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Trematoda is a class within the phylum Platyhelminthes. It includes two groups of parasitic flatworms, known as flukes.
Metagonimiasis is a disease caused by an intestinal trematode, most commonly Metagonimus yokagawai, but sometimes by M. takashii or M. miyatai. The metagonimiasis-causing flukes are one of two minute flukes called the heterophyids. Metagonimiasis was described by Katsurasa in 1911–1913 when he first observed eggs of M. yokagawai in feces. M. takahashii was described later first by Suzuki in 1930 and then M. miyatai was described in 1984 by Saito.
Microphallus piriformes is a parasitic trematode (fluke). It belongs to the Plagiorchiata, a large suborder of the digenean fluke order Plagiorchiida. M. piriformes is unusual among the flukes in having only one intermediate host rather than two, and no free-swimming cercarian stage.
Microphallus is a genus of parasitic trematodes (flukes) in the family Microphallidae. The Greek name means "tiny penis".
Trematodes are parasitic flatworms of the class Trematoda, specifically parasitic flukes with two suckers: one ventral and the other oral. Trematodes are covered by a tegument, that protects the organism from the environment by providing secretory and absorptive functions.
Paragonimus westermani is the major species of lung fluke that infects humans, causing paragonimiasis. The species sometimes is called the Japanese lung fluke or oriental lung fluke. Human infections are most common in eastern Asia and in South America. Paragonimus westermani was discovered when two Bengal tigers died of paragonimiasis in zoos in Europe in 1878. Several years later, infections in humans were recognised in Formosa.
Echinostoma is a genus of trematodes (flukes), which can infect both humans and other animals. These intestinal flukes have a three-host life cycle with snails or aquatic organisms as intermediate hosts, and a variety of animals, including humans, as their definitive hosts.
Paragonimiasis is a food-borne parasitic infection caused by the lung fluke, most commonly Paragonimus westermani. It infects an estimated 22 million people yearly worldwide. It is particularly common in East Asia. More than 30 species of trematodes (flukes) of the genus Paragonimus have been reported; among the more than 10 species reported to infect humans, and only 8 bringing about infections in humans, the most common is P. westermani, the oriental lung fluke.
Metagonimoides oregonensis is a trematode, or fluke worm, in the family Heterophyidae. This North American parasite is found primarily in the intestines of raccoons, American minks, frogs in the genus Rana, and freshwater snails in the genus Goniobasis. It was first described in 1931 by E. W. Price. The parasite has a large distribution, from Oregon to North Carolina. Adult flukes vary in host range and morphology dependent on the geographical location. This results in different life cycles, as well as intermediate hosts, across the United States. On the west coast, the intermediate host is freshwater snails (Goniobasis), while on the east coast the intermediate host is salamanders (Desmognathus). The parasites on the west coast are generally much larger than on the east coast. For example, the pharynx as well as the body of the parasite are distinctly larger in Oregon than in North Carolina. The reverse pattern is observed on the east coast for uterine eggs, which are larger on the west coast. In snails, there is also a higher rate of infection in female snails than in males. Research on the life history traits of the parasites have been performed with hamsters and frogs as model species.
Leucochloridium variae, the brown-banded broodsac, is a species of trematode whose life cycle involves the alternate parasitic invasion of certain species of snail and bird. While there is no external evidence of the worm's existence within the bird host, the invasion of the snail host involves the grotesque swelling of one or both of the snail's eye stalks as well as the takeover of the snail's brain. This invasion does not cause the snail's death, and snails who are thus invaded sometimes live longer than those which are not.
Ribeiroia ondatrae is a parasite in the genus Ribeiroia which is believed to be responsible for many of the recent increases in amphibian limb malformations, particularly missing, malformed, and additional hind legs.
Nanophyetus salmincola is a food-borne intestinal trematode parasite prevalent on the Pacific Northwest coast. The species may be the most common trematode endemic to the United States.
Halipegus eccentricus is a monoecious, digenea parasitic trematode commonly found in true frogs in North America. It was first described in 1939.
Telogaster opisthorchis is an endoparasite in the class Trematoda within the phylum Platyhelminthes. This fluke is known for causing tumor like malformations in fishes by attaching onto its spinal region in the metacercariae form. Malformations cause fish to become more susceptible to fish eating predators allowing T. opisthorchis to continue with its lifecycle.
