Taeniasis - Cysticercosis - Tapeworm

The taeniasis, popularly known as solitary, is a worm infestation caused by parasites Taenia solium or Taenia saginata, which are worms flatworms of cestoda class.

Taenia solium
Taenia solium

The cysticercosis is also a disease caused by these parasites, however, unlike the taeniasis, which is caused by adult worms of Taenia solium or Taenia saginata, cysticercosis is a disease caused only by the larva (cysticercus) of Taenia solium.

Taeniasis and cysticercosis are completely different diseases with symptoms, life cycle and different treatments.

What is Taenia saginata and Taenia solium

Taenia solium larva
Taenia solium larva
There are 32 species of tapeworm, but only two of them are capable of causing disease in humans: Taenia saginata and Taenia solium. Recently, a third kind of gentler tapeworm called Taenia asiatica was identified in some humans in Southeast Asia.

Tapeworms are large flattened body of worms that can reach several meters in length. The Taenia saginata is a major worm can reach up to 25 meters in length, although the average is 5 meters. Since the Taenia solium usually be between 2 and 7 meters.

The tapeworm is a parasite that can be found on almost every continent. It is estimated that, worldwide approximately 50 million are currently infected with Taenia solium or Taenia saginata.

The lone nickname comes from the fact taeniasis be a parasitic disease usually caused by a single worm. In some cases, however, the patient may be parasitized by more than one tapeworm.

Life cycle of tapeworm

Humans are the only definitive hosts of T. saginata and T. solium . Cattle are the intermediate hosts of Taenia saginata, and pigs are the intermediate hosts of Taenia solium.

The life cycle of the taeniasis begins when a human infected evacuates in a place without basic sanitation and releases to the environment or medium eggs pregnant proglottids (tapeworm body segment containing the reproductive organs) mixed with feces. Once on the ground, this tapeworm eggs can survive for days to months, depending on weather conditions. Cows in the case of T. saginata, and pigs, in the case of T. solium, become contaminated by infected vegetation ingestion of eggs or gravid segments.

In the intestine of animals, the embryo tapeworm is released from the egg, invades the intestinal wall and can reach the bloodstream. Once in the blood, the embryo travels to various organs such as the brain, eyes, heart and muscles, where they develop into the form of cysticercosis. The cysticercosis contains about 0.5 to 1 cm and can survive in the muscles of cattle and pigs for many years.

Humans become infected by eating raw meat or undercooked containing cysticerci. After being swallowed, to reach the human intestine, the cysticercus uses its suckers and hooks to be adhered to the mucosa. Once established in the gut, the parasite can complete its life cycle, making up an adult worm within 2 months. Most people has only a single tapeworm, a lone call, but if there are many cysticerci intake, it is possible that the patient develops a more adult worm at the same time.

The tapeworm is a worm that has male and female sexual organs in their proglottids and can become pregnant without the need for a partner. The tapeworm has about 1,000 proglottids, that when they become pregnant, stand out from the worm's body and are released in the feces. Each of these proglottids can produce between 50,000 and 100,000 eggs.

Cycle of cysticercosis

At the time the newly infected human being releases the proglottids and eggs in faeces, taeniasis disease cycle is complete. But for human cysticercosis disease, we are only halfway.

Human cysticercosis begins when the infected individual releases the eggs of Taenia solium in the stool, and he and other humans, accidentally ingest, as in cases of contaminated water or food handling with hands not properly sanitized after a bowel movement . People living in the same household of a person infected with Taenia solium are those that have the highest risk of developing cysticercosis.

When a person accidentally ingests the eggs of T. solium , the process takes place similarly to what occurs in pigs. The eggs release the embryo inside the parasite intestines, it falls into the bloodstream and spreads through the body of the patient. If the egg is able to reach the brain, one cysticercosis will develop in the body, leading to neurocysticercosis, the most severe form of the disease.

The cysticercosis occurs only with egg intake of Taenia solium . The eggs of Taenia saginata can not turn into cysticercosis in humans, only in cattle.

