Sparganosis

Adult Spirometra species and Sparganum proliferum tapeworms infect dogs, cats, and other carnivores. Eggs are passed into freshwater where they are ingested by copepods (small crustaceans such as Cyclops). Fish, reptiles, and amphibians (including frogs) ingest them and serve as intermediate hosts. The tapeworms that cause sparganosis are present worldwide, but most human cases occur in Southeast Asia.

Humans and other mammals become infected by

• Accidental ingestion of copepods from water contaminated by cat or dog feces

• Ingestion of inadequately cooked flesh from another intermediate host

• Contact with poultices containing flesh from these sources

In humans, larvae typically migrate to subcutaneous tissue or muscle and form slowly growing masses. Other sites, including the central nervous system, may be involved but are much less common. Symptoms are caused by mass effect. Spargana masses in the central nervous system can cause weakness, headache, seizures, numbness, tingling, or abnormal skin sensations.

Diagnosis of sparganosis is typically made after surgical removal of the plerocercoid mass of larvae, although it may be suggested when imaging detects a mass. IgG antibodies specific for plerocercoid proteins can also be detected in peripheral blood and cerebrospinal fluid by enzyme-linked immunosorbent assay (ELISA) (1).

Surgery is the primary treatment and is typically done for symptomatic, space-occupying lesions (2). Generally, treatment with anthelmintics has not been effective.