Main Article Content


Clinostomum is a trematode genus in the family Clinostomidae. The mentioned trematode species is parasitizing many fish species as intermediate hosts, while piscivorous birds and mammals are the main definitive hosts. Total of 58 metacercariae of Clinostomum larvae were dissected out from 25 infected fish specimens from eight different species from a number of water bodies of Sulaimani Province, Kurdistan Region, Iraq. In this investigation, 959 fish specimens were collected. These includes five cyprinid species: Capoeta trutta (Heckel), C. umbla (Heckel), Carasobarbus kosswigi (Ladiges), Cyprinion macrostomum Heckel and Garra rufa (Heckel), two leuciscid species: Alburnus sellal Heckel and Squalius lepidus Heckel and the mugilid fish Planiliza abu (Heckel). The prevalence of infection for each of these species was 1.8%, 5%, 20%, 1.5%, 1.7%, 4.9%, 4.9% and 1.3%, respectively. The morphology of the Clinostomum metacercariae was studied by using a compound microscope; their ultra-morphology was evaluated with a scanning electron microscopy (SEM); and the molecular analysis were performed by amplifying, sequencing and comparing the ITS1-5.8S-ITS2 and 28S rDNA gene loci from isolated Clinostomum metacercariae. The obtained sequences confirmed that all metacercariae of the Clinostomum, collected during the present study, represented with C. complanatum (Rudolphi, 1814) based on percent identity with sequences in the GenBank subject database. The molecular characterisations of the C. complanatum metacercariae in the present study were deposited in GenBank NCBI.


Digenea Freshwater fishes Genetics Iraq Metacercaria Yellow grub disease

Article Details

How to Cite
Abdullah, Y. S. ., Bilal, S. J. ., Soor, T. A. H. ., & Mohammad, Y. O. . (2023). Surface Ultrastructure and Molecular Studies of Clinostomum complanatum (Rudolphi, 1814) Braun, 1899 (Trematoda: Clinostomidae) Metacercariae in some Freshwater Fishes from Sulaimani Province, Iraq. Basrah Journal of Agricultural Sciences, 36(2), 81–98.


  1. Abdulla, F., & Al-Badranih, L. (2000). Application of a rainfall-runoff model to three catchments in Iraq. Hydrological Sciences Journal, 45(1), 13-25.
  3. Abdullah, S. M. A., & Mhaisen, F. T. (2010). Comparative study on the parasitic infections of some sympatric fish species in Greater Zab and Lesser Zab rivers, north of Iraq. Basrah Journal of Agricultural Sciences, 23(s2), 70-80.
  4. Abdullah, S. M. A., & Rasheed, A. A. (2004). Parasitic fauna of some freshwater fishes from Dokan Lake, north of Iraq. I: Ectoparasites. Ibn Al-Haitham Journal of Pure & Applied Sciences, 17(1), 34-46.
  5. Abdullah, Y. S., Abdullah, S. M. A. (2015). Observations on fishes and their parasites of Darbandikhan Lake, Kurdistan Region in north Iraq. American Journal of Biological Life Sciences, 3(5), 176-180.
  6. Abdullah, Y. S., Bilal, S. J., Rahman, S. K., & Abdullah, S. M. A. (2018). Study of Helminthes in Glyptothorax kurdistanicus (Actinopterygii: Sisoridae) in Greater Zab and Lesser Zab rivers, Kurdistan Region, Iraq. Zanko Joiurnal of Pure & Applied Sciences, 31(s4), 131-137.
  8. Abidi, S. M. A., Ahmad, M., Nizami, W. A., & Hanna, R. E. B. (1988). Clinostomum complanatum: Tegumental surface changes during in vivo development. International Journal of Parasitology, 18(4), 433-439.
  10. Acosta, A. A., Caffara, M., Fioravanti, M. L., Utsunomia, R., Zago, A. C., Franceschini, L., & Silva, R J. (2016). Morphological and molecular characterization of Clinostomum detruncatum (Trematoda: Clinostomidae) metacercariae Infecting Synbranchus marmoratus. Journal of Parasitology, 102(1), 151-156.
  12. Ahammed-Shareef, P. A., & Abidi, S. M. A. (2012). Incidence and histopathology of encysted progenetic metacercaria of Clinostomum complanatum (Digenea: Clinostomidae) in Channa punctatus and its development in experimental host. Asian Pacific Journal Tropical Biomedicine, 2(6), 421-426.