Clinostomum marginatum is a species of parasitic fluke. It is commonly called the "yellow grub". It is found in many freshwater fish in North America, and no fish so far is immune to this parasite. It is also found in frogs. Clinostomum marginatum can also be found in the mouth of aquatic birds such as herons and egrets. They are commonly present in the esophagus of fish-eating birds and reptiles. Eggs of these trematodes are shed in the feces of aquatic birds and released into water. Aquatic birds become hosts of this parasite by ingesting infected freshwater fish. The metacercariae are found right beneath the skin or in the muscles of host fish.
Coitocaecum parvum is a digeneic trematode or flatworm (Platyhelminthes) that is parasitic to the intestine of the common bully or upland bully. The common and upland bully are freshwater fish of New Zealand that C. parvum uses as its definitive host. C. parvum is a hermaphroditic freshwater trematode that can omit its definitive host and produce eggs by selfing or progenesis inside its amphipod second intermediate host
Behavior-altering parasites are parasites with two or more hosts, capable of causing changes in the behavior of one of their hosts to enhance their transmission, sometimes directly affecting the hosts' decision-making and behavior control mechanisms. They do this by making the intermediate host, where they may reproduce asexually, more likely to be eaten by a predator at a higher trophic level which becomes the definitive host where the parasite reproduces sexually; the mechanism is therefore sometimes called parasite increased trophic facilitation or parasite increased trophic transmission. Examples can be found in bacteria, protozoa, viruses, and animals. Parasites may also alter the host behaviour to increase the protection to the parasites or their offspring. The term bodyguard manipulation is used for such mechanisms.
Eustrongylidosis is a parasitic disease that mainly affects wading birds worldwide; however, the parasite's complex, indirect lifecycle involves other species, such as aquatic worms and fish. Moreover, this disease is zoonotic, which means the parasite can transmit disease from animals to humans. Eustrongylidosis is named after the causative agent Eustrongylides, and typically occurs in eutrophicated waters where concentrations of nutrients and minerals are high enough to provide ideal conditions for the parasite to thrive and persist. Because eutrophication has become a common issue due to agricultural runoff and urban development, cases of eustrongylidosis are becoming prevalent and hard to control. Eustrongylidosis can be diagnosed before or after death by observing behavior and clinical signs, and performing fecal flotations and necropsies. Methods to control it include preventing eutrophication and providing hosts with uninfected food sources in aquaculture farms. Parasites are known to be indicators of environmental health and stability, so should be studied further to better understand the parasite's lifecycle and how it affects predator-prey interactions and improve conservation efforts.
Metagonimus yokogawai is a species of a trematode, or fluke worm, in the family Heterophyidae.
Cardiocephaloides longicollis is a species of flukes. The life cycle of C. longicollis is asexual as well as complex. Its asexual stage resides in the body of whelks where it replicates many times, and eventually its eggs are dispersed in the water through feces. C.longicollis begin their early life as free swimming miracidia larvae in the water. They go on to infect snails, and a variety of fishes, usually second intermediate host, in the form of a cercariae. While C.longicollis has previously been recorded in 19 fish species, researchers have found 12 other species which are viable hosts for C.longicollis making for a grand total of 31 aquatic species. The final host for this parasite are the gulls that eat the infected fish in which the parasite has formed cysts in.
References
- ↑ Diesing, K. M. (1850). Systema helminthum. Vienna: W. Braumüller.
- 1 2 Leung, Tommy (8 September 2016). "Parasite of the Day: Tylodelphys sp".
- ↑ Blasco-Costa, I., Poulin, R. & Presswell, B. (2017). Morphological description and molecular analyses of Tylodelphys sp. (Trematoda: Diplostomidae) newly recorded from the freshwater fish Gobiomorphus cotidianus (common bully) in New Zealand. Journal of Helminthology, 91(3), 332–345.
- ↑ Stumbo, A. & Poulin, R. (2016). Possible mechanism of host manipulation resulting from a diel behaviour pattern of eye-dwelling parasites. Parasitology, 143(10), 1261–1267.