All tapeworms (cestodes) go through three stages – eggs, larvae and adult worms. Adult worms live in the intestine of definitive hosts, carnivorous mammals. Some of the adult tapeworms that infect humans are named after its intermediate host: The FischbandwurmDiphyllobothrium latum The beef tapeworm (Taenia saginata) The pork tapeworm (Taenia solium) An exception is the Asian tapeworm (Taenia asiatica), of the T. saginata in many respects is similar, but it is acquired by eating pork in Asia. Eggs that are laid by adult tapeworms that live in the intestine of definitive hosts, are excreted in the feces in the environment and absorbed by an intermediate host (usually another species) in the developing larvae that pass into the bloodstream and in muscle or other organs cysts. If the intermediate host consumed, the parasites are liberated from the acquired cysts in the gut and develop in the final host into adult tapeworms and the cycle begins again. Some Zestodenarten (z. B. T. solium) of the definitive host can also act as an intermediate host. This means that if eggs are eaten instead of cysts develop, the eggs hatch into larvae, which enter the circulation and encyst in various tissues. Adult tapeworms are multi-segmented flat worms that have no digestive tract and gain their nutrients directly from the small intestine of the host. In the digestive tract of the host, adult tapeworms can be large; the longest parasite in the world is the 40 m long Walbandwurm, Polygonoporus sp. Tapeworms consist of 3 recognizable parts: the scolex (head) serving as anchoring element, which attaches itself to the intestinal mucosa. The neck is a non-segmented region with a strong ability to regenerate. If not neck and scolex be eliminated with a therapy may develop a whole worm from it again. The rest of the worm consists of numerous Proglottiden (segments). The proglottids, which are adjacent to the neck directly, are not differentiated. With the migration of Proglottiden caudal developed each one hermaphrodite genitals. Distal proglottids are pregnant and contain egg in a uterus. Representative structure of a tapeworm, based on Taenia solium. Size and morphology vary depending on the type and maturity. Symptoms and complaints Adult tapeworms are so well adapted to the gastrointestinal tract of their host, they usually result in only minimal discomfort. There are some exceptions. Severe infection with Hymenolepis nana can cause abdominal pain, diarrhea and weight loss; Diphyllobothrium latum can lead to vitamin B12 deficiency and megaloblastic anemia. Unlike adult tapeworms larvae cause severe and even fatal diseases can result if they develop outside of the intestine, especially in the brain, but also in the liver, lungs, eyes, muscles and subcutaneous connective tissue. In humans, T. solium causes cysticercosis, and Echinococcus granulosus and E. multilocularis caused Hydatidenzysten. The larvae of Spirometra spp, Sparganum proliferum, T. and T. multiceps serialis can also infect humans. Diagnosis For infections with adult tapeworms, microscopic examination of the stool for larvae disease imaging infections by adult tapeworms are detected by the detection of eggs or pregnant Proglottidensegmenten in the stool. Larvae related diseases are best detected by imaging techniques (eg. B. Skull CT and / or MRI). Serological tests may also be helpful. The therapy anthelmintic drugs anthelmintic praziquantel is effective against intestinal tapeworm infections. Niclosamide is an alternative that is not available in the US. Nitazoxanide can be used for H. nana infections. Some extra-intestinal infections respond to a anthelmintic therapy with albendazole and / or praziquantel, others require surgical intervention. Prevention prevention and control include: Thorough cooking (at a temperature> 57 ° C [> 135 ° F]) of pork, beef, lamb, venison and fish Prolonged freezing of meat for some tapeworms (eg fish tapeworm.) Regular deworming of dogs and cats The life cycle of host organisms should be interrupted (eg., dogs deter dead wild or breeding animals to eat) reducing and avoiding intermediate hosts such as rodents, fleas and weevils meat inspection Hygienic proper treatment of human waste, the smoking and drying meat is ineffective to prevent infections.


Leave a Reply

Sign In


Reset Password

Please enter your username or email address, you will receive a link to create a new password via email.