fish and shellfish diseases

Fish and shellfish diseases

Wageningen Bioveterinary Research (WBVR) has a specialised fish and shellfish diseases laboratory. The laboratory was set up in 1985 and offers broad experience on diseases of cultured fish for human consumption, ornamental and wild fish, crustaceans and shellfish.

Healthy aquaculture

Fish production via aquaculture is increasing strongly worldwide. One of the threats to intensive aquaculture is the occurrence of contagious fish, crustaceans and shellfish diseases, which can cause serious illness and death and thereby economic losses.

Role of Wageningen Bioveterinary Research

At the specialised laboratory in Lelystad, accredited and fast diagnostics are performed to identify new outbreaks at an early stage. We offer broad experience and expertise on various fish and shellfish diseases. We are consulted frequently for our diagnostic service, expertise on diseases, and as partner for collaboration in research and network projects by both national and international parties.


  • Diagnosing diseases for the aquatic industry, and the ornamental and wild fish branches:
    • In case of fish disease at fish farms
    • At suspicion of notifiable fish and shellfish diseases, in cooperation with the Food and Consumer Product Safety Authority (NVWA)
    • For certification of live fish for export, in cooperation with the NVWA
  • Serving as a knowledge and advisory centre for the Dutch Ministry of Agriculture, Nature and Food Quality (LNV) and provide consultancy to the aquaculture branch regarding fish and shellfish diseases
  • Research on fish and shellfish diseases that occur in the Netherland, with specialisation in eel and carp diseases

National Reference Lab

The laboratory is the Dutch National Reference Lab (NRL) for fish and shellfish diseases for the EU. It was the first fish diseases laboratory in Europe accredited for quality standards ISO 9001 and 17025 (EN 45001). The laboratory has an impressive national and international network, in which knowledge and materials are exchanged.

Appointment and order form

Live diseased or healthy fish and shellfish can be diagnosed at appointment (after a phone call) with the Fish and Shellfish Disease Laboratory in Lelystad, preferably via a veterinarian. When submitting research material, please fill in the submission form for fish diseases, print it and send it along.

For diagnostic research - necropsy (including parasitology), bacteriology, virology, and histopathology - reasonable rates are charged.

View the turnaround times per test

Export certification

Export certification is arranged via the Dutch Food and Consumer Product Safety Authority (NVWA). A notification period of 14 days prior to this must be taken into account.


Following the anamnesis, necropsy is performed, including external and internal investigation for parasites. At suspicion of a virological or bacteriological disorder, further tests are performed. For example, in the event of a bacteriological suspicion, specimens from the lesions and internal organs of the fish are inoculated onto agar. For virology organs of the fish are sampled, and in histopathology (microscopy of sections of affected tissue) pieces of tissue are put into a fixative.

Once the diagnostic tests have been completed, a diagnosis is made. This is indicated in the written results.


The inoculated agar plates are incubated at room temperature, as fish are cold-blooded animals and their pathogenic organisms have adapted to that temperature. In case a pure culture of bacteria results, an antibiogram is made, so that the fish owner can choose an appropriate antibiotic to treat the disease. In parallel to this process, the bacteria are characterized by classic and/or molecular techniques.


WBVR has many PCR tests for the virus diagnostics of fish, crustaceans and shellfish.

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For histopathology, the fixed tissue is sliced and stained in such a way that it can be examined with a microscope. This makes it possible to see alterations at cell level that indicate a viral, bacteriological or other disease. This method also enables detection of very small parasites in the tissue or in cells.

Diagnosis of shellfish diseases

For research on live shellfish, they are fixed and processed for histopathology. Light microscopy is used to read the sections. At the same time, inoculations can be used for bacteriological research. WBVR also offers PCR tests for the most important shellfish pathogens.

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Research examples of WBVR

The laboratory has studied various fish disease subjects in more detail, with or without infection trials: the swimbladder parasite (Anguillicola crassus) in eels, common eel parasites in the open waters, eel bacteria and currently eel viruses. In addition, various molecular detection methods have been developed for KHV (koi herpes virus), HVA (eel herpes virus), Bonamia (oyster parasite) and Nocardia (shellfish bacteria). Scientific publications have appeared based on the results of these studies. The scientists collaborate with other partners in new research projects that optimally utilize the specific knowledge of all participants.


As a member of (inter-)national advisory committees, the laboratory experts also give advice to parties like the Ministry of LNV, the EU, the EFSA (European Food Safety Authority), the OIE and FAO. The laboratory also publishes frequently in professional bulletins of the aquaculture and ornamental fish industry, and in international peer reviewed fish and shellfish disease journals, and books. Researchers of the laboratory present posters and oral presentations at (inter-)national meetings and conferences.

