From the Departments of Child Health (F.C.,
P.S.E.G.H.) and Parasitohogy (R.H.M.) University of
Dar-es-Salaam, Tanzania; Department of Community
Health (A.O.H.), University of Bristol, England; The
Departments of Haematohogy (RIP.) and Chemical Pathology
(J.H.), Bristol Royal Infirmary, England. 2 Supported by the Wehlcome Research Trust, England
and the Research Committee of the University of
Dar-es-Sahaam, Tanzania.