Experimental schistosomiasis mansoni: II- efficacy of RO 15-5458 Hoffmann-la Roche on different intensities of infection

ABSTRACT

Efficacy of RO 15-5458, as an antischistosomal drug in a dose of 15 mg/kg body weight, has been evaluated on 370 infected mice at different intensities [50, 100, and 150 Schistosoma mansoni cercariae/mouse]. Praziquantel [Biltricide 2 x 50 mg/kg body weight], for comparison and a vehicle as control, were included in the study. At the 2nd week post treatment [post ttt] praziquantel gave better effect than that of RO 15-5458. However, at the 4th week, both drugs gave more or less similar results. RO 15-5458 showed significant reduction of fecal eggs of 97.3%, 96.7% and 94.6% in mild, moderate and heavy infections, respectively, versus control group [P <0.001]. It also decreased ova/g liver and intestine significantly [P <0.001]. Oogram patterns revealed that immature stages disappeared in light infection, but persisted in moderate and heavy infections, while Praziquantel was effective in all stages. Worm burdens decreased significantly [P <0.001] in mild [79%], moderate [91.6%] and heavy [89%] infections recording a significant difference [P <0.01] in heavy infection with Praziquantel which gave a better effect [93.0%]. Regarding hepatic shift, it reached 85% by the 4th week post ttt. So, RO 15-548 showed a higher antischistosomal efficacy in light and moderate infection than in heavy one. It may need a higher dose to be as efficient as Praziquantel. Furthermore, it might be a good substitute for Praziquantel when resistance developed in a certain endemic area