Pork tapeworm

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Pork tapeworm
Proglottid (Taenia solium)

Proglottid ( Taenia solium )

Systematics
Class : Cestoda (tapeworms)
Subclass : Eucestoda (true tapeworms)
Order : Cyclophyllidea
Family : Taeniidae
Genre : Taenia
Type : Pork tapeworm
Scientific name
Taenia solium
( Linnaeus , 1758)

The pork tapeworm ( Taenia solium ), also pigs Finn tapeworm called, is a parasitic living worm in the intestines of humans. Pigs serve as intermediate hosts . Other mammals can also be infected experimentally . Humans can also serve as false intermediate hosts .

distribution

The pork tapeworm, like the beef tapeworm, was spread worldwide with humans as its main host . Humans become infected by eating (finned) meat that is infected with the larvae (fins) of the tapeworm.

features

The body of the pork tapeworm has all the typical features of the tapeworm , it reaches a length of 3 to 7 m and a width of up to 7 mm.

Life cycle

fully grown Taenia solium

As with all tapeworms, the life cycle of the pork tapeworm includes a fin stage ( Cysticercus cellulosus ), which in this case is found in pigs. A fin is the turned up front end of the future tapeworm in a bladder. The main host (carnivore or omnivore, e.g. humans) takes in the Finns in the form of infected meat. In the intestine, the outer skin of the fin (bladder) is digested, the tapeworm hooks onto the mucous membrane of the small intestine with suction cups and hooks and grows by continuously forming new limbs, proglottids . These become sexually mature one after the other and fertilize each other. The last proglottids, which contain ripe eggs, detach and are excreted with the feces. The main host excretes up to nine proglottids per day. The eggs are ingested in large quantities by the intermediate host (herbivores or omnivores, e.g. pigs); hook larvae (Oncosphaera) are released from the eggs in the intestine. These leave the intestine and mainly settle in the muscles (diaphragm, tongue, heart), where they transform into fins ( cysticercosis ). The Finns remain in the intermediate host and can thus be transferred to the ultimate host (to humans, e.g. through insufficient cooking of the meat). In contrast to the beef tapeworm, humans can also serve as intermediate hosts when eggs are ingested (e.g. due to poor hygiene during food preparation).

Harmful effect

The infection with the adult tapeworm usually has no symptoms. But if humans serve as false intermediate hosts, the Finns settle mainly on the fasciae of skeletal muscles, on the diaphragm, larynx, heart, lymph glands or in the brain. There they cause headaches, increased intracranial pressure, neurological deficits and meningitis.

therapy

Mebendazole and praziquantel or niclosamide , among others, are used for therapy .

prevention

In Europe, pork tapeworms have mainly been eliminated through meat inspection , as the Finns are quite conspicuous and occur frequently. Areas of particular concern are Mexico, where the Finn stage is often found in humans (up to 3.6% of the population are affected in Mexico City). The curing and smoking of pork does not provide sufficient protection. To prevent infection, meat should always be cooked or roasted and, if possible, only controlled meat should be consumed. Freezing (−20 ° C over 24 hours) also kills the Finns.

Web links

Commons : Pork Tapeworm  - Collection of images, videos and audio files

Individual evidence

  1. ^ Marianne Abele-Horn: Antimicrobial Therapy. Decision support for the treatment and prophylaxis of infectious diseases. With the collaboration of Werner Heinz, Hartwig Klinker, Johann Schurz and August Stich, 2nd, revised and expanded edition. Peter Wiehl, Marburg 2009, ISBN 978-3-927219-14-4 , p. 290.
  2. Gerd Herold and colleagues: Internal Medicine 2007.
  3. Federal Food Safety and Veterinary Office: Parasitic pathogens in food and drinking water . In: admin.ch , accessed on February 12, 2020.
  4. ^ Hof, Dörries: Medical Microbiology . Georg Thieme Verlag, 2005, ISBN 3131253134 , pp. 573-575.