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Impact and control of protozoan parasites in maricultured fishes

Published online by Cambridge University Press:  01 March 2013

KURT BUCHMANN
KURT BUCHMANN*
Affiliation:
Laboratory of Aquatic Pathobiology, Section of Biomedicine, Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
*
* Corresponding author: Laboratory of Aquatic Pathobiology, Section of Biomedicine, Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 7, DK-1870 Frederiksberg C., Denmark. Tel: +45-35332700. Fax: +45-35332755. E-mail: [email protected]
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Summary

Aquaculture, including both freshwater and marine production, has on a world scale exhibited one of the highest growth rates within animal protein production during recent decades and is expected to expand further at the same rate within the next 10 years. Control of diseases is one of the most prominent challenges if this production goal is to be reached. Apart from viral, bacterial, fungal and metazoan infections it has been documented that protozoan parasites affect health and welfare and thereby production of fish in marine aquaculture. Representatives within the main protozoan groups such as amoebae, dinoflagellates, kinetoplastid flagellates, diplomonadid flagellates, apicomplexans, microsporidians and ciliates have been shown to cause severe morbidity and mortality among farmed fish. Well studied examples are Neoparamoeba perurans, Amyloodinium ocellatum, Spironucleus salmonicida, Ichthyobodo necator, Cryptobia salmositica, Loma salmonae, Cryptocaryon irritans, Miamiensis avidus and Trichodina jadranica. The present report provides details on the parasites’ biology and impact on productivity and evaluates tools for diagnosis, control and management. Special emphasis is placed on antiprotozoan immune responses in fish and a strategy for development of vaccines is presented.

Keywords

fishparasitesprotozoanshealthproductivityimpactvaccinecontrol
Type
Mariculture
Information
Parasitology , Volume 142 , Special Issue 1: Parasites in fisheries and mariculture , January 2015 , pp. 168 - 177
Copyright
Copyright © Cambridge University Press 2013 

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References

REFERENCES

Adams, M. B. and Nowak, B. F. (2003). Amoebic gill disease (AGD): sequential pathology in cultured Atlantic salmon (Salmo salar L.). Journal of Fish Diseases 26, 601–614.Google Scholar
Alishahi, M. and Buchmann, K. (2006). Temperature-dependent protection against Ichthyophthirius multifiliis following immunisation of rainbow trout using live theronts. Diseases of Aquatic Organisms 72, 269–273.Google Scholar
Alvarez-Pellitero, P., Quiroga, M. I., Sitja-Bobadilla, A., Redondo, M. J., Palenzuela, O., Padros, F., Vazquez, S. and Nieto, J. M. (2004). Cryptosporidium scophthalmi n. sp. (Apicomplexa: Cryptosporidiidae) from cultured turbot Scophthalmus maximus. Light and electron microscope description and histopathological study. Diseases of Aquatic Organisms 62, 133–145.CrossRefGoogle Scholar
Ardelli, B. F. and Woo, P. T. K. (1999). The therapeutic use of isometamidium chloride against Cryptobia salmositica in rainbow trout (Oncorhynchus mykiss). Diseases of Aquatic Organisms 37, 195–203.Google Scholar
Bakke, T. A., Jansen, P. A. and Hansen, L. P. (1990). Differences in host resistance of Atlantic salmon Salmo salar L. stocks to the monogenean Gyrodactylus salaris Malmberg, 1957. Journal of Fish Biology 37, 577–587.Google Scholar
Bergh, O., Nilsen, F. and Samuelsen, O. B. (2001). Diseases, prophylaxis and treatment of the Atlantic halibut Hippoglossus hippoglossus: a review. Diseases of Aquatic Organisms 48, 57–74.Google Scholar
