Pathogen

Opisthorchis felineus a trematode (fluke) lives in intrahepatic bile and in pancreatic ducts. Adult flukes measure 4-13 mm x 1-3.5 mm. Oval eggs of yellow-brown colour measure 0.01-0.019 mm x 0.020.034 mm. The parasite delivers about 1 000 eggs per day. Eggs excreted with faeces and ingested by snails Bithinia inflata, develop in two months into cercaria to be released into water. Cercaria penetrate the skin and flesh of a second intermediate host - freshwater carp fishes. In six weeks, encysted larvae, metacercariae, become invasive and can be consumed by fish-eating wild and domestic mammals (cats, dogs, pigs) and by humans. Comparative study of O. felineus and O. viverrini somatic and metabolic antigens by electrophoresis and immunoblotting technique revealed that they share a number of proteins including p89 and p70. Protein p70 in both species is considered to be of high immunogenecity. Common epitopes in protein p89 and protein p70 have been found using monoclonal antibody technique. The possibility of the identity of these proteins was discussed (Kotelkin et al. 1996). The sequencing of O. felineus paramyosin cDNA showed only 66-70% of homologue with paramyosins of Schistosoma mansoni and S. japonicum (Shustov et al. 2001).

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