Taeniasis and Cysticercosis includes beef tapeworm, pork tapeworm, and neurocysticercosis. Both beef and pork tapeworms infect the intestine. The larval stage of the pork tapeworm also infects the other parts of the body (cysticercosis) and the central nervous system (neurocysticercosis).
CASES/YEAR
2,000 (US); 55,000,000 (Global)
OTHER NAMES
Taenia saginata (Beef tapeworm); Taenia solium (Pork tapeworm); Neurocysticercosis;
INCUBATION
Symptoms of cysticercosis: months to years; Eggs in stool: about 10 weeks; [CCDM]
INITIAL SYMPTOMS
Taeniasis (intestinal infection) after eating undercooked meat: asymptomatic or abd. pain, wt. loss, & insomnia; Cysticercosis from ingestion of eggs in feces causes calcified cysts anywhere in the body including brain: headaches, seizures; [CCDM]
PRECAUTIONS
Human cysticercosis occurs either directly from the feces of people harboring an adult worm or indirectly by ingestion of food or water contaminated with eggs. [CCDM, p. 605]
COMMENTS
FINDINGS:
Both beef and pork tapeworms infect the intestine. The larval stage of the pork tapeworm also infects the other parts of the body (cysticercosis) and the central nervous system (neurocysticercosis). Larval infection results from ingestion of eggs in feces from people who have an intestinal infection. Autoinfection is also possible. The infection may occur directly from the feces or from feces-contaminated food or water. [CCDM, p. 604] Constipation is a symptom of intestinal infection. Paresthesias and radicular pain are symptoms of spinal cysticercosis. [Guerrant, p. 819, 839] Cysticerci in muscle can cause myositis, fever, and eosinophilia. [Cohen, p. 1778]
NEUROCYCYSTICERCOSIS:
The infection is often asymptomatic for years. Cysticerci may form in the brain (neurocysticercosis), and also in the skin, muscle, eye, and spinal cord. [Merck Manual, p. 1535-6] Possible complications include meningitis and acute hydrocephalus with confusion, vomiting, dizziness, impaired vision, ataxia, and coma. [ID, p. 2390] Findings in neurocysticercosis include seizures, hydrocephalus, and increased intracranial pressure (headache, vomiting, impaired vision). [Harrisons, p. 634] Uncommon in travelers, but seen in immigrants from endemic areas; "Cysticercosis should be ruled out in any adult with new-onset seizures who comes from an endemic area or has potential exposure to a tapeworm carrier." [CDC Travel, p. 196]
LABORATORY:
Egg release and proglottid detachment are irregular, so serial examination of stool samples over several days is recommended in the diagnosis of intestinal infections. [PPID, p. 3467] Diagnosis of cysticercosis is made by neuroimaging studies (CT or MRI) and confirmed with serologic testing. The enzyme-linked immune-transfer blot is the most reliable, although up to 30% of patients with a single parenchymal lesion will have a negative result. [CDC Travel, p. 196]
DIAGNOSTIC
Identification of segments (proglottids), eggs or antigens in stool; Cysticerci in skin may be detected by palpation and in the brain by MRI or CT; "Specific serological tests should support the clinical diagnosis of cysticercosis." [CCDM, p. 604-5]
SCOPE
Where human feces contaminate water or feed of cattle and pigs, and undercooked meat is eaten; Most prevalent in Latin America, Africa, parts of Asia, and eastern Europe; [CCDM]
SIGNS & SYMPTOMS
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>fatigue, weakness
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>fever
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G abdominal pain
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G constipation
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G diarrhea
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G nausea, vomiting
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H eosinophilia
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N confusion, delirium
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N headache
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N lethargy
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N paresthesia
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N seizure
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N stiff neck
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S skin or subcutaneous nodule
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*blindness
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*bowel obstruction
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*brain abscess or lesion
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*cranial neuropathy
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*encephalitis
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*meningitis
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*myelitis
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*pancreatitis
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*paralysis
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*stupor, coma
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*uveitis
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*weight loss
SOURCE
Person-to-Person, Human Fecal-Oral, Animal Tissue, Eating Contaminated Food, Eating Contaminated or Infected Meat, Waterborne (Ingesting, Inhaling, or Swimming)
RESERVOIR
Cattle, Goats and Sheep, Swine, Human
RISK FACTORS
- Eat undercooked meat or fish
TREATMENT
No treatment for somatic cysticerci identified as calcified lesions by plain x-ray; [ABX Guide: Taenia solium]
REFERENCES FOR CASES/YEAR
1. (US) Infection uncommon in US cattle because of federal inspections; Pork tapeworm infection in the US is usually in immigrants from endemic areas; [Merck Manual, p. 1534-5] Cysticercosis: over 2000 cases/year diagnosed in the US, mainly immigrants from pig-raising farms in Latin America; [Cecil, p. 2119]
2. (Global) 80% of 50 million with epilepsy live in poor countries where exposed to T. solium; [Fact sheets from WHO 2013] Cases of taeniasis reported in England & Wales: 70 (2009), 108 (2010), 90 (2011) and 65 (2012); About 45-60 million people are infected with the beef tapeworm. Only a few million people carry the pork tapeworm. [Cecil, p. 2118]