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Trematodes
Trematoda is a class of flatworms known as flukes. They are obligate internal parasites with a complex life cycle requiring at least two hosts. The intermediate host, in which asexual reproduction occurs, is usually a snail. The definitive host, where the flukes sexually reproduce, is a vertebrate. Infection by trematodes can cause disease in all five traditional vertebrate classes: mammals, birds, amphibians, reptiles, and fish. Etymology Trematodes are commonly referred to as flukes. This term can be traced back to the Old English name for flounder, and refers to the flattened, rhomboidal shape of the organisms. Taxonomy There are 18,000 to 24,000 known species of trematodes, divided into two subclasses — the Aspidogastrea and the Digenea. Aspidogastrea is the smaller subclass, comprising 61 species. These flukes mainly infect bivalves and bony fishes.https://www.biotaxa.org/Zootaxa/article/view/zootaxa.3918.3.2 Digenea — which comprise the majority of trematodes � ... [...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 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 proven no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parasitism
Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted structurally to this way of life. The entomologist E. O. Wilson has characterised parasites as "predators that eat prey in units of less than one". Parasites include single-celled protozoans such as the agents of malaria, sleeping sickness, and amoebic dysentery; animals such as hookworms, lice, mosquitoes, and vampire bats; fungi such as Armillaria mellea, honey fungus and the agents of ringworm; and plants such as mistletoe, dodder, and the Orobanchaceae, broomrapes. There are six major parasitic Behavioral ecology#Evolutionarily stable strategy, strategies of exploitation of animal hosts, namely parasitic castration, directly transmitted parasitism (by contact), wikt:trophic, trophicallytransmitted parasitism (by being eaten), Disease vector, vector-transmitted paras ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schistosomiasis
Schistosomiasis, also known as snail fever, bilharzia, and Katayama fever, is a disease caused by parasitic flatworms called schistosomes. The urinary tract or the intestines may be infected. Symptoms include abdominal pain, diarrhea, bloody stool, or blood in the urine. Those who have been infected for a long time may experience liver damage, kidney failure, infertility, or bladder cancer. In children, it may cause poor growth and learning difficulty. The disease is spread by contact with fresh water contaminated with the parasites. These parasites are released from infected freshwater snails. The disease is especially common among children in developing countries, as they are more likely to play in contaminated water. Other high-risk groups include farmers, fishermen, and people using unclean water during daily living. It belongs to the group of helminth infections. Diagnosis is by finding eggs of the parasite in a person's urine or stool. It can also be confirmed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lancetfish
Lancetfishes are large oceanic predatory fishes in the genus ''Alepisaurus'' ("scaleless lizard") in the monogeneric family Alepisauridae. Lancetfishes grow up to in length. Very little is known about their biology, though they are widely distributed in all oceans, except the polar seas. Specimens have been recorded as far north as Greenland. They are often caught as bycatch by vessels long-lining for tuna. The generic name is from Greek ''a-'' meaning "without", ' meaning "scale", and ''sauros'' meaning "lizard". Species The two currently recognized extant species in this genus are: * '' Alepisaurus brevirostris'' Gibbs, 1960 (short-snouted lancetfish) * '' Alepisaurus ferox'' R. T. Lowe, 1833 (long-snouted lancetfish) The anatomic difference between the two species is the shape of the snout, which is long and pointed in ''A. ferox'', and slightly shorter in ''A. brevirostris''. The long-snouted lancefish is found in the tropical and northern sub-tropical waters of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusca
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estimated between 60,000 and 100,000 additional species. The proportion of undescribed species is very high. Many taxa remain poorly studied. Molluscs are the largest marine phylum, comprising about 23% of all the named marine organisms. Numerous molluscs also live in freshwater and terrestrial habitats. They are highly diverse, not just in size and anatomical structure, but also in behaviour and habitat. The phylum is typically divided into 7 or 8 taxonomic classes, of which two are entirely extinct. Cephalopod molluscs, such as squid, cuttlefish, and octopuses, are among the most neurologically advanced of all invertebrates—and either the giant squid or the colossal squid is the largest known invertebrate species. The g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cercaria
A cercaria (plural cercariae) is the larval form of the trematode Trematoda is a Class (biology), class of flatworms known as flukes. They are obligate parasite, obligate internal Parasitism, parasites with a complex biological life cycle, life cycle requiring at least two Host_(biology), hosts. The intermedia ... class of parasites. It develops within the germinal cells of the sporocyst or redia. A cercaria has a tapering head with large penetration glands. It may or may not have a long swimming "tail", depending on the species. The motile cercaria finds and settles in a host where it will become either an adult, or a mesocercaria, or a metacercaria, according to species. Rotifers ('' Rotaria rotatoria'') produce a chemical, Schistosome Paralysis Factor, suppressing cercaria swimming and reducing infections.{{cite journal , editor1-last=Khosla , editor1-first=Chaitan , last1=Gao, first1=Jiarong, last2=Yang, first2=Ning, last3=Lewis, first3=Fred A., last4=Yau, first4=Peter, l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schistosoma Mekongi
