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Life Cycle of Diphyllobothrium Latum

Diphyllobothrium Latum is the largest tapeworm known to infect humans. Its name means "the fish" or "broad tapeworm." It is also known by the name Diphyllobothrium. Diphyllobothriasis is when this type of tapeworm infects a person or animal. A person with diphyllobothriasis may not have any noticeable symptoms and may be infected for decades. Some symptoms that may develop include stomach pains, diarrhea, vomiting or weight loss. An infected person may also suffer from a vitamin B12 deficiency. An increase in the popularity of sushi, which is made from raw fish, has meant an increase in the instances of this type of infection. How the tapeworm is born, develops and reproduces is called its life cycle.

  1. Unembryonated Egg

    • Immature eggs of a Diphyllobothrium Latum do not have an embryo, which is why they are called unembryonated eggs. These eggs are found in the feces of an infected human. When the feces containing the unembryonated eggs gets to a freshwater source, the life cycle continues.

    Coracidium

    • The egg matures and develops in the water for 1 to 3 weeks and turns into a coracidium, which is a tiny organism with cilia that allow it to swim around in the water. Cilia are tiny hair-like projections. The life cycle advances when the coracidium is swallowed by a copepod, which is a small crustacean or water flea.

    Procercoid Larva

    • The coracidium loses its cilia inside the copepod and then penetrates the copepod's intestines. There it matures into the next stage of development, which is called the procercoid larva, which has a tail and is about half a millimeter long. This takes about 2 or 3 weeks.

    Plerocercoid Larva

    • The life cycle continues when a small fish eats the copepod. The fish becomes infected by the procercoid, which develops into the next stage, which is called the plerocercoid larva. A human can be infected by the plerocercoid if he were to eat a small fish that wasn't cooked properly, but this is a rare occurrence. What typically happens is the smaller fish is eaten by a larger fish. As larger fish eat the small fish, the plerocercoid continues to grow and develop.

    Adult Diphyllobothrium Latum

    • When a human eats an undercooked fish that is infected, the human becomes infected by the plerocercoid, which then develops into an adult inside the small intestines. The tapeworm attaches to the mucous membrane of the small intestine. The adult tapeworm has proglottids, which are sections of its body. The proglottids release immature eggs, which end up in the feces and starts the life cycle all over. A tapeworm can grow to be 10 meters long and produce over 1 million eggs per day.

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