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Scientific classification
Kingdom: Animalia
Phylum: Platyhelminthes
Class: Trematoda
Order: Plagiorchiida
Family: Paramphistomatidae
Genus: Paramphistomum
Fischoeder, 1901
Type species
Paramphistomum cervi
Zeder, 1790

Paramphistomum is a genus of parasitic flatworms belonging to the digenetic trematodes. It includes flukes which are mostly parasitising livestock ruminants, as well as some wild mammals. They are responsible for the serious disease called paramphistomiasis, also known as amphistomosis, especially in cattle and sheep. Its symptoms include profuse diarrhoea, anaemia, lethargy, and often result in death if untreated.[1][2] They are found throughout the world, and most abundantly in livestock farming regions such as Australia, Asia, Africa, Eastern Europe, and Russia.[3]

The generic name was introduced by F. Fischoeder in 1901 for the replacement of the then existing genus Amphistoma (Rudolphi, 1809). Under the new genus he redescribed both Paramphistomum cervi and P. bothriophoron and designated the former as the type species.[4][5]


Due to striking resemblance with each other and with other amphistomes, a number of described species are known to be synonymous.[5][6] Some important species are:


The generic name (Greek: para meaning "similar" [to Amphistoma], amphi meaning "on both sides", and stoma for "mouth") is given due to the presence of an anterior oral sucker and a posterior larger ventral sucker in adult worms.[3] The body is minute, measuring less than a centimetre. The body is covered with a highly folded tegument, which in turn is provided with sensory papillae. Paramphistomum are all hermaphrodite, having both male and female reproductive systems in the posterior region of the body.[2]

Life cycle[edit]

Their life cycle is indirect, requiring a definitive host such as ruminants, an intermediate host such as snail, and a free-living of external phases in water and plants. The sexually mature monoecious self-fertilises in the mammalian rumen, and release the eggs along with faeces. Eggs hatch in water into ciliated miracidia. The miracidia then enters the body of an intermediate host, which are snails belonging to the genera Bulinus, Planorbis, Physa Stagnicola and Pseudosuccinea.[7][8][9][10] Then the miracidia lost their cilia to become sporocysts. After a few days they develop up to 8 rediae, which are rapidly liberated. Each redia contains about 15-30 cercariae. Mature cercariae are possess by two eyespots and a long slender tail, by which they find aquatic plants or other suitable substrata, to which they get attached and encyst to become metacercariae.[11] The mammalian hosts ingest the infective larvae. Once inside the duodenum and jejunum, their cysts are removed.[12] They penetrate the intestinal wall by actively destroying the mucosa, and then migrate to the rumen, where the grow into adult.[13]

Pathogenicity and pathology[edit]

Paramphistomiasis causes enteritis and anaemia in livestocks mammals and result in substantial production and economic losses. Pathological symptoms are produced by immature flukes. When the young flukes start to gather in the intestine, there is a watery and fetid diarrhoea which is often associated with high mortality (even up to 80-90%) in ruminants. At a given time, as many as 30,000 flukes may accumulate, fervently attacking the duodenal mucosa to induce acute enteritis. Adult flukes are relatively harmless.[14] Liver tissue are generally damaged extensively, indicated by swelling, haemorrhage, discolouration, necrosis, bile duct hyperplasia, and fibrosis.[15]

Diagnosis and treatment[edit]

Symptoms are easily indicated by infected sheep and cattle as they become severely anorexic or inefficiently digest food, and become unthrifty. Fetid diarrhoea is an obvious indication so that fluid faeces are examined for immature flukes.[2]

Paramphistomiasis is considered a neglected tropical disease, with no prescription drug for treatment and control. Thus management of infection is based mainly on control of the snail population. Drugs shown to be effective are resorantel, oxyclozanide, clorsulon, ivermectin, niclosamide, bithional and levamisole.[7][16][17][18] An in vitro demonstration shows that plumbagin exhibits high efficacy on adult flukes.[19]


