A 6 year old boy presented with intermittent abdominal cramps, loose stools and on stool examination ova of size 100 micrometre are seen. Which of the following is NOT the causative organism?

Some species of Opisthorchis which resemble C.sinensis can cause human infection. O.felineus, the cantilever fluke which is common in Europe and the erstwhile Soviet Union may infect humans. Infection is usually asymptomatic but may sometimes cause liver disease resembling clonorchiasis. O.viverrini is common in Thailand where the civet cat is the reservoir host. The eggs of Opisthorchis viverrini are 30 x 12 mm in size. Human infection is usually asymptomatic. Ref: CK Jayaram Paniker's textbook of parasitology 5th Ed Pg - 119