Biosci 221 - Helminths

Parasitic worms that are multicellular, eukaryotic, invertebrae animals, most are macroscopic but have microscopic life stages

Classification of the Helminths

Phylum Platyhelminthes (Class Trematoda and Cestoda) and Phylum Nematoda

Class Trematoda

flukes, leaf shaped, intermediate host are mollusks, definitive hosts are vertebrae, digestive system

Class Cestoda

tapeworms, long/ribbon-like bodies, scolex for attachment, two or more hosts, no digestive system

Phylum Nematoda

roundworms, cylindrical, one host, complete digestive system, diverse and numerous

Clonorchis sinensis

Trematoda, oriental river fluke, by eating undercooked fish

Fasciola hepatica

Trematoda, liver fluke

Schistosoma spp.

Trematoda, blood fluke, burrows into the skin, urine/fecal contamination, intermediate host is snails

Taenia solium

Cestoda, tapeworm

Dipyllidium

Cestoda, dog tapeworm, by ingesting a flea

Ascaris lumbricoides

Nematoda, most common in the world, fecal/oral route

Necator americanus

Nematoda, hookworm, in swamps, burrow into your skin

Trichinella spiralis

Nematoda, was transmitted by pigs eating rat infested trash

Enterobius vermicularis

Nematoda, pinworm, most common in the U.S., lays eggs in the anus