Metorchis conjunctus

Metorchis conjunctus
Drawing of ventral view of Metorchis conjunctus, scale bar is 1 mm
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Platyhelminthes
Class: Trematoda
Order: Plagiorchiida
Family: Opisthorchiidae
Genus: Metorchis
Species:
M. conjunctus
Binomial name
Metorchis conjunctus
Cobbold, 1860
Synonyms[3]

Parametorchis noveboracensis (Hung, 1926)[1]
Parametorchis intermedius (Price, 1929)[2]
Parametorchis canadensis (Price, 1929)[2]
Parametorchis manitobensis (Allen & Wardle, 1934)

Metorchis conjunctus, common name Canadian liver fluke, is a species of trematode parasite in the family Opisthorchiidae. It can infect mammals that eat raw fish in North America. The first intermediate host is a freshwater snail and the second is a freshwater fish.

Taxonomy

This species was discovered and described by Thomas Spencer Cobbold in 1860.

Distribution

The distribution of M. conjunctus includes:

Description

The body of M. conjunctus is pear-shaped and flat.[6] The body length is 1⁄4–3⁄8 inch (6.4–9.5 mm).[6] It has a weakly muscular terminal oral sucker.[2] No prepharynx is present.[2] The pharynx is strongly muscular.[2] The esophagus is very short.[2] The intestinal ceca vary from almost straight to sinuous.[2] The acetabulum is slightly oval and weakly muscular.[2] The male has an anterior testis and a posterior testis.[2] The testes vary from almost round to oval, and may be deeply lobed or slightly indented.[2] No cirrus pouch is found.[2] The seminal vesicle is slender.[2] The ovary is trilobed.[2] The receptaculum seminis is elongated or pyriform, and slightly twisted, and situated to the right and behind the ovary.[2]

The eggs are oval and yellowish brown.[2]

Drawing of dorsal view of M. conjunctus, scale bar is 1 mm
Drawing of dorsal view of M. conjunctus, scale bar is 1 mm

Lifecycle

The first intermediate host of M. conjunctus is a freshwater snail, Amnicola limosus.[4]

The second intermediate host is a freshwater fish: Catostomus catostomus,[4] Salvelinus fontinalis,[4] Perca flavescens,[4] or Catostomus commersoni.[7] Metacercaria of M. conjunctus were also found in northern pike (Esox lucius).[8]

The definitive hosts are fish-eating mammals such as domestic dogs (Canis lupus familiaris), domestic cats (Felis catus), wolves (Canis lupus),[5] red foxes (Vulpes vulpes),[9] gray foxes (Urocyon cinereoargenteus),[3] coyotes (Canis latrans), raccoons (Procyon lotor),[5] muskrats (Ondatra zibethicus), American minks (Neovison vision),[5] fishers (Martes pennanti),[4][10] or bears.[8] It can also infect humans.[7] It lives in the bile duct and in the gallbladder.[6]

Effects on human health

M. conjunctus causes a disease called metorchiasis.[11] It has been known to infect humans since 1946.[4] Humans had eggs of M. conjunctus in their stools, but they were asymptomatic.[8] Sashimi from raw Catostomus commersoni was identified as a source for an outbreak in Montreal in 1993.[7] It was the first symptomatic disease in humans caused by M. conjunctus.[8]

Symptoms

After ingestion of fish infected with M. conjunctus, about 1–15 days are needed for symptoms to occur, namely for eggs to be detected in the stool (incubation period).[12]

The acute phase consists of upper abdominal pain and low-grade fever.[7] High concentrations of eosinophil granulocytes are in blood.[7] Also, higher concentrations of liver enzymes are seen.[7] When untreated, symptoms may last from 3 days to 4 weeks.[7] Symptoms of chronic infection were not reported.[12]

Diagnosis and treatment

Eggs of M. conjunctus can be found by stool analysis.[8] Serologic analysis can be also used - ELISA test for IgG antibodies against antigens of M. conjunctus.[8]

Drugs used to treat infestation include praziquantel:[7] 75 mg/kg in three doses per day (the same dosage applies for adults and for children).[8][13]

Effects on animal health

Watson and Croll (1981)[14] studied symptoms of cats. Prevention includes feeding with cooked fish (not raw fish).[6]

M. conjunctus was found to be a common infection of domestic dogs in First Nations settlements in 1973.[15] It has been in found in other animals including raccoons, minks, and gray foxes.[3]

The prevalence of M. conjunctus in wolves in Canada is 1–3%.[12] In wolves, M. conjunctus causes cholangiohepatitis with periductular fibrosis in the liver.[5] It sometimes causes chronic inflammation and fibrosis of the pancreas in wolves.[5]

References

This article incorporates public domain text from the reference[2]

