Thesis Ref. No. _______________ SEROEPIDEMIOGICAL INVESTIGATION OF BOVINE BRUCELLOSIS AND ITS ZOONOTIC IMPLICATION IN SELECTED TOWNS OF OROMIA REGION, CENTRAL ETHIOPIA MVSc Thesis BY ABEJE ABERA ADDIS ABABA UNIVERSITY, COLLEGE OF VETERINARY MEDICINE AND AGRICULTURE, DEPARTMENT OF VETERINARY MICROBIOLOGY, IMMUNOLOGY AND PUBLIC HEALTH JUNE, 2018 BISHOFTU, ETHIOPIA SEROEPIDEMIOGICAL INVESTIGATION OF BOVINE BRUCELLOSIS AND ITS ZOONOTIC IMPLICATION IN SELECTED TOWNS OF OROMIA REGION, CENTRAL ETHIOPIA MSc Thesis A THESIS SUBMITTED TO THE COLLEGE OF VETERINARY MEDICINE AND AGRICULTURE, ADDIS ABABA UNIVERSITY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF VETERINARY SCIENCE IN VETERINARY MICROBIOLOGY BY ABEJE ABERA JUNE, 2018 BISHOFTU, ETHIOPIA Addis Ababa University College of Veterinary Medicine and Agriculture Department of Veterinary Microbiology, Immunology and Public Health As members of the Examining Board of the final MSc open defense, we certify that we have read and evaluated the thesis prepared by Abeje Abera entitled: Seroepidemiological investigation of bovine brucellosis and its zoonotic implication in selected towns of Oromia Region, Central Ethiopia. And recommend that it be accepted as fulfilling the thesis requirement for the degree of: Masters of Science in Veterinary Microbiology. Prof. Birhan Tamir ______________ _______________ Chairman Signature Date Dr. John Kiru _______________ ________________ External Examiner Signature Date Mr. Hika Waktola _____________ ________________ Internal Examiner Signature Date Dr. Bedaso Mammo ______________ ________________ Major Advisor Signature Date Dr. Tilaye Demissie ______________ _________________ Co- Advisor Signature Date Dr. Gezahegn Alemayehu _______________ _________________ Co- Advisor Signature Date Dr. Gezahegne Mamo ________________ _________________ Department Chairperson Signature Date TABLES OF CONTENTS Pages TABLES OF CONTENTS ............................................................................................................. i STATEMENT OF AUTHOR ...................................................................................................... iv ACKNOWLEDGEMENTS .......................................................................................................... v DEDICATION .............................................................................................................................. vi LIST OF TABLES ....................................................................................................................... vii LIST OF FIGURE ...................................................................................................................... viii LIST OF ANNEXES ..................................................................................................................... ix LIST OF ABBREVIATIONS ....................................................................................................... x ABSTRACT ................................................................................................................................... xi 1. INTRODUCTION ................................................................................................................... 1 2. LITRATURE REVIEW .......................................................................................................... 4 2.1. Historical overview of brucellosis ......................................................................................... 4 2.2. Etiology .................................................................................................................................... 5 2.3. Occurrence .............................................................................................................................. 5 2.3.1. Global distribution and economic impact of bovine brucellosis ............................... 5 2.3.2. Bovine brucellosis in Sub Saharan Africa (SSA) ....................................................... 6 2.3.3. Status of brucellosis in Ethiopia ................................................................................ 7 2.3.4. Host range and Brucella diversity ............................................................................. 8 2.3.5. Transmission .............................................................................................................. 9 2.4. Pathology and immune response to Brucella infection ....................................................... 9 2.5. Diagnosis ............................................................................................................................... 10 2.5.1. Diagnostic procedures ............................................................................................. 10 i 2.5.2. Direct methods for diagnosis of brucellosis ............................................................ 11 2.5.3. Indirect methods for diagnosis of brucellosis .......................................................... 14 2.6. Treatment .............................................................................................................................. 16 2.7. Impact of brucellosis on production and public health .................................................... 16 3. MATERIALS AND METHODS .......................................................................................... 18 3.1. Study Areas ........................................................................................................................... 18 3.2. Study population, study design and sample size determination ....................................... 20 3.3. Questionnaire for risk factors assessment ......................................................................... 22 3.4. Sample collection and laboratory test ................................................................................ 23 3.4.1. Serological blood sample collection ........................................................................ 23 3.4.2. Serological laboratory techniques ........................................................................... 