Effects of Artemether Treatment on Prepatent and Patent Schistosoma mansoni Infection in Experimentally Infected Mice

Background: Schistosomiasis is a chronic debilitating parasitic disease. Long-term repeated use of praziquantel (PZQ) for control of the disease morbidity may lead to resistance or reduced susceptibility to the drug. Artemether (ART), the anti-malarial drug may become an alternative therapy to PZQ as it also displays anti-schistosomal properties. Objective: To assess the effects of artemether experimentally on prepatent (juvenile worms) and patent (adult worms) Schistosoma mansoni infection. Methodology: Three groups each composed of twenty mice were used in the study. The first group (prepatent infection) was treated with double dose of ART (each 400 mg/kg) three and four weeks post infection (PI), the second group (patent infection) was treated with the same dose at six and seven weeks PI and the third group represented the infected control group. The effect of the drug was assessed by parasitological, histopathological and ultrastructural studies. Results: It was found that ART significantly decreased the number of worms and their body sizes in treated mice groups. It also decreased the tissue egg load and decreased the granuloma size in the liver of mice in the second group. It had a more potent effect on juvenile worms (group 1) as no or few fibrous granulomas appeared in the tissues. Scanning electron microscope revealed swelling and erosion of the tubercles with breaks in some areas of the tegument in both groups of treated mice groups. The oral sucker showed breaks and focal lysis of the underlying muscle fibers. Conclusion: Artemether is an effective drug against Schistosoma mansoni infection. It has schistosomicidal and ovicidal effects and hence anti-pathologic activities especially in those treated early after infection (3 and 4 weeks PI). Recommendations: Additional clinical studies using artemether in different epidemiologic settings with higher doses as well as future trials to study its ability to prevent reinfection and against S. hematobium are also recommended.