Tapeworm

Definition

Tapeworms (cestodes) belong to the flatworms (Plathelminthes). There are well over 3000 different species. All types of tapeworms live as parasites in the intestines of their end hosts.

They do not have a digestive tract (endoparasites). The structure consists of a head (scolex) and the limbs (proglottids). In addition, tapeworms are hermaphrodites and can therefore fertilise themselves.

The eggs are taken up by an intermediate host and settle as fins – this is how the larvae are called – in its musculature. Humans then ingest them with their food, for example in the form of pork. The finished tapeworm then develops in the intestine. The tapeworm gets its nutrients from the intestinal wall.

Causes

The way in which humans get a tapeworm depends on the subspecies of the tapeworm. There is the beef tapeworm (Taenia saginata) and the pig tapeworm (Taenia solium). By eating half raw or raw beef or pork, the fins can enter the human intestine and develop into tapeworms.

There are also the benign dog tapeworm (Echinococcus granulosus) and the malignant fox tapeworm (Echinococcus multilocularis). In these tapeworms, humans are mistakenly the carrier. This is also known as false host.

The tapeworm eggs are found in the faeces of the respective animal. In the form of contaminated wild berries or mushrooms they then enter the human body. They can also be found on unwashed fruit and vegetables that have come into contact with appropriate fertilizers.

The own house dog is also a potential carrier. Finally there is the fish tapeworm (Diphyllobothrium latum). Humans are mainly infected by eating raw fish products.

Diagnosis

Often, the affected persons notice the tapeworm eggs or components of the tapeworm in their own stool. Sometimes the individual limbs still move like small threads in the stool. The only way to be sure is to take a stool sample to the doctor.

The doctor can make a better assessment with the help of a microscope. If the tapeworm has colonised humans as a false host and is spreading throughout the body, further diagnostic procedures may be possible. Direct detection can be done, for example, by biopsy or ophthalmoscopy.

Neuroradiology can also be consulted. Cysts with tapeworm components can be easily detected by CT and MRT thanks to their good resolution. There is also a specific and sensitive antibody test for the porcine tapeworm, which allows detection by means of a blood sample and immunoblot.

Symptoms

Most of the symptoms that occur during a tapeworm infection are rather unspecific and very diverse. Frequently, those affected complain of ubiquitous abdominal pain without clear localisation. In addition there is a feeling of pressure and fullness.

Accordingly, loss of appetite and weight loss is very common. In some cases, patients also suffer from nausea with vomiting, as well as an alternation of diarrhoea and constipation. Itching in the anal region further increases the pressure of suffering.

Infection with the eggs of the fox tapeworm is particularly dangerous and life-threatening. The larvae can attach themselves to all organs and destroy them. There are often several years between the first contact and the onset of the disease during which the parasite can spread unnoticed.

Especially the liver is affected. The related dog tapeworm, however, is more harmless. However, it can also settle with its larvae in various organs such as the lungs and thus cause irritable cough.

If eggs of the pig tapeworm are accidentally ingested, e.g. through the dog’s own faeces, a serious disease, cystiscercosis, can result. The symptoms then depend on the organ affected and range from muscle pain to neurological deficits. Sometimes the infection with a tapeworm goes completely unnoticed.

The harmless dwarf tapeworm, for example, colonizes tens of millions of people without causing any symptoms. The fish tapeworm is equally asymptomatic. In chronic infections, however, it can cause vitamin B12 anaemia.

As already described, the symptoms of tapeworm infestation are very varied, so anything and everything can point to a tapeworm. Flatulence can be a sign of an inflammatory process in the intestine and can certainly occur in the context of a tapeworm disease. But flatulence is not a symptom that is groundbreaking and specific.

Rather, the overall context must be considered: Are there other symptoms that make the diagnosis likely? Are there any recurrent events that make infection with a tapeworm possible? If the flatulence has only existed for a short time, the cause is probably to be found elsewhere.

The most common trigger is flatulent food. If you suspect a tapeworm disease, it is worthwhile to talk to other mothers who may have noticed the same symptoms in their children. Infection is possible through oral ingestion of faeces.

The symptoms do not differ from those of adults. Abdominal pain and nausea are equally common. In children, anal itching is most often caused by an infection with pinworms (Enterobius vermicularis).

Children itch especially at night on their buttocks when the worms crawl out to lay their eggs. There are many different differential diagnoses for abdominal pain in children, most of which are more likely than a tapeworm. A clarification by the pediatrician is advisable in any case.