Bridle, A. R., Carter, C. G., Morrison, R. N. and Nowak, B. F. (2005). The effects of beta-glucan administration on macrophage respiratory burst activity in Atlantic salmon challenged with amoebic gill disease (AGD) – evidence of inherent resistance. Journal of Fish Diseases 28, 347–356.CrossRefGoogle ScholarPubMed
Buchmann, K., Dalsgaard, I. and Larsen, J. L. (1993). Diseases and injuries associated with mortality of hatchery reared Baltic cod (Gadus morhua L.) larvae. Acta Veterinaria Scandinavica 34, 385–390.Google Scholar
Buchmann, K., Lyholt, H. K. and Uldal, A. (1995). Parasite infections in Danish trout farms. Acta Veterinaria Scandinavica 36, 283–298.Google Scholar
Buchmann, K., Ogawa, K. and Lo, C.-F. (1992). Immune response of the Japanese eel (Anguilla japonica) against major antigens from the microsporean Pleistophora anguillarum) Hoshina, 1951. Fish Pathology 27, 157–161.Google Scholar
Buchmann, K. and Pedersen, K. (1994). A study on teleost phylogeny using specific antisera. Journal of Fish Biology 45, 901–903.Google Scholar
Cecchini, S., Saroglia, M., Terova, G. and Albanesi, F. (2001). Detection of antibody response against Amyloodinium ocellatum (Brown, 1931) in serum of naturally infected European sea bass by an ezyme-linked immunoabsorbent assay (ELISA). Bulletin of the European Association for Fish Pathologists 21, 104–108.Google Scholar
Chettri, J. K., Holten-Andersen, L., Raida, M. K., Kania, P. and Buchmann, K. (2011) PAMP induced expression of immune relevant genes in head kidney leukocytes of rainbow trout (Oncorhynchus mykiss). Developmental and Comparative Immunology 35, 476–482.Google Scholar
Chettri, J. K., Kuhn, J. A., Jaafar, R. M., Kania, P. W., Møller, O. S. and Buchmann, K. (2012). Immune response of rainbow trout juveniles to the protozoan parasite Ichthyobodo necator: immunohistochemical and gene expression studies. In Immune Responses in Fish. DAFINET Workshop (ed. Kania, P. W. and Buchmann, K.), p. 6. Frederiksberg Bookprinter, Frederiksberg, Denmark (www.dafinet.dk).Google Scholar
Cobb, C. S., Levy, M. G. and Noga, E. J. (1998). Development of immunity by the tomato clownfish Amphiprion frenatus to the dinoflagellate parasite Amyloodinium ocellatum . Journal of Aquatic Animal Health 10, 259–263.Google Scholar
Colorni, A. and Diamant, A. (1993). Ultrastructural features of Cryptocaryon irritans, a ciliate parasite of marine fish. European Journal of Protistology 29, 425–434.Google Scholar
Dalgaard, M. B., Nielsen, C. V. and Buchmann, K. (2003). Comparative susceptibility of two races of Salmo salar (Baltic Lule river and Atlantic Conon river strains) to infection with Gyrodactylus salaris . Diseases of Aquatic Organisms 53, 173–176.Google Scholar
Desmukh, S., Raida, M. K., Dalsgaard, I., Chettri, J. K., Kania, P. W. and Buchmann, K. (2012). Comparative protection of two different commercial vaccines against Yersinia ruckeri serotype O1 and biotype 2 in rainbow trout (Oncorhynchus mykiss). Veterinary Immunology and Immunopathology 145, 379–385.Google Scholar
Dyková, I., Nowak, B. F., Peckova, H., Fiala, I., Crosbie, P. and Dvorakova, H. (2007). Phylogeny of Neoparamoeba strains isolated from marine fish and invertebrates as inferred from SSU rDNA sequences. Diseases of Aquatic Organisms 74, 57–65.Google Scholar
FAO (2012). The State of World Fisheries and Aquaculture. Fisheries and Aquaculture Department. www.FAO.org.Google Scholar
