Oral regimens of the compound 1-maleinyl-4-(3′-chloro-4′-methyl-phenyl)-piperazine (Hoechst S 688) were found to have a strong chemotherapeutic effect on mature infections of Schistosoma mansoni (Puerto Rican) in white mice and monkeys. Some of these animals were completely cured of their infection. The dosage level necessary to bring about clearance of monkeys of all their schistosome parasites approached toxic levels. There was no evidence of curative effect on a S. japonicum (Formosan) infection in a dog which was given a low dosage of the chemical. When S 688 was given to mice up to 72 hours after exposure to S. mansoni, it prevented many of the larval schistosomes from developing. This was not observed in monkeys. There was a suggestion that the chemical had prophylactic activity in preventing some of the S. japonicum infection from developing in dogs treated for the three days after the exposure day. The present results are in agreement with those of de Meillon, England and Lammler (1956), and Lammler (1958) who discovered the curative and prophylactic activity of the compound against South African and Liberian S. mansoni in rodents and monkeys.
Laboratory of Parasite Chemotherapy, National Institute of Allergy and Infectious Diseases, N.I.H., P.H.S., U. S. Department of Health, Education, and Welfare, Bethesda, Md.
Department of Medical Zoology, Walter Reed Army Institute of Research, Walter Reed Army Medical Center, Washington, D. C.