Diagnosis and epidemiology of Strongyloides stercoralis in Cambodia INAUGURALDISSERTATION Zur Erlangung der Würde eines Doktors der Philosophie Vorgelegt der Philosophisch-Naturwissenschaftlichen Fakultät der Universität Basel Von Fabian Schär aus der Schweiz Basel 2016 Originaldokument gespeichert auf dem Dokumentenserver der Universität Basel edoc.unibas.ch Genehmigt von der Philosophisch-Naturwissenschaftlichen Fakultät auf Antrag von Prof. Dr. Marcel Tanner, Prof. Dr. med Marco Albonico und Dr. Peter Odermatt Basel, den 22.04.2014 Prof. Dr. Jörg Schibler Dekan Dedicated to my beloved family Table of Contents List of figures ....................................................................................................................... viii List of tables .......................................................................................................................... ix List of abbreviations ............................................................................................................... x Acknowledgements .............................................................................................................. xii Summary .............................................................................................................................. xv 1. Introduction ....................................................................................................................... 1 1.1 Strongyloides stercoralis .............................................................................................. 1 1.2 Morphology and biology of S. stercoralis ...................................................................... 3 1.3 Genetic aspects of S. stercoralis .................................................................................. 4 1.4 Clinical outcome and pathology ................................................................................... 4 1.5 Risk factors: HTLV-1, HIV and alcoholism.................................................................... 6 1.6 Diagnosis ..................................................................................................................... 7 1.7 Treatment .................................................................................................................... 9 1.8 S. stercoralis in animals ..............................................................................................10 1.9 S. stercoralis and other soil-transmitted helminths ......................................................11 2. Aim and objectives ...........................................................................................................14 2.1 Aim .............................................................................................................................14 2.2 Main objectives ...........................................................................................................14 3. Material and methods .......................................................................................................15 3.1 Approach ....................................................................................................................15 3.2 Cambodia ...................................................................................................................15 3.3 Field sites and surveys conducted ..............................................................................15 3.4 Ethical considerations .................................................................................................17 4. Outline of thesis ................................................................................................................18 5. Strongyloides stercoralis: Global Distribution and Risk Factors ........................................19 5.1 Abstract ......................................................................................................................20 5.2 Introduction .................................................................................................................21 5.3 Materials and Methods ................................................................................................23 5.4 Results ........................................................................................................................25 5.5 Discussion ..................................................................................................................42 5.6 Supporting information ................................................................................................48 5.7 Acknowledgements .....................................................................................................48 5.8 Author contributions ....................................................................................................48 6. Treatment of Strongyloides stercoralis ..............................................................................49 6.1 Introduction .................................................................................................................50 v 6.2 Methods ......................................................................................................................51 6.3 Results ........................................................................................................................52 6.4 Discussion ..................................................................................................................61 7. The prevalence and diversity of intestinal parasitic infections in humans and domestic animals in a rural Cambodian village ....................................................................................64 7.1 Abstract ......................................................................................................................65 7.2 Introduction .................................................................................................................67 7.3 Materials and Methods ................................................................................................68 7.4 Results ........................................................................................................................70 7.5 Discussion ..................................................................................................................75 7.6 Acknowledgements .....................................................................................................77 7.7 Author Contributions ...................................................................................................77 7.8 Conflict of interest .......................................................................................................78 7.9 Financial Support ........................................................................................................78 8. High prevalence of Ancylostoma ceylanicum hookworm infections in humans, Cambodia, 2012 .....................................................................................................................................79 8.1 Abstract ......................................................................................................................80 8.2 Introduction .................................................................................................................81 8.3 Materials and methods ................................................................................................82 8.4 Results ........................................................................................................................85 8.5 Discussion ..................................................................................................................89 8.6 Acknowledgements .....................................................................................................91 9. Evaluation of real-time PCR for Strongyloides stercoralis and hookworm as diagnostic tool in asymptomatic schoolchildren in Cambodia .......................................................................92 9.1 Abstract ......................................................................................................................93 9.2 Introduction .................................................................................................................94 9.3 Materials and Methods ................................................................................................94 9.4 Results ........................................................................................................................97 9.5 Discussion ................................................................................................................ 100 10. Strongyloides stercoralis larvae excretion pattern before and after treatment ............... 102 10.1 Summary ................................................................................................................ 103 10.2 Introduction ............................................................................................................. 104 10.3 Materials and methods ............................................................................................ 104 10.4 Results .................................................................................................................... 106 10.5 Discussion .............................................................................................................. 110 10.6 Acknowledgements ................................................................................................