All seven varieties of tapeworms are parasites. Some of these worms reach lengths of up to 2 feet, and one species reaches 45 feet. Tapeworms affect many animals, including dogs, cats, rats, mice, sheep, cattle and pigs. Many times, an infestation occurs after ingestion of larvae-infected fleas or direct ingestion of the worms' eggs while grazing in areas where the feces of infested animals are left.
Dogs and cats both get this tapeworm, though its name reflects that it's common mostly to dogs. The dog tapeworm infestation begins when the pet eats infested fleas -- which happens when the animal bites a flea irritating his skin. Dipylidium caninum is the most common of the tapeworms that dogs get. The animal's stool contains tiny white worm segments that resemble pieces of rice. Each segment contains eggs that emerge when the segment dries.
Taenia Taeniaformis and Hymenolepsis Diminuta
Taenia taeniaformis is another of the dog tapeworms that cats, mice and rats as well as sheep and other farm animals can contract. This infection commonly passes to cats who eat infected mouse livers. Hymenolepsis diminuta is a small tapeworm parasite of rats, who usually get infected by eating infested insects. This tapeworm also spreads through contaminated animal feces on grass.
Another dog tapeworm, Echinococcus granulosus is also found in mice and is only 8 millimeters long. This tiny tapeworm is known as the minute dog tapeworm and is contracted when a dog eats raw meat such as that of the herbivorous sheep, or by biting dead animals during hunting. The sheep pick up the infection by eating the eggs of the worm that were passed in the manure of other sheep and are found on grasses.
The fish tapeworm is an unusually long worm, with adult specimens reaching up to 45 feet. Diphyllobothrium latum is found in fish from cool, fresh water areas, including the great lakes and the lakes of Alaska and Canada. Eating these infected fish raw is how the worms spread to other animals, including humans. While many types of smaller tapeworms cause few or no symptoms, this species often causes pernicious anemia in humans.
Taenia Saginata and Taenia Solium
Bovines contract Taenia saginata, the beef tapeworm, when they graze on grasses infested with the eggs of these tapeworms. The feces of other cattle in the area is the cause of the grass contamination. Taenia solium is the pork tapeworm, acquired when pigs graze on grasses covered in tapeworm eggs distributed through the feces of other infested pigs. Eating the undercooked meat of these animals causes infestation in humans.
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