We compared 19 stocks of Trypanosoma brucei rhodesiense
collected in 1991 and 1994 from Tanzania with representative
stocks from other foci of Rhodesian sleeping sickness in Zambia, Kenya
and Uganda. Stocks were characterized by
isoenzyme electrophoresis, restriction fragment length polymorphisms in
variant surface glycoprotein genes and random
amplification of polymorphic DNA; the banding patterns obtained were coded
numerical analysis. In addition, the
Tanzanian stocks were compared by pulsed field gel electrophoresis.
Overall the Tanzanian stocks formed a homogeneous
group and the predominant genotype isolated in 1991 was still present in
the 1994 sample, although at a reduced level.
The Tanzanian stocks were distinct from representative stocks from other
East African foci. This observation does not
support the proposal that there are northern and southern strains of
T. b. rhodesiense, but is consistent with the view that
T. b. rhodesiense stocks form a mosaic of different genotypes
varying from focus to focus in East Africa.