Tapeworms

By Stephanie Bedoya

Tapeworm FactsThe tapeworm eats whatever the host eats. It lives in the internal organs of the host. In addition, tapeworms can be less than 1 inch but they can grow up to 16 feet!

Fun Facts: o All tapeworms have male and female segments.o The pork tapeworm lays its eggs in the host’s face.o Tapeworms lay their eggs in the meat of the animal you would eat.o Most of the invasions happen in poor countries.o A tapeworm can live in a host for over 10 years without the host

knowing.o Hosts become infected by eating undercooked meat that has cysts

in it.

Parts of a Tapeworm

Taenia Saginata

Taenia Saginata: Beef Tapeworm/ Hookless Tapewormo The beef tapeworm is a parasite of both cattle and humans.o The beef tapeworm is normally 4 to 10 meters in length, but can grow

over 12 meters long.o It is whitish in color.o The strobila is composed of a series of ribbon-like segments

called proglottids. o The segments are made up of mature and gravid proglottids. o The eggs are in the proglottids and they are only going to infect the

cattle. If a human eats the eggs, it will not cause any infection. The human is only infected by eating the beef containing the larvae.

o The segments are eliminated individually through the human feces.o T. saginata is the largest of genus Taenia consisting between 1000 to

2000 proglottids and can also have a lifespan of 25 years in a host's intestine.

o The disease is called Teaniasis and the symptoms are weakness, weight loss, epigastric pain, appetite loss, anal obstruction, and anal itching produced when the proglottids are coming out.

Taenia Saginata

Beef Tapeworm Life Cycle

Taenia SoliumTaenia Solium: Pork Tapeworm/ Hook Tapeworm• T. solium is normally 2 m to 3 m in length, but can become very large, over 50 m long in

some situations.• It has 800-900 proglottids.• The proglottids are expulsed in groups of 5 or 6.• Humans and pigs get infected by eating these eggs, and the human is also contaminated

by eating raw pork containg larvae.• T. solium has a very similar life cycle to Taenia saginata.• These parasites can cause Taeniaosis , causing moderate abdominal pain. If the eggs

contaminate any organ or tissue, it is called cysticercosis. If the eggs travel to the central nervous system, it is called neurocysticercosis.

• Infection with T. solium adults is treated with niclosamide, which is one of the most popular drugs for adult tapeworm infections, as well as for fluke infections.

• As cysticercosis is a major risk, it is important to wash one's hands before eating and to suppress vomiting if a patient may be infected with T. solium. If neurocysticercosis occurs the drug of choice is either albendazole or praziquantel. These drugs damage the parasites skin internally causing it to disintegrate and is then removed by the host's immune system.

• Infection may be prevented with proper disposal of human feces around pigs, cooking meat thoroughly and/or freezing the meat at −10 °C for 5 days. Most cases occur because infected food handlers contaminate the food.

Taenia Solium

Pork Tapeworm Life Cycle

Human Cysticercosis

Cysticercosis refers to tissue infection after exposure to eggs of Taenia solium, the pork tapeworm.

Symptoms: The symptoms vary according to where the cysticercosis are located, the number of parasites, and the immune host response. The most frequent symptoms are: headaches, seizures, blurred vision, and lymph nodes swelling.

Human Cysticercosis

Human Cysticercosis

Hymenolepsis Nana Hymenolepsis Nana: Dwarf Tapeworm• Dwarf tapeworm (Hymenolepis nana, previously known as Vampirolepis

nana, Hymenolepis fraterna, and Taenia nana) is a cosmopolitan species that is one of the most common cestodes of humans in the world, especially among children.

• It can be found throughout the world, but is usually most common in temperate zones. • It is the most common cestode of humans and is found wherever there are human

inhabitants.• As its name implies, it is a small species, exceeding 40 mm long and 1 mm wide.• The scolex bears a retractable rostellum armed with a single circle of 20 to 30 hooks.

The scolex also has four suckers, or a tetrad. • The neck is long and slender, and the segments are wider than long.• This is the only cestode that can complete its life cycle in one host: a human.• The human can store the not only the adult, but larvae parasites.• It has about 200 proglottides.• The scolex has 4 suckers with a crown that has 20-30 hooks. • The eggs are round and similar to Taenia Saginata.

Hymenolepsis NanaDevelopement:Infection can be direct or indirect. Direct is infection is acquired most commonly from eggs in the feces of another

infected individual, which are transferred in food, by contamination. Eggs hatch in the duodenum, releasing oncospheres, which penetrate the mucosa and come to lie in lymph channels of the villi. Oncospheres develops into a cysticercoid which has a tail and a well formed scolex.

The indirect life cycle is doubtless a recent modification of the ancestral two-host life cycle, found in other species of hymenolepidids, because cysticercoids of H. nana can still develop normally within larval fleas and beetles.

Direct contaminative infection by eggs is probably the most common route in human cases, but accidental ingestion of an infected grain beetle or flea cannot be ruled out.

The direct infectiousness of the eggs frees the parasite from its former dependence upon an insect intermediate host, making rapid infection and person-to-person spread possible. The short life span and rapid course of development also facilitate the spread and ready availability of this worm.

Hymenolepsis Nana

Dwarf Tapeworm Life Cycle

The End