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Dissertation Defense: Surveillance Enhancing Strategies for the Mitigation of Emerging Cattle Parasite Theileria orientalis Ikeda

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Catharine Burgess

Dissertation Defense: Surveillance Enhancing Strategies for the Mitigation of Emerging Cattle Parasite Theileria orientalis Ikeda

Catharine Burgess

Graduate Student, Translational Biology, Medicine, and Health
Graduate Research Assistant, Lahmers Lab, VA-MD College of Veterinary Medicine
April 24, 2025, at 12 p.m.
VMCVM, Classroom 100
Watch via Zoom

More About the Candidate and Project

Education

Virginia Tech, Translational Biology, Medicine, and Health, Ph.D. Candidate

William & Mary, B.S., Biology

Training

Graduate Research Assistant, Lahmers Lab, VA-MD College of Veterinary Medicine

Mentors

Kevin Lahmers, DVM, Ph.D., DACVP, VA-MD College of Veterinary Medicine

Committee Members

  • Kylene Kehn-Hall, MS, Ph.D, Professor, VA-MD College of Veterinary Medicine
  • Roger Ramirez-Barrios, DVM, MSc, Ph.D., DACVM, Clinical Associate Professor, VA-MD College of Veterinary Medicine
  • Laura Hungerford, DVM, MPH, Ph.D., CPH, Department Head, Population Health Sciences; Professor, Veterinary Public Health and Epidemiology
  • James Weger-Lucarelli, Ph.D., Research Assistant Professor, VA-MD College of Veterinary Medicine
  • Burgess, C., Todd, S. M., Hungerford, L., & Lahmers, K. (2025). Determining diagnostic sensitivity loss limits for sample pooling in duplex rtPCR surveillance testing: Theileria orientalis and Anaplasma marginale. Journal of Veterinary Diagnostic Investigation, 37(1), 71-78.


  • Burgess, C., Hungerford, L., Curran, A., & Lahmers, K. Development of a Prevalence Estimation Method for Sample Pooling Optimization and Enhancement of Surveillance Testing Capacity When Prevalence is Unpredictable. Available at SSRN 5164040. (Preprint, under review)



Under Review:

  • Burgess, C., Loy, Duan S., Loy, John D., Curran, A., Lahmers, K. (2025). Simulation of pooling optimization methods for differing infection dynamics, sampling practices, and desired outcomes in surveillance testing of Bovine Viral Diarrhea Virus and Theileria orientalis Ikeda. Submitted April 2025.



In Preparation:

  • Burgess, C. Curran, A., Ceci, A., Finkielstein, C.V., Lahmers, K. (2025). Simulation of pooling optimization approaches for reduction in resource consumption, processing time, and adaptation to lapses in testing capacity. In preparation.
  • Burgess, C., Todd, S.M., Pudlo, A., Guynn, S., Abdelrazek, S., Ibarguen, L., Lahmers, K. (2025). Identification of Theileria orientalis Ikeda antigens over multiple infection types. In preparation.
  • Epidemiology Committee Trainee Travel Award, AAVLD-USAHA Annual Meeting (2024)
  • Second Place for Methods, Flip the Fair, Roanoke City Schools (2024)
  • Second place, Best Presentation, AAVLD-USAHA Annual Meeting (2023)
  • Best Recorded Presentation, AAVLD-USAHA Annual Meeting (2022)
  • Second place, Health Sciences and Technology Hokie Pitch (2021)

Oral Presentations:

  • Burgess, C., Loy, D., Loy, J., Lahmers, K. (2024). Determining Testing Economy and Cost Reduction of Various Pooling Optimization Approaches for Bovine Viral Diarrhea Virus and Theileria orientalis Ikeda Surveillance using Mote Carlo Simulations. USAHA-AAVLD National Meeting. Nashville, TN
  • Burgess, C., Hungerford, L., Lahmers, K. (2023). Estimating Optimal Pool Size for Surveillance Testing When Prevalence is Unknown . USAHA-AAVLD National Meeting. National Harbor, MD.
  • Burgess, C., Todd, M., Hungerford, L., Lahmers, K. (2022). Pooling Series to Determine Sensitivity Loss in Theileria orientalis Surveillance Testing, USAHA-AAVLD National Meeting. Virtual.

