parasitic helminths (trematodes) of marine fishes under a microscope.

tissue platyhelminthes ascariasis roundworms cestoda anisakiasis fluke trematoda larva parasitology microscopic intestinal danger fresh fish stomach ache food raw parasites fishes diseases parasitic opisthorchiidae intermediate host cyst trematode digenean scientific flatworm meat zoology science microscope nematode helminths medical biology background intestine isolated medicine parasite healthy tapeworm worm infection helminth roundworm disease