  14. Al-Maliki, G. M., Al-Khafaji, K. K., & Al-Shemary, A. J. (2015). Incidence of parasites in Tilapia zillii from Tigris at north of Qurna with some environmental parameters of the river. Journal of Basrah Research, (Science), 41(2)A, 86-92.
  16. Al-Joborae, F. F., Mhaisen, F. T., & Al-Awadi, H. M. H. (2010). Parasitic fauna of fishes in Bahr Al-Najaf depression, mid Iraq. Bulletin of Iraq National Historical Museum, 11(1), 1-9.
  18. Ali, B. A. (1989): Studies on parasites of some freshwater fishes from Greater Zab- Iski-Kalak. M. Sc. Thesis, Salahaddin Univ., Erbil, 79pp. (In Arabic).
  19. Bashě, S. K. R., & Abdullah, S. M. A. (2010). Parasitic fauna of spiny eel Mastacembelus mastacembelus from Greater Zab River in Iraq. Iran Journal of Veterinary Research, Shiraz University, 11(1), Ser. 30, 18-27.
  21. Bilal, S. J., & Abdullah, S. M. A. (2009). Helminthic fauna of some cyprinid fishes from Bahdinan River, northern Iraq. Journal of Arab University Basic Applied Sciences, 8, 17-29.
  22. Bonett, R. M., Steffen, M. A., Trujano-Alvarez, A. L., Martin, S. D., Bursey, C. R., & Mcallister, C. T. (2011). Distribution, abundance, and genetic diversity of Clinostomum spp. metacercariae (Trematoda: Digenea) in a modified Ozark Stream system. Journal of Parasitology, 97, 177-184.
  24. Caffara, M., Locke, S. A., Gustinelli, A., Marcogliese, D. J., & Fioravanti, M. L. (2011). Morphological and molecular differentiation of Clinostomum complanatum and Clinostomum marginatum (Digenea: Clinostomidae) metacercariae and adults. Journal of Parasitology, 97(5), 884-891.
  26. Caffara, M., Locke, S. A., Echi, P. C., Halajian, A., Benini, D., Luus-Powell, W. J., Tavakol, S., & Fioravanti, M. L. (2017). A morphological and molecular study of Clinostomid metacercariae from African fish with a redescription of Clinostomum tilapiae. Parasitology, 144(11), 1519-1529.
  28. Caffara, M., Locke, S. A., Echi, P. C., Halajian, A., Luus-Powell, W. J., Benini, D., Tedesco, P., & Fioravanti, M. L. (2020). A new species of Clinostomum Leidy, 1856 based on molecular and morphological analysis of metacercariae from African siluriform fishes. Parasitology Research, 119(3), 885-892.
  30. Caffara, M., Locke, S. A., Halajian, A., Luus-Powell, W. J., Benini, D., Tedesco, P., Kasembele, G. K., Fioravanti, M. L. (2019). Molecular data show Clinostomoides Dollfus, 1950 is a junior synonym of Clinostomum Leidy, 1856, with redescription of metacercariae of Clinostomum brieni n. comb. Parasitology, 146(6), 805-813.
  32. Chai, J. Y., Murrell, K. D., & Lymbery, A. J. (2005). Fish-borne parasitic zoonoses: status and issues. International Journal of Parasitology, 351, 233-1254.
  34. Chai, J. Y., Sohn, W. M., Choi, S. Y., & Lee, S. H. (2002). Surface ultrastructure of Pygidiopsis summa (Digenea: Heterophyidae) adult flukes. Korean Journal of Parasitology, 40(3), 107-112.
  36. Chung, D. I., Moon, C. H., Kong, H. H., Choi, D. W., & Lim, D. K. (1995). The first human case of Clinostomum complanatum (Trematoda: Clinostomidae) infection in Korea. Korean Journal of Parasitology, 33, 219-223.
  38. Coad, B. W. (2010). Freshwater fishes of Iraq. Pensoft Publisher, Sofia-Moscow, 294 pp.
  39. Feizullaev, N. A., & Mirzoeva, S. S, (1983). Revision of the superfamily Clinostomoidea and analysis of its system. Parazitologiya, 17, 3-11.