Publications 2021


Eilenberg J., O. Haenen, H.J. van der Fels-Klerx, L. Van Campenhout,  M.M. van Oers, and B. Schoelitsz, 2021. Management of pathogens and other unwanted organisms in insect production. In: The Basics of Edible Insect Rearing: HANDBOOK FOR THE PRODUCTION CHAIN. Veldkamp, T., J. Claeys, O.L.M. Haenen, J.J.A. van Loon and T. Spranghers (Eds.), 2021. Wageningen Acad. Publ. Textbook. 250 pp. eISBN: 978-90-8686-902-2 | ISBN: 978-90-8686-365-5.

FAO, 2021. Report of the Round-Table Discussion: Moving Forward through Lessons Learned on Response Actions to Aquatic Animal Disease Emergencies, Rome, 16–18 December 2019. FAO Fisheries and Aquaculture Report No.1333. Rome. (O. Haenen pages: 18-19)

Gorgoglione, B., C. Whipps, N. Stinton, T. Ito, C. M. Dover, S. Baron, K. Yuasa, M. Adamek, D. Verner Jeffreys, O. L. M. Haenen, 2021. Diseases of ornamental and laboratory fishes. Bull. EAFP 41(5) (in press)

Székely, Csaba, Olga Haenen and Kálmán Molnár, 2021. Anguillicoloides crassus. Chapter 19 in: Fish Parasites: A Handbook of Protocols for their Isolation, Culture and Transmission. Edited by Ariadna Sitjà-Bobadilla, James. E. Bron, Geert Wiegertjes and M. Carla Piazzon. 5M Publishing, Sheffield, UK. 256 pp. 286-297.

Veldkamp, T., J. Claeys, O.L.M. Haenen, J.J.A. van Loon and T. Spranghers (Eds.), 2021. The basics of edible insect rearing. Handbook for the production chain. Textbook. 250 pp. eISBN: 978-90-8686-902-2 | ISBN: 978-90-8686-365-5.

Publications 2016 - 2020


Gorgoglione, B., C.Bailey, M.D.Fast, D.Bass,  M. Saraiva , M. Adamek, P. Noguera, S. Ciulli, M. Palíková, I. Aguirre-Gil, L.Bigarré and O.Haenen, 2020. Co-infections and multiple stressors in fish. EAFP 19TH INTERNATIONAL CONFERENCE ON DISEASES OF FISH AND SHELLFISH SPECIAL EDITION WORKSHOP REPORT. Bull. Eur. Ass. Fish Pathol., 40(1) : 4-19.

Joosten, Lotte, Antoine Lecocq, Annette Bruun Jensen, Olga Haenen, Eric Schmitt, Jørgen Eilenberg, 2020. Insect pathogen risks for black soldier fly Hermetia illucens and guidelines for reliable production. Mini Review. Entomologia Experimentalis et Applicata. Special Issue: Insects in production, 1-16. DOI:10.1111/eea.12916 

Baron, Sandrine, Daniela Ceccarelli, Inger Dalsgaard, Sophie A. Granier, Olga Haenen, Eva Jansson, Lone Madsen, Eric Jouy, Isabelle Kempf, Emeline Larvor, Thierry Morin, Joop Testerink, Kees Veldman, Kári Karbech Mouritsen, Betty Van Gelderen, Michal Voorbergen-Laarman, Eva Säker, Eva Blomkvist, Peter Smith, 2020. Influence of incubation time on antimicrobial susceptibility testing of pathogenic Vibrio anguillarum and Vibrio vulnificus isolated from fish. Aquaculture 524, 15 July 2020, 735258. 

Haenen, Olga, Kees Veldman, Daniela Ceccarelli, Nedzib Tafro, Tina Zuidema, and Dik Mevius, 2020. Potential transfer of antimicrobial resistance and zoonotic bacteria through global ornamental fish trade. In: Understanding Antimicrobial Resistance in Aquaculture. FAO technical publication (Asian Fisheries Science), Volume 33S: 46-54. 

Haenen, Olga, Iddya Karunasagar, Amedeo Manfrin, Snjezana Znrcic, Celia Lavilla-Pitogo, Mark Lawrence, Larry Hanson, Rohana Subasinghe, Melba Bondad-Reantaso, Indrani Karunasagar, 2020. Contact-zoonotic bacteria of warm water ornamental and cultured fish. In: Understanding Antimicrobial Resistance in Aquaculture. FAO technical publication (Asian Fisheries Science), Volume 33S: 39-45.