23 3.5. Ethical clearance .................................................................................................................. 25 3.6. Data analysis ......................................................................................................................... 25 4. RESULTS ............................................................................................................................... 26 4.1. Questionnaire survey ........................................................................................................... 26 4.1.1. Socio-demographic characteristics of the respondents ........................................... 26 4.1.2. Occupational risk and awareness among dairy cattle farmers about brucellosis .. 27 4.1.3. Association of herd level risk factors with bovine brucellosis seropositivity .......... 28 4.2. Seroprevalence of dairy cattle Brucellosis by c-ELISA test ............................................. 29 4.2.1. Brucella seropositivity at animal level and associated risk factors ........................ 29 4.2.2. Brucella seropositivity at farm level and associated risk factors ............................ 31 4.3. Univariable logistic regression analysis of the variables associated with animal and herd level sero-positivity ...................................................................................................... 33 4.4. Multivariable logistic regression analysis of risk factors for Brucella seropositivity .... 35 ii 5. DISCUSSION ......................................................................................................................... 36 6. CONCLUSION AND RECOMMENDATIONS ................................................................. 43 7. REFERENCES ...................................................................................................................... 44 8. ANNEXES .............................................................................................................................. 59 iii STATEMENT OF AUTHOR First, I declare that this thesis is my bonafide work and that all sources of material used for this thesis have been duly acknowledged. This thesis has been submitted in partial fulfillment of the requirements for an advanced (MSc) degree at Addis Ababa University, College of Veterinary Medicine and Agriculture and is deposited at the University/College library to be made available to borrowers under rules of the library. I solemnly declare that this thesis is not submitted to any other institution anywhere for the award of any academic degree, diploma, or certificate. Brief quotations from this thesis are allowable without special permission provided that accurate acknowledgement of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the College when in his or her judgment the proposed use of the material is in the interests of scholarship. In all other instances, however permission must be obtained from the author. Name: Abeje Abera Signature: ______________ College of Veterinary Medicine and Agriculture, Bishoftu Date of Submission: _________________________ iv ACKNOWLEDGEMENTS I would like to thank my advisors Dr. Bedaso Mammo, Dr. Tilaye Demissie and Dr. Gezahegn Alemayehu for their unreserved help, constructive advice and time devotion to correct this manuscript. I also thank them for their genuine and energetic encouragement, suggestion, insight and scientific and professional guidance. I would like to acknowledge Addis Ababa University Research and Technology transfer for funding my thesis work through the thematic research “Promotion of Improved Dairy Technology & Investigation into Reproductive Diseases of Dairy for better Health, Productivity, and Development of Dairy sector in central Ethiopia” I would like to express my sincere appreciation to the Oromia Regional State for allowing me full time and salary of course by self sponsorship to attend my studies and the Addis Ababa University for admitting me to the course and allowing me to use all facilities. I want to express my deepest gratitude and appreciation to National Animal Health Diagnostic and Investigation Center (NAHDIC), Sebeta, Ethiopia for providing me valuable support and assistance during sample processing in the laboratory. I am grateful to the staff members of the center, especially to Mr. Teferi Benti, Dr. Getachewu Tuli, Dr. Biniyam Tadesse, Mr. Melaku Sonbo, and Mr. Abde Aliyi for their positive cooperation and encouragement during laboratory work at NAHDIC. I would like to extend my appreciation to Asela Regional Veterinary Laboratory staffs as a whole for their cooperation throughout sample collection and especially my recognition goes to Mr. Ali Desalegn for his unreserved support during the study time. Once more I owe my gratitude to my dear all MSc. students of batch 2017 for we peacefully and friendly enjoyed life together in the college for two years Most importantly, I would like to be grateful for my wife, w/ro Tigist Betru, for her unreserved encouragement and patience, for the reason that without her enthusiasm success was unachievable. v DEDICATION This paper is dedicated: To my father, Abera Dejenu and my mother Yewubnesh Hailu, who never went to school themselves for raising me up and sending me to school and supporting me financially and morally throughout my academic career. vi LIST OF TABLES TABLE 1: SERO-PREVALENCE OF BOVINE BRUCELLOSIS FROM DIFFERENT LOCATIONS OF ETHIOPIA . 8 TABLE 2: SOCIO- DEMOGRAPHIC CHARACTERISTIC OF THE RESPONDENTS USING CHI SQUARE ANALYSIS ................................................................................................................................ 26 TABLE 4: ASSOCIATION OF HERD LEVEL RISK FACTORS WITH BRUCELLOSIS ................................... 29 TABLE 7: ASSOCIATION BETWEEN ANIMAL AND HERD CHARACTERISTICS AND SEROPOSITIVITY OF BRUCELLOSIS ASSESSED BY UNIVARIATE LOGISTIC REGRESSION ANALYSIS ........................ 34 TABLE 8: MULTIVARIABLE LOGISTIC REGRESSION MODEL OF RISK FACTORS FOR BRUCELLA SEROPOSITIVITY IN DAIRY CATTLE AT INDIVIDUAL (N =803) AND FARM (N=110) LEVELS. ...... 35 vii