Bandwurme

Bandwurme, known in English as tapeworms, are a group of parasitic flatworms in the class Cestoda. They inhabit the small intestine of vertebrates, including humans, and lack a digestive tract, absorbing nutrients across their surface. A typical tapeworm consists of a scolex (head) with attachment organs, a neck, and a segmented body (strobila) made of proglottids that mature as they move away from the neck.

Most tapeworms have indirect life cycles involving intermediate hosts. Eggs or gravid proglottids pass in feces, reaching water or soil. Ingested by an intermediate host, they develop larvae that encyst in tissues. Humans become definitive hosts by eating undercooked meat or fish containing cysticerci or other larval forms; in some species, humans may harbor larval cysts if eggs are ingested, leading to cysticercosis.

Notable examples include Taenia solium (pork tapeworm) and Taenia saginata (beef tapeworm), common in regions with undercooked meat. Diphyllobothrium latum (fish tapeworm) uses fish as intermediate hosts and can cause vitamin B12 deficiency. Echinococcus species form hydatid cysts in intermediate hosts and pose distinct health risks.

Clinical features vary; many infections are asymptomatic. When symptoms occur, they may include abdominal discomfort, nausea, or weight loss. Heavy infections and certain species can cause complications such as megaloblastic anemia or cystic disease. Diagnosis typically relies on stool examination for eggs or proglottids; imaging or serology may be used for tissue-associated infections. Treatment usually involves praziquantel or albendazole; surgery is rarely needed for hydatid disease. Prevention centers on cooking meat and fish thoroughly, meat inspection, and good hygiene to prevent fecal contamination.