent, DVM, PhD., Principal Investigator
Dr. Holly Shelton, PhD., Co-Investigator
The University of Oxford Researchers:
Prof. Oliver Pybus, PhD., Co-Investigator
Dr. Sarah François (SF), PhD., Research Associate