[1] DEUTSCH PRIMATENZENTRUM, KELLNERWEG 4, D-3400 GOTTINGEN, GERMANY
[2] AHMADU BELLO UNIV, DEPT HAEMATOL & BLOOD TRANSFUS, ZARIA, NIGERIA
[3] AHMADU BELLO UNIV, DEPT PATHOL, ZARIA, NIGERIA
[4] UNIV CALABAR, DEPT HAEMATOL & BLOOD TRANSFUS, CALABAR, NIGERIA
[5] UNIV CALABAR, DEPT BIOL SCI, CALABAR, NIGERIA
[6] UNIV LAGOS, DEPT HAEMATOL & BLOOD TRANSFUS, LAGOS, NIGERIA