Poster Presentations:

  • Burgess, C., Hungerford, L., Lahmers, K. (2023). Estimating Optimal Pooling Configurations to Enhance Surveillance Testing Capacity When Disease Prevalence is Unknown. TBMH Annual Research Symposium. Roanoke, VA.
  • Burgess, C., Todd, M., Hungerford, L., Lahmers, K. (2022). Pooling Series to Determine Sensitivity Loss in Theileria orientalis and Anaplasma marginale Surveillance Testing. TBMH Annual Research Symposium. Roanoke, VA.
  • Panny, L., Burgess, C., Kehn-Hall, K. (2022). Vasolin-Containing Protein Inhibition in Venezuelan Equine Encephalitis Virus. TBMH rotation presentations. Blacksburg, VA.
  • Burgess, C. (2023, 2024). Tracking Disease Spread Through Cattle Markets with Sample Pooling. Roanoke City Public Schools Flip the Fair. Roanoke, VA.
  • Roanoke City Public Schools Flip the Fair, Presenter (2023, 2024)
  • Bodies and Bites (2023)
  • Skype a Scientist (2024)
  • Roanoke Graduate Student Association Executive Board (2022-2023)
  • Salem Red Sox Spooktacular (2022)

About this Dissertation

The most virulent genotype of Theileria orientalis, Ikeda, has been spreading through the Eastern and Midwestern United States since its initial detection in Virginia in 2017. Facilitated by its invasive Longhorned tick vector, spread of Ikeda to naïve regions of North America has been characterized by costly clinical outbreaks of Bovine Infectious Anemia, with severe cases resulting in abortion, stillbirth, and death, with still more production costs incurred due to lowered dairy and beef production in surviving animals. As such, Ikeda represent an enormous economic threat to the cattle industry in North America. In the absence of any FDA-approved vaccine or treatment and the infeasibility of vector control, surveillance testing to avoid introducing the parasite to naïve stock is the only mitigation strategy currently available. Expansion of surveillance testing through sample pooling has been infeasible as the high incidence of asymptomatic infection makes prevalence difficult to anticipate to optimize pooling approaches, which can become costly with high misestimation of prevalence. This work demonstrated that the addition of a subsampling test to estimate prevalence within a surveillance submission was sufficient to allow for economical pooling as well as avoid high costs when prevalence exceeded the pooling threshold (32%) when compared to conventional pooling of simulated T. orientalis surveillance herds. Additionally, the resulting prevalence estimation testing (PET) method was shown to be applicable to other surveillance pathogen through Monte Carlo Simulation, with the reduction in test savings not being statistically significantly different from simulated pooling with the true optimal pool size for both Bovine Viral Diarrhea Virus, and COVID-19 (p > 0.05). While PET pooling resulted in additional processing time in most scenarios, it was shown through Discrete Event Simulation to reduce processing time when laboratory capacity was at its minimum and sample intake was high. Otherwise, the primary advantage of PET in other surveillance programs was shown to be reduction in test count through improved optimization, and resource conservation. Further expansion of surveillance with serological methods was also shown in this work to be a feasible avenue, as 20 recombinantly expressed surface/secreted proteins were shown to be seropositive (OD ratio > 2) across multiple infection types (Chitose, acute Ikeda, and persistent Ikeda). Additionally, 7 antigens showed variable degrees of seropositivity between infection type suggesting there may antigenic diversity between strain and/or infection stage that could allow serological diagnostics that differentiate between strain/infection stage, both of which have major clinical implications. The present work demonstrates the ability to enhance Ikeda mitigation through surveillance by maximizing the effectiveness of currently available rtPCR testing through pooling, as well as the potential to fill currently unmet surveillance needs with improved serological detection.