Pork Tapeworm, Taenia solium

The pork tapeworm (Taenia solium), also known simply as a tapeworm, is a species of parasitic worm that is classified within the Platyhelminthes phylum. This species infects pigs and humans in many areas of the world including Africa, Southern Europe, Asia, South America, and some areas of North America. This species can cause cysticercosis in its larval stage, which is one of the major causes of seizures in humans. The pork tapeworm can reach an average body length between 2 to 3 meters, but individuals have reached over 50 meters long in some cases.

The life cycle of the pork tapeworm begins when a human or pig host consumes feces that is infected with tapeworm eggs or pregnant segments. The eggs hatch into oncospheres that will penetrate through the intestinal wall and travel to many areas of the body including striated muscles, the liver, the brain, or other internal tissues. Once the larvae have stopped traveling, they will encyst in an area of the body. If this area is the brain of a human, the resulting infection can cause neurocysticercosis. The cysticerci form of this worm is when the worm is able to fully mature and develop within the intestine of its host. Adult tapeworms are hermaphroditic and can create up to one thousand proglottids, or segments, within its lifetime. These segments contain male and female reproductive organs and can hold up to fifty thousand eggs.

The most common disease caused by the pork tapeworm is known as cysticercosis, a dangerous disease that affects humans in areas where sanitation is poor. This disease occurs when the segments or eggs within the host’s intestine break, causing the larvae to be released. The larvae encyst in different tissues of the body, causing possible symptoms like dizziness, headaches, and seizures. The severity of each case varies depending upon the level of infection and the location of the encysted larvae, with severe cases causing hosts to experience hypertension, dementia, brain system dysfunctions, sensory deficits, involuntary movements, and neurocysticercosis, which can cause blindness, tumor-like growths, and lesions on the brain.

Common methods of diagnosing a pork tapeworm infection include a tissue biopsy and an examination of a feces sample. When using a fecal sample to diagnose an infection, it is impossible to confirm cysticercosis, which is typically done by looking for hooks on the scolex of the worm. Radiological tests such as an MRI, CT scan, and X-rays can be used to diagnose cysticercosis in different areas of the body. Although Praziquantel is the most commonly used drug to treat a pork tapeworm infection, some experts consider niclosamide to be the most efficient drug. Combined treatments of steroids and albendazole are often used to treat the inflammation caused by cysticercosis. Surgical procedures can be used to treat lesions in the central nervous system along with Albendazole to treat neurocysticercosis. It is important to practice good hygiene and properly dispose of human waste near sources of pork products, but the best way to avoid a pork tapeworm infection is to refrain from eating raw or under cooked pork.

Image Caption: Pork Tapeworm, Taenia solium. Credit: Roberto J. Galindo/Wikipedia (CC BY-SA 3.0)