Jansson E., Haenen O., Nonnemann B. , Madsen L., van Gelderen E., Aspán A., Säker E. , Boonstra M., Gulla S., Colquhoun D.J., Roozenburg-Hengst I., Dalsgaard I., 2020. MALDI-TOF MS: a diagnostic tool for identification of bacterial fish pathogens. EAFP Bull. 40 (6) : 241-248.


Gulla, Snorre & Bayliss, Sion & Björnsdóttir, Bryndís & Dalsgaard, Ingeri & Haenen, Olga & Jansson, Eva & McCarthy, Una & Scholz, Felix & Vercauteren, Maaike & Verner-Jeffreys, David & Welch, Timothy & Wiklund, Tom & Colquhoun, Duncan. (2019). Biogeography of the fish pathogen Aeromonas salmonicida inferred by vapA genotyping. FEMS Microbiology Letters. 366. 10.1093/femsle/fnz074.

Haenen, Olga, 2019. Major eel diseases in Europe: the past 30 years. Ch. 17 in: Eels: Biology, Monitoring, Management, Culture and Exploitation: Proceedings of the First International Eel Science Symposium, Eds. A. Don & P. Coulson. 5M Publishing, Sheffield, UK. pp. 257-279.

Haenen, O., A. Borghuis, B. Weller, J. van Eijk, E. van Gelderen, M. Boonstra, E. Weerman, L. Bonte, L. Dingboom, R. Petie, P. de Cocq, 2019. Bacteriële gezondheid in Nederlandse insectenkweek: een pilot. In: Staat van Zoönosen, 2019.

Lewin, Neil C., Amy J. Reading, Joanna James, Jo Cable, Gareth D. Davies, Derek Evans, Claude Belpaire, Alan M. Walker, Keith Way, Olga L. M. Haenen, Dave Hoole, and Chris F. Williams, 2019. Silver service: a standard protocol for eel health examinations. Ch. 20 In: Eels: Biology, Monitoring, Management, Culture and Exploitation: Proceedings of the First International Eel Science Symposium, Eds. A. Don & P. Coulson. 5M Publishing, Sheffield, UK. pp 305-313.


Haenen, O., L. Bigarré, T. Ito, J.-C. Avarre, N. Vendramin, 2018. Workshop Neglected viral diseases of freshwater fish farming. EAFP Bulletin 38, 3: 105-115.

Saucedo, Bernardo, Joseph Hughes, Annemarieke Spitzen-van der Sluijs, Natasja Kruithof, Marc Schills, Jolianne M. Rijks, Mónica Jacinto-Maldonado, Nicolás Suarez, Olga L. M. Haenen, Michal Voorbergen-Laarman, Jan van den Broek, Maarten Gilbert, Andrea Gröne, Steven J. van Beurden & M. Hélène Verheije, 2018. Ranavirus genotypes in the Netherlands and their potential association with virulence in water frogs (Pelophylax spp.). Emerging Microbes & Infections, 7, 56.


Ceccarelli, Daniela, Alieda van Essen-Zandbergen, Kees T. Veldman, Nedzib Tafro, Olga Haenen, Dik Mevius. 2017. Chromosome-encoded blaOXA-48-like variants in Shewanella spp. from food-producing animals, fish and the aquatic environment. Antimicrob. Agents Chemother. February 2017, 61, 2: e01013-16.

Cieslak Michael, Thomas Wahli, Nicolas Diserens, Olga L. M. Haenen, Heike Schütze, 2017. Phylogeny of the Infectious Hematopoietic Necrosis Virus in European Aquaculture. PLoS One 12, 9. - ISSN 1932-6203.

Haenen, O., L. Bigarré, T. Ito, J.-C. Avarre, N. Vendramin, 2017. Workshop Neglected viral diseases of freshwater fish farming. EAFP Bulletin 38, 3: 105-115.

Ito T, Kurita J, Haenen O, 2017. Importation of CyHV-2 infected goldfish into the Netherlands. Dis. Aquat. Org. 126: 51–62.

Saucedo B, Hughes J, van Beurden SJ, Suárez NM, Haenen OLM, Voorbergen-Laarman M, Gröne A, Kik MJL. 2017. Complete genome sequence of Frog virus 3, isolated from a strawberry poison frog (Oophaga pumilio) imported from Nicaragua into the Netherlands. Genome Announc 5:e00863-17.

