EPIDEMIOLOGY OF Q FEVER AMONG DAIRY CATTLE FARMS AND FARMERS, CHIANG MAI, THAILAND 2015 Pawinee Doung-ngern A dissertation submitted to the faculty of the University of North Carolina at Chapel Hill in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Epidemiology in the Gillings School of Global Public Health. Chapel Hill 2016 Approved by: Steven Meshnick Michael Emch Gilbert Kersh Gary Koch David Weber © 2016 Pawinee Doung-ngern ALL RIGHTS RESERVED ii ABSTRACT Pawinee Doung-ngern: Epidemiology of Q fever among dairy cattle and dairy farmers, Chiang Mai, Thailand 2015 (Under the direction of Steven Meshnick) Q fever is a zoonosis, caused by the gram negative bacteria Coxiella burnetii. Knowledge of the epidemiology of Q fever in Thailand is limited. This study was conducted to determine the burden and the risk factors of C.burnetii infection in dairy cattle farms and farmers in Chiang Mai, Thailand. A prospective cohort study was conducted in five dairy cooperatives where evidence of C.burnetii was reported. The project included three components 1) a cohort study among farmers, 2) bulk tank milk (BTM) screening, and 3) farm investigation and specimen collection from cows and their environments in milk positive farms. Samples and data collection were obtained at baseline, 6, and 12 month intervals. Human sera were tested using Indirect Immunofluorescense Assay; cow sera and BTM were tested using Enzyme Linked Immunosorbent Assay; and vaginal swab and environmental samples were tested using Polymerase Chain Reaction. Baseline data were analyzed using logistic regression and Generalized Estimating Equation models to estimate the odds ratio (OR) and 95% confidence interval (CI). Among 306 randomly selected farms, 282 farms (92.2%) and 532 from 637 randomly selected farmers (83.5%) participated. The prevalence of C.burnetii antibodies in BTM was 40.8% (115/282) and the C.burnetii seroprevalence among farmers was 16.9% (90/532). Investigation in BTM positive farms showed C.burnetii seroprevalence was 28.4% (224/790) at the individual cow level and 91.9% (91/99) at the farm level. Multivariate analysis showed that having more than 80% of cows ≥ 2 years of age (OR 2.34, 95%CI 1.09 - 5.06) and having an infected farms within 1 km (OR 2.88, 95%CI 1.17 – 7.06) were positively associated with the odds of C.burnetii antibodies in BTM. Cleaning the birthing area (OR 0.27, 95%CI 0.08 - 0.86) and quarantining newly purchased animals (OR 0.54, 95%CI 0.30 - 0.97) provided protection. Working in a milk positive farm and exposure to birth products during calving were associated with seropositivity among farmers. This study provides useful information for Q fever prevention and control. Health education regarding Q fever prevention should be provided to farmers and public health and iii animal health officers in high risk areas in Thailand. iv To livestock farmers in Thailand. This work could not be accomplished without their support. I hope this work will contribute to an improvement in the awareness of occupational risk to prevent the occurrence of Q fever among this high risk population. v ACKNOWLEGDEMENTS This work was made possible with support from several people and organizations. I would like to first express the deepest appreciation to all my committee members, especially Dr. Steven Meshnick, my dissertation chair, who has been very supportive and encouraging. When I first discussed this project with him, he was very enthusiastic and provided his insightful comments about conducting research in the field. He trained me to be a researcher and allowed me to work and think independently, but he made sure that my ideas were feasible and practical. With his guidance, I have learned the skills necessary to conduct scientific research in the real world. I am also very fortunate to work with Dr. Gary Koch. As a student in his Categorical Data Analysis class, I am glad to apply the knowledge I have learned from the class to my real data set. Dr. Koch provided critical suggestions on sampling and data analyses, as well as sharing his experiences about cattle farms. He has always provided intuitive comments and clear answers for all the questions that I had in a timely fashion even when I was far away in the field. I have learned a lot from him. I am grateful for Dr. Gilbert Kersh for his support and suggestions, not only for this project, but also to other Q fever researchers in Thailand. As a Q fever expert, he has always provided insightful advice; he was one of the key persons to push this research forward. I am thankful for Dr. Michael Emch for his suggestions on spatial analysis. I am always curious to learn about spatial epidemiology and with Dr. Emch’s guidance I have gained more knowledge in spatial analysis. I am also grateful for Dr. David Weber, who always provided valuable feedback and suggestions. His enthusiasm about my project and his