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Coenurosis

[Taenia multiceps] [Taenia serialis]

Cross-section of a human eye, showing multiple protoscoleces within a coenurus at 200x magnification.

Cross-section of a human eye, showing multiple protoscoleces within a coenurus at 200x magnification.


Large, polycephalic coenurus removed from the shoulder of a baboon (Papio sp).

Polycephalic coenurus removed from the shoulder of a baboon (Papio sp.).


Causal Agents

Coenurosis is infection by the metacestode larval stage (coenurus) of Taenia multiceps and T. serialis.


Life Cycle

Life cycle of Coenurosis

The definitive hosts for Taenia multiceps and T. serialis are members of the family Canidae. Many canids can serve as definitive hosts for T. multiceps, but only dogs and foxes can serve as hosts for T. serialis. Eggs and gravid proglottids are shed in feces into the environment The number 1, where they are ingested by an intermediate host The number 2. Many animals may serve as intermediate hosts, including rodents, rabbits, horses, cattle, sheep and goats. Eggs hatch in the intestine, and oncospheres are released The number 3 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 The number 4. The adult cestodes reside in the small intestine of the definitive hostThe number , The number 6. Humans become infected after the accidental ingestion of eggs on fomites or in food and water contaminated with dog feces The number 7. Eggs hatch in the intestine, and oncospheres are released The number 8 that circulate in blood until they lodge in suitable organs and after about three months develop into coenuri The number 9. Coenuri of T. multiceps are usually found in the eyes and brain; those of T. serialis are usually found in subcutaneous tissue.

Geographic Distribution

Widespread; most of the cases are from Africa, although cases also appear in sheep-raising areas of Europe, South America, the United States and Canada.

Clinical Presentation

Coenuri in the skin or subcutaneous tissue usually present as painless nodules. The lesions are often fluctuant and tender. Most subcutaneous nodules manifest on the trunk, sclera, subconjuctiva, neck, shoulders, head and limbs. 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. Localizing neurologic symptoms may also develop, including nerve palsies, jacksonian epilepsy, pachymeningitis, obstructive or communicating hydrocephalus, and intracranial arteritis with transient hemiparesis. 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.

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  • Page last reviewed November 29, 2013
  • Page last updated November 29, 2013
  • Content source: Global Health - Division of Parasitic Diseases and Malaria
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