RESEARCH NOTE - Activity of Oxamniquine at Skin, Pulmonary and Sexual Maturation Phases, on a Schistosoma mansoni Strain (R1) Previously Reported as Resistant at the Adult Phase

The R1 strain of Schistosoma mansoni was isolated from a patient previosuly submitted to treatment with oxamniquine and praziquantel, and considered not cured. The chemotherapeutic tests carried out with that strain, using oxamniquine (250 mg/kg) in outbred mice, 50 days after infection, showed a significant resistance to the drug. The present work aims at verifying the activity of oxamniquine against the R1 strain at the skin (1 day), pulmonary (5 days), and sexual maturity (25 days) phases. Thus, outbred albino mice were infected with 65 (non-resistant, standard LE strain) and 30 (R1 strain) cercariae, by transcutaneous route. All the infected animals related to each strain were subdivided into groups, and were given 200 mg/kg oxamniquine, by oral route, on days 1, 5 and 25 after infection. Sixty days after each treatment, all groups were sacrificed and perfused for worms, the control group (infected and untreated) being perfused on day 50 after infection