Your Guide to
Neglected Tropical Diseases

Cysticercosis is an infection caused by the pork tapeworm parasite. The most serious form, neurocysticercosis, occurs when the parasite forms cysts in the brain or spinal cord. These cysts can cause seizures, chronic headaches, blindness, and other serious problems. Neurocysticercosis is the most frequent preventable cause of epilepsy worldwide, causing about 30% of all epilepsy cases in countries where the disease is common. Many infected people have no symptoms for months or years.

Symptoms typically appear when cysts begin dying and cause inflammatory swelling in the brain. People get cysticercosis by accidentally swallowing tapeworm eggs through contaminated food, water, or poor hygiene (not by eating pork).

There are two distinct clinical forms (parasitic forms) of the infection. One is taeniasis, in which mature, egg-laying parasites inhabit the digestive tract. The other is cystic taeniasis or cysticercosis, in which immature larvae form cysts and reside in various organs within the body, including the muscles and the brain. This distinction stems from the fact that, in the former case, the ingested material consists of larvae within cysts, while in the latter, it consists of tapeworm eggs.

Cysticercosis spreads when infected people pass tapeworm eggs in their feces, contaminating food, water, and surfaces in areas with poor sanitation. People become infected by drinking contaminated water, eating unwashed vegetables, or touching their mouth with contaminated hands. Importantly, eating pork does not cause cysticercosis; only contact with tapeworm eggs causes infection.

Pigs have long been reared in close proximity to humans as domestic animals. The mode of infection with Taenia solium is similar to that in humans, and pigs play a vital role throughout the entire infection cycle in sustaining the prevalence of Taenia solium infection in humans. When pigs consume tapeworm eggs, they develop cysts in their tissues. People who eat undercooked infected pork develop an intestinal tapeworm that sheds eggs, continuing the cycle. Free-roaming pigs with access to human waste perpetuate transmission in communities.

Geographic scope:

• An estimated 2.5-8 million people are infected across Latin America, sub-Saharan Africa, South Asia, Southeast Asia, and parts of China. While these figures represent historical benchmark estimates, recent Global Burden of Disease (GBD) data indicate approximately 4.36 million cases of neurocysticercosis (NCC)-associated epilepsy globally.
• The disease accounts for 30% of epilepsy cases in affected countries overall, and up to 70% in some specific communities.
• Cases also occur in developed countries among immigrants and travelers.

Population affected:

• The disease mainly affects farming communities in developing countries where pigs are raised with poor sanitation.
• Most affected people are between 30-40 years old, though it can occur at any age.
• Over 50 million people worldwide have epilepsy, with most living in poor countries where this disease is a major cause.
• Epilepsy rates are 3-6 times higher in developing countries compared to developed countries, largely due to this infection.

Treatment depends on where the cysts are located, how many there are, and how severe the symptoms are. The main medicines used are albendazole and praziquantel, often given together for better results. Treatment typically lasts 10-15 days and includes other medicines to reduce brain swelling and control seizures. Surgery may be needed for cysts in the eyes or brain ventricles. Many people without symptoms may not need treatment. Dead cysts do not respond to medicine.

Prevention requires addressing human health, animal health, and environmental factors together. Key actions include treating people who have intestinal tapeworm infections, vaccinating pigs and treating infected pigs, improving access to clean water and toilets, inspecting meat properly, promoting handwashing and toilet use, and educating communities about how the disease spreads.