The trypanosomostatic and trypanosomicidal effects of four anti-protozoal d
rugs, namely halofantrine hydrochloride, chloroquine phosphate, benzoylmetr
onidazole and pyrimethamine, on species of trypanosomes, viz. Trypanosoma b
rucei brucei (MBOS/NG/94/NITR) Bassa strain, T. congolense (MBOS/NG/93/NVRI
) Zaria strain and T. brucei gambiense (MHOM/NG/92/NITR) Abraka strain, wer
e investigated. In vitro and in vivo studies on these drugs vis-a-vis the p
arasites were carried out. The histopathological changes in organs and tiss
ues of experimentally infected rats were also studied. Results from the in
vitro studies indicated that halofantrine hydrochloride, chloroquine phosph
ate, benzoylmetronidazole and pyrimethamine appeared to be effective trypan
osomicidal agents against T. brucei brucei (Bassa strain), T. congolense (Z
aria strain) and T. brucei gambiense (Abraka strain). The in vivo studies s
howed that these drugs were subcurative by prolonging the survival period o
f the trypanosome-infected rats, but not necessarily curing the infection.
Histopathological findings indicated inflammatory reactions characterised b
y infiltration to variable degrees in the majority of tissues, mostly in th
e lungs and liver. The most consistent lesions were interstitial pneumonia,
multifocal necrosis and oedema. Pathological findings showed the T. brucei
brucei and T. brucei gambiense strains studied to be both intravascular an
d extravascular parasites. These results suggest that halofantrine hydrochl
oride, chloroquine phosphate, benzoylmetronidazole and pyrimethamine could
be used as supportive, suppressive and/or synergistic/additive drugs in the
treatment of African trypanosomiasis. Their effects on species of trypanos
omes have been studied and are reported for the first time. (C) 2001 Federa
tion of European Microbiological Societies. Published by Elsevier Science B
.V. All rights reserved.