Clonorchis spp.

Opisthorchis viverrini. Egg in fecal smear (unstained, high power). The eggs of O. viverrini are difficult to distinguish from those of Clonorchis sinensis. Opisthorchis eggs often appear to be broader and have less prominent shoulders, as seen here. The knob at the abopercular end may be prominent (as seen here), inconspicuous, or absent.