So, in short:
  • The teniasis occurs by eating undercooked meat from animals with cysticercosis, whether by cysticercus of Taenia saginata (beef) or cysticercus of Taenia solium (pork).
  • Human cysticercosis has nothing to do with eating undercooked meat. It only happens if accidental ingestion of eggs T. solium released in human faeces.

Symptoms of taeniasis

Most patients with taeniasis does not have significant symptoms. When they arise, they are more common in cases of Taenia saginata. Abdominal pain, nausea, diarrhea, weight loss and constipation are the most common symptoms of teniasis. Children tend to be more symptomatic than adults.

Some infected patients may go years without knowing who are lonely, until one day, notice the presence of proglottids in your stool. These proglottids have own movement and can also come out spontaneously through the anus, not during the evacuation, going to stay in lingerie.

One of the complications taeniasis is appendicitis, which can arise if one of these proglottids with release of tapeworm end getting trapped inside the appendix (appendicitis). Similarly, the bile duct can also get clogged.

Symptoms of cysticercosis

The symptoms of cysticercosis are completely different from taeniasis. This is not a surprise, since both are distinct diseases.

Symptoms of cysticercosis vary according to the locations where the cysticercus implants. The most severe form is neurocysticercosis, which arises when there is implementation of cysticercosis in the brain. In neurocysticercosis, the most common symptoms are headache and epilepsy. However, not uncommon to completely asymptomatic cases of neurocysticercosis.

The onset of symptoms may take years. In most cases, symptoms occur only 3 to 5 years after infection.

In cases of massive contamination with multiple brain cysticercus deployments, the patient may develop cerebral edema frame, seizures, nausea, headache, personality changes, and even coma.

Cysticercosis may also affect the eyes. The subretinal space, vitreous and the conjunctiva are the most frequent sites of infection. The most common clinical manifestations of infection include eye pain, blurred vision or blindness.

The cysticerci may also be deposited in muscle, causing a myositis frame (muscle inflammation) or on the skin, leading to the formation of subcutaneous nodules.

Diagnosis of taeniasis and cysticercosis

The diagnosis of taeniasis is done by stool testing for the identification of eggs or proglote the tapeworm. As the elimination of eggs is intermittent, it may take more than one test until it can establish the diagnosis. The ideal is to collect at least three stool samples on different days.

In the case of cysticercosis, the diagnosis is usually made by imaging studies such as computed tomography or magnetic resonance imaging of the skull, which can identify the cysticerci housed in the central nervous system.

In patients with cysticercosis, examination of stool for tapeworm research is important because many patients contract the cysticercosis by self-contamination with the eggs present in their own feces.

Treatment of taeniasis and cysticercosis

Treatment options for taeniasis include:
  • Mebendazole: 200 mg, 2 times daily for 3 days orally.
  • Praziquantel, single-dose, 5 to 10 mg/kg body weight, orally.
  • Albendazole, 400 mg / day for 3 days orally.
  • Niclosamida, adult 2 grams and 1 gram for children in single dose orally.

After the treatment, the pieces may remain tapeworm being disposed for several days. After 3 months, new parasitological examination of feces is suggested to confirm the absence of eggs in the faeces.

Treatment of cysticercosis

Not all cases of cysticercosis in need of treatment, especially if the patient is asymptomatic. Generally, treatment is indicated in the symptomatic cases of neurocysticercosis or ocular cysticercosis.

The neurocysticercosis treatment options are:
  • Albendazole 15 mg/kg daily for 15 to 30 days depending on the severity of the disease.
  • Praziquantel 50 mg/kg per day for 15 to 21 days depending on the severity of the disease.

In addition to the parasite, also indicates it is the use of corticosteroids such as dexamethasone or prednisone to relieve brain swelling that occurs by the inflammatory process generated by the death of cysticercosis.

In cases of cysticercosis muscle or skin, the drug treatment has little effect. In general, we suggest that surgical removal of the cysticercosis in symptomatic cases.
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