Different Stages of a Pork Tapeworm

Pork tapeworms, just like any other living organism, have a life cycle. The worm is scientifically classified as a parasite and it causes an infectious human disease called cysticercosis. Humans acquire the disease by eating cysts of the worm that are found in raw or undercooked pork. According to the Merck Manual, these cysts hatch into adult tapeworms in the human intestines, then latch onto the intestinal walls where, if untreated, they can grow up to eight to11 feet at maturity.

The Beginning Stage

• Tapeworms have segments called proglottid,s which contain the eggs.

  Adult pork tapeworms begin as eggs. The eggs are found in untreated human waste. If the waste gets into the environment, pigs can ingest the eggs, which may be mixed in with their food or water supply. The pigs, as the carrier of the eggs, are known as "intermediate hosts" for the incubation period while the eggs grow and become larvae and then adults.

Larval Stage

• Cyst-infested pork may be sent to market and prepared as food.

  The second stage of tapeworm development is called the larval stage. These larvae get inside the pig's intestinal wall and from there are transported by the bloodstream to the pig's muscles or other tissues. While in the muscles and tissues, the larvae form cysts (oncospheres). Infected pigs can then be prepared for market and sent out as food. If the meat is not sufficiently cooked, human can then ingest the infected live larvae.

The Human Component

• Thoroughly cooking pork will kill the cysts that cause cysticercosis.

  Pork that is eaten raw or undercooked will still contain the cysts, if they are present in the meat. When the meat is consumed, the cysts are ingested as well. Now the human becomes the intermediate host. In turn, these cysts will once again latch onto the intestinal wall. According to the Centers for Disease Control, the cysts can migrate through the bloodstream and infect the muscles of the host. From the cyst stage, the worms develop into adult tapeworms, which then begin to produce eggs.

Cysticercosis

• Once again, the eggs hatch inside the intestinal wall and develop into larvae. The larvae penetrate the intestinal wall, and can travel to through the blood to the rest of the body, particularly to the muscles and brain. If left untreated, adult pork tapeworms can live for up to 25 years. According to the Merck Manual, treatment is a single dose of an oral medication called praziquantel. Cysticercosis is usually not treated unless the brain is infected. If the tapeworms are located in the intestine, there are usually no symptoms. The disease is diagnosed through a stool sample if it is localized in the intestines. If it has traveled to the brain or other tissues, its presence can be seen in a CT scan or MRI image. Freezing pork for a prolonged period of time, or cooking it to an internal temperature of more than 135 degrees Fahrenheit will kill the cysts.