Cysticercosis is a tissue infection caused by the young form of the pork tapeworm. People may have little or no symptoms for years. In some cases, particularly in Asia, solid lumps of between one and two centimetres may develop under the skin. After months or years these lumps can become painful and swollen and then resolve. A specific form called neurocysticercosis which affects the brain can give neurological symptoms. In developing countries this is one of the most common causes of seizures.