Cysticercosis

Cysticercosis is a disease that develops when the larval stage of the pork tapeworm Taenia solium enters human body tissues and forms cysts (small fluid-filled sacs). The disease begins when a person ingests tapeworm eggs, usually from food or water contaminated by faeces from an infected individual carrying the adult tapeworm.

It is important to distinguish two related but separate conditions. Taeniasis occurs when the adult tapeworm lives in an infected person's intestine, usually resulting from eating undercooked pork. Cysticercosis, by contrast, occurs when eggs are ingested; the larvae penetrate the intestinal wall, enter the bloodstream, and spread to muscles, heart, eyes, and brain.

Transmission

The disease cycle depends on contact between humans and pigs. A person carrying the adult tapeworm sheds large numbers of eggs in faeces. When pigs eat contaminated material, larvae develop in their muscle tissue. Humans acquire the adult tapeworm by eating undercooked pork. However, if a person ingests eggs directly—without consuming infected meat—that person becomes the site where larvae develop, resulting in cysticercosis. For this reason, the disease can occur in someone who has never eaten pork.

Clinical features

Cysts in muscles or subcutaneous tissue may form small nodules that cause little discomfort and can remain asymptomatic for years. The most severe form is neurocysticercosis, when cysts lodge in the brain or spinal cord. Common symptoms include seizures, persistent headaches, vision changes, and increased intracranial pressure. When larvae die or begin to degenerate, the inflammatory response they trigger can worsen symptoms.

Diagnosis and treatment

Neurocysticercosis is usually diagnosed through brain imaging (CT or MRI), which reveals cysts or calcified lesions, along with blood tests detecting antibodies. Treatment includes antiparasitic drugs such as albendazole or praziquantel, typically given with anti-inflammatory medication (steroids) to prevent severe inflammation. Seizure management is a key part of treatment. Some cases require surgery or drainage of large cysts. Treatment decisions depend on the number, location, and stage of cysts.

Prevention

Prevention relies on clean water and sanitation, regular hand washing, thorough cooking of pork, and market meat inspection. Mass treatment of infected individuals and pig vaccination or treatment programmes are also used. The World Health Organization classifies cysticercosis among neglected tropical diseases; it is among the leading causes of acquired seizures in developing countries.