Acknowledgements
The authors dearly thank the Karen Elise Jensen Foundation in Denmark for sponsoring this Twin Ph.D. project. Further, we thank the University of Rwanda and Aarhus University, Denmark for supporting the project through smooth collaborations. We gratefully acknowledge the contributions of Michael Miller, Calvin Wilson, Laetitia Nyirazinyoye, Sylvere Itangishaka, Peter Vedsted, Henrik Støvring, Jørn Atterman and Ditte Andreasen.