helpful critiques on the questionnaires and the research results has always been appreciated. It has been a privilege to work with all these splendid mentors. I cannot thank enough my mentors in Thailand, Dr. Pawin Padungtod, who introduced me to the Q fever project and guided me through the process of developing the proposal, submission for funding, and conducting research in the field. As public health is multidisciplinary, Dr. Pawin has shown me the power of networking and collaboration, as well as the importance of the “One Health” principle and its application vi to real world research practice. Although he moved to work in another country, he consistently gave comments or suggestions whenever I asked for help. My sincere thank also goes to Dr. Saowapak Hinjoy, my colleague and mentor, who has always provided mental and academic advice whenever I needed it. I would like to express my deepest gratitude to P’Mae, my colleague, my sister, and my dear friend who has always been supportive and believed in me. She encourages me to pursue my dream and teaches me to be optimistic, whatever the challenges in life I may have faced. She was one of the key persons who helped me run this project even when I was far away from Thailand. It would not be possible to conduct this project without the collaboration and precious support from the dairy cooperatives and Chiang Mai One Health Team consisting of the staff from the regional, provincial, and district health offices and the livestock office. I am grateful for the dairy cooperative members and the farmers who participated in our study. This project would not be accomplished without their support and participation. In addition, I would like to thank Drs. Somphorn Phornwisetsirikun, Pranee Rodtian, Phruetthiphon Sukpom, P’Yee, and P’Mai from Chiang Mai One Health Team, Drs. Natinee Kittiwan, Phornpan Laoleu, and staff from the Veterinary Research and Development Center in Lampang, Drs. Pattarin Opaschaitat and Tapakorn Chamchoy from the Thai National Institute of Animal Health, Dr. Decha Pangjai and his team from the Thai National Institute of Health, Ms. Dararat Danklai from the immunology laboratory at Maharaj Nakorn Chiang Mai Hospital, the veterinarians from Mae-on animal hospital, and Drs. Wittawat Modethed, Kanin, Puttipol Kongsook, Narin, and all the staff from the herd health units for all their support and suggestions during data collection and field works. Further acknowledgements go to the staff of the IEIP-Q team; Dr. Teerasak Chuxnam, Dr.Charatdao Bunthi, Ms. Somreuthai Na Nan, Apiladee Soonngam, Pajaree Kongsoon, Somkid Kongyu, and Janjao Rodchangphuen who helped with logistics and coordination, and Mr. Benz and his family for taking us to the field. The generous assistance and oversight of the Bureau of Epidemiology, Ministry of Public Health, and Chiang Mai livestock and health offices administration is also acknowledged, with thanks. I would also like to thank to the Centers for Disease Control and Prevention, USA for their financial support of this project. From the beginning of my PhD, I would like to thank Drs. Sopon Iamsiritaworn, Sujarti Jetanasen, Pasakorn Akarasewi, Chuleeporn Jiraphongsa, Potjaman Siriarayaporn, Tanarak Plipat, and the staff vii from the Field Epidemiology Training Program, and the Bureau of Epidemiology, Department of Disease Control for their support and for giving me the opportunity to pursue the doctoral degree in epidemiology. I am also grateful for the Royal Thai Ministry of Public Health which provided me with the scholarship. My profound appreciation also goes to Dr. Pradya Somboon from the Department of Parasitology, Faculty of Medicine, Chiang Mai University; and Ajarn Surachai, Leepitakrat, and Dr. Alongkot Polawat from the Armed Forces Research Institute of Medical Sciences (AFRIMS) for their kind support in tick identification; the students and staff from the Biomedical Consulting Laboratory, Department of Biostatistics, University of North Carolina at Chapel Hill for their suggestions and help with sampling methods; Dr. Sharon Weir for her supports during my first year in Chapel Hill, and our department student service specialists-Nancy Colvin, Carmen Woody, Valerie Hudock, and Jennifer Joyce Moore, who always supported us and were there whenever we had questions. My sincere thanks also go to Dr. Leedom Lefferts for proofreading my dissertation and Dr. Rungsima Kullapat for her kind hospitality. Most importantly, I would like to thank my family who always supports me with love and encouragement although thousands of miles away from the United States. Thanks to my dad, mom, sisters, and brother who are always on my side. I could not go this far without all their support. In addition, I would like to acknowledge my friends and classmates here at UNC-CH for all the good times we spent together and that made me feel that Carolina was like home.