Guselle, N. J., Speare, D. J. and Markham, R. J. F. (2010). Efficacy of intraperitoneally and orally administered ProVale, a yeast beta-(1,3)/(1,6)-D-glucan product, in inhibiting xenoma formation by the microsporidian Loma salmonae on rainbow trout gills. North American Journal of Aquaculture 72, 65–72.Google Scholar
Heuch, P. A., Jansen, P. A., Hansen, H., Sterud, E., MacKenzie, K., Haugen, P. and Hemmingsen, W. (2011). Parasite faunas of farmed cod and adjacent wild cod populations in Norway: a comparison. Aquaculture Environment Interactions 2, 1–13.Google Scholar
Holten-Andersen, L., Dalsgaard, I. and Buchmann, K. (2012). Baltic salmon, Salmo salar, from Swedish River Lule Älv is more resistant to furunculosis compared to rainbow trout. PLoS ONE 7: e29571, 1–5.Google Scholar
Hung, H. W., Lo, C. F., Tseng, C. C. and Kou, G. H. (1996). Humoral immune response of Japanese eel, Anguilla japónica Temminck & Schlegel, to Pleistophora anguillarum Hoshina, 1951 (Microspora). Journal of Fish Diseases 19, 243–250.Google Scholar
Iglesias, R., Paramá, A., Alvarez, M. F., Leiro, J., Fernandez, J. and Sanmartín, M. L. (2002). Antiprotozoals effective in vitro against the scuticociliate fish pathogen Philasterides dicentrarchi . Diseases of Aquatic Organisms 49, 191–197.Google Scholar
Isaksen, T. E., Karlsbakk, E., Repstad, O. and Nylund, A. (2012). Molecular tools for the detection and identification of Ichthyobodo spp. (Kinetoplastida), important fish parasites. Parasitology International 61, 675–683.Google Scholar
Jaafar, R. M. and Buchmann, K. (2011). Toltrazuril (Baycox vet.) in feed can reduce Ichthyophthirius multifiliis invasion of rainbow trout (Salmonidae). Acta Ichthyologica et Piscatoria 41, 63–66.Google Scholar
Jaafar, R. M., Skov, J., Kania, P. W. and Buchmann, K. (2011). Dose-dependent effects of dietary immunostimulants on rainbow trout immune parameters and susceptibility to the parasite Ichthyophthirius multifiliis . Journal of Aquaculture Research and Development S3, S3–001.Google Scholar
Jørgensen, A. and Sterud, E. (2006). The marine pathogenic genotype of Spironucleus barkhanus from farmed salmonids redescribed as Spironucleus salmonicida n. sp. Eukaryote Microbiology 53, 531–541.Google Scholar
Jørgensen, L. v. G. and Buchmann, K. (2011). Cysteine proteases as potential antigens in antiparasitic DNA vaccines. Vaccine 29, 5575–5583.Google Scholar
Jørgensen, L. v. G., Heinecke, R. D., Skjoedt, K., Rasmussen, K. J. and Buchmann, K. (2011). Experimental evidence for direct in situ binding of IgM and IgT to early trophonts of Ichthyophthirius multifiliis (Fouquet) in the gills of rainbow trout, Oncorhynchus mykiss (Walbaum). Journal of Fish Diseases 34, 749–755.Google Scholar
Jørgensen, T. R., Larsen, T. B., Jørgensen, L. v. G., Bresciani, J. and Buchmann, K. (2007). Isolation and characterisation of non-pathogenic form of Gyrodactylus salaris from rainbow trout. Diseases of Aquatic Organisms 73, 235–244.Google Scholar
Kent, M. L., Fournie, J. W., Dawe, S. C., Bagshaw, J. W. and Whitaker, D. J. (1992). Systemic hexamitid (Protozoa: diplomonadida) infection in seawater pen-reared Chinook salmon Oncorhynchus tshawytscha . Diseases of Aquatic Organisms 14, 81–89.Google Scholar
Lee, E. H. and Kim, K. H. (2009). CpG-ODN increases resistance of olive flounder (Paralichthys olivaceus) against Philasterides dicentrarchi (Ciliophora: Scuticociliatea) infection. Fish and Shellfish Immunology 26, 29–32.CrossRefGoogle ScholarPubMed
León-Rodríguez, L., Luzardo-Alvares, A., Blanco-Méndez, J., Lamas, J. and Leiro, J. (2012). A vaccine based on biodegradable microspheres induces protective immunity against scuticociliates without producing side effects in turbot. Fish and Shellfish Immunology 33, 21–27.Google Scholar
