Graduated in medicine in 1975. Then worked as a primary care physician in India and Ethiopia and as a district medical officer in Zimbabwe. In 1992, he started as a research fellow in the LSHTM. He is now a professor of public health in the Department of Infectious and Tropical Diseases. His research interests include epidemiology and control of malaria, meningitis, indirect methods to assess causes of death, and interventions to improve mother and child health. He is now leading several clinical trials and studies on innovative ways of delivering curative and perventive care to control burden of malaria and childhood pneumonia. He is a member of two consortia (ACT and MiP consortia) funded by the Bill and Melida Gates Foundation, and a temporary advisor on several WHO Technical Expert Groups on malaria and global burden of disease.