Important pathogens and parasites of molluscs Genetic and Pathology Laboratory

Pathogen or parasite Host species Host impact Geographical distribution Infection period Diagnostic Cycle Species Group

Denmark, Netherland, Incubation period : 3-4 month edulis, O. Parasite of haemocytes Throughout the year France, Ireland, Great Britain in infected area. Histology, Protozoan Conchaphila, O. Angasi, O. (=>all the tissues can be invaded). (with a peak in Direct (except Scotland), Italy, tissue imprint, PCR, ISH, Puelchana, Tiostrea chilensis Oyster mortality September) Spain and USA electron microscopy

Parasite of oyster haemocytes Throughout the year Histology, tissue imprint, , Ostrea Australia, New Zéland, Bonamia exitiosa Protozoan (=>all the tissues can be invaded). (with a peak during PCR, ISH, electron Unknown chilensis, Ostrea edulis Tasmania, Spain (in 2007) Oyster mortality Australian autumn) microscopy

Parasites present in connective Histology, tissue imprint, Haplosporidium tissue (mantle, gonads, digestive Protozoan virginica USA, Canada Spring-summer PCR, ISH, electron Unknown costale gland) but not in digestive tubule microscopy epithelia. Mortality in May-June

Parasites present in gills, connective tissue. Sporulation only Histology, tissue imprint, Unknown but Haplosporidium Crassostrea virginica, USA, Canada, Japan, Korea, Summer (May until Protozoan in the epithelium of digestive gland smear, PCR, HIS, electron intermediate host is nelsoni Crassostrea gigas France October) in C. virginica, Mortalities in C. microscopy suspected virginica. No mortality in C. gigas

Parasite present in connective Haplosporidium Protozoan O. edulis, O. angasi tissue. Sometimes, mortality can France, Netherland, Spain Histology, tissue imprint Unknown armoricanum be observed

Ostrea edulis , Tiostrea Spring-summer Histology, tissue imprint, ISH, Intermediate host: Extracellular parasite of the refringens Protozoan chilensis, O. angasi , Mytilus France, Portugal, Spain (Temperature PCR, PCR-RFLP, electron copepod (Paracartia digestive gland. Oyster mortalities edulis > 17°C) microscopy grani )

Saccostrea glomerata, Histology, tissue imprint, Parasite of palps, gills, the Australian summer-- Marteilia sydneyi Protozoan Striostrea mytiloides, Australia PCR, ISH, electron Unknown digestive gland. Oyster mortalities autumn Saccostrea forskali microscopy

Parasite of the digestive gland. Mytilus edulis, M. France, Italy, Spain, Portugal, Histology, tissue imprint, ISH, Marteilia maurini Protozoan Sometimes, mortality can be Unknown galloprovincialis Greece, Croatia PCR, electron microscopy observed

From winter to late Green pustules on the mantle, Crassostrea gigas, C. spring. Incubation Histology, tissue imprint, palps. Intracellular parasites Microcytos mackini Protozoan virginica, Ostrea edulis, Canadian west coast, USA period: 3-4 month in PCR, ISH, electron Direct present in connective tissue cells. Ostrea conchaphila infected area (Temp. microscopy Oyster mortality <10°C)

Abscess in the gonad, mantle, gills Parasite of oyster haemocytes Microcytos roughleyi Protozoan Australia Australian winter Histology, PCR Unknown (=>all the tissues can be invaded). Oyster mortality

Parasite present in the connective Summer Histology, thioglycolate Crassostrea virginica, C. marinus Protozoan tissue and epithelial cells. USA (Temperature culture, PCR, electron Unknown gigas, C. ariakensis C. virginica mortalities > 20°C) microscopy

Nodules in the mantle, muscle, Haliotis ruber, H. laevigata, gills, digestive gland. Parasite H. cyclobates, H. scalaris, Australia, New Zealand, Histology, thioglycolate present in connective tissue and Perkinsus olseni Protozoan Ruditapes decussatus, R. Korea, China, Japan, France, culture, PCR, electron Direct epithelial cells. mortalities philippinarum, R. pullastra, Portugal, Spain, Italy microscopy in Australia and mortalities Venerupis aurea… in Portugal, Korea, China, Japan

Haliotis cracherodii, Candidatus Atrophy of foot muscle. Bacteria in Gross observation, histology, Bacteria H. rufescens , H. corrugata , Xenohaliothis the epithelium of intestinal tract. USA, Iceland, Spain, Ireland Summer PCR, ISH, electron Unknown (Rickettsia) H. fulgens , H. discus hannai, californiensis Abalone mortalities microscopy H. tuberculata, H. midae

