Photomicrograph of an adult O.<unk>  in bile ducts of experimentally infected hamster An egg of O.<unk> . 400× magnification. Structurally, O.<unk>  is basically similar to C. sinensis and O. felineus, but it is slightly smaller than the two flukes. The body of an adult O.<unk>  is flat (dorsoventrally flattened) like a leaf, shaped like a lancet, and can be seen through (transparent). They are monoecious, so no male or female individuals exist; each fluke has the complete sets of both male and female reproductive systems. A typical individual is 7 mm long and 1.5 mm wide. The anterior end is more pointed and marked by a mouth-like structure called oral sucker. About 1.5 mm behind the oral sucker is a similar structure called ventral sucker. These suckers are the organs of attachment. Two testes are seen towards the posterior end. The testes are lobed in contrast to the branched (dendritic) testes of C.sinensis. It is connected to the seminal vesicle, which is a coiled tube running up to the ejaculatory duct, which in turn opens through a small opening called genital pore just in front of the ventral sucker. Two<unk> aries are situated in front of the testes, and they form several lobes. The uterus runs along the ejaculatory duct and opens at the genital pore. A sac-like S-shaped tube called excretory bladder is between the two testes. The remaining body spaces are mostly occupied by a highly branched glandular organ called vitellaria (often called vitelline glands). Unlike the anterior end, the posterior end is rounded. The eggs of O.<unk>  are 30 × 12 μm in size and they are slightly narrower and more regularly<unk> oid than in C. sinensis. The eggs are visually indistinguishable in Kato technique smears from other eggs of flukes from other fluke family Heterophyidae. The infective larvae, metacercariae, of O.<unk>  are brownish and elliptical, with two nearly equal-sized suckers – the oral sucker and the ventral sucker. They are 0.19–0.25 × 0.15–0.22 mm in size.
Opisthorchis viverrini
Echinostoma cinetorchis
Opisthorchis felineus
Schistosoma japonicum
Haplorchis taichui
Taenia asiatica
Taenia solium
Echinostoma revolutum