Taenia solium, a cestode parasite.
Ingestion of eggs, excreted by a human carrier of the adult T. solium tapeworm, via fecally contaminated food or through close contact with the carrier. Autoinfection is also possible. Larval cysts of T. solium infect brain, muscle, or other tissues. Eating undercooked pork with cysticerci results in tapeworm infection (taeniasis), not human cysticercosis.
Common where sanitary conditions are poor and where pigs have access to human feces. Occurs globally; endemic areas include Mexico, Latin America, sub-Saharan Africa, India, and East Asia. Uncommon in travelers. Seen in immigrants from endemic regions.
Median latent period of 5 years (range, 1–30 years). Symptoms depend on the number, location, and stage of cysts. The most common location is brain parenchyma. Most common presentation is seizures. Other presentations include increased intracranial pressure, encephalitis, symptoms of space-occupying lesion, and hydrocephalus. Cysticercosis should be excluded in any adult with new-onset seizures who comes from an endemic area or has potential exposure to a tapeworm carrier.
Neuroimaging studies (CT or MRI) and confirmatory serologic testing. The most specific serologic test is the enzyme-linked immunotransfer blot, but this test may be negative in up to 30% of patients with a single parenchymal lesion.
Control of symptoms is the cornerstone of therapy. Anticonvulsants, corticosteroids, or both may be indicated. For some lesions, surgical intervention may be the treatment of choice. Antiparasitic treatment (albendazole, praziquantel) should not be initiated in patients with heavy infections, cysticercotic encephalitis, or increased intracranial pressure, as dying cysts can cause or worsen some symptoms. In these cases, the priority is neurologic management (steroids, mannitol), neurosurgical management, or both. In the clinical setting antiparasitic treatment reduces the risk of recurrent seizures. Clinicians can consult CDC to obtain more information about diagnosis and treatment (CDC Parasitic Diseases Inquiries: 404-718-4745 or firstname.lastname@example.org).
Food and water precautions (see Chapter 2, Food & Water Precautions).
CDC website: www.cdc.gov/parasites/cysticercosis
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Paul T. Cantey, Susan Montgomery