  1. ^ Horak IG (1971). "Paramphistomiasis of domestic ruminants". Advances in Parasitology. 9 (1): 33–72. doi:10.1016/s0065-308x(08)60159-1. PMID 4927976. 
  2. ^ a b c Olsen OW (1974). Animal Parasites: Their Life Cycles and Ecology (3 ed.). Dover Publications, Inc., New York/University Park Press, Baltimore, US. pp. 273–276. ISBN 0486651266. 
  3. ^ a b Boray J (1959). "Studies on intestinal amphistomosis in cattle". Australian Veterinary Journal. 35 (6): 282–287. doi:10.1111/j.1751-0813.1959.tb08480.x. 
  4. ^ Fischoeder F (1904). Beschreibung dreier Paramphistomiden-Arten aus Säugethieren. Fischer, Germany. pp. 1–18. 
  5. ^ a b Eduardo SL (1982). "The taxonomy of the family Paramphistomidae Fischoeder, 1901 with special reference to the morphology of species occurring in ruminants. II. Revision of the genus Paramphistomum Fischoeder, 1901". Systematic Parasitology. 4 (3): 189–238. doi:10.1007/BF00009622. 
  6. ^ Lotfy WM, Brant SV, Ashmawy KI, Devkota R, Mkoji GM, Loker ES (2010). "A molecular approach for identification of paramphistomes from Africa and Asia". Veterinary Parasitology. 174 (3–4): 234–40. doi:10.1016/j.vetpar.2010.08.027. PMID 20880634. 
  7. ^ a b Bowman DD, Georgi JR (2008). Georgis' Parasitology for Veterinarians (9 ed.). W.B. Saunders Company. p. 124. ISBN 1416044124. 
  8. ^ Duri PH (1978). "A preliminary note on the life cycle of Paramphistomum cotylophorum (Fisohoeder, 1901), and P. cervi (Schrank, 1790) (Trematoda: Paramphistomatidae)". Australian Veterinary Journal. 25 (9): 209. doi:10.1111/j.1751-0813.1949.tb04802.x. 
  9. ^ Altaif KI, Al-Abbassy SN, Al-Saqur IM, Jawad AK (1978). "Experimental studies on the suitability of aquatic snails as intermediate hosts for Paramphistomum cervi in Iraq". Annals of Tropical Medicine and Parasitology. 72 (2): 151–155. PMID 666386. 
  10. ^ Albaret, J.-L.; Bayssade-Dufour, Christiane; Guilhon, J.; Kulo, S. D.; Picot, H. (1978). "Cycle biologique de Paramphistomum togolense n. sp. (Trematoda, Paramphistomidae)". Annales de Parasitologie Humaine et Comparée. 53 (5): 495–510. doi:10.1051/parasite/1978535495.  open access publication – free to read
  11. ^ Kraneburg W (1977). "Contribution to the biology and pathogenicity of domestic omasal leech Paramphistomum cervi. 1. Developmental stages in the free state and in the intermediary host". Berl Munch Tierarztl Wochenschr. 90 (16): 316–320. PMID 588222. 
  12. ^ Arru E, Deiana S, Muzzetto P (1970). "Intestinal paramphistomiasis in ruminants. Experimental infection of sheep with metacercariae and immature forms of Paramphistomum cervi (Schrank, 1790)". Rivista di Parassitologia. 31 (1): 33–42. PMID 5530163. 
  13. ^ Sanabria RE, Romero JR (2008). "Review and update of paramphistomosis". Helminthologia. 45 (2): 64–68. doi:10.2478/s11687-008-0012-5. 
  14. ^ Singh RP, Sahai BN, Jha GJ (1984). "Histopathology of the duodenum and rumen of goats during experimental infections with Paramphistomum cervi". Veterinary Parasitology. 15 (1): 39–46. doi:10.1016/0304-4017(84)90108-0. PMID 6541393. 
  15. ^ Bilqees Fm; Mirza S; Khatoon N (2011). Paramphistomum Cervi Infection and Liver Tissue Damage in Buffaloes. VDM Verlag. pp. 1–112. ISBN 3639325540. 
  16. ^ Georgiev B, Gruev A (1979). "Effectiveness of levamisole and oxyclozanide in paramphistomiasis in sheep and cattle". Vet Med Nauki. 16 (3): 45–51. PMID 524749. 
  17. ^ Rolfe PF, Boray JC (1987). "Chemotherapy of paramphistomosis in cattle". Australian Veterinary Journal. 64 (11): 328–332. doi:10.1111/j.1751-0813.1987.tb06060.x. PMID 3447575. 
  18. ^ Rolfe PF, Boray JC (1988). "Chemotherapy of paramphistomosis in sheep". Australian Veterinary Journal. 65 (5): 148–150. doi:10.1111/j.1751-0813.1988.tb14443.x. PMID 3401161. 
  19. ^ Saowakon N, Lorsuwannarat N, Changklungmoa N, Wanichanon C, Sobhon P (2013). "Paramphistomum cervi: the in vitro effect of plumbagin on motility, survival and tegument structure". Experimental Parasitology. 133 (2): 179–186. doi:10.1016/j.exppara.2012.11.018. PMID 23206952. 

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