[Taenia multiceps] [Taenia serialis]
Coenurosis is infection by the metacestode larval stage (coenurus) of Taenia multiceps and T. serialis.
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 , where they are ingested by an intermediate host . Many animals may serve as intermediate hosts, including 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 . The adult cestodes reside in the small intestine of the definitive host, . Humans become infected after the accidental ingestion of eggs on fomites or 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; those of T. serialis are usually found in subcutaneous tissue.
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.
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.
Gross coenurus specimens.
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.
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