Infection with the tapeworm Taenia solium can result in two distinct conditions: taeniasis and cysticercosis. Taeniasis is the intestinal infection with the tapeworm and it occurs when a person eats raw or undercooked, infected pork. Taeniasis has no major impact on human health. However, tapeworm eggs pass in the faeces of the tapeworm carrier and in the absence of a proper sanitation may contaminate the environment. While tapeworm eggs are infective for pigs, T. solium eggs may also infect humans if they are ingested by a person (via the fecal-oral route, or by ingesting contaminated food or water). Ingestion of tapeworm eggs causes infection with the larval parasite in the tissues such as muscles, skin, eyes and the central nervous system (human cysticercosis), with possible devastating effects on health.
When cysts develop in the brain, the condition is referred to as neurocysticercosis.
Taeniasis is usually characterized by mild and non-specific symptoms associated to an intestinal infection (abdominal pain, nausea, diarrhoea, etc.). These symptoms may continue until the tapeworm dies following treatment, otherwise it may live for years.
For cysticercosis, the incubation period is variable, and infected people may remain asymptomatic for years. In some endemic regions, infected people may develop visible or palpable nodules (a small solid bump or node which is solid that can be detected by touch) beneath the skin.
Neurocysticercosis is associated with a variety of signs and symptoms depending on the number, size, stage and location of the pathological changes as well as the host’s immune response and the parasite’s genotype, but it can also be clinically asymptomatic. Symptoms may include chronic headaches, blindness, seizures (epilepsy if they are recurrent), hydrocephalus, meningitis, dementia and symptoms caused by lesions occupying spaces of the central nervous system.
The treatment of taeniasis by Taenia solium is important to prevent neurocysticercosis and as a tool to assist in controlling or stopping the parasite transmission cycle. The treatment can be done on an individual bases, or as Mass Drug Administration depending on the local circumstances and the control approaches being implemented. Taeniasis can be treated using anthelmintics (Praziquantel, Niclosamide, Albendazole).
In neurocysticercosis, since the destruction of cysts may lead to an inflammatory response, specialised treatment of active disease is required and may include long courses with high doses of anthelmintic, as well as supporting therapy with corticosteroids and/or anti-epileptic drugs, and possibly surgery. The dosage and the duration of treatment can vary greatly and depend mainly on the number, size, location and developmental stage of the cysts, their surrounding inflammatory edema, acuteness and severity of clinical symptoms or signs.