Levy, M. G., Poore, M. F., Colorni, A., Noga, E. J. and Litaker, R. W. (2007). A PCR assay for detection of Amyloodinium ocellatum . Diseases of Aquatic Organisms 73, 219–226.Google Scholar
Lindenstrøm, T., Sigh, J., Dalgaard, M. B. and Buchmann, K. (2006). Skin expression of IL-1beta in East Atlantic salmon, Salmo salar L., highly susceptible to Gyrodactylus salaris infection is enhanced compared to a low susceptibility Baltic stock. Journal of Fish Diseases 29, 123–128.Google Scholar
Lom, J. and Dyková, I. (1992). Protozoan Parasites of Fishes. Developments in Aquaculture and Fisheries Science 26. Elsevier, Amsterdam. 315 pp.Google Scholar
Lorenzen, E., Einer-Jensen, K., Martinussen, T., LaPatra, S. and Lorenzen, N. (2000). DNA vaccination of rainbow trout against viral haemorrhagic septicemia virus: a dose-response and time course study. Journal of Aquatic Animal Health 12, 167–180.Google Scholar
Lovy, J., Wright, G. M. and Speare, D. J. (2006). Morphological presentation of a dendritic-like cell within the gills of Chinook salmon infected with Loma salmonae . Developmental and Comparative Immunology 30, 259–263.Google Scholar
Madsen, H. C. K., Buchmann, K. and Mellergaard, S. (2000 a). Treatment of trichodiniasis in eel Anguilla anguilla in recirculated systems in Denmark: alternatives to formaldehyde. Aquaculture 186, 221–231.Google Scholar
Madsen, H. C. K., Buchmann, K. and Mellergaard, S. (2000 b). Association between trichodiniasis in eel (Anguilla anguilla) and water quality in recirculation systems. Aquaculture 187, 275–281.Google Scholar
Millet, C. O. M., Lloyd, D., Williams, C., Williams, D., Evans, G., Saunders, R. A. and Cable, J. (2011). Effect of garlic and allium derived products on the growth and metabolism of Spironucleus vortens . Experimental Parasitology 127, 490–499.Google Scholar
Misumi, I., Lewis, T. D., Takemura, A. and Leong, J. A. C. (2011). Elicited cross-protection and specific antibodies in Mozambique tilapia (Oreochromis mossambicus) against two different immobilization serotypes of Cryptocaryon irritans isolated in Hawai. Fish and Shellfish Immunology 30, 1152–1158.CrossRefGoogle Scholar
Mori, K. I., Yamamoto, K., Teruya, K., Shiozawa, S., Yoseda, K., Sugaya, T., Shirakashi, S., Itoh, N. and Ogawa, K. (2007). Endoparasitic dinoflagellate of the genus Ichthyodinium infecting fertilized eggs and hatched larvae observed in the seed production of leopard coral grouper Plectropomus leopardus . Fish Pathology 42, 49–57.Google Scholar
Nelson, J. S. (2006). Fishes of the World, 4th Edn. John Wiley & Sons, Hoboken, NJ, USA.Google Scholar
Noga, E. J. (1987). Propagation in cell culture of the dinoflagellate Amyloodinium, an ectoparasite of marine fishes. Science 236, 1302–1304.Google Scholar
Noga, E. J. (2012). Amyloodinium ocellatum . In Fish Parasites – Pathobiology and Protection (ed. Woo, P. T. K. and Buchmann, K.), pp. 19–29. CAB International, Wallingford, UK.Google Scholar
Nowak, B. F. (2012). Neoparamoeba perurans . In Fish Parasites – Pathobiology and Protection (ed. Woo, P. T. K. and Buchmann, K.), pp. 1–18. CAB International, Wallingford, UK.Google Scholar
Olsen, M. M., Heinecke, R. D., Skjødt, K., Rasmussen, K. J., Kania, P. and Buchmann, K. (2011). Cellular and humoral factors involved in the response of rainbow trout gills to Ichthyophthirius multifiliis infections: molecular and immunohistochemical studies. Fish and Shellfish Immunology 30, 859–869.Google Scholar
Paperna, I. (1981). Amyloodinium ocellatum (Browne, 1931) (Dinoflagellida) infestations in cultured marine fish at Eilat, Red Sea: epizootiology and pathology. Journal of Fish Diseases 3, 363–272.Google Scholar
