Prepared By:

Sajad Al-Ramahy

Daniel Rawand

Hawler Medical University- College of Medicine

Taenia multiceps or T. serialis, a rare cause of human infection, is acquired by accidental ingestion of eggs from dog feces.

Canines are the definitive hosts for adult Taenia multiceps or T. seralis tapeworms; sheep and other herbivorous animals are intermediate hosts. Ingestion of material contaminated by dog feces causes human disease. The larvae invade and form a cyst (coenurus) in human tissue, usually in the CNS.

Symptoms require several years to develop and depend on the organ infected. Involvement of the brain causes increased intracranial pressure, seizures, loss of consciousness, and focal neurologic deficits.

The definitive hosts for Taenia multiceps are members of the family Canidae (dogs, foxes…) Eggs and gravid proglottids are shed in feces into the environment , where they are ingested by an intermediate host(rodents, rabbits, horses, cattle, sheep and goats).  Eggs hatch in the intestine, and oncospheres are released  that circulate in blood until they lodge in suitable organs (including skeletal muscle, eyes, brain and subcutaneous tissue).  After about three months, oncospheres develop into coenuri. 

The definitive host becomes infected by ingesting the tissue of an infected intermediate host containing a coenurus containing a coenurus .  The adult cestodes reside in the small intestine of the definitive host.  Humans become infected after the accidental ingestion of eggs in food and water contaminated with dog feces .  Eggs hatch in the intestine, and oncospheres are released  that circulate in blood until they lodge in suitable organs and after about three months develop into coenuri .  Coenuri of T. multiceps are usually found in the eyes and brain and subcutaneous tissue.

The parasite is not transmissible to man from the intermediate hosts.

Coenuri in the skin or subcutaneous tissue usually present as painless nodules. Coenuri in the neck may affect neck movement and swallowing.  Clinically, coenuri may mimic lymphomas, lipomas, pseudotumors, or neurofibromas.  Coenuri in the central nervous system may cause headache, fever and vomiting..  Coenuri in the eye cause both intraocular and orbital infections, and patients may present with varying degrees of visual impairment.  If not removed, coenuri in the eye may cause painful inflammation, glaucoma and eventually blindness.

Diagnosis is made by the observation

of coenuri in biopsy or autopsy specimens.  Coenuri are usually readily distinguished from cysticerci by the presence of multiple protoscoleces, and it is 2 - 5 cm.

Removal of the coenurus effectively treats intracranial coenurosis in most cases.  There have also been reports of successful removal of coenuri from patients' eyes, resulting in a recovery of sight.  Coenuri are susceptible to praziquantel, but caution should be used, especially in cases of intraocular coenurosis.

http://www.ncbi.nlm.nih.gov/books/NBK8399/ http://www.unbc.ca/nlui/wildlife_diseases/

taenia_multiceps.htm http://www.merckmanuals.com/professional/sec14/

ch184/ch184g.html http://www.dpd.cdc.gov/dpdx/html/Coenurosis.htm