  40. Fricke, R., Eschmeyer, W. N., & Van der Laan, R. (eds.) (2023). Eschmeyer's catalog of fishes: genera, species, references. Electronic version accessed 3th August 2023.
  42. Galazzo, D. E., Dayanandan, S., Marcogliese, D. J., & Mclaughlin, J. D, (2002). Molecular systematics of some North American species of Diplostomum (Digenea) based on rDNA-sequence data and comparisons with European congeners. Canada Journal of Zoology, 80, 2207-2217.
  44. Ghatani, S., Shylla, J. A., Tandon, V., Chatterjee, A., & Roy, B. (2012). Molecular characterization of pouched amphistome parasites (Trematoda: Gastrothylacidae) using ribosomal ITS2 sequence and secondary structures. Journal of Helminthology, 86, 117-124
  46. Gholami, Z., Mobedi, I., Esmaeili, H. R., & Kia, E. B. (2011). Occurrence of Clinostomum complanatum in Aphanius dispar (Actinoptrygii: Cyprinodontidae) collected from Mehran River, Hormuzgan Province, South of Iran. Asian Pacific Journal Tropical Biomedical, 1(3), 189-192.
  48. Gibson, D. I., Jones, A., & Bray, R. A. (2002). Keys to Trematoda of vertebrates. Vol. 1. CABI and Natural History Museum. 521pp.
  50. Goldberg, S. R., Bursey, C. R., & Cheam, H. (1998). Helminths of two native frog species (Rana chiricahuensis, Rana yavapaiensis) and one introduced frog species (Rana catesbeiana) (Ranidae) from Arizoana. Journal of Parasitology, 84(1), 175-177.
  52. Gustinelli, A., Caffara, M., Florio, D., Otachi, E. O., Wathuta, E. M., & Fioravanti, M. L. (2010). First description of the adult stage of Clinostomum cutaneum Paperna, 1964 (Digenea: Clinostomidae) from grey herons Ardea cinerea L. and a redescription of the metacercaria from the Nile tilapia Oreochromis niloticus niloticus (L.) in Kenya. Systematic Parasitology, 76, 39-51.
  54. Hara, H., Miyauchi, Y., Tahara, S., & Yamashita, H. (2014). Human laryngitis caused by Clinostomum complanatum. Nagoya Journal of Medical Sciences, 76, 181-185.
  56. Kanev, I., Radev, V., & Fried, B. (2002). Family Clinostomidae Luehe, 1901. Pp. 113-120. In Gibson, D., Jones, A., & Bray, R. (Eds.). Keys to the Trematoda, vol. I, D. CAB International, Wallingford, U.K., 521pp.
  58. Lane, R. L., & Morris, J. E. (2000). Biology, prevention, and effects of common grubs (digenetic trematodes) in freshwater fish. U.S. Department of Agriculture. Technical Bulletin Series, 115, 1-6.
  60. Lee, G. S., Park, S. W., Kim, J., Seo, K. S., You, K. W., Chung, J. H., Moon, H. C., & Hong, G. Y. (2017). A case of endoscopically treated laryngopharyngitis resulting from Clinostomum complanatum infection. Korean Journal of Gastroenterology, 69(3), 177-180.
  62. Lo, C. F., Huber, F., Kou, G. H., & Lo, C. J. (1981). Studies of Clinostomum complanatum (Rud., 1814). Fish Pathology, 15(3-4), 219-227.
  64. Locke, S. A., Mclaughlin, J. D., Dayanandan, S., & Marcogliese, D. J. (2010). Diversity and specificity in Diplostomum spp. metacercariae in freshwater fishes revealed by cytochrome c oxidase I and internal transcribed spacer sequences. Int. Journal of Parasitology, 40, 333-343.
  66. Locke, S. A., Caffara, M., Barčák, D., Sonko, P., Tedesco, P., Fioravanti, M. L., & Li, M. (2019). A new species of Clinostomum Leidy, 1856 in East Asia based on genomic and morphological data. Parasitology Research, 118, 3253-3265.
  68. Malek, M., & Mobedi, I. (2001). Occurrence of Clinostomum complanatum (Rudolphi, 1819) (Digenea: Clinostomatidae) in Capoeta capoeta gracilis (Osteichthys: Cyprinidae) from Shiroud River, Iran. Iranian Journal of Public Health, 30(3-4), 95-98.
