| [search of natural occurrence of xiphidiocercariae (trematoda) in fresh water snails of nine countries from são paulo state, brazil]. | xiphidiocercariae, aquatic larval stages of some trematodes are considered a potential instrument for biological control of mosquitoes. in this study we evaluated its natural occurrence in campinas region and two places in vale do ribeira (registro and miracatu), são paulo state. snails were obtained from fresh water collections from september 1996 to february 1999. the species collected were lymnaea columella, physa marmorata, biomphalaria tenagophila, biomphalaria sp., drepanotrema cimex, d. l ... | 2001 | 12058671 |