Way K., O. Haenen, D. Stone, M. Adamek, S.M. Bergmann, L. Bigarré, N. Diserens, M. El-Matbouli, M.C. Gjessing, V. Jung-Schroers, E. Leguay, M. Matras, N.J. Olesen, V. Panzarin, V. Piačková, A. Toffan, N. Vendramin, T. Veselý, T. Waltzek, 2017. The emergence of carp edema virus (CEV) and its significance to European common carp and koi, Cyprinus carpio. Dis.Aquat.Org. 126: 155–166.


Michael Cieslak, Susie S. Mikkelsen, Helle F. Skall, Marine Baud, Nicolas Diserens, Marc Y. Engelsma, Olga L. M. Haenen, Shirin Mousakhani, Valentina Panzarin, Thomas Wahli, Niels J. Olesen, Heike Schütze. 2016. Phylogeny of the viral hemorrhagic septicemia virus in European aquaculture. PLoS One 11: e0164475. doi:10.1371/journal.pone.0164475. WOT-01-002-004.02

Haenen O.L.M., H. Schuetze,  M. Cieslak, S. Oldenburg, M.A.H. Spierenburg, I. Roozenburg-Hengst, M. Voorbergen-Laarman, M.Y. Engelsma  and N.J. Olesen, 2016. First evidence of Infectious Hematopoietic Necrosis Virus (IHNV) in the Netherlands. J. Fish Dis. 39: 971-979. Doi 10.1111/jfd.12434. WOT-01-002-004.02

Gittenberger A, Voorbergen-Laarman M, Engelsma MY. 2016. Ostreid herpesvirus OsHV-1 μVar in Pacific oysters Crassostrea gigas (Thunberg 1793) of the Wadden Sea, a UNESCO world heritage site. J. Fish. Dis. 39: 105-109. WOT-01-002-004.03

van Beurden, S.J., Voorbergen-Laarman, M.A., Roozenburg, I., van Tellingen, J., Haenen, O.L.M., Engelsma, M.Y. 2016. Development and validation of a real-time PCR assay for the detection of anguillid herpesvirus 1. J. Fish Dis. 39: 95-104. WOT-01-002-004.02

Publications 2010 - 2015


Engelsma MY, Culloty SC, Lynch SA, Arzul I, Carnegie RB. 2014. Bonamia parasites: a rapidly changing perspective on a genus of important mollusc pathogens. Dis. Aquat. Org. 110: 5-23.

Carnegie, R.B., Engelsma, M.Y. 2014. Microcell parasites of molluscs: introduction to DAO Special 7.Dis. Aquat. Org. 110: 1-4.

Hine PM, Carnegie RB, Kroeck MA, Villalba A, Engelsma MY, Burreson EM. 2014. Ultrastructural comparison of Bonamia spp. (Haplosporidia) infecting ostreid oysters.Dis. Aquat. Org. 110: 55-63.

Tilmans, M., Mrugala, A., Svoboda, J., Engelsma, M. Y., Petie, M., Soes, D. M., Nutbeam-Tuffs, S., Oidtmann, B.. Roessink, I., Petrusek, A. 2014. Survey of the crayfish plague pathogen presence in the Netherlands reveals a new Aphanomyces astaci carrier. J. Invertebr. Pathol. 120: 74-79.

Haenen OLM, van Zanten E, Jansen R, Roozenburg I, Engelsma MY, Dijkstra A, Boers SA, Voorbergen-Laarman M, and Möller AVM. 2014. Vibrio vulnificus outbreaks in Dutch eel farms since 1996, strain diversity and impact. Dis. Aquat. Org. 108: 201-209. WOT-01-002-004.02

Marc Y. Engelsma, Keith Way, Melanie J. Dodge, Michal Voorbergen-Laarman, Valentina Panzarin, Miriam Abbadi, Mansour El-Matbouli, Helle Frank Skall, Søren Kahns, David  M Stone, 2014. Detection of novel strains of Cyprinid herpesvirus closely related to koi herpesvirus. Dis.Aquat.Org. 107: 113-120. WOT-01-002-004.02


Haenen, O.L.M., J.J. Evans, and F. Berthe, 2013. Bacterial infections from aquatic species: Contact zoonotic potential and prevention. Rev. sci. Epiz. 32 (2): 497-507.

Noèlia Carrasco, Ineke Roozenburg, MichalVoorbergen-Laarman, Naoki Itoh, Marc Y. Engelsma. 2013. Development of a real time PCR for detection of the oyster pathogen Nocardia crassostrea based on its homogeneous16S-23S rRNA intergenic spacer region. J. Invertebr. Pathol. 114:120-127.Project BAS nr: WOT-01-002-004.03.

