Tapeworm infection of the intestine occurs when people eat raw, undercooked meat like beef, pork or even
freshwater fish. Tapeworms belong to a branch of platyhelminths known as the cestodes. They are highly specialized parasites.
Some of the common causes of tapeworm infections in humans are as follows:
1. Taenia saginata or beef tapeworm.
2. Taenia solium or pork tapeworm.
3. Diphyllobothrium latum or fish tapeworm.
4. Hydatid tapeworm or Echinococcus granulosis which is found in dogs.
5. Dwarf tapeworm or hymenolepis nana.
Tapeworm infection in humans can occur after accidental ingestion of tapeworm eggs
The tapeworm eggs are passed through the feces of the human or animal that is infected with tapeworm. If a person accidentally consumes food or drink that is contaminated with infected feces then they ingest microscopic tapeworm eggs. For example, an infected animal like a dog or a pig can pass infected eggs through the feces. The soil becomes contaminated with these feces. If a person consumes any food or drink that comes in contact with such infected soil then the eggs are passed into his body in the form of watery hydatid cysts and he becomes infected with tapeworm.
These cysts then break into hundreds of tapeworm heads. The tapeworm heads travel through the blood stream into the intestine. With the help of scolex the head of tapeworm attaches itself firmly into the intestine. Once inside the intestine, the eggs develop into larvae. At this stage, the larvae become mobile.
If they migrate out of the intestines, they may travel to other organs like the kidneys and the brain. The organ that is most commonly affected by tapeworm infestation is the liver. Once inside the internal organs they form watery cysts. Taenia solium or pork tapeworm is the tapeworm that most commonly attacks the internal organs. The most dangerous variety of tapeworm is the hydatid tapeworm which is commonly found in the intestine of the dogs.
Tapeworm infection can also occur after ingestion of larvae in undercooked or raw meat
When an animal becomes infected with tapeworm, then the tapeworm larvae are lodged inside its intestine and the muscle tissue. If a person eats undercooked or raw meat of an infected animal such as raw beef, pork or fish then the tapeworm larvae are directly passed into the human body. Once inside the human body the tapeworm larvae travel into the gut through the intestine. Then the life cycle of the tapeworm continues inside the human body as it attaches itself firmly into the intestine with the help of hooks and suckers that are present on the scolex. The body of tapeworm consists of segments which are also called as proglottids. These proglottids are the reproductive organs of the tapeworm. They consist of both male and female reproductive organs.
In some people the tapeworm do not produce any symptoms, whereas in others the tapeworms cause irritation of the intestine and thereby produce symptoms like abdominal discomfort, diarrhea, vomiting and even anemia.