Destruction of the intermediate host of Schistosoma mansoni, Australorbis glabratus, in the endemic area at Hato Mayor in the Dominican Republic was accomplished by using sodium pentachlorophenate (Santobrite) in briquette form. A single application of sodium pentachlorophenate at an estimated rate of 15 p.p.m. eradicated Australorbis glabratus from the arroyo Paña Paña, a flowing stream, for a period of six months. A single application of the chemical at an estimated rate of 5 p.p.m. destroyed Australorbis glabratus in the arroyo Las Guamas, a series of connected pools with negligible flow, as evidenced by examination of the stream one week after treatment. Several methods of applying sodium pentachlorophenate, using the briquette form, were used and evaluated by colorimetric tests of water samples. Higher concentrations of sodium pentachlorophenate were required to destroy invertebrates in the arroyo Paña Paña than were required to destroy fish.
Department of Zoology, University of South Dakota, Vermillion, South Dakota, formerly with Field Service Unit, American Foundation for Tropical Medicine, New York, New York.
Laboratory of Tropical Diseases, National Microbiological Institute, National Institutes of Health, Public Health Service, U. S. Department of Health, Education, and Welfare Bethesda, Maryland.
School of Public Health, University of North Carolina, Chapel Hill, North Carolina.
Director, Field Service Unit, American Foundation for Tropical Medicine, New York, New York, with the assistance of Johnnie A. Klutts, L. L. A. Moore, Jr., and M. N. Lunde, all of the Field Service Unit.