The Epidemiology of Ixodes scapularis and Borrelia burgdorferi Collected from Pet Dogs in an Emerging Lyme Disease Risk Area of Southeastern Ontario, Canada by Christine Anne James A Thesis presented to The University of Guelph In partial fulfilment of requirements for the degree of Master of Science in Pathobiology Guelph, Ontario, Canada © Christine Anne James, July, 2017 ABSTRACT THE EPIDEMIOLOGY OF IXODES SCAPULARIS AND BORRELIA BURGDORFERI COLLECTED FROM PET DOGS IN AN EMERGING LYME DISEASE RISK AREA OF SOUTHEASTERN ONTARIO, CANADA Christine Anne James Advisors: University of Guelph, 2017 Dr. Claire Jardine Dr. David Pearl The major objectives of this thesis were to identify the tick species parasitizing companion dogs in southeastern Ontario, determine demographic and management factors associated with the carriage of I. scapularis and B. burgdorferi-positive ticks, and identify clustering of the carriage of these organisms in space, time, and space- time. Seven species of ticks from 543 companion dogs were collected from 20 participating veterinary hospitals. Ixodes scapularis were detected on 85.6% of parasitized dogs, and 7.5% of these dogs were carrying at least one B. burgdorferi- positive tick. The odds of I. scapularis parasitism was significantly greater in fall and spring compared to summer, with closer proximity to Lake Ontario, in female compared to male dogs, in dogs weighing over 30 kg, and in dogs that had not visited a farm. Significant spatial, temporal and space-time clusters were identified that were frequently consistent with surveillance data acquired from active tick surveillance. ii ACKNOWLEDGEMENTS I am very grateful for the all of the people who helped make this thesis possible. The “dynamic duo” of my co-advisors, Dr. Claire Jardine (Department of Pathobiology) and Dr. David Pearl (Department of Population Medicine), provided me with the gentle encouragement and decisive direction needed to guide me through the research process. Claire you are exceptionally generous, supportive, and wise. David your attention to detail, infectious belly laugh, and knowledge of epidemiology are worthy of “modelling” in research and in life! I am also thankful for Dr. Andrew Peregrine’s (Department of Pathobiology) continued energy and enthusiasm for the project, as well as his keen clinical parasitology perspective. I am indebted to Dr. Robbin Lindsay, and his team at the National Microbiology Laboratory in Winnipeg, for their expertise and the time spent on tick identification and pathogen testing. I would like to acknowledge the generous fellowship from the Ontario Veterinary College, research funding from the OVC Pet Trust, and support from the Centre for Public Health and Zoonoses. I am grateful for the support of Donna, Marni and Tami in the Department of Pathobiology who helped with the details of graduate work. This project would not have been possible without the commitment and time donated by the veterinarians and support staff from the 20 participating veterinary hospitals, the hundreds of pet owners who took the time to fill out a questionnaire, and the pets that collected ticks! There are too many individuals to count, and I would not want to leave someone out. Your input and time was vital to the collection of data. This iii project took longer than expected to complete, and I am most grateful for your patience and participation. A special thank you goes to the “Wild Epi Group” of Jamie, Katie, Kathryn, Jon, Nadine, Shannon, and Kristin for the laughs, late night pizza, writing support, and statistical questions. This research was an iterative process, but it was completed…by zombies. I wish you all much success for your work and in your life. Don’t ever stop seeking the truth. I also wish to thank my family for their logistical and emotional support. Especially Johanna, Vera, my mother-in-law, Barb, and my mom, Kathryn, who helped keep our home running smoothly. To my best friend and life partner, Rob Walsh: you work hard, you are my compass, and you are “doing awesome”. Thank you for picking me up when I needed help. Finally to our sons, Henry and Gordon, I love you so much. Thank you for driving with me to pick up ticks, laughing with me about the fact that I went back to school, and for always reminding me of what is most important in life. The natural world is remarkable; please take the time to understand it. “Unless someone like you cares a whole awful lot, nothing is going to get better. It’s not.” Dr. Seuss (1904 - 1991) “The question is not what you look at, but what you see?” Henry David Thoreau (1817 – 1862) iv DECLARATION OF WORK I declare that all of the work reported in this thesis was performed by me, with the exception of the items indicated below. The tick identification and diagnostic testing for tick pathogens were performed by Dr. Robbin Lindsay’s lab at the Public Health Agency of Canada’s National Microbiology Laboratory in Winnipeg, Manitoba. v TABLE OF CONTENTS ABSTRACT ..................................................................................................................... ii ACKNOWLEDGEMENTS .......................................................................................... iii DECLARATION OF WORK ........................................................................................ v LIST OF TABLES ....................................................................................................... viii LIST OF FIGURES ........................................................................................................ x LIST OF SYMBOLS, ABBREVIATIONS AND NOMENCLATURE ................... xii CHAPTER 1: LITERATURE REVIEW AND RESEARCH OBJECTIVES ......... 1 1.1 BRIEF HISTORY AND INTRODUCTION TO TICKS ..................................... 1 1.1.1 Nuttalliellidae .................................................................................................... 1 1.1.2 Argasidae – Soft Ticks ...................................................................................... 2 1.1.3 Ixodidae – Hard Ticks ....................................................................................... 3 1.1.4 Global changes in tick distribution ................................................................... 7 1.2 IXODIDAE AND COMPANION ANIMALS ..................................................... 8 1.2.1 Tick Collection.................................................................................................. 8 1.2.2 Risk factors for tick infestation ....................................................................... 12 1.2.3 Tick-borne disease serology ........................................................................... 16 1.2.4 National database surveillance ........................................................................ 18 1.3 LYME DISEASE ................................................................................................ 20 1.3.1 History of Lyme disease ................................................................................. 20 1.3.2 The vector ....................................................................................................... 21 1.3.3 The pathogen ................................................................................................... 23 1.3.4 The disease ...................................................................................................... 25 1.3.5 Current distribution of Ixodes scapularis and Borrelia burgdorferi in Ontario ........................................................................................................................ 30 1.3.6 Other tick-borne pathogens of Ixodes scapularis and co-infections ............... 31 1.3.7 Prevention ....................................................................................................... 32 1.4 STUDY RATIONALE AND OBJECTIVES ..................................................... 37 1.5 REFERENCES ................................................................................................... 39 vi CHAPTER 2: A CASE-CASE STUDY EXAMINING RISK FACTORS FOR IXODES SCAPULARIS CARRIAGE RELATIVE TO OTHER TICK SPECIES; INCLUDING RISK FACTORS FOR BORRELIA BURGDORFERI-POSITIVE TICK CARRIAGE IN A POPULATION OF PET DOGS FROM SOUTHEASTERN ONTARIO. .................................................................................. 60 2.1 ABSTRACT .............................................................................................................. 60 2.2 INTRODUCTION .................................................................................................... 61 2.3 METHODS ............................................................................................................... 64 2.4 RESULTS ................................................................................................................. 72 2.5 DISCUSSION ........................................................................................................... 76 2.6 REFERENCES ......................................................................................................... 85 CHAPTER 3: SPATIAL, TEMPORAL, AND SPACE-TIME CLUSTERING OF IXODES SCAPULARIS PARASITISM IN COMPANION DOGS FROM SOUTHEASTERN ONTARIO, CANADA. ............................................................. 102 3.1 ABSTRACT ............................................................................................................ 102 3.2 INTRODUCTION .................................................................................................