Taeniarhynchus saginatus

 

Phylum Cestoidea

Order Cyclophyllidea

Family Taeniidae

Taeniarhynchus saginatus

Background:

-The beef tapeworm of humans

Morphology:

-The eggs of different species in the family Taenidae are all morphologically the same.
-The worm has four circular suckers on its scolex (head).

Definitive Host:

-Humans

Intermediate Hosts:

-Cattle, sheep, goats, lamas

Geographic Range:

-Worldwide

Life Cycle:

-The intermediate host ingests the parasite egg in its feed.
-The egg hatches in the intermediate host into a hexicanth larva.
-It penetrates the host’s small intestine.
-The larvae penetrate and are carried by the circulatory system to muscles.
-It then forms a cycticercus in the muscle.
-It will be infective in the intermediate host in 2-3 months.
-Humans become infected when they eat infected undercooked meat.
-The adult worm resides in the small intestine of the human host.
-Gravid proglottids (segments filled with eggs) break off the worm and travel out with the feces, or the worm may crawl out.
-When outside the body, the proglottids burst open and release all the eggs, which are then able to get into the feed of the intermediate host.

Pathogenesis:

-Usually low

Diagnosis:

-Look for eggs or proglottids in the feces.
-Identifies the Taenidae in general.
-Identify species by scolex.

Treatment:

-Niclosamide for humans
-Praziquantel for cattle

Control:

-Inspect meat.
-Freeze meat for 10 days before use.
-Cook meat adequately.
-Control the contamination of the cattle feed by keeping sanitary conditions and educate.

This page was last modified on January 26, 2004
Send questions and comments to Kim Bates