Helminths

Helminths

Highest order we have studied

Multicellular eukaryotic animals that generally possess systems. (circulatory, etc)

May lack a digestive system. Absorbs nutrients from the host’s food, body fluids, and tissues.
Nervous system is reduced.
Means of locomotion reduced or lacking.
Complex reproductive system.

I Flatworms (Platyhelminthes)
A. Trematodes (flukes)
1. Clonorchis sinesis (Asian/Chinese liver fluke)
2. Paragonimus westermani (lung fluke)
a. definitive host: human lung
b. intermediate host: snail and crayfish
3. Schistosoma (blood fluke)
B. Cestodes (tapeworms)
1. have a scolex and proglottids
2. Taenia saginata (beef tapeworm)
a. definitive host: human
3. Taenia solium (pork tapeworm)
a. definitive host: human
b. intermediate host: human
4. Echinococcus granulose (canine?)
a. definitive host: dog or coyote
b. intermediate host: humans, sheep, deer
II Roundworms (Nematodes)
A. Have complete digestive systems
B. Egg infective in humans:
1. Enterbius vermicularis (pinworm)
a. adults in large intestine
b. females lay in perianal folds
C. Larvae infective in humans:
1. Necator americanus (hookworms)
a. skin, lungs, swallow sputum, small intestines, hatch in soil.
2. Trichinells spiralis (trichinellosis)
a. from eating encysted pork