Impact and determinants of level SODIS interventions: a ... Andri Christen aus Affoltern i.E. (BE),...

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Transcript of Impact and determinants of level SODIS interventions: a ... Andri Christen aus Affoltern i.E. (BE),...

  • Impact and determinants of  

    community­level SODIS­interventions:  Experience from a community­randomised trial on  

    solar water disinfection 



    Erlangung der Würde eines Doktors der Philosophie  vorgelegt der 

    Philosophisch‐Naturwissenschaftlichen Fakultät  der Universität Basel 

    von  Andri Christen 

    aus Affoltern i.E. (BE), Basel‐Stadt (BS) 

    Basel, 2011 

        Originaldokument gespeichert auf dem Dokumentenserver der Universität Basel

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  • Genehmigt von der Philosophisch-Naturwissenschaftlichen Fakultät auf Anfrage von

    Prof. M Tanner und Prof. C Braun-Fahrländer.

    Basel, den 24. März 2009

    Prof. Dr. Eberhard Parlow



  • Acknowledgements 1 Executive Summary 4

    PART I: Introduction to BoliviaWET: Background, objectives and methodological overview of the SODIS evaluation trail

    CHAPTER I: Introduction 1. Background 22 1.1. Water and excreta related diseases and defining diarrhoea 23 1.2. Prevention of diarrhoeal disease 27 1.3. Improving access to drinking water 29 1.4. Point-of-use household water treatment 31 1.5. Solar water disinfection – SODIS, efficacy, health impact,

    and worldwide application 34 1.6. Conclusion 38 1.7. References 40

    CHAPTER II: Goals and Objectives 2. Goals and Objectives 49

    CHAPTER III: The implementation of BoliviaWET: A methodological overview of the SODIS evaluation trail 3. Background 51 3.1. Objectives of the community-cluster randomised SODIS intervention trial 52 4. Overview of the design 52 4.1. Study site 53 4.2. Community-cluster selection 54 4.3. Enrolment of communities and study participants 55 4.4. Primary outcome: diarrhoeal disease 57 4.6. Covariates: Socio-demography, environment, water quality and SODIS-compliance 58 4.7. Sample size 59 5. Randomisation 60 6. Intervention 61 6.1. The device: Solar water disinfection – SODIS 61 6.3. SODIS implementation: Promotion at district-, community-and

    household level 61 6.4. Implementation strategy: establishing demand and sustainable SODIS-use 66 6.5. Standardisation 68 7. Data collection 68 7.1. Field staff: Recruitment and training 69 7.2. Establishing a morbidity surveillance system 72 7.3. Supervision of the field staff 72 7.4. Measuring SODIS compliance 73 7.5. Stool analysis 73 7.6. Water analysis 74

  • 8. Ethics 74 9. References 76

    PART II: SODIS effectiveness

    Manuscript I: Solar Drinking Water Disinfection (SODIS) to Reduce Childhood Diarrhoea in Rural Bolivia: A Cluster-Randomized, Controlled Trial 80

    PART III: SODIS adoption and use

    Manuscript II: Adoption of home-based solar water disinfection (SODIS) in rural Bolivian homes 95

    Manuscript III: Factors associated with compliance among users of solar water disinfection in rural Bolivia 113

    PART IV: Improving water quality and indoor air

    Manuscript IV: Safe drinking water and clean air: An experimental study evaluating the concept of combining household water treatment and indoor air improvement using the Water Disinfection Stove (WADIS) 140

    PART V: Discussion and conclusion

    CHAPTER IV: Discussion 10. Effectiveness of SODIS 153 10.1. Current evidence of the SODIS health effectiveness: internal and external validity 154 10.2. Interpretation current evidence for health impact of SODIS 158 11. Compliance with SODIS: Factors for adoption and use 160 11.1. Measuring compliance with SODIS 160 11.2. Acceptance of SODIS 162 11.3. Adoption of SODIS 164 12. Sustainability of Point-of-use household water treatment systems 165 13. References 168

    CHAPTER V: Conclusion 14. Conclusion 173 15. References 175 Appendices 176 Curriculum vitae 193

  • 1


    It is a matter of common knowledge that the acknowledgements section is one of the most read sections in a thesis. Thus, I thought it should include some main findings and conclusions:

    • To implement this community-randomised trial (BoliviaWET), 38 intercontinental flights were necessary. This makes 478’040 air miles and a mileage of 26’890 litre Kerosene!

    • Working 3 years with more than 26 rural communities of the Totora district makes you the top-selling godfather of approx. 1500 children.

    • Coffee consumption during the course of obtaining a PhD is exorbitant. It is associated with an unexpectedly high financial investment (on average 2 cups/day is about 1825 sFr!)

    • Buying a car in Bolivia turned out to be something else than a bargain…

    • Deciding to conduct a PhD, travelling to the other end of the world and live in rural commu- nities in Bolivia for 3 years, conducting a community-randomised controlled trial in a crisis- ridden area, and finally writing a thesis is not possible without a social network, which leads me to the people and institutions I would like to acknowledge in this thesis.

    Daniel Mäusezahl – supervisor, a good mixture of “supervisor”, “co-worker” and “normal, down to earth person”. He made it possible for me to run the so far biggest SODIS randomised controlled trial and to embed my PhD within this trial. He gave me always the support and the degrees of freedom I needed. Thank you so much! Marcel Tanner – Professor and Director of the Swiss Tropical Institute (STI). It was his merit that I ended up running this project in the first place. He linked me to the BoliviaWET project and en- couraged me to undertake this adventure. He kept himself in the background, but never refused to provide valuable guidance when asked for. This was much valued. Myriam Cevallos – wife, fellow sufferer, field coordinator, and my anchor windward. I express my deepest admiration to her. Beyond doubt she was the key personality in the field, the heart of the study. She was the kind-hearted soul for the whole BoliviaWET team and the rescuer of so many children suffering severe K’echalera and their worried mommies. Monica Daigl, Michael Hobbins, Jan Hattendorf, and Gonzalo Duran – brain storming part- ners, source of inspiration, and engaged co-authors. Monica and Michael were of great help at the beginning when I was a “greenhorn”, Gonzalo was my counterpart throughout the project, and Jan was my tireless companion until the very end of my PhD. Thank you all so much! Jack Colford and Ben Arnold – Professor and PhD student at the University of California, Berke- ley. Jack helped to develop the BoliviaWET trial toward a NIH-fundable proposal. The enthusiastic help Jack and Ben offered and the permanent drive for perfectionism were key issues to the realisa- tion of this work. The friendship that I experience from them and their families is outstanding. Carlos Morante – trusted friend, genius innovator, and chief implementer of the SODIS interven- tion. He is one of the best trouble shooters I have ever met! His working philosophy was so inspir- ing. Roy Cordova – project administrator. He was always keeping up a structure, even if there wasn’t one. Thank you for exercising patience and being appreciative of all of us and truly tolerant of our bookkeeping!