Van Beurden, S.J., Peeters, B.P.H., Rottier, P.J.M.,Davison, A.J., Engelsma, M.Y. 2013. Genome-wide gene expressionanalysis of anguillid herpesvirus 1. BMC Genom. 14: 83

Lynch, S. A., Villalba, A., Abollo, E., Engelsma, M.,Stokes, N. Culloty, S. C. 2013. The occurrence of haplosporidian parasites, Haplosporidiumnelsoni and Haplosporidium sp., in oysters in Ireland. J. Invert.Pathol. 112: 208-212.


Steven van Beurden, Derek Gatherer, Karen Kerr, JulieGalbraith, Pawel Herzyk, Ben Peeters, Peter J. Rottier, Marc Engelsma, andAndrew Davison. 2012.Anguillid herpesvirus 1 transcriptome. J. Virol. 86: 10150-10161.

Carrasco,N., Villalba, A., Andree, K.B., Engelsma, M.Y., Lacuesta, B., Ramilo, A.,Gairin, I., Furones, M.D. 2012. Boanamia exitiosa (Haplosporidia) observedinfecting the European flat oyster Ostrea edulis cultured on the Spanish Mediterranean coast. J. Invert. Pathol. 110: 307-313.

Galinier,R., van Beurden, S., Amilhat, E., Castric, J., Schoehn, G., Verneau, O., Fazio,G., Allienne, J-F., Engelsma, M., Sasal, P., Faliex, E. 2012. Complete genomesequence and toxonomic position of Eel virus European X (EVEX), a rhabdovirus ofEuropean eel. Virus Res. 166: 1-12.

Van Beurden, S.J., Engelsma, M.Y. 2012. Herpesviruses of fish, amphibians andinvertebrates. In: Herpesviridae, pp 217-242. Intech Open Acces Publishers,december Croatia. ISBN978-953-51-0186-4. Ed. G.D. Magel. Project BAS nrs WOT-01-001-003 enWOT-01-002-004.02


Steven J. van Beurden, Maria Forlenza, Adrie H. Westphal,,Geert F. Wiegertjes, Olga L.M. Haenen, Marc Y. Engelsma. 2011. : The alloherpesviral counterparts ofinterleukin 10 in European eel and common carp. Fish Shellfish Immun. 31:1211-1217. Project BAS nrs WOT-01-001-003 en WOT-01-002-004.02

Steven J van Beurden, Baptiste Leroy, Ruddy Wattiez, Olga LMHaenen, Sjef A Boeren, Jacques JM Vervoort, Ben PH Peeters, Peter JM Rottier,Marc Y Engelsma,  Alain FVanderplasschen. 2011.Identification and localization of the structural proteins of anguillidherpesvirus 1. Vet. Res. 42: 105. Project BAS nrs WOT-01-001-003 enWOT-01-002-004.02

Saleh, M.,Soliman, H., Haenen, O., El-Matbouli, M., 2011. Antibody coatedgold-nanoparticles immunoassay for direct detection of Aeromonas salmonicida infish tissues. J. Fish Dis. 34: 845-852.

Jean-ChristopheAvarre, Jean-Paul Madeira, Ayi Santika, Zakki Zainunb, Marine Baud, JoëlleCabon, Domenico Caruso, Jeannette Castric, Laurent Bigarré, Marc Engelsma,Maskur Maskur. 2011. Investigation of Cyprinid herpesvirus-3 genetic diversityby a multi-locus variable number of tandem repeats analysis. J. Virol.Meth. 173: 320-327. Project BAS nr: WOT-01-002-004.02.

Steven J. van Beurden, Michal A. Voorbergen-Laarman, InekeRoozenburg, Annette S. Boerlage, Olga L.M. Haenen, Marc Y. Engelsma. 2011. Development and validation of a two-step real-time RT-PCR for  thedetection of eel virus European X in European eel, Anguilla anguilla. J. Virol.Meth. 171: 352-359


Engelsma,M.Y., Kerkhoff, S., Roozenburg, I. Haenen, O.L.M., van Gool, A., Sistermans, W,Wijnhoven, S. Hummel, H. Epidemiology of Bonamia ostreae infecting European flat oysters (Ostrea edulis) from Lake Grevelingen, The Netherlands. Mar.Ecol. Prog. Ser. 409: 131-142.

Beurden S.J. van, Bossers A., Voorbergen-Laarman M.H.,Haenen O.L., Peters S., Abma-Henkens M.H., Peeters B.P., Rottier P.J., EngelsmaM.Y., 2010. Complete genome sequence and taxonomic position of anguillidherpesvirus 1. J Gen Virol. 2010 Apr;91(Pt 4):880-7.

Publications before 2010