The disease is most commonly found in East and Southeast Asia as a result of consuming infected raw snake, frog, or pig. In North America, sparganosis is endemic in animals, but human cases are rare. The most common cause for these cases is drinking contaminated water. The most prevalent species in Southeast Asia is Spirometra mansoni, while Spirometra mansonoides is predominant in the Western hemisphere.
Sparganosis is a rare infection. There are no obvious sex differences, and individuals of any age may be affected. Cerebral sparganosis most often occurs in adults. Most patients are from rural areas, and there does not seem to be a higher risk of infection among immunocompromised patients.
Symptoms of sparganosis depend upon the location where the sparganum invades. Once ingested, the parasite migrates, often asymptomatically, from the digestive system through the capillaries to diverse locations of the human body. The larvae most commonly affect subcutaneous tissues and muscles, eyes, the central nervous system, the genitourinary system, and visceral organs.
In the subcutaneous tissue, sparganosis forms a slowly growing nodule that can migrate, hence a "creeping tumor." Prolonged presence of the parasite provokes an infiltration of eosinophils, epithelioid cells, and lymphocytes. Erythema and edema develop around the parasite, causing discomfort, itchiness, and pain. If the spargana invade the eye, there can be inflammation and edema around the eye, leading to pain and vision changes. Invasion of the brain can lead to headaches, confusion, and seizures. In case of infection with Spirometra proliferum, the spargana may break up and invade many organs, which may lead to tissue damage, paralysis, blindness, and death.
The incubation period depends on the route of infection, but is usually 6-11 days. The life span of spargana is usually less than a year, but may be up to 20 years.
B70.1 – Sparganosis
31659000 – Infection caused by Spirometra larvae
Differential Diagnosis & Pitfalls
- Brain tumor
- Cerebral cysticercosis
- Cerebral paragonimiasis
- Cerebral schistosomiasis
- Other inflammatory granulomas