Iridovirus (different Crassostrea angulata, C. angulata mortalities. C. gigas Spain, France, Portugal, Histology, electron types of iridovirus Virus Direct C. gigas larvae mortalities in USA Great Britain, USA microscopy exist) Pathogen or parasite Host species Host impact Geographical distribution Infection period Diagnostic Cycle Species Group Crassostrea gigas, C. virginica, Ostrea edulis, O. angasi, Tiostrea chilensis, C. Virus present in the connective Summer , USA, Australia, New PCR, ISH, electron Herpesvirus Virus angulata, Saccostrea tissues Sometimes larvae and Direct Zealand (Temperature microscopy, histology commercialis, Ruditapes juvenile mortalities > 19°C) decussatus, R. philippinarum,

Copepod Marine bivalves (oyster, Parasites present in the gut Mytilicola sp. USA, Japan, Europe Histology, gross observation Direct (metazoan) , …) lumen. Minimal impact on host

Copepod Marine bivalves (oyster, Parasites present in the gills. Myicola sp. Ubiquitous Histology, squash preparation Unknown (metazoan) mussel, clam…) Minimal impact on host

Rickettsia sp. Bacteria present in the digestive Marine bivalves (oyster, Histology, electron Chlamydia sp. Bacteria gland, gills, kidney, epithelial cells. Ubiquitous Unknown mussel, clam…) microscopy Mycoplasma sp. Minimal impact on

Parasites present in the digestive Marine molluscs (oyster, Histology, squash Pseudoklossia sp., gland, gills, kidney, mantle Protozoan mussel, clam, , Ubiquitous preparation, electron Unknown Margolisiella sp. epithelial cells, connective tissue abalone…) microscopy Minimal impact on shellfish

Urastoma sp. is present in the gills Marine molluscs (oyster, Urastoma sp. Plathelminthe Paravortex sp. is present in the Histology, whole mount, mussel, clam, scallop, Probably ubiquitous Unknown Paravortex sp. (metazoan) digestive gland. Few impact on gross observation abalone…) molluscs

Labratrema sp. Cycle with Meiogymnophalus Marine molluscs (oyster, Parasites present in connective intermediate hosts Plathelminthe sp. Himasthla sp. mussel, clam, scallop, tissues, gills, mantle. Variable Probably ubiquitous Histology, squash preparation Molluscs are often (metazoan) Prosorhynchus sp. abalone…) impact on molluscs an intermediate host Renicola sp. etc… for the parasite

Nodule in the mantle (heavy Marteilioïdes Crassostrea gigas, C. infection) Parasite present in the Histology, smear, ISH, Protozoan Korea, Japan, Australia Unknown chungmuensis echinata (only the females) ovocyte. Impact on oyster Summer electron microscopy reproduction

Marteilioïdes Gross observation, histology, Protozoan Saccostrea glomerata Parasite of gill epithelial cells Australia Unknown branchialis electron microscopy

Crassostrea virginica, Crassostrea gigas, Saccostrea glomerata, Family of Crassostrea rhizophorae, Virus present in connective USA, Korea, Japan, France, Histology, electron Virus Direct Papovaviridae Ostrea edulis, Ostrea tissues, gametocytes Australia microscopy concaphila, maxima, Mya arenaria, Macoma baltica.

Vibrio tapeti,s Vibrio Marine molluscs (oyster, Histology, culture, PCR, slide harveyi, Vibrio Bacteria in all tissues Variable Bacteria mussel, clam, scallop, Ubiquitous agglutination test, DNA Direct splendidus, Vibrio impact on molluscs abalone…) sequencing pectinicida etc…

Marine molluscs (oyster, Polychaetes Parasite present in mollusc shell. Gross observation, wet Polydora sp. mussel, clam, scallop, Ubiquitous Direct (Metazoan) Variable impact on molluscs Spring/summer mount abalone…)

Ostrea edulis, Crassostrea Summer Ostracoblabe Gross observation, histology, Fungus gigas, , Shell abnormalities Europe, India, Canada Unknown implexa (temperature >22° culture, squash preparation Crassostrea angulata C)

Cycle with intermediate hosts. Marine molluscs (oyster, Parasite present in connective Histology, electron Molluscs are Nematopsis sp. Protozoan mussel, clam, scallop, tissue, gills. Few impact on Ubiquitous microscopy generally abalone…) molluscs intermediate hosts for the parasite

In red: Pathogens listed by the European Commission In blue: Species found in Europe Document updated in August 2008