Endemic in regions where a substantial amount of pork is consumed, notably in Asia, Africa and Latin America.
Transmission
Taenia solium eggs enter the human digestive tract either from the person's own faeces or those of someone else. The larvae that are released from the eggs will penetrate the internal organs and become encapsulated in the tissues.
Significance worldwide
Causes 30% of all epilepsy cases in Africa and Asia.
In non-endemic regions, the disease may be encountered in visitors to and immigrants from endemic areas.
Symptoms
Symptoms will not emerge until several months, cerebral symptoms usually not until after 2-8 years after the initial infection, and symptom onset can be delayed for up to 30 years.
Symptomatology is dependent on the target organ. Cysticercus cysts are found most frequently in the skin, muscle, internal organs and the central nervous system. The eye and heart may also act as target organs.
The most common symptoms of central nervous system involvement are headache, epilepsy and hemiparesis, but the following are also possible: visual disturbances, psychosis and mental deterioration.
Diagnosis
A typical finding in a CT or MRI scan of the head consists of one or more nonenhancing roundish lesions with a diameter of less than 2 cm. The lesions are partially filled with fluid and can be calcified.
Eosinophilia is possible.
Antibody testing may be beneficial for the confirmation of diagnosis. Negative antibody test results do not exclude the possibility of cysticercosis.
Calcified cysts in the muscles and skin are visible on plain x-rays.
A cysticercus cyst that is located under the skin can be removed surgically and sent for histological analysis.
The detection of T. solium eggs or segments in the faeces will support diagnosis. However, in most cases eggs are not detected.
If a biopsy is feasible, a histopathologic or PCR analysis of the biopsy will aid diagnosis in uncertain cases.
Treatment may be centralised in specialised hospitals.
Treatment is decided according to the location and activity of the lesions. Treatment options include plain follow-up, pharmacotherapy for epilepsy, specific pharmacotherapy and surgery.
If specific pharmacotherapy is chosen, albendazole can be used either alone or combined with praziquantel (both may require special license).
Cerebral oedema may develop as a complication to the treatment, and glucocorticoids should always be used prophylactically with specific drug therapies.
Prevention
Proper meat inspection practices, food hygiene, adequate cooking of pork and washing of vegetables
Stool samples from close family members should be analysed to enable the treatment of the possible carrier of the adult worm.
References
Garcia HH, Nash TE, Del Brutto OH. Clinical symptoms, diagnosis, and treatment of neurocysticercosis. Lancet Neurol 2014;13(12):1202-15. [PubMed]
Garcia HH, Gonzales I, Lescano AG et al. Efficacy of combined antiparasitic therapy with praziquantel and albendazole for neurocysticercosis: a double-blind, randomised controlled trial. Lancet Infect Dis 2014;14(8):687-95. [PubMed]