A method for detecting therapeutic activity against Schistosoma mansoni in mice

A simple and rapid assay, suitable for routine screening against Schistosoma mansoni in mice, can be achieved by using a reduction in the severity of hepatic lesions as the chief criterion of efficacy. Previous attempts to use this criterion were largely hampered by the use of inappropriate time schedules. Provided the timing of treatment and necropsy is restricted to a certain schedule, a mere glance at the opened abdomen of an infected mouse is sufficient to determine whether schistosome reproduction has been suppressed (by chemosterilization or by broader anthelmintic effects). The essence of the necessary schedule is treatment beginning at 4 weeks after infection and prolonged (continuously or intermittently) for 2 weeks, followed by necropsy at 8 weeks after infection. Using the methods described, two persons can easily examine mice for therapeutic response at the rate of 300 per hour. The assay has been shown to detect both schistosomaticidal and chemosterilizing compounds.