1. Department of Microbiology, Faculty of Life Sciences, University of Benin, Benin City, Edo State, Nigeria
2. Division of Epidemiology & Public Health, University of Nottingham, Nottingham, NG5 1PB, UK
3. Institute of Child Health, University of Benin, Benin City, Edo State, Nigeria
4. Nottinghamshire County Council, Nottingham, UK