PREVENTION OF SNAIL MIRACIDIA INTERACTIONS USING PHYTOLACCA-DODECANDRA (LHERIT) (ENDOD) AS A MIRACIDIACIDE - AN ALTERNATIVE APPROACH TO THEFOCAL CONTROL OF SCHISTOSOMIASIS

The effect of ended berry extract against schistosome miracidia has be en tested to determine the sensitivity of these organisms to the mollu scicide and to see whether miracidia subjected to sublethal doses of t he toxicant will be able to infect their specific host snails. Short c ontact (30 min) LC(50) of ended extract with miracidia of Schistosoma mansoni was 8.2 parts per million (p.p.m.) (95% CL 5-13) However, expo sure of S. haematobium to sublethal doses of 3 p.p.m. for 30 min or ov ernight in open air ponds reduced their infectivity 3.5-5.6-fold when compared with controls. It is suggested that the toxicant could be use d in low doses at transmission foci to reduce schistosome infection in snails. This could be done by using a controlled release system to ap ply the toxicant material at such foci where transmission is likely to occur.