Cysticercosis

Cysticercosis is a tissue infection caused by the larval (cysticercus) stage of Taenia solium, commonly known as the pork tapeworm. The condition falls under the broader classification of human helminthiasis and is coded as B69 in the ICD-10 classification system. Infection develops after ingestion of Taenia solium eggs, which hatch in the intestine and release oncospheres that penetrate the intestinal wall, enter the bloodstream, and disseminate to various tissues where they develop into fluid-filled cysts approximately 0.6 to 1.8 centimeters in length.

Clinical presentation varies considerably depending on the number, location, and stage of cysticerci, with many infections remaining asymptomatic for years. When symptoms occur, they reflect the specific tissues involved: subcutaneous cysts present as firm, mobile nodules primarily on the trunk and extremities, which may become painful and swollen before eventual resolution. Muscular involvement typically causes inflammation with fever and eosinophilia, progressing to atrophy and scarring as cysts calcify. The most clinically significant manifestation is neurocysticercosis, characterized by seizures and headaches; parenchymal brain cysts measure 5-20 mm, while subarachnoid lesions may reach 6 cm and become life-threatening through mass effect or cerebrospinal fluid obstruction. Ocular involvement can produce visual disturbances, retinal complications, and potential vision loss depending on cyst location.

Cysticercosis occurs worldwide but exhibits marked geographic variation, with highest burden in developing countries where inadequate sanitation infrastructure enables fecal contamination of water and agricultural products. Asia is specifically noted for prominent subcutaneous disease manifestations. The disease represents one of the most common causes of seizures in endemic regions, contributing substantially to neurological disease burden. Transmission requires an infected human host shedding eggs (from concurrent taeniasis) and environmental contamination, creating household and community transmission clusters where close contacts face elevated infection risk.

Human cysticercosis is acquired through the fecal-oral route by ingesting Taenia solium eggs from contaminated sources, most commonly vegetables and water. The eggs originate from feces of individuals harboring adult intestinal tapeworms (taeniasis), establishing an auto-infectious cycle within households. Consumption of undercooked pork containing cysticerci causes taeniasis, a distinct condition, but does not directly cause cysticercosis; rather, individuals with taeniasis become potential sources of environmental contamination that can infect themselves or others. Household contacts of tapeworm carriers face substantially elevated risk of cysticercosis.

Individuals residing in or traveling to endemic areas with poor sanitation infrastructure face elevated exposure risk. Household contacts of persons with taeniasis demonstrate substantially higher cysticercosis incidence due to shared environmental exposure to egg-contaminated surfaces, food, or water. Agricultural workers using untreated human feces as fertilizer and consumers of raw vegetables from contaminated sources represent occupational and dietary risk populations.

Prevention centers on interrupting fecal-oral transmission through improved sanitation, safe water access, and rigorous food hygiene including thorough washing of vegetables potentially contaminated with human feces. Health education regarding the distinction between taeniasis (pork-associated) and cysticercosis (fecal-oral associated) transmission routes supports targeted prevention behaviors. Control of taeniasis in human carriers reduces environmental egg shedding and subsequent transmission risk to contacts.

Cysticercosis surveillance should prioritize neurocysticercosis given its clinical severity and epidemiological significance as a leading cause of adult-onset seizures in endemic areas. Diagnosis relies heavily on neuroimaging (CT/MRI) demonstrating characteristic cystic lesions, supported by eosinophilia in cerebrospinal fluid and blood. Subcutaneous nodule aspiration provides tissue confirmation when neurological imaging is inconclusive. Case reporting should distinguish cysticercosis from taeniasis, as these represent different transmission pathways and intervention priorities. Geographic clustering around tapeworm carriers suggests household-level contact tracing may identify additional cases.

1. 1 Wikidata. cysticercosis.
2. 2 Wikipedia. Cysticercosis - Wikipedia.

ICD-10

B69

ICD-11

Total cases

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Peak month

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Coverage

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