This section is made to bring you some general information about the molluscs diseases.

1 - Molluscs diseases

Click on the images at the bottom of the page to have access to the full description of each pathogen and recommended diagnostic techniques. Most of the information contained in these pages was prepared by the EURL for the European project PANDA (Permanent Advisory Network for Diseases in Aquaculture).

Notifiable diseases to the OIE and/or to the European Commission (EC)
  • Bonamia ostreae (OIE / EC - endemic)
  • Bonamia exitiosa (OIE / EC - endemic*)
  • Marteilia refringens (OIE / EC - endemic)
  • Perkinsus marinus (OIE / EC - exotic)
  • Perkinsus olseni (OIE - endemic)
  • Xenohaliotis californiensis (OIE - endemic)
  • Mikrocytos mackini ( EC - exotic)
  • Abalone herpes-like virus AbHV (OIE - exotic)

(*) Bonamia exitiosa is classified as exotic in EU directive 2006/88, however, the parasite has been discovered in 2007 for the first time in Europe in flat oysters (Ostrea edulis) from Galicia (Spain). Since then, B. exitiosa has also been observed in several other European countries. 

Diseases of concern in Europe
  • Herpes virus OsHV-1
  • Vibrio bacteria 
  • Nocardia crassostreae
  • Marteilioides chungmuensis (exotic)

2 - General topics


You can access to a 1h webinar on marine mollusc diseases, presented by Dr. Isabelle Arzul in October 2020,  on the website of the World Aquatic Veterinary Medical Association (WAVMA): https://www.wavma.org/Webinars/b-1037-main-marine-mollusc-diseases. Other WAVMA  webinars are also  available on https://www.wavma.org/WebCEPD

Fact sheets on mollusc pathogens

You can download below several fact sheets on the main mollusc pathogens (Sheet n°1 to 8; OsHV-1 virus, Vibrio aestuarianus, Splendidus clade, Bonamia ostreae, Bonamia exitiosa,  Marteilia refringens, Mikrocytos mackini, Perkinus marinus) as well as on general information about micro-organisms and diagnostic methods (sheet A and B). These fact sheets are addressed to the general public and can be useful for training.

Download fact sheets n°1 to 8 on mollusc pathogens (pdf, 2017)

Download general fact sheet A on micro-organisms and fact sheet B on diagnostic methods (pdf, 2017)

Other documents
  • Short list of some of the most important pathogens and parasites of molluscs observed in the world (last up-date: 2008)
application/pdf Pathogens list
  • Powerpoint presentation on Marteilia refringens 

application/pdf Marteiliosis

  • Powerpoint presentation on Bonamia ostreae

application/pdf Bonamiosis

  • Anatomy of the oyster Crassostrea gigas

  • Anatomy of the cockle Acanthocardia tuberculata

 If you cannot open the Pdf files, click here to get Adobe Reader      

We also propose some standard operating procedures that can be used by histopathology laboratories building their quality management documentation system. You will find this documents on the page "SOPs"