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Proglottids
Cestoda is a class of parasitic worms in the flatworm phylum (Platyhelminthes). Most of the species—and the best-known—are those in the subclass Eucestoda; they are ribbon-like worms as adults, known as tapeworms. Their bodies consist of many similar units known as proglottids—essentially packages of eggs which are regularly shed into the environment to infect other organisms. Species of the other subclass, Cestodaria, are mainly fish infecting parasites. All cestodes are parasitic; many have complex life histories, including a stage in a definitive (main) host in which the adults grow and reproduce, often for years, and one or two intermediate stages in which the larvae develop in other hosts. Typically the adults live in the digestive tracts of vertebrates, while the larvae often live in the bodies of other animals, either vertebrates or invertebrates. For example, '' Diphyllobothrium'' has at least two intermediate hosts, a crustacean and then one or more freshwater fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proglottids
Cestoda is a class of parasitic worms in the flatworm phylum (Platyhelminthes). Most of the species—and the best-known—are those in the subclass Eucestoda; they are ribbon-like worms as adults, known as tapeworms. Their bodies consist of many similar units known as proglottids—essentially packages of eggs which are regularly shed into the environment to infect other organisms. Species of the other subclass, Cestodaria, are mainly fish infecting parasites. All cestodes are parasitic; many have complex life histories, including a stage in a definitive (main) host in which the adults grow and reproduce, often for years, and one or two intermediate stages in which the larvae develop in other hosts. Typically the adults live in the digestive tracts of vertebrates, while the larvae often live in the bodies of other animals, either vertebrates or invertebrates. For example, '' Diphyllobothrium'' has at least two intermediate hosts, a crustacean and then one or more freshwater fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taenia Solium
''Taenia solium'', the pork tapeworm, belongs to the cyclophyllid cestode family Taeniidae. It is found throughout the world and is most common in countries where pork is eaten. It is a tapeworm that uses humans as its definitive host and pigs as the intermediate or secondary hosts. It is transmitted to pigs through human feces that contain the parasite eggs and contaminate their fodder. Pigs ingest the eggs, which develop into larvae, then into oncospheres, and ultimately into infective tapeworm cysts, called cysticercus. Humans acquire the cysts through consumption of uncooked or under-cooked pork and the cysts grow into an adult worms in the small intestine. There are two forms of human infection. One is "primary hosting", called taeniasis, and is due to eating under-cooked pork that contains the cysts and results in adult worms in the intestines. This form generally is without symptoms; the infected person does not know they have tapeworms. This form is easily treated wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taenia Saginata
''Taenia saginata'' (synonym ''Taeniarhynchus saginatus''), commonly known as the beef tapeworm, is a zoonotic tapeworm belonging to the order Cyclophyllidea and genus ''Taenia''. It is an intestinal parasite in humans causing taeniasis (a type of helminthiasis) and cysticercosis in cattle. Cattle are the intermediate hosts, where larval development occurs, while humans are definitive hosts harbouring the adult worms. It is found globally and most prevalently where cattle are raised and beef is consumed. It is relatively common in Africa, Europe, Southeast Asia, South Asia, and Latin America. Humans are generally infected as a result of eating raw or undercooked beef which contains the infective larvae, called cysticerci. As hermaphrodites, each body segment called proglottid has complete sets of both male and female reproductive systems. Thus, reproduction is by self-fertilisation. From humans, embryonated eggs, called oncospheres, are released with faeces and are transmitted t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eucestoda
Eucestoda, commonly referred to as tapeworms, is the larger of the two Class (biology), subclasses of flatworms in the class Cestoda (the other subclass is Cestodaria). Larvae have six posterior hooks on the scolex (head), in contrast to the ten-hooked Cestodaria. All tapeworms are Parasitism, endoparasites of vertebrates, living in the digestive tract or related ducts. Examples are the pork tapeworm (''Taenia solium'') with a human Host (biology)#Definitive and secondary hosts, definitive host, and pigs as the Host (biology)#Definitive and secondary hosts, secondary host, and ''Moniezia expansa'', the definitive hosts of which are ruminants. Body structure Adult Eucestoda have a white-opaque dorso-ventrally flattened appearance, and are elongated, ranging in length from a few millimeters to 25 meters. Almost all members, except members of the orders Caryophyllidea and Spathebothriidea, are polyzoism, polyzoic with repeated sets of reproductive organs down the body length, and al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flatworm
The flatworms, flat worms, Platyhelminthes, or platyhelminths (from the Greek πλατύ, ''platy'', meaning "flat" and ἕλμινς (root: ἑλμινθ-), ''helminth-'', meaning "worm") are a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrates. Unlike other bilaterians, they are acoelomates (having no body cavity), and have no specialized circulatory and respiratory organ (anatomy), organs, which restricts them to having flattened shapes that allow oxygen and nutrients to pass through their bodies by diffusion. The digestive cavity has only one opening for both ingestion (intake of nutrients) and egestion (removal of undigested wastes); as a result, the food cannot be processed continuously. In traditional medicinal texts, Platyhelminthes are divided into Turbellaria, which are mostly non-parasitic animals such as planarians, and three entirely parasitic groups: Cestoda, Trematoda and Monogenea; however, since the turbellarians have since been prove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetragonoporus
