In the past decade, David has served as an expert adviser and consultant to a number of World Health Organization (WHO), regional and national health programmes in the African and Pacific Regions. He also served as the Director of a World Health Organization Collaborating Centre in Vectorborne Diseases.
David's research interests include: novel infectious disease surveillance methods, control of zoonotic diseases and strategies for reducing inequity in public health service delivery. He has over 200 peer-reviewed publications, and has published several scientific monographs and chapters in leading public health texts.