Corbett, Elizabeth L.a; Churchyard, Gavin J.b; Clayton, Tim C.a; Williams, Brian G.c; Mulder, Daand; Hayes, Richard J.a; De Cock, Kevin M.a
From the aDepartment of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK, the bDepartment of Medicine, Ernest Oppenheimer Hospital, Welkom, South Africa, the cEpidemiology Research Unit, Johannesburg, South Africa and dTropical Epidemiology and Public Health, Institute of Social Medicine, University of Amsterdam, The Netherlands.
Correspondence to Dr E.L. Corbett, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK. Fax: 020 7637 4314; e-mail: [email protected]
Received: 3 February 2000;
revised: 17 May 2000; accepted: 3 July 2000.