Photo credit: Fedaro
Both male and female, this hermaphrodite species reproduces in our bodies by eating our food. Without treatment to eliminate it, the tapeworm grows in our intestine to the point of reaching 10 m long and living for 20 years! This is the case of the smooth tapeworm, which can be ingested while eating beef tartare. In this article, we will learn how to detect the presence of a tapeworm in our body, its mode of transmission, its life cycle and above all, how to get rid of it.
What are the different types of tapeworm?
Tapeworms are worms belonging to the class Cestodes and the order Cyclophyllidae. Among the different species that infect humans, we can cite:
Taenia saginata (smooth tapeworm or beef tapeworm); Taenia solium (armed tapeworm or pork tapeworm); Hymenolepis nana (bread tapeworm); Diphyllobothrium latum (fish tapeworm). What do tapeworms look like?
Cestodes are flatworms, shaped like a segmented ribbon, whose morphology has 3 parts: a head (scolex), a narrow neck and a body (strobile) made up of a succession of rings (proglottids). Tapeworms usually have hooks or suction cups at the end of their heads that help anchor themselves firmly to the host’s intestinal wall. Each ring is an independent hermaphrodite reproductive unit (male when young, then female as an adult) and the last ones are filled with eggs. Lacking a digestive tract, tapeworms assimilate food through the integument, the surface of which is entirely covered with microvilli, visible only under a microscope. Adult tapeworms have a whitish or yellowish tint. The largest human cestodes is Diphyllobotrium latum (fish tapeworm) which can exceptionally reach 20 m in length. Taenia saginata (beef tapeworm) can exceed 10 m and Hymenolepis nana (bread tapeworm) measures 1 to 5 cm.
What tapeworms are found in France?
Tapeworms have a cosmopolitan distribution but are more common in developing countries. Their spread depends on hygiene, culinary habits and veterinary controls observed in these regions.
Taenia saginata is most common in France where we readily consume raw meat (beef tartare) or undercooked meat (blue or rare meat); Taenia solium is absent from France where the search for cysticerci (larval form of tapeworms) is obligatory in pigs at slaughter (not obligatory for beef). The very rare cases of appearance of these species of tapeworm concern foreigners or French people returning from abroad. The pork tapeworm is more present in the Iberian Peninsula, Eastern Europe, Asia, Africa and South America; Diphyllobothrium latum affects certain parts of Northern Europe (such as Scandinavia, Russia and the Baltic countries) where raw or poorly cooked freshwater fish, such as salmon or trout, are traditionally consumed; Hymenolepsis nana, the bread tapeworm, is widespread in Africa, India, Central and South America. How are tapeworms caught?
First of all, you should know that the beef tapeworm, the most common in France, has 2 hosts during its life:
An intermediate host (the ox), which carries the eggs of the tapeworm but does not develop the parasite; A definitive host (man), within which the tapeworm will proliferate.
Most transmissions occur through the consumption of raw or undercooked meat. Tapeworm larvae live in the muscles of intermediate hosts then are transmitted to humans, via food, who become their definitive host. In the case of the bread tapeworm, the intermediate host is an insect or invertebrate (cockroach, flea, mealworm, etc.) that humans (especially children) ingest in undercooked bread. For this infection, however, we note that the usual mode of contamination is self-infestation (dirty hands), without an intermediate host.
What is the life cycle of the tapeworm?
Want to know what happens to your body after ingesting a tapeworm? Here is the life cycle of a tapeworm in detail:
Tapeworm eggs are passed in the stools of infected people. These eggs are ingested by cattle (intermediate host) via grass or water contaminated by human feces; The eggs hatch in the livestock’s digestive system, releasing larvae that pass through the intestinal wall and migrate to the animals’ muscles; When a human consumes infested, raw or undercooked meat, the larvae settle in their stomach; The larvae pass from the stomach to the intestinal mucosa of the man where they attach themselves using the hooks located on his head; The larvae grow thanks to the food consumed by humans (which explains weight loss in humans who do not metabolize their food); The larvae then develop into adult tapeworms in the small intestine where they reproduce; Eggs produced by adults are passed into the environment through human feces; Ingestion of the rings by livestock will perpetuate the life cycle of the tapeworm. Tapeworm: what are the symptoms?
A person infected with a tapeworm may be asymptomatic or have only mild symptoms. In addition, clinical signs are sometimes confused with other conditions, which is why years can pass before a diagnosis is made. Please note that Taenia saginata can live for 20 years! In addition to the presence of rings in the stool, in the underwear or in the sheets, the symptoms likely to appear in the presence of a tapeworm are the following:
Loss of appetite causing abnormal weight loss; An increase in appetite (food no longer being metabolized by humans but by the worm); Abdominal pain; Digestive disorders (nausea, diarrhea, constipation, bloating, etc.); Headaches ; Significant fatigue (the worm absorbs nutrients essential for the proper functioning of the body); Itching (at the anal level); Rashes or hives (if allergic). Tapeworm: how to make a diagnosis?
In addition to the symptoms described above, which are often minimal and non-specific, the patient is especially alerted by the discovery of rings in his stools, sheets or underwear. The rings appear in the form of whitish debris approximately 2 cm long by 1 cm wide and 1 mm thick. The anal tape test method consists of applying adhesive tape to the anus, then examining the sample under a microscope and detecting the possible presence of eggs. A coproculture may be necessary to determine the type of parasite responsible and provide appropriate treatment. The doctor can also carry out a blood test because in the early stage of the infestation, an increase in eosinophilic white blood cells is sometimes observed in certain cases (as in many infections). Serology can also demonstrate a vitamin B12 deficiency caused by the fish tapeworm which massively engulfs this substance.
What treatment for tapeworms?
Tapeworm infestation is a benign condition but must be eliminated because without treatment, the tapeworm continues to grow in the body. An antiparasitic medication (dewormer), usually prescribed in a single dose, is enough to kill the tapeworm. The cestode is then expelled through the stool. The treatment is sometimes repeated 2 to 3 weeks later, to guarantee definitive removal of the parasite. In the presence of fish tapeworm, vitamin B12 may be necessary to correct anemia, if present.
How to prevent the appearance of tapeworm?
Prevention against tapeworm involves simple hygienic and dietary measures such as:
Thoroughly cooking meat and fish (carpaccios, tartars and sushi should be avoided); Prolonged freezing (at least 10 days at -20°C) kills the larvae of tapeworm saginata and solium; Cleaning your hands after touching meat or an animal, after using the toilet and after a walk in the forest if you have touched vegetation; Washing fruits and vegetables, especially those collected in the wild (as they may have residue of excrement containing eggs); Deworming your pets.