INCIDENCE AND RISK FACTORS OF CIGUATERA FISH POISONING IN THE CARIBBEAN AND FLORIDA By ELIZABETH G. RADKE A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2013 1 © 2013 Elizabeth G. Radke 2 ACKNOWLEDGMENTS I have been incredibly fortunate to receive support and encouragement from many different people. I would like to express my deep appreciation and gratitude to my research mentor, Dr. Glenn Morris, for the guidance he provided me at every step along the way. Dr. Bob Cook has been a wonderful unofficial advisor, and helped me make progress whenever I got stuck. I am also so appreciative to the rest of my dissertation committee, Drs. Stephanie Staras, John Kairalla, and Don Behringer, for their insightful advice and constructive comments on my work. I am also grateful to many research partners, including those from the CaribCATCH project: Lynn Grattan, Sparkle Roberts, Margaret Abbott, Tyler Smith, Alison Robertson, Don Anderson, Mindy Richlen, Vasu Misra, and Dave Olsen. Andy Reich at the Florida Department of Health and Kevin Hanson at the Emerging Pathogens Institute also provided assistance and support. Lastly, I would like to thank my family – my parents Sally and Bill Radke, my husband Earl Farabaugh, my siblings, and my animals for their emotional support through this process. 3 TABLE OF CONTENTS page ACKNOWLEDGMENTS .................................................................................................. 3 LIST OF TABLES ............................................................................................................ 7 LIST OF FIGURES .......................................................................................................... 8 ABSTRACT ..................................................................................................................... 9 CHAPTER 1 LITERATURE REVIEW .......................................................................................... 11 Clinical Presentation in Humans ............................................................................. 12 Incidence ................................................................................................................ 15 Risk factors ............................................................................................................. 20 Environmental Influences ........................................................................................ 24 Seawater Temperature ..................................................................................... 24 Disturbance to Coral Reefs .............................................................................. 26 Conclusions ............................................................................................................ 28 2 SPECIFIC AIMS AND RATIONALE ........................................................................ 30 Aim 1 – Estimate Incidence .................................................................................... 30 Aim 2 – Identify Risk Factors .................................................................................. 30 Aim 3 – Assess Population-level Changes in Risk Factors ..................................... 31 Aim 4 – Describe Illness Causing Fish.................................................................... 31 3 CIGUATERA INCIDENCE IN THE U.S. VIRGIN ISLANDS HAS NOT INCREASED OVER A 30 YEAR TIME PERIOD, DESPITE RISING SEAWATER TEMPERATURES ............................................................................. 32 Introduction ............................................................................................................. 32 Methods .................................................................................................................. 33 Telephone Survey ............................................................................................ 33 Emergency Department Visits .......................................................................... 34 Incidence Calculations ..................................................................................... 34 Incidence from telephone survey ............................................................... 35 Incidence from emergency department visits ............................................. 35 Risk Factor Analysis ......................................................................................... 35 Behavioral and Demographic Changes from 1980 to 2010 .............................. 36 Seawater Temperature ..................................................................................... 36 Results .................................................................................................................... 37 Telephone Survey ............................................................................................ 37 Emergency Department Visits .......................................................................... 37 Incidence .......................................................................................................... 38 4 Risk Factors ..................................................................................................... 38 Behavioral and Demographic Changes from 1980 to 2010 .............................. 39 Discussion .............................................................................................................. 40 4 INFLUENCE OF CARDIAC DISEASE AND ALCOHOL USE ON THE DEVELOPMENT OF SEVERE CIGUATERA ILLNESS .......................................... 50 Introduction ............................................................................................................. 50 Methods .................................................................................................................. 50 Case and Control Selection .............................................................................. 50 Data Collection ................................................................................................. 51 Analysis ............................................................................................................ 52 Results .................................................................................................................... 52 Discussion .............................................................................................................. 53 5 EPIDEMIOLOGY OF CIGUATERA IN FLORIDA ................................................... 57 Introduction ............................................................................................................. 57 Methods .................................................................................................................. 58 Data .................................................................................................................. 58 Public health reports .................................................................................. 58 Survey of recreational fishermen ............................................................... 58 Analysis ............................................................................................................ 60 Incidence and demographic risk factors ..................................................... 60 Types and catch locations of illness causing fish ....................................... 60 Results .................................................................................................................... 61 Incidence and Demographic Risk Factors ........................................................ 62 Types and Catch Locations of Illness Causing Fish ......................................... 62 Discussion .............................................................................................................. 63 6 CONCLUSIONS ..................................................................................................... 75 Summary of Findings .............................................................................................. 75 Aim 1 – Estimate Incidence .............................................................................. 75 Aim 2 – Identify Risk Factors ............................................................................ 78 Aim 3 – Assess Population-level Changes in Risk Factors .............................. 81 Aim 4 – Describe Illness Causing Fish ............................................................. 81 Strengths and Limitations ....................................................................................... 82 Public Health Implications and Suggestions for Future Research .......................... 84 APPENDIX A ST. THOMAS TELEPHONE SURVEY QUESTIONNAIRE ..................................... 86 B FLORIDA CIGUATERA CASE DEFINITION AND DATA COLLECTION FORM .... 97 C CIGUATERA QUESTIONNAIRE FOR RECREATIONAL FISHERMEN ............... 101 5 D ROLES OF COAUTHORS .................................................................................... 103 LIST OF REFERENCES ............................................................................................. 105 BIOGRAPHICAL SKETCH .......................................................................................... 111 6 LIST OF TABLES Table page 1-1 Symptoms of ciguatera fish poisoning reported in all clinical studies in the Caribbean ..........................................................................................................