![]() The adults can reach more than 10 m (up to 30 ft) in length in some species such as D. The adults attach to the intestinal mucosa by means of the two bilateral grooves ( bothria) of their scolices. After ingestion of the infected fish, the plerocercoids develop into immature adults and then into mature adult tapeworms which will reside in the small intestine. ![]() In this case, the sparganum can migrate to the musculature of the larger predator fish and mammals can acquire the disease by eating these later intermediate infected host fish raw or undercooked. ![]() Nevertheless, these small second intermediate hosts can be eaten by larger predator species, for example trout, perch, walleye, and pike. īecause humans do not generally eat undercooked minnows and similar small freshwater fish, these do not represent an important source of infection. The plerocercoid larvae are the infective stage for the definitive host (including humans). ![]() Following ingestion of the copepod by a suitable second intermediate host, typically a minnow or other small freshwater fish, the procercoid larvae are released from the crustacean and migrate into the fish's flesh where they develop into a plerocercoid larvae (sparganum). After ingestion by a suitable freshwater crustacean such as a copepod (the first intermediate host), the coracidia develop into procercoid larvae. Immature eggs are passed in feces of the mammal host (the definitive host, where the worms reproduce). Diphyllobothrium latum proglottid Diphyllobothrium latum - fertilized eggĪdult tapeworms may infect humans, canids, felines, bears, pinnipeds, and mustelids, though the accuracy of the records for some of the nonhuman species is disputed. As in all pseudophyllid cestodes, the genital pores open midventrally. In adults, proglottids are wider than they are long (hence the name broad tapeworm). Unlike many other tapeworms, Diphyllobothrium eggs are typically unembryonated when passed in human feces. latum is the longest tapeworm in humans, averaging ten meters long. From the neck grow many proglottid segments which contain the reproductive organs of the worm. The scolex attaches to the neck, or proliferative region. Each side of the scolex has a slit-like groove, which is a bothrium for attachment to the intestine. The adult worm is composed of three fairly distinct morphological segments: the scolex (head), the neck, and the lower body. More recently, a molecular study found D. nihonkaiense, which was only identified as a separate species from D. In Japan, the most common species in human infection is D. yonagoensis, all of which infect humans only infrequently. dendriticum (the salmon tapeworm), which has a much larger range (the whole northern hemisphere), D. Other members of the genus Diphyllobothrium include D. klebanovskii, having Pacific salmon as its second intermediate host, was identified. latum is native to Scandinavia, western Russia, and the Baltics, though it is now also present in North America, especially the Pacific Northwest. latum is a pseudophyllid cestode that infects fish and mammals. latum, known as the broad or fish tapeworm, or broad fish tapeworm. The principal species causing diphyllobothriasis is D. ( August 2022) ( Learn how and when to remove this template message)Ĭordicephalus Wardle, McLeod & Stewart, 1947ĭiphyllobothrium is a genus of tapeworms which can cause diphyllobothriasis in humans through consumption of raw or undercooked fish. Several templates and tools are available to assist in formatting, such as Reflinks ( documentation), reFill ( documentation) and Citation bot ( documentation). Please consider converting them to full citations to ensure the article remains verifiable and maintains a consistent citation style. klebanovskii to be a single species.This article uses bare URLs, which are uninformative and vulnerable to link rot. ▼ DiphyllobothriumĬordicephalus Wardle, McLeod & Stewart, 1947 Quick facts: Diphyllobothrium, Scientific classification.
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