THE PIG, THE WORM, AND THE HIDDEN CAUSE OF EPILEPSY

From pork ribs, pork chemsha, and pork choma, the distance between your plate and your brain could be just two to eight metres the length of a tapeworm. Its scientific name is Taenia solium, better known as the pig tapeworm.

Harmless as it may seem when confined to the gut, this parasite can take a deadly detour when its microscopic eggs enter the body, finding their way to the brain and triggering neurocysticercosis ,one of the leading preventable causes of epilepsy worldwide, according to the World Health Organization (WHO).

Horrific twist, right? A tapeworm several metres long quietly living in your gut, unnoticed. But the real nightmare begins when its eggs are accidentally swallowed  not just from poorly cooked pork, but from contaminated hands, vegetables, or utensils. Those eggs hatch into larvae, travel through the bloodstream, and invade the brain. The result: neurocysticercosis.

This parasite is far more than a gut nuisance; it’s a public health threat driven by poor hygiene, unsafe food handling, and weak pig husbandry in the world’s most vulnerable regions.

Dr. Bernadette Abela-Ridder, Team Leader for Neglected Zoonotic Diseases at WHO, explains:

“The tapeworm itself just lives in the gut with you and doesn’t really do very much. It can be several metres long, but most of the time people don’t even know they’re infected. The real danger begins when people ingest the eggs that’s when the larvae can migrate to the brain, causing seizures, epilepsy, or severe headaches.”

As the WHO fact sheet notes, Taenia solium causes two very different infections in humans:

• Taeniasis — when an adult tapeworm lives in the intestine after someone eats raw or undercooked pork containing larval cysts. Most cases are symptomless and eventually resolve.
• Cysticercosis — when humans or pigs ingest tapeworm eggs, often through food contaminated with faeces from a human carrier. The larvae cross into tissues, and when they reach the brain, they cause neurocysticercosis.

“Good hygiene, safe food preparation, and avoiding untreated human manure are the linchpins of prevention,” says Dr. Abela-Ridder. She emphasizes that the worm’s reach extends far beyond pork consumption:
“Vegetarians and people who don’t eat pork are able to get infected … because of contaminated vegetables or cooking utensils.”

She adds:

“Humans can develop neurocysticercosis when they ingest T. solium eggs through faecal-oral contamination or by eating food contaminated with eggs from the faeces of a person who has the adult tapeworm.”

If most adult carriers show no symptoms, why is this parasite a global health priority? Because when the larvae invade the brain, the impact is devastating. WHO estimates that between 2.5 and 8 million people are affected worldwide in endemic regions, the parasite may account for up to 70% of epilepsy cases.

In simple terms: a significant share of epilepsy, especially in rural or low-resource settings, could be prevented by breaking the tapeworm’s life cycle.

A Simple but Vicious Life Cycle

1. A person eats undercooked pork containing larval cysts → develops an adult tapeworm (taeniasis) → sheds thousands of eggs daily in faeces.
2. The eggs contaminate soil, water, or vegetables — or are eaten by free-roaming pigs feeding on human waste.
3. Humans or pigs ingest the eggs → larvae hatch and form cysts (cysticercosis).
4. If cysts lodge in the brain → neurocysticercosis → seizures, headaches, or lasting neurological damage.

In areas with poor sanitation and free-roaming pigs, the risk multiplies. Backyard pigs feeding near open defecation sites are common in endemic regions.

Symptoms and Diagnosis: The Silent Threat

Most adult tapeworm carriers never realize they’re infected. The worm may grow several metres long without symptoms. But when larvae invade the brain, the effects can be life-altering from headaches and seizures to paralysis. Many remain asymptomatic for years, and diagnosis is difficult where CT or MRI scans are scarce.

For intestinal infections, treatment is straightforward  antiparasitic drugs such as praziquantel or niclosamide eliminate the worm. Neurocysticercosis, however, requires specialized neurological care, imaging, and prolonged therapy with antiparasitic drugs, corticosteroids, and anticonvulsants.

The 2021 WHO guidelines highlight the urgent need for better diagnostic tools and treatment capacity in endemic areas, where health systems are weakest.

“While deworming people helps, it doesn’t completely break the cycle,” says Dr. Abela-Ridder.

Prevention: The One Health Solution

Since the adult worm is mostly harmless but its eggs are deadly, prevention must target transmission. WHO promotes a One Health approach that integrates human, animal, and environmental action.

Key prevention measures:

• Wash hands after using the toilet and before handling food.
• Cook pork thoroughly and avoid cross-contamination.
• Confine pigs, prevent access to human waste, and vaccinate or deworm them (e.g., TSOL18 vaccine).
• Inspect meat before sale.
• Educate communities about transmission and prevention.

“The other piece is really about building awareness about this disease the cycle and how it’s transmitted,” says Dr. Abela-Ridder. “One of the main points of infection is undercooked pork. To truly stop transmission, we need to vaccinate and deworm pigs, improve human hygiene, and protect the environment.”

Though neurocysticercosis might sound distant, sub-Saharan Africa ,including Kenya, bears its quiet burden. Poor sanitation, backyard pig farming, inadequate meat inspection, and low public awareness create ideal conditions for T. solium to thrive.

The disease disproportionately affects rural and low-income communities where humans and pigs live in close contact. As urban areas expand and informal food systems grow, the risks follow. Even non–pork eaters remain vulnerable through contaminated vegetables or utensils.

“Cook your pork well, wash your vegetables, wash your hands every time you use the washroom,” reminds Dr. Abela-Ridder. “And keep yourself safe from this really awful tapeworm.”

In many African communities, epilepsy is still blamed on genetics, witchcraft, or spiritual causes. Yet science tells a different story.

Where the Pig Tapeworm Thrives

Africa:

Highly prevalent across sub-Saharan Africa, where it remains a leading cause of preventable epilepsy (neurocysticercosis). Hotspot countries include Kenya, Uganda, Tanzania, and Zambia, where pigs often scavenge in open environments.

Asia:

Endemic in much of Southeast Asia: notably Vietnam, Laos, Indonesia, and rural parts of China and India, where traditional pig-rearing and limited meat inspection persist.

Latin America:

Common in Central and South America, particularly in remote farming areas where sanitation and veterinary oversight are weak.