  70. Marcilla, A., Bargues, M. D., & Mas-Coma, S. (2002). A PCR-RFLP assay for the distinction between Fasciola hepatica and Fasciola gigantica. Molecular and Cellular Probes, 16(5), 327-333.
  72. Margolis, L., Esch, G. W., Holmes, J. C., Kuris, A. M., & Schad, G. A. (1982). The use of ecological terms in parasitology (Report of an ad hoc committee of the American Society of Parasitologists), Journal of Parasitology, 68(1), 131-133.
  74. Mhaisen, F. T. (2019). Checklists of parasites of fishes of Thi-Qar Province, Iraq. Biology of Applied Environmental Research, 3(2), 152-167.
  75. Mhaisen, F. T. (2023). Index-catalogue of parasites and disease agents of fishes of Iraq. (Unpublished).
  76. Mhaisen, F. T., & Abdullah, S. M. A. (2017). Parasites of fishes of Kurdistan region, Iraq: Checklists. Biology of Applied Environmental Research, 1(2), 131-218.
  77. Mhaisen, F.T.; Al-Salim, N.K. & Khamees, N.R. (1986). The parasitic fauna of two cyprinid and a mugilid fish from Mehaijeran creek, Basrah. Journal Biological Sciences Research, 17(3), 63-73.
  78. Mhaisen, F. T., Khamees, N. R., & Ali, A. H. (2013). Checklists of trematodes of freshwater and marine fishes of Basrah province, Iraq. Basrah Journal of Agricultural Sciences, 26(Special 1), 50-77.
  79. Mohammadian- Kalat, T., Esmaeili, H. R., Mansour Aliabadian, M., & Freyhof, J. (2017). Re-description of Alburnus doriae, with comments on the taxonomic status of A. amirkabiri, A. mossulensis, A. sellal and Petroleuciscus esfahani (Teleostei: Cyprinidae). Zootaxa, 4323, 487-502.
  80. Nolan, M. J., & Cribb, T. H. (2005). The use and implications of ribosomal DNA sequencing for the discrimination of digenean species. Advance Parasitology, 60, 101-163.
  82. Olsen, W. O. (1974). Animal parasites: Their life cycles and ecology. 3rd ed. Baltimore: University Park Press, 562pp.
  84. Park, C. W., Kim, J. S., Joo, H. S., & Kim, J. (2009). A human case of Clinostomum complanatum infection in Korea. Korean Journal of Parasitology, 47, 401-404.
  86. Pinto, H. A., Caffara, M., Fioravanti, M. L., & Melo, A. L. (2015). Experimental and molecular study of cercariae of Clinostomum sp. (Trematoda: Clinostomidae) from Biomphalaria spp. (Mollusca: Planorbidae) in Brazil. Journal of Parasitology, 101(1), 108-113.
  88. Scholz, T. (1989). Amphilinida and cestoda, parasites of fish in Czechoslovakia. Acta Scientific National of Brno, 23(4), 1-56.
  90. Simsek, E., Yildirim, A., Yilmaz, E., Inci, A., Duzlu, O., Onder, Z., Ciloglu, A., Yetismis, G., & Pekmezci, G. Z. (2018). Occurrence and molecular characterization of Clinostomum complanatum (Trematoda: Clinostomidae) in freshwater fishes caught from Turkey. Parasitology Research, 117(7), 2117–2124.
  92. Smyth, J. D. (1994). Introduction to animal parasitology, 3rd ed. Cambridge University Press, Cambridge, 549pp.
  94. Wang, M. L., Chen, H. Y., & Shih, H. H. (2017). Occurrence and distribution of yellow grub trematodes (Clinostomum complanatum) infection in Taiwan. Parasitology Research, 116, 1761-1771.
  96. Yamaguti, S. (1958). Systema Helminthum. Vol. I. The digenetic trematodes of vertebrates. Interscience, New York, 1575 pp.
  98. Yooyen, T., Wongsawad, C., Kumchoo, K., & Chaiyapo, M. (2006). A new record of Clinostomum philippinensis (Valasquez, 1959) in Trichogaster microlepis (Gunther, 1861) from Bung Borapet, Nakhon Sawan, Thailand. Southeast Asian Journal of Tropical Medicine and Public Health, 37, 99-103.