  1. ^ Hung See-Lü (1926). "A new species of fluke, Parametorchis noveboracensis, from the cat in the United States". Proceedings of the United States National Museum 69(2627): 1–2.
  2. ^ a b c d e f g h i j k l m n o p Price E. W. (1929). "Two new species of trematodes of the genus Parametorchis from fur-bearing animals". Proceedings of the United States National Museum 76(2809): 1–5.
  3. ^ a b c Mills J. H., Hirth R. S. (1968). "Lesions Caused by the Hepatic Trematode, Metorchis conjunctus, Cobbold, 1860: A Comparative Study in Carnivora". Journal of Small Animal Practice. 9 (1): 1–6. doi:10.1111/j.1748-5827.1968.tb04678.x. PMID 5688935.
  4. ^ a b c d e f g h i Chai J. Y., Darwin Murrell K., Lymbery A. J. (2005). "Fish-borne parasitic zoonoses: Status and issues". International Journal for Parasitology. 35 (11–12): 1233–1254. doi:10.1016/j.ijpara.2005.07.013. PMID 16143336.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  5. ^ a b c d e f g h Wobeser G., Runge W., Stewart R. R. (1983). "Metorchis conjunctus (Cobbold, 1860) infection in wolves (Canis lupus), with pancreatic involvement in two animals". Journal of Wildlife Diseases. 19 (4): 353–356. doi:10.7589/0090-3558-19.4.353. PMID 6644936.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  6. ^ a b c d Axelson R. D. (1962). "Metorchis Conjunctus Liver Fluke Infestation in a Cat". Canadian Veterinary Journal. 3 (11): 359–360. PMC 1585985. PMID 17421548.
  7. ^ a b c d e f g h MacLean J. D., Arthur J. R., Ward B. J., Gyorkos T. W., Curtis M. A., Kokoskin E. (1996). "Common-source outbreak of acute infection due to the North American liver fluke Metorchis conjunctus". The Lancet. 347 (8995): 154–158. doi:10.1016/S0140-6736(96)90342-6. PMID 8544550.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  8. ^ a b c d e f g Behr M. A., Gyorkos T. W., Kokoskin E., Ward B. J., MacLean J. D. (1998). "North American liver fluke (Metorchis conjunctus) in a Canadian aboriginal population: a submerging human pathogen?" Canadian Journal of Public Health 89: 258–259. PMID 9735521. PDF.
  9. ^ Smith H. J. (1978). "Parasites of red foxes in New Brunswick and Nova Scotia". Journal of Wildlife Diseases. 14 (3): 366–370. doi:10.7589/0090-3558-14.3.366. PMID 691132.
  10. ^ Dick T. A, Leonard R. D. (1979). "Helminth parasites of fisher Martes pennanti (Erxleben) from Manitoba, Canada". Journal of Wildlife Diseases. 15 (3): 409–412. doi:10.7589/0090-3558-15.3.409. PMID 574167.
  11. ^ Dennis J. Richardson; Peter J. Krause (6 December 2012). North American Parasitic Zoonoses. Springer Science & Business Media. p. 86. ISBN 978-1-4615-1123-6.
  12. ^ a b c Waikagul J. & Thaekham U. (2014). Approaches to Research on the Systematics of Fish-Borne Trematodes. Academic Press, 130 pp., page 6–7.
  13. ^ "FLUKE, hermaphroditic, infection".[1], 2 pp., accessed 31 December 2015.
  14. ^ Watson T. G, Croll N. A. (1981). "Clinical changes caused by the liver fluke Metorchis conjunctus in cats". Veterinary Pathology. 18 (6): 778–785. doi:10.1177/030098588101800608. PMID 7292895.
  15. ^ Unruh D. H., King J. E., Eaton R. D., Allen J. R. (1973). "Parasites of dogs from Indian settlements in northwestern Canada: a survey with public health implications". Canadian Journal of Comparative Medicine. 37 (1): 25–32. PMC 1319720. PMID 4265550.{{cite journal}}: CS1 maint: multiple names: authors list (link)
Wikimedia Commons logo
Wikimedia Commons has media related to Metorchis conjunctus.

Content Disclaimer

Informasi ini disarikan dari Wikipedia dan disajikan kembali untuk tujuan edukasi. Konten tersedia di bawah lisensi CC BY-SA 3.0. Kami tidak bertanggung jawab atas ketidakakuratan data yang bersumber dari kontribusi publik tersebut.

  1. The information displayed on this website is sourced in part or in whole from Wikipedia and has been adapted for the purpose of restating it. We strive to provide accurate and relevant information, however:
  2. There is no guarantee of absolute accuracy. Wikipedia is an open, collaborative project that can be edited by anyone, so information is subject to change.
  3. It is not intended to constitute professional advice. The content displayed is for informational and educational purposes only. For important decisions (e.g., medical, legal, or financial), please consult a professional.
  4. Content copyright. Wikipedia is licensed under the Creative Commons Attribution-ShareAlike License (CC BY-SA). This means that content may be reused with appropriate attribution and shared under a similar license.
  5. Responsible use. Any risk arising from the use of information from this website is entirely the responsibility of the user.