Nonetheless, size and shape of the organism are distinctions often made at the. For many years tarebia granifera was believed to be an intermediate host for the paragonimus westermani, but michelson showed in 1992 that this was erroneous. Paragonimus westermani was discovered when two bengal tigers died of paragonimiasis in zoos in europe in 1878. They infect snails in which they undergo three generations of asexual reproduction redia, daughter redia, and cercaria. The life cycle of paragonimus westermani includes ovum, miracidium sporocyst, redia, cercaria, metacercariae and adults. When the ovum passed into water, it would grow and mature under appropriate environment for almost three weeks, then the miracidium would be hatched from ovum. Recent research progress on study of paragonimus westermani.
Eggs are excreted in sputum or stool of infected people. The eggs are excreted unembryonated in the sputum, or alternately they are swallowed and. Southeast asia in particular is affected because raw seafood is very popular there. Paragonimiasis is a disease caused by species of lung flukes of the genus paragonimus. Unembryonated eggs are expelled by coughing or passed with stool and develop in water.
The first report of human infection was from taiwan during the latter part of the 19th century. Human infections are most common in eastern asia and in south america. Among the more than 10 species reported to infect humans, the most common is p. The eggs are excreted from the definitive host, including humans, via their sputum or feces and this begins the life cycle of paragonimus spp. Paragonimus kellicotti fluke infections in missouri, usa. Paragonimus westermani life cycle paragonimiasis is infection with the lung fluke paragonimus westermani and related species. Paragonimus westermani, the oriental lung fluke, belongs to the family troglotrematidae and is one of several digeneans of the same genus that infect the human respiratory tract.
Life cycle the life cycle of paragonimiasis begins with expectoration of unembryonated eggs in the sputum. Inside the snail, the miracidia go through several stages to develop into a. Life cycle of fasciola hepatica this animation is part of. Paragonimus has a quite complex lifecycle that involves two intermediate hosts as well as humans. The present case is reported here to discuss the approach to a case of hemoptysis and to highlight the fact that every case of hemoptysis is not and must not be treated as pulmonary tuberculosis. Life cycle characters the life cycle of paragonimus westermani includes ovum, miracidium sporocyst, redia, cercaria, metacercariae and adults. Paragonimus westermani infection of the lung is a perplexing diagnostic entity. Human lung fluke, paragonimus westermani, infects 22 million people in africa, asia and south and central america. Parasitology teacher and author, rosemary drisdelle joins me to discuss the life cycle, the geography of a. Paragonimus organisms andor eggs were identified in 2 cases. Paragonimus is a typical digenean trematode of carnivorous mammals. The life cycle involves two intermediate hosts, the first a freshwater snail and the second a freshwater crab or crayfish. The parasites utilize two intermediate hosts and a definitive hosts like wild mammals and humans to complete its life cycle. Eggs first develop in water after being expelled by coughing unembryonated or being passed in human feces.
Pdf development and pathogenicity of lung fluke, paragonimus. Paragonimus westermani introduction to medical parasitology. Humans get infected with the disease, paragonimiasis, by eating raw crabs or fish that are carrying the parasite. Wholegenome sequence of the oriental lung fluke paragonimus. Since discovery of this lung fluke in 1878 by kerbert, paragonimus westermani has been found to occur in many parts of asia. Large immature eggs are spread throughout in stool, and mature to miracidia in freshwater. Paragonimus is an infection caused by paragonimus westermani. All paragonimus species exhibit the same complex life cycle, which requires 2 sequential intermediate transport hosts, a freshwater. The species sometimes is called the japanese lung fluke or oriental lung fluke. Paragonimus westermani eggcdc general information there are numerous species in the genus paragonimus that are found worldwide. Paragonimus westermani is the major species of lung fluke that infects humans, causing. The first morphological description is made of all stages of the life cycle of a paragonimus species infecting humans in colombia. Ppt paragonimus westermani powerpoint presentation. Symptoms include chronic cough, chest pain, dyspnea, and hemoptysis.
Paragonimus westermani is the major species of lung fluke that infects humans, causing paragonimiasis. Laboratory diagnostics of paragonimus westermani and treatment. Dec 20, 2010 paragonimiasis is a foodborne trematode infection that primarily affects the lungs. Case series of paragonimiasis from nepal oxford medical.
The eggs are excreted unembryonated in the sputum, or alternately they are swallowed and passed with stool. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Worldwide, about nine species of paragonimus are known to cause human paragonimiasis in which many of the species reside in east asia, west africa, and in north and south america. The miracidia invade soft tissue of snails where they reproduce asexually. On ingestion of these freshwater products, the immature flukes which often occurs in pairs are released into the body. Oct 11, 2019 the life cycle of these flukes involves 2 intermediate hosts plus humans. Paragonimiasis more than 30 species of trematodes flukes of the genus paragonimus have been reported to infect animals and humans.
The life cycle of these flukes involves 2 intermediate hosts plus humans. More than 30 species of trematodes flukes of the genus paragonimus have been reported which infect animals and humans. The most common is the oriental lung fluke, paragonimus westermani. Summary paragonimus species are highly evolved parasites with a complex life cycle that involves at least three different hosts, i. Paragonimus westermani an overview sciencedirect topics. Paragonimus westermani most commonis also known as. Although human paragonimiasis is uncommonly encountered in north america, both autochthonous and. A free powerpoint ppt presentation displayed as a flash slide show on id.
