Effects of anti-protozoal drugs and histopathological studies on trypanosome species

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.