''Schistosoma mekongi'' is a species of trematodes, also known as flukes. It is one of the five major schistosomes that account for all human infections, the other four being ''S. haematobium'', ''S. mansoni, S. japonicum, and S. intercalatum''. This trematode causes schistosomiasis Schistosomiasis, also known as snail fever, bilharzia, and Katayama fever, is a disease caused by parasitic flatworms called schistosomes. The urinary tract or the intestines may be infected. Symptoms include abdominal pain, diarrhea, bloody ... in humans. Freshwater snail '' Neotricula aperta'' serves as an intermediate host for ''Schistosoma mekongi''. History Schistosomiasis was first reported in the Mekong River's Lower Basin region in 1957, from Laotian island of Khong to Cambodian province of Kratié, specifically. It was believed that the cause of these cases was ''Schistosoma japonicum'' until 1978, when ''Neotricula aperta'' was discovered and it was determined that the Schistos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schistosoma Mansoni
file:Couple of Schistosoma mansoni.jpg, A paired couple of ''Schistosoma mansoni''. ''Schistosoma mansoni'' is a Waterborne diseases, water-borne List of parasites (human), parasite of humans, and belongs to the group of blood flukes (''Schistosoma''). The adult lives in the blood vessels (Inferior mesenteric vein, mesenteric veins) near the human intestine. It causes intestinal schistosomiasis (similar to ''Schistosoma japonicum, S. japonicum'', ''Schistosoma mekongi, S. mekongi'', ''S. guineensis'', and ''Schistosoma intercalatum, S. intercalatum''). Clinical symptoms are caused by the eggs. As the leading cause of schistosomiasis in the world, it is the most prevalent parasite in humans. It is classified as a neglected tropical disease. As of 2021, the World Health Organization reports that 236.6 million people have schistosomiasis and most of it is due to ''S. mansoni''. It is found in Africa, the Middle East, the Caribbean, Brazil, Venezuela and Suriname. Unlike other fluke ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schistosoma Malayensis
''Schistosoma malayensis'' is a schistosome parasite. It was first described in 1988 in Peninsular Malaysia and appears to be a zooenotic infection. The species is named after the country of Malaysia. The natural vertebrate host is van Müller's rat ('' Rattus muelleri''). The intermediate hosts are aquatic snails, ''Robertsiella kaporenisis''. Among ''Robertsiella kaporenisis'' are two other ''Roberstiella'' species. Among humans exposed to this parasite the lifetime incidence appears to be 5–10%.Sagin D.D., Ismail G., Fui J.N., Jok J.J. (2001) ''Schistosomiasis malayensis''-like infection among the Penan and other interior tribes (Orang Ulu) in upper Rejang River Basin Sarawak Malaysia. Southeast Asian J. Trop. Med. Public Health 32(1):27–32 The symptoms are unclear, because the symptoms have never been reported. The disease has been little studied and it is currently considered to be a relatively minor public health problem. Taxonomy ''Schistosoma malayensis'' is a membe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schistosoma Japonicum
''Schistosoma japonicum'' is an important parasite and one of the major infectious agents of schistosomiasis. This parasite has a very wide host range, infecting at least 31 species of wild mammals, including 9 carnivores, 16 rodents, one primate (human), two insectivores and three artiodactyls and therefore it can be considered a true zoonosis. Travelers should be well-aware of where this parasite might be a problem and how to prevent the infection. ''S. japonicum'' occurs in the Far East, such as China, the Philippines, Indonesia and Southeast Asia. Discovery ''Schistosoma japonicum'' was discovered in Kofu basin by Fujiro Katsurada, a pathologist in Okayama University in 1904. Later, Katsurada named the parasite ''Schistosoma japonicum''. Social impacts Individuals at risk to infection from ''S. japonicum'' are farmers who often wade in their irrigation water, fishermen who wade in streams and lakes, children who play in water, and people who wash clothes in streams. Import ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schistosoma Intercalatum
''Schistosoma intercalatum'' is a parasitic worm found in parts of western and central Africa. There are two strains: the Lower Guinea strain and the Zaire strain. ''S. intercalatum'' is one of the major agents of the rectal form of schistosomiasis, also called bilharzia. It is a trematode, and being part of the genus '' Schistosoma'', it is commonly referred to as a blood-fluke since the adult resides in blood vessels. Humans are the definitive host and two species of freshwater snail make up the intermediate host, '' Bulinus forskalii'' for the Lower Guinea strain and '' Bulinus africanus'' for the Zaire strain.Tchuem Tchuenté LA, Southgate, VR, Jourdane J, Webster BL, Vercruysse J (2003) ''Schistosoma intercalatum'': an endangered species in Cameroon? ''Trends Parasitol'' 19: 141-153. Morphology The clinically defining characteristic of most schistosome species are their eggs' size and shape. The eggs of ''Schistosoma intercalatum'' have a terminal spine and tend to be mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schistosoma Haematobium
''Schistosoma haematobium'' (urinary blood fluke) is a species of digenetic trematode, belonging to a group (genus) of blood flukes ('' Schistosoma''). It is found in Africa and the Middle East. It is the major agent of schistosomiasis, the most prevalent parasitic infection in humans. It is the only blood fluke that infects the urinary tract, causing urinary schistosomiasis, and is the leading cause of bladder cancer (only next to tobacco smoking). The diseases are caused by the eggs. Adults are found in the venous plexuses around the urinary bladder and the released eggs travels to the wall of the urine bladder causing haematuria and fibrosis of the bladder. The bladder becomes calcified, and there is increased pressure on ureters and kidneys otherwise known as hydronephrosis. Inflammation of the genitals due to ''S. haematobium'' may contribute to the propagation of HIV. ''S. haematobium'' was the first blood fluke discovered. Theodor Bilharz, a German surgeon working in C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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