adhesion of cercaria (larva of helminth parasites) to host by lectins- carbohydrates bonds as a model for evaluation of schistosoma entrance mechanisms in cercarial dermatitis

background: cercariae (larva of helminth parasites) are covered by a thick glycocalyx coat, which serves as an osmotic pro­tection during their free existence, and contain carbohydrates conjugated as glycoproteins, glycolipids and mu­co­polysaccharides. although, limited studies have been made on life cycle of cercariae from fresh water snails, however, car­bo­hydrate studies on cercariae have not been done in iran so far. this study was made to determine the cercariae speci­fica­tions from lymnaea gedrosiana and evaluation of surface carbohydrates as receptors for host lectins in a host-parasite rela­tionship system as a model in human schistosomiasis including cercarial dermatitis in khuzestan province. methods: for this purpose, snails were collected from dezful region in khuzestan province and cercariae were obtained by shed­ding method and identified by valuable keys. experimental infection was established in the culex pipiens (culicidae mos­quitoes) larvae for further identification and mode of adhesion. to detect the mode of adhesion, surface carbohydrates of cercariae were detected by lentil (lens culinaris) lectins. results: examined snails were infected with xiphidiocerceria of trematodes and metacercariae were obtained from culex pipiens . also, mannose monosaccharides- ch2oh (choh) 4cho - were detected particularly on the glands of cercariae. conclusion: adhesion of cercariae to their host by lectins-carbohydrates bonds is the first stage of host-parasite relation­ship. this phenomenon could be happened for animal schistosome's cercaria in cercarial dermatitis.