Principal Investigator

Greg Habing, DVM, PhD, DACVPM |

Dr. Habing is a veterinary epidemiologist at The Ohio State University. He graduated from the University of Illinois College of Veterinary Medicine in 2004, and worked in mixed animal practice in Franklin County, PA. He left practice to complete a dairy production medicine residency and a doctorate at Michigan State University. He came to OSU in 2012, and has focused his research on the epidemiology of pathogens and antimicrobial resistance in livestock production systems. He has specific interests in antimicrobial stewardship on dairy farms and understanding the transmission of multi-drug resistant Salmonella in dairy production systems.  Dr. Habing also leads the food safety course within the Veterinary Public Health specialization, and teaches within the epidemiology and zoonoses courses taught to veterinary students at OSU.

Project Collaborator

Andréia Arruda DVM, MS, PhD |

Dr. Andréia Arruda is originally from Brazil, where she graduated as a veterinarian from São Paulo State University in 2010. After spending one year working on a farm, Dr. Arruda started her training as a scientist graduating with a Master in Science from the University of Minnesota in 2012. In 2013, she moved to Canada to pursue a Ph.D. in Epidemiology at the University of Guelph, which she finalized in 2015. She then held a one-year research position at the University of Minnesota (Post-Doctoral Associate), and joined the Department of Veterinary Preventive Medicine at The Ohio State University as an Assistant Professor in 2017. Dr. Arruda’s main research interest is in infectious disease epidemiology. She aims to better understand how emerging and re-emerging diseases spread between farms, animals and humans and how to control and prevent them. As an epidemiologist, Dr Arruda has projects related to several animal species and public health topics; and she is very interested in international collaborations so she can always learn how other researchers, veterinarians and communities deal with similar problems in different scenarios. In her free time, she enjoys travelling, hiking, cuddling with her dog Finn, and trying new combinations of cheese and wine!

PhD Students

Rafael Portillo-Gonzalez, DVM |

Dr. Portillo-Gonzalez completed his DVM program from the University of Zulia Venezuela. After that, he worked for several years in the pharmaceutical industry as a dairy cattle specialist. Later, he came to the US to finish an MBA program at Troy University in Montgomery Alabama. Today, Dr. Portillo-Gonzalez is doing a Ph.D. program in antimicrobial stewardship in dairy cattle. He is focused on reducing AMU and AMR on dairy farms while keeping animal health and producer profitability. He is currently living in Columbus, Ohio and spends most of his free time with his wife Dr. Dubra and his dog Lukas cheering for his beloved Red Sox.

Alejandra Arevalo-Mayorga, B.Sc, M.Sc. | 

Alejandra received her degree in Microbiology and her Master’s in Biological Sciences from La Universidad de los Andes, Colombia. Over the last 10 years, she has participated in multiple collaborative projects with the United States and the United Kingdom, focusing on the detection and characterization of zoonotic pathogens and ESKAPE bacteria. From 2019 to 2023, she was involved in the implementation and coordination of the Genomics Laboratory at the Global Health Research Unit in Colombia. Nowadays, she is pursuing a Doctorate in Comparative Biomedical Sciences at The Ohio State University, where her primary interest is the development of diagnostic methods and genomic epidemiology of Salmonella Dublin, particularly under the One Health approach.

Sara Sequeira, DVM |

Sara graduated from Faculdade de Medicina Veterinária at the University of Lisbon, Portugal in 2021 with a Degree in Veterinary Medicine. While completing her studies, she went on to take a position as a research assistant at the Center for Applied One Health Research and Policy Advice (OHRP) at City University of Hong Kong, SAR China. At this position, she undertook different projects, and particularly focused on analysis of poultry trade networks of Gujarat, India. Currently, she is pursuing a Doctorate in Comparative Biomedical Sciences at The Ohio State University, where her main focus is on epidemiology and understanding calf production and distribution networks in the United States. Sara’s research interests include epidemiology of infectious diseases, applied One-Health research, and particularly spatial epidemiology and network analysis.

Postdoc Fellows

Samantha Locke, B.Sc, PhD |

Sam received her BS in Animal Science from the University of Florida. She worked as an assistant heifer manager at a large commercial dairy focusing on preweaned calf care for several years before moving to Columbus and completing a PhD in the OneHerd Lab. Her research interests include elucidating the epidemiology of AMR Salmonella, particularly within calf populations, and developing preharvest interventions to disrupt Salmonella transmission. Outside of research, Sam enjoys reading, hiking, and spending time with her husband, Zac, new daughter, Daphne, and their cat, Barnes.

Ting-Yu Cheng, DVM, PhD,  DACVPM |

Ting-Yu received his DVM and Master’s in Veterinary Science from the National Chiayi University, Taiwan, and went to Iowa State University to pursue a PhD in veterinary microbiology and preventive medicine with a minor in statistics. With over 10 years of research experience, Ting-Yu is currently holding the position of postdoctoral scholar at The Ohio State University and is dedicated to research and teaching in food animal medicine, epidemiology, diagnosis, and advanced data analysis, with specific interests in the transmission, surveillance, and prevention of contagious animal diseases. He spends most of his spare time gaming, hiking, watching basketball, and foodventuring with his wife I-Chin.

B. Alexander Fonseca-Martinez, DVM, MVSc, PhD |

Dr. Fonseca-Martinez completed his DVM program at the Universidad Nacional de Colombia. He later pursued a master’s degree in veterinary sciences from the Federal University of Rio Grande do Sul in Brazil. He came to the US in 2019 to pursue a PhD at Michigan State University, specializing in epidemiological methods and synthesis research. His interests lie in implementing evidence-synthesis techniques to facilitate a holistic understanding of primary research outcomes in fields such as environmental health, public health, and animal health. This comprehensive approach empowers decision-makers to integrate available evidence into their critical decision-making processes. In his leisure time, he finds joy in hiking, cycling, cooking, and cherishing moments with his wife, Susana.