Most cases of paragonimiasis occur throughout eastern china, japan, philippines, south korea and taiwan, southeastern laos, thailand and vietnam, and southwestern china asia and are caused by paragonimus westermani. Produces vacuolization and disintegration of schistosome tegument, followed by. Oct 12, 2018 paragonimus westermani operculated egg life cycle of paragonimus westermani. The trematodes are of the paragonimus genus and there are eight species that can cause significant infection in humans. Adult flukes live in human lungs and deposit eggs into the bronchi. Paragonimus westermani was discovered when two bengal tigers died of paragonimiasis in zoos in. Paragonimus westermani is the major species of lung fluke to infects humans, causing paragonimiasis. Paragonimus westermani is a common parasite of humans, and it has been used for research purposes to help better understand trematode infections positive impacts. Paragonimus westermani was initially discovered during the necropsy of a. Adult worms that are in pairs are in fibrotic tissue of lungs humans, cats, dogs, rats, mongooses eggs either get coughed up or pass into bronchioles carried into pharynx and swallowed eggs passed in feces by 2 weeks miracidiae hatches from egg and infect snails undergo asexual reproduction. In the environment, the eggs develop, hatch into an immature form called miracidia, and are ingested by snails. The life cycle of the lung fluke and its mode of transmission are partially shown in fig. An underdiagnosed entity of endemic hemoptysis is highlighted here.
Paragonimus kellicotti in north america and paragonimus westermani in asia are generally asymptomatic fluke infections in fisheating species. Scribd is the worlds largest social reading and publishing site. Among them, more than 10 species are reported to infect humans, the most common is p. Paragonimiasis, or lung fluke disease, is caused by infection with a number of species of trematodes belonging to the genus paragonimus. This parasite lives in the human lung, though some ectopic parasites are found in other locations, suggesting that this parasite is not well adapted to living in man. Paragonimus have been reported which infect animals and humans. Eggs in sputum or feces get into fresh water and undergo several developmental stages. Paragonimus westermani is the most common and widely distributed of the species. History most discoveries made between 18741918 discovered in brazil in 1850 by diesing first described in bengal tigers housed in zoos in hamburg and amsterdam in 1877 coenraad kerbert named the parasite after the manager of the zoo g. Pdf paragonimiasis is a foodborne parasitic zoonosis caused by the genus. Recent research progress on study of paragonimus westermani in. Although cats are infected, the common definitive host are minks, dogs, muskrat, raccoons and foxes. The adult forms of paragonimus species reside and mate in the lungs of a variety of permissive mammalian hosts, including humans.
Introduction paragonimiasis is a foodborne parasitic infection caused by 15 different species of paragonimus trematodes cause a subacute to chronic inflammatory disease of the lung 2. Life cycle requires more than one intermediate host a. There are numerous species in the genus paragonimus that are found worldwide. Three patients ate live crabs at sushi bars including crabs in martinis, a previously unreported mechanism for infection. More than 30 species of trematodes flukes of the genus paragonimus have been. Eight species have been identified which use man as a host, and the disease has a range of asia, africa, and the americas. Eggs are expelled either by coughing or by being swallowed and passed in human feces.
The most prominent species of paragonimus in human medicine is paragonimus westermani, an infectious lung fluke originating in eastern asia. Paragonimus species have complex life cycles that require 2 intermediate hosts. The genus paragonimus has undergone considerable taxonomic splitting over the past 40 years. Paragonimiasis is a zoonois which is caused by a trematode called paragonimus westermani. In creating the taxonomy of paragonimus westermani, a morphological approach is almost always taken. However, classification can be pretty tricky business, as the fluke is not only closely related to other paragonimus spp. North american paragonimiasis caused by paragonimus kellicotti. When liberated in feces, the eggs are at an immature stage without miracidia inside. Ppt paragonimus westermani powerpoint presentation free. Humans are infected by eating raw, pickled, or poorly cooked freshwater crustaceans. Paragonimus westermani is the most common of these and it is also known as the oriental lung fluke.
Larval stages were obtained both in vitro and from field collections. Adult paragonimus metacercariae are formed in the intermediate hosts usually snails, but also freshwater crabs and crayfish which are eaten by the cat. Finally i am uploading the last part to my trematode series, going over the 2 liver and 1 lung fluke for step 1. The first case described in humans was at autopsy in taiwan in 1879, when adult flukes were found in the lung. In the external environment, the eggs become embryonated. Life cycle terminology cercaria very small leaves the snail to find the next host looks like a miniature adult with a tail utilizes tail for swimming, and will lose it as it penetrates the next host metacercaria infective stage for the definitive host resting stage in the life cycle. Pleuropulmonary infection by paragonimus westermani in the u. Nov 19, 2015 chris body had been invaded by paragonimus kellicottia fluke that uses mammalian lungs to complete part of its life cycle. Dont miss monsters inside me thursdays at 98c on animal planet. Although human paragonimiasis is uncommonly encountered in north america, both. Some tens of species have been described, but they are difficult to distinguish, so it is not clear how many of the named species may be synonyms. Paragonimiasis is a parasitic infection caused by paragonimus westermani. Today on the podcast well look at the parasitic lung fluke, paragonimus. Paragonimus westermani also known as the oriental lung fluke.188 1037 278 336 60 1055 409 1348 568 1581 1556 269 715 1413 1087 1190 621 1136 1666 517 1358 1031 1307 1021 1461 1410 431 1163 384