''Tetragonoporus'' is a genus of cestodes in the order Pseudophyllidea. It is a monotypic genus, and the only species is ''Tetragonoporus calyptocephalus'', previously known as ''Polygonoporus giganticus''. This tapeworm is a gut parasite of whales. Description The adult ''T. calyptocephalus'' is found in the gut of whales such as the sperm whale. It is normally present in the intestine, but can also occur in the bile duct. The tapeworm can be almost in length with as many as 45,000 proglottids (segments). The scolex (head) of the tapeworm is attached to the lining of the gut and the proglottids continuously develop from behind the scolex. As more segments are produced, the older ones become larger and more mature. In this species, the scolex is short and equipped with two suckers, and the proglottids develop in groups of three different sizes – small, medium and large – which are repeated throughout the length of the strobila (segmented body). The cuticle is thin and there ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hymenolepis (tapeworm)
''Hymenolepis'' is a genus of cyclophyllid tapeworms responsible for hymenolepiasis. They are parasites of humans and other mammals. The focus in this article is in ''Hymenolepis'' commonly parasitizing humans. Species include: * '' Hymenolepis apodemi'' - in rodents * '' Hymenolepis asymetrica'' — in rodents * ''Hymenolepis diminuta'' — in humans * '' Hymenolepis horrida'' — in rodents * '' Hymenolepis rymzhanovi'' - in rodents * '' Hymenolepis microstoma'' — in rodents * ''Hymenolepis nana'' — in humans Signs and symptoms Most infections do not have many worms and therefore can have no symptoms. Patients with more than 15,000 eggs per gram of stool may experience cramps, diarrhea, irritability, anorexia, or enteritis caused by cystercoids destroying the intestinal villi in which they develop. Cause Hymenolepiasis is the most common cestode infection in humans. Infections are seen more often among children. It is most widespread in warm climates and around uns ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diphyllobothrium
''Diphyllobothrium'' is a genus of tapeworms which can cause diphyllobothriasis in humans through consumption of raw or undercooked fish. The principal species causing diphyllobothriasis is ''D. latum'', known as the broad or fish tapeworm, or broad fish tapeworm. ''D. latum'' is a pseudophyllid cestode that infects fish and mammals. ''D. latum'' is native to Scandinavia, western Russia, and the Baltics, though it is now also present in North America, especially the Pacific Northwest. In Far East Russia, ''D. klebanovskii'', having Pacific salmon as its second intermediate host, was identified. Other members of the genus ''Diphyllobothrium'' include '' D. dendriticum'' (the salmon tapeworm), which has a much larger range (the whole northern hemisphere), ''D. pacificum'', ''D. cordatum'', ''D. ursi'', ''D. lanceolatum'', ''D. dalliae'', and ''D. yonagoensis'', all of which infect humans only infrequently. In Japan, the most common species in human infection is ''D. nihonkaiense ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echinococcus
''Echinococcus'' is a genus within Cestoda, a parasitic class of the platyhelminthes phylum (colloquially known as flatworms). Human echinococcosis is an infectious disease caused by the following species: E. granulosus, E. multilocularis, or E. vogeli. ''Echinococcus'' is triploblastic – it has three layers – outermost ectoderm, middle mesoderm, and inner endoderm. An anus is absent, and it has no digestive system. Its body is covered by tegument and the worm is divided into a scolex, a short neck, and three to six proglottids. Its body shape is ribbon-like. In humans, this causes a disease called echinococcosis. The three types of echinococcosis are cystic echinococcosis caused by '' E. granulosus'', alveolar echinococcosis caused by ''E. multilocularis'', and polycystic echinococcosis caused by ''E. vogeli'' or ''E. oligarthrus''. A worm's incubation period is usually long and can be up to 50 years. Cystic echinococcosis is mostly found in South and Central America, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arvicolinae
The Arvicolinae are a subfamily of rodents that includes the voles, lemmings, and muskrats. They are most closely related to the other subfamilies in the Cricetidae (comprising the hamsters and New World rats and mice). Some authorities place the subfamily Arvicolinae in the family Muridae along with all other members of the superfamily Muroidea. Some refer to the subfamily as the Microtinae (yielding the adjective "microtine") or rank the taxon as a full family, the Arvicolidae. The Arvicolinae are the most populous group of Rodentia in the Northern Hemisphere. They often are found in fossil occlusions of bones cached by past predators such as owls and other birds of prey. Fossils of this group are often used for biostratigraphic dating of paleontological and archeological sites in North America and Europe. Description The most convenient distinguishing feature of the Arvicolinae is the nature of their molar teeth, which have prismatic cusps in the shape of alternati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Oceanic And Atmospheric Administration
The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditions, charts the seas, conducts deep sea exploration, and manages fishing and protection of marine mammals and endangered species in the U.S. exclusive economic zone. Purpose and function NOAA's specific roles include: * ''Supplying Environmental Information Products''. NOAA supplies to its customers and partners information pertaining to the state of the oceans and the atmosphere, such as weather warnings and forecasts via the National Weather Service. NOAA's information services extend as well to climate, ecosystems, and commerce. * ''Providing Environmental Stewardship Services''. NOAA is a steward of U.S. coastal and marine environments. In coordination with federal, state, local, tribal and international authorities, NOAA manages the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shrew
Shrews (family Soricidae) are small mole-like mammals classified in the order Eulipotyphla. True shrews are not to be confused with treeshrews, otter shrews, elephant shrews, West Indies shrews, or marsupial shrews, which belong to different families or orders. Although its external appearance is generally that of a long-nosed mouse, a shrew is not a rodent, as mice are. It is, in fact, a much closer relative of hedgehogs and moles; shrews are related to rodents only in that both belong to the Boreoeutheria magnorder. Shrews have sharp, spike-like teeth, whereas rodents have gnawing front incisor teeth. Shrews are distributed almost worldwide; among the major tropical and temperate land masses, only New Guinea, Australia, and New Zealand have no native shrews; in South America shrews appeared only relatively recently, as a result of the Great American Interchange, and are present only in the northern Andes. The shrew family has 385 known species, making it the fourth-most spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
