CHOLERA IN A TIME OF EL NIÑO AND VULNERABILITY IN PIURA, PERU: A CLIMATE AFFAIRS APPROACH By Iván J. Ramírez A DISSERTATION Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Geography 2012 ABSTRACT CHOLERA IN A TIME OF EL NIÑO AND VULNERABILITY IN PIURA, PERU: A CLIMATE AFFAIRS APPROACH By Iván J. Ramírez The goal of my dissertation research is to reconstruct the temporal and spatial associations among El Niño-Southern Oscillation (ENSO), social vulnerability and cholera incidence in Piura, Peru from 1991 to 2001 in order to better understand El Niño’s impact on the cholera epidemic in Peru during the 1990s. Piura is important to study because it was one of the first places to report cholera in Peru. It also had one of the highest incidence rates in the country, and historically, the region is known for El Niño. My overarching research questions are: (1) What was the impact of ENSO on cholera incidence in Piura; and (2) How did social vulnerability influence this relationship? My research hypotheses are: (a) There was a temporal association between ENSO, climate and cholera cases in Piura in the 1990s. Furthermore, these associations were stronger after 1992 compared to the onset of the epidemic in 1991; and (b) The spatial variability of the ENSO-climate-cholera associations in Piura in 1997-98 will be explained by the spatial distribution of social vulnerability. Moreover, the level of social vulnerability within districts in Piura will either antagonize or buffer the effects of ENSO and climate on cholera incidence. I address my research questions and hypotheses using a climate affairs approach that is informed by disease ecology and vulnerability theories from the geographic subfields of medical and human-environment geography. Climate affairs is an integrating concept in the earth and social sciences used to understand the interrelationships among climate, environment and society worldwide. Using climate affairs, I developed a conceptual framework that: 1) examines cholera transmission within a broader conception of ENSO; 2) links ENSO-cholera associations to social vulnerability; and 3) considers ENSO-cholera interactions at multiple scales. The key findings of this research suggest that cholera’s temporal association with ENSO was transient throughout the 1990s; the strongest association was found during the 1997-98 El Niño. I also found that cholera transmission occurred through the interactions of global and local sea surface temperatures with rainfall. Furthermore, I demonstrated that the spatial distribution of social vulnerability can in part explain the associations between global and local climate and cholera during the 1997-98 El Niño. However, these associations varied by time lag, district and variable. It also appears that districts on the west coast of the subregion of Piura were the most vulnerable. Lastly, important to the understanding of these findings is that interpretation of ENSO and its association with cholera will highly depend on the Niño definition and region chosen for analysis. This research contributes to future climate-informed initiatives that enhance societal capacities, while focusing on population health and the monitoring of populations during future climate events in Piura, Peru and the Latin American region. Copyright by IVÁN J. RAMÍREZ 2012 This thesis is dedicated to my parents Jorge and Nilda Ramírez v ACKNOWLEDGEMENTS I would like to greatly thank my dissertation advisor Dr. Sue C. Grady for guidance through the years. I really would not have made it without her full-hearted support. I would also like to thank my committee: Dr. Antoinette WinklerPrins ([Geography] who I credit for bringing me to MSU), Dr. Julie Winkler (Geography), and Dr. Steve Esquith (Philosophy). I would like to express my deep appreciation to Dr. Michael H. Glantz (CCB), my external committee member, for the strong support and Niño wisdom he has bestowed on me since 2006. I am indebted to my collaborators in Peru: Ing. Norma Ordinola, University of Piura, Ing. Grover Otero (Proyecto Chira-Piura), Dr. Elsa Galarza and Joanna Noelia Kamiche Zegarra (University of the Pacific) and Dr. Luis Miguel Castrov V. I would also like to thank: INEI (Piura), the Ministry of Health (Piura and Lima), General Office of Epidemiology (Piura and Lima), Dr. Ana Gil (International Institute of Nutrition), Dr. Marcos Cueto (Institute of Peruvian Studies), Dr. Hildegardo Córdova Aguilar (Applied Geography Research Center at the Pontifical Catholic University), and Pablo Lagos (IGP). I would also like to thank Dr. Gil Compo (wavelet script), Mark Finn (ArcGIS genius), and Moises Smart (Matlab wizard) for their technical support; and a special thank you to Dr. Diane M. Doberneck (UOE) . This study was supported through grants by the following institutions at Michigan State University: Department of Geography, Department of Philosophy (Ethics and Development Specialization), Center for Latin American and Caribbean Studies, and the Graduate School. Support was also provided by CCB in Boulder, CO. In closing, I am forever grateful to my wife Jieun Lee for supporting my dreams and aspirations. vi TABLE OF CONTENTS LIST OF TABLES ........................................................................................................................... x LIST OF FIGURES ........................................................................................................................ xi CHAPTER 1: INTRODUCTION ....................................................................................................... 1 1.1 The Cholera Epidemic in Peru.......................................................................................... 6 1.2 Explaining the Cholera Epidemic in Peru ......................................................................... 8 1.2.1 Passing Ship Hypothesis ..................................................................................... 8 1.2.2 El Niño-cholera Hypothesis ................................................................................ 8 1.3 Challenging the El Niño-cholera Hypothesis .................................................................. 10 1.4 Study Significance ......................................................................................................... 13 1.5 Dissertation Format ...................................................................................................... 13 CHAPTER 2: LITERATURE REVIEW ............................................................................................. 15 2.1 ENSO Science and Knowledge ....................................................................................... 15 2.1.1 ENSO Events .................................................................................................... 16 2.1.2 ENSO Monitoring and Definition ...................................................................... 17 2.1.3 ENSO Teleconnections in Peru ......................................................................... 21 2.1.4 ENSO Ecosystem and Societal Impacts in Peru ................................................. 23 2.2 Climate and Cholera Ecology ......................................................................................... 25 2.2.1 Global Climate Parameters and Cholera ........................................................... 27 2.2.2 Local Sea Surface Temperature ........................................................................ 30 2.2.3 Local Rainfall .................................................................................................... 33 2.2.4 Temporal Lags .................................................................................................. 34 2.3 Cholera Transmission and Human Ecology .................................................................... 35 2.4 Cholera and Population Vulnerability ............................................................................ 38 2.4.1 Cholera and Determinants of Health ................................................................ 39 2.4.2 Vulnerable Subpopulations .............................................................................. 42 CHAPTER 3: REEXAMINING EL NIÑO AND CHOLERA IN PERU .................................................... 45 3.1 Recounting El Niño Impacts on Cholera in Peru ............................................................. 45 3.2 The Importance of Definition ........................................................................................ 48 3.3 The La Niña Factor ........................................................................................................ 53 3.4 Geography of El Niño Impacts ....................................................................................... 56 3.5 Rainfall Extremes .......................................................................................................... 60 3.6 Social Dimensions ......................................................................................................... 61 3.7 Summary....................................................................................................................... 62 3.8 Research Questions, Hypotheses and Objectives .......................................................... 63 vii CHAPTER 4: RESEARCH DESIGN ................................................................................................. 65 4.1 Approach, Concepts and Framework............................................................................