Autoradiographic quantification of the efficacy of niridazole in mice infected with 75Se-labelled cercariae of Schistosoma mansoni

Abstract

The effects of the anti-schistosomal drug, niridazole, on the migration of Schistosoma mansoni larvae, biosynthetically radioisotope-labelled with 75[Se]-selenomethionine, was evaluated by autoradiography of compressed tissues of mice treated daily from Days 6 to 10 post-infection with 200 mg kg-1 niridazole. The results were compared with the migration of schistosomula in untreated controls. The distribution of schistosomula was altered in niridazole-treated mice, where there was a delayed migration from the lungs relative to the controls and significantly fewer schistosomula in total appeared to reach the liver. The total percentage of schistosomula detected as autoradiographic foci was significantly lower in treated mice than in the untreated controls. Niridazole-treated mice were free of any foci 10 days after the last treatment and no adult worms were recovered on perfusion of the hepatic portal system relative to control mice from which 5.8% of the infective cercariae were recovered as adult worms at Day 42 post-infection.