Pedersen, B. H., Buchmann, K. and Køie, M. (1993). Baltic larval cod Gadus morhua are infested with a protistan endoparasite in the yolk sac. Diseases of Aquatic Organisms 16, 29–33.Google Scholar
Pereira, J. C., Abrantes, I., Martins, I., Barata, I., Frias, P. and Pereira, I. (2011). Ecological and morphological features of Amyloodinium ocellatum occurrences in cultivated gilthead seabream Sparus aurata L.: a case study. Aquaculture 310, 289–297.Google Scholar
Picón-Camacho, S. M., Ruiz de Ybáñez, M. R., Holzer, A. S., Arizcun, M. A. and Muñoz, P. (2011). In vitro treatments for the theront stage of the ciliate protozoan Cryptocaryon irritans . Diseases of Aquatic Organisms 94, 167–172.Google Scholar
Poppe, T. T., Mo, T. A. and Iversen, L. (1992). Disseminated hexamitosis in sea-caged Atlantic salmon, Salmo salar . Diseases of Aquatic Organisms 14, 91–97.Google Scholar
Rodgers, C. J. and Furones, M. D. (1998). Disease problems in cultured marine fish in the Mediterranean. Fish Pathology 33, 157–164.Google Scholar
Rodríguez-Tovar, L. E., Becker, J. A., Markham, R. J. and Speare, D. J. (2006). Induction time for resistance to microsporidial gill disease caused by Loma salmonae following vaccination of rainbow trout (Oncorhynchus mykiss) with a spore based vaccine. Fish and Shellfish Immunology 21, 170–175.Google Scholar
Rozas, M., Bohle, H., Grothusen, H. and Bustos, P. (2012). Epidemiology of amoebic gill disease (AGD) in Chilean salmon industry between 2007 and 2010. Bulletin of the European Association of Fish Pathologists 32, 181–188.Google Scholar
Rückert, S., Palm, H. W. and Klimpel, S. (2008). Parasite fauna of seabass (Lates calcarifer) under mariculture conditions in Lampung Bay, Indonesia. Journal of Applied Ichthyology 24, 321–327.Google Scholar
Sánchez, J. G., Speare, D. J., Markham, R. J. F. and Jones, S. R. M. (2001). Experimental vaccination of rainbow trout against Loma salmonae using a live low-virulence variant of L. salmonae . Journal of Fish Biology 59, 427–441.Google Scholar
Saraiva, A., Ramos, M. F., Barandela, T., Sousa, J. A. and Rodrigues, P. N. (2009). Cryptosporidium sp. (Apicomplexa) from cultured turbot Psetta máxima . Bulletin of the European Association of Fish Pathologists 29, 34–36.Google Scholar
Saraiva, A., Jeronimo, D. and Cruz, C. (2011). Amyloodinium ocellatum (Chromalveolata, Dinoflagellata) in farmed turbot. Aquaculture 320, 34–36.Google Scholar
Schmahl, G., Taraschewski, H. and Mehlhorn, H. (1989). Chemotherapy of fish parasites. Parasitology Research 75, 503–511.Google Scholar
Segner, H., Sundh, H., Buchmann, K., Douxfils, J., Sundell, K. S., Mathieu, C., Ruane, N., Jutfelt, F., Toften, H. and Vaughan, L. (2012). Health of farmed fish: its relation to fish welfare and its utility as welfare indicator. Fish Physiology and Biochemistry 38, 85–105.Google Scholar
Skov, J., Kania, P. W., Holten-Andersen, L., Fouz, B. and Buchmann, K. (2012). Immunomodulatory effects of dietary beta-1,3-glucan from Euglena gracilis in rainbow trout (Oncorhynchus mykiss) immersion vaccinated against Yersinia ruckeri . Fish and Shellfish Immunology 33, 111–120.CrossRefGoogle ScholarPubMed
Skovgaard, A., Meyer, S., Overton, J. L., Støttrup, J. and Buchmann, K. (2010). Ribosomal RNA gene sequences confirm that protistan endoparasite of larval cod Gadus morhua is Ichthyodinium sp. Diseases of Aquatic Organisms 88, 161–167.Google Scholar
Smith, S. A., Levy, M. G. and Noga, E. J. (1992). Development of an enzyme-linked immunosorbent assay (ELISA) for the detection of antibody to the parasitic dinoflagellate Amyloodinium ocellatum in Oreochromis aureus . Veterinary Parasitology 42, 145–155.Google Scholar
