Bacterial disease in marine bivalves, a review of recent studies: Trends and evolution

Abstract

The main microbial diseases affecting marine cultured bivalves have been revised on the basis of the etiologic agents, pathogenesis and pathogenicity. Several recent bivalve-interaction models have been studied, including Pecten larvae-Vibrio pectinicida, brown ring disease, juvenile oyster disease, Pacific oyster nocardiosis and summer mortalities of oysters. In addition, the taxonomy and phylogeny of new potential bivalve pathogens and their virulence factors have been established. Facing the difficulty of identifying bacterial strains associated with molluscan diseases (mainly vibriosis), polyphasic approaches have been developed to correlate the phenotype and genotype of potential pathogens. By evaluating likely virulence mechanisms, developing biotests to screen virulent strains and characterising the genes implicated in pathogenesis, a new generation of diagnostic tools, based on potential virulence, will be developed. Acquisition of pertinent diagnostic tools will be of major benefit in disease management, health surveillance and monitoring will contribute to maintaining sustainable aquaculture industries. Résumé -Les maladies bactériennes chez les bivalves marins, synthèse des travaux récents : tendances et évolution.Les principales maladies bactériennes affectant les bivalves marins aquacoles ont été synthétisées en se basant sur trois aspects, la démarche étiologique, l'étude de la pathogenèse et le mode d'action du pathogène. Plusieurs modèles d'interactions chez les bivalves ont été récemment étudiés, tels que Pecten-Vibrio pectinicida, la maladie de l'anneau brun chez les palourdes japonaises, la maladie des juvéniles d'huîtres américaines, la Nocardiose et les mortalités estivales chez les huîtres du pacifique. Ainsi, la taxonomie et la phylogénie de ces nouveaux pathogènes ont pu être établis et des facteurs de virulence identifiés. Face à la difficulté d'identification des souches bactériennes associées aux maladies des mollusques (principalement des vibrioses), une approche polyphasique a été développée afin de corréler le phénotype et le génotype des pathogènes potentiels. Des bio-tests utilisant toute une nouvelle génération d'outils sont en cours de développement afin de cribler les souches virulentes, d'évaluer les mécanismes potentiels de virulence et de caractériser les gènes impliqués dans la pathogenèse. L'acquisition de ces outils diagnostics permettra de mieux contrôler l'état sanitaire des bivalves aquacoles et contribuera ainsi à maintenir toute une filière industrielle conchylicole performante. 478C. Paillard et al.: Aquat. Living Resour. 17, 477-498 (2004)

Long-term effects of ocean warming on the prokaryotic community: evidence from the vibrios

“…Other vibrios capable of causing disease in humans include V. parahaemolyticus, the agent of seafood-associated gastroenteritis worldwide (Levin, 2006), and V. vulnificus, the cause of septicaemia and serious wound infections, as well as the leading cause of shellfish-associated deaths in the United States (Shapiro et al, 1998). Several Vibrio species are also pathogenic towards marine animals, including molluscs (Paillard et al, 2004), corals and fish (Austin, 2005), with major economic and environmental impacts.…”

“…Similarly, climate anomalies have been implicated in the expansion of the geographical and seasonal range of seafood-borne illnesses caused by V. parahaemolyticus and V. vulnificus (MartinezUrtaza et al, 2010). Evidence has also been gathered linking Vibrio infections to the increasing mass mortality of marine life in the coastal marine environment (Paillard et al, 2004;Vezzulli et al, 2010).…”

Responses of Mytilus galloprovincialis to bacterial challenges by metabolomics and proteomics

“…The outbreaks of bacterial diseases can cause massive moralities of marine aquaculture bivalve mollusks and lead to significant losses of production and economic values [1]. Therefore studies on the biological responses and their mechanisms are necessary, which can probably provide useful information for disease control strategies.…”

Characterization of abalone Haliotis tuberculata–Vibrio harveyi interactions in gill primary cultures

“…Diseases affecting cultured molluscs are caused by protozoans, fungi, bacteria or viruses, leading to severe damages at any stage of production from larvae to adults (Paillard et al 2004). Bacterial diseases like Brown Ring disease (BRD) and Juvenile oyster disease (JOD) caused high mortalities in hatcheries and were commonly described in larval and adult bivalves (Lauckner 1983;Paillard et al 2004;Paillard and Maes 1989;Boettcher et al 1999Boettcher et al , 2000.…”

“…Bacterial diseases like Brown Ring disease (BRD) and Juvenile oyster disease (JOD) caused high mortalities in hatcheries and were commonly described in larval and adult bivalves (Lauckner 1983;Paillard et al 2004;Paillard and Maes 1989;Boettcher et al 1999Boettcher et al , 2000. Summer mortalities caused by Vibrio bacterial strains have recently been described in various cultured mollusc as the Pacific oyster Crassostrea gigas (Le Roux et al 2002;Saulnier et al 2010) and the European abalone Haliotis tuberculata .…”