Predicting disease vector distributions through space and ... Predicting disease vector distributions

  • View
    0

  • Download
    0

Embed Size (px)

Text of Predicting disease vector distributions through space and ... Predicting disease vector...

  • Predicting disease vector distributions through space and time

    using environmental and vector control data

    by

    Emily Acheson

    Thesis submitted to the Faculty of Graduate and Postdoctoral Studies

    University of Ottawa

    in partial fulfillment of the requirements for the M.Sc. Degree in the

    Ottawa-Carleton Institute of Biology

    Thèse soumise à la Faculté des études supérieures et postdoctorales,

    Université d’Ottawa en vue de l’obtention de la maîtrise en sciences de

    L’Institut de Biologie d’Ottawa-Carleton

    © Emily Acheson, Ottawa, Canada, 2015

  • ii

    Acknowledgements

    I would first like to thank my supervisor, Dr. Jeremy Kerr, for providing the most

    patient editing of often-painful manuscripts, opportunities and financial support for

    conferences, generous recommendation letters, an unforgettable trip to Tanzania, and Basil,

    the lab therapy dog. I also thank my committee members Dr. Antoine Morin and Dr. Scott

    Mitchell for their advice and guidance over the past two years.

    I am grateful to NSERC and the Queen Elizabeth II Graduate Scholarship for funding

    my research. I would also like to acknowledge the University of Ottawa for providing me

    with tuition scholarships and other award opportunities.

    To Cassie, Alana, Laura, and Bronwyn, you have each selflessly offered help without

    hesitation the moment I needed it. A special thanks to Juan Zuloaga, who became a second

    supervisor when R or ArcGIS just would not work (which was all the time) and Rosana

    Soares for all the hugs and laughs and pizza binge eating.

    I thank my loving boyfriend Andrew. You have never stopped pushing me forward

    and gently reminding me of what matters most while also serving as an example of someone

    who works harder than anyone else I know.

    My family deserves several pages for all the home-cooked food sent up in suitcases,

    cars, planes and trains, and for the love and encouragement that have gotten me this far. First

    and foremost, my parents are the reason I am still pursuing this crazy career. Neither of you

    ever doubted I could do it and I might not still be trying without your constant support and

    late-night phone calls. I dedicate this thesis to you both.

  • iii

    Table of Contents

    Acknowledgements ................................................................................................................. ii

    Table of Contents .................................................................................................................. iii

    Abstract .................................................................................................................................. iv

    Résumé .................................................................................................................................... v

    List of Tables ......................................................................................................................... vi

    List of Figures ....................................................................................................................... vii

    General Introduction ............................................................................................................. 1

    Chapter 1: Looking forward by looking back: Using historical calibration to improve

    forecasts

    of human disease vector distributions ...................................................................................... 7

    Abstract .............................................................................................................................. 7

    Introduction ....................................................................................................................... 8

    Methods ............................................................................................................................ 12

    Results and Discussion .................................................................................................... 13

    Validating spatial models ............................................................................................. 13

    Projecting vector distributions into the future .............................................................. 18

    Historical calibration ................................................................................................... 22

    Conclusions ...................................................................................................................... 25

    Tables ................................................................................................................................ 27

    Figures .............................................................................................................................. 30

    Chapter 2: Where have all the mosquito nets gone? Spatial modelling reveals mosquito net

    distributions across Tanzania do not target optimal Anopheles mosquito habitats ................. 36

    Abstract ............................................................................................................................ 36

    Introduction ..................................................................................................................... 38

    Methods ............................................................................................................................ 41

    Study area ..................................................................................................................... 41

    Entomological records .................................................................................................. 41

    Niche model .................................................................................................................. 42

    Environmental data ...................................................................................................... 44

    Mosquito net survey data .............................................................................................. 46

    Mosquito net use layers ................................................................................................ 46

    Statistical analyses ........................................................................................................ 48

    Results ............................................................................................................................... 48

    Habitat suitability model .............................................................................................. 48

    ITN use and mosquito habitat suitability ...................................................................... 50

    Discussion ......................................................................................................................... 51

    Conclusions ...................................................................................................................... 55

    Tables ................................................................................................................................ 56

    Figures .............................................................................................................................. 57

    Conclusions ............................................................................................................................ 65

    References .............................................................................................................................. 68

    Appendix A: Anopheles occurrence records used in Chapter 2. ........................................... 84

    Appendix B: References for Appendix A. ............................................................................. 87

  • iv

    Abstract

    Within this thesis, I performed a systematic review of approaches to broad-scale

    modelling of disease vector distributions and determined the most widely used methods

    predict current species niches and project the models forward under future climate scenarios

    without temporal validation. I then provided a forward-looking summary of emerging

    techniques to improve the reliability and transferability of those models, including historical

    calibration.

    I then predicted Anopheles mosquito distributions across Tanzania in 2001 (before

    large-scale ITN distributions) and compared this model with countrywide ITN use by 2012

    to assess where the most suitable mosquito habitats were located and whether ITN rollouts in

    Tanzania ensured coverage of such areas. I concluded that ITNs in Tanzania did not

    optimally target areas most at risk of malaria. In doing so, I provided a new approach to

    monitoring and evaluating vector control interventions across large spatial scales.

  • v

    Résumé

    Dans cette thèse, j’ai effectué une revue systématique des approches de modélisation

    de distribution de vecteurs de maladie à grande échelle et j’ai déterminé que les méthodes de

    modélisation les plus couramment utilisées prédisent les niches d'espèces actuelles et

    produisent des modèles prévisionnels selon des scénari

Recommended

View more >