Smith, S. A., Levy, M. G., Noga, E. J. and Gerig, T. M. (1993). Effect of serum from tilapia Oreochromis aureus, immunized with dinospores of Amyloodinium ocellatum, on the motility, infectivity and growth of the parasite in cell culture. Diseases of Aquatic Organisms 15, 73–80.Google Scholar
Soares, F., Quental-Ferreira, H., Moreira, M., Cunha, E., Ribeiro, L. and Pousao-Ferreira, P. (2012). First report of Amyloodinium ocellatum in farmed meagre (Argyrosomus regius). Bulletin of the European Association for Fish Pathologists 32, 30–33.Google Scholar
Song, J. Y., Kitamura, S. I., Oh, M. J., Kang, H. S., Lee, J. H., Tanaka, S-J. and Jung, S.-J. (2009). Pathogenicity of Miamiensis avidus (syn. Philasterides dicentrarchi), Pseudocohnilembus persalinus, Pseudocohnilembus hargisi and Uronema marinum (Ciliophora, Scuticociliatida). Diseases of Aquatic Organisms 83, 133–143.Google Scholar
Speare, D. J. and Lovy, J. L. (2012). Loma salmonae and related species. In Fish Parasites – Pathobiology and Protection (ed. Woo, P. T. K. and Buchmann, K.), pp. 109–130. CAB International, Wallingford, UK.Google Scholar
Sterud, E., Mo, T. A. and Poppe, T. T. (1998). Systemic spironucleosis in sea-farmed Atlantic salmon Salmo salar, caused by Spironucleus barkhanus transmitted from feral Arctic char Salvelinus alpinus . Diseases of Aquatic Organisms 33, 63–66.Google Scholar
Tan, C. W., Jesudhasan, R. R. R. and Woo, P. T. K. (2008). Towards a metalloprotease-DNA vaccine against piscine cryptobiosis caused by Cryptobia salmositica . Parasitology Research 102, 265–275.Google Scholar
Uldal, A. and Buchmann, K. (1996). Parasite host relations: Hexamita salmonis in rainbow trout Oncorhynchus mykiss . Diseases of Aquatic Organisms 25, 229–231.Google Scholar
Urawa, S. (1992). Epidermal responses of chum salmon (Oncorhynchus keta) fry to the ectoparasitic flagellate Ichthyobodo necator . Canadian Journal of Zoology 70, 1567–1575.Google Scholar
Urawa, S., Ueki, N. and Karlsbakk, E. (1998). A review of Ichthyobodo infection in marine fishes. Fish Pathology 33, 311–320.Google Scholar
Woo, P. T. K. (1979). Trypanoplasma salmositica: experimental infections in rainbow trout, Salmo gairdneri . Experimental Parasitology 47, 36–48.Google Scholar
Woo, P. T. K. (2012). Cryptobia (Trypanoplasma) salmositica . In Fish Parasites – Pathobiology and Protection (ed. Woo, P. T. K. and Buchmann, K.), pp. 30–54. CAB International, Wallingford, UK.Google Scholar
Woo, P. T. K. and Li, S. (1990). In vitro attenuation of Cryptobia salmositica and its use as a live vaccine against cryptobiosis in Oncorhynchus mykiss . Journal of Parasitology 78, 752–755.Google Scholar
Xueqin, J., Kania, P. W. and Buchmann, K. (2012). Comparative effects of four feed types on white spot disease susceptibility and skin immune parameters in rainbow trout, Oncorhynchus mykiss (Walbaum). Journal of Fish Diseases 35, 127–135.Google Scholar
Yambot, A. V., Song, Y. L. and Sung, H. H. (2003). Characterization of Cryptocaryon irritans, a parasite isolated from marine fishes in Taiwan. Diseases of Aquatic Organisms 54, 147–156.Google Scholar
Young, N. D., Crosbie, P. B. B., Adams, M. B., Nowak, B. F. and Morrison, R. N. (2007). Neoparamoeba perurans n.sp., an agent of amoebic gill disease of Atlantic salmon (Salmo salar). International Journal for Parasitology 37, 1469–1481.Google Scholar
Young, N. D., Dyková, I., Nowak, B. F. and Morrison, R. N. (2008). Development of a diagnostic PCR to detect Neoparamoeba perurans, agent of amoebic gill disease (AGD). Journal of Fish Diseases 31, 285–295.Google Scholar