Pathology and significance of fatal inflammatory bacteraemia in the Pacific oyster, Crassostrea gigas Thünberg

• Published in: Journal of Fish Diseases
• Main Authors: ELSTON, R. A., BEATTIE, J. H., FRIEDMAN, C., HEDRICK, R., KENT, M. L.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1987
• Subjects: Crassostrea gigas; Pacific oyster
• Online Access: http://dx.doi.org/10.1111/j.1365-2761.1987.tb00727.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-2761.1987.tb00727.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2761.1987.tb00727.x

Abstract. Inflammatory bacteraemia was found in 27–31% of Pacific oysters in two bays over 2 years in Puget Sound, Washington, USA. Mantle discolouration and raised yellow to green nodules are associated with the disease in 52% and 85% of the observed cases, respectively. The disease is caused by systemically distributed, branching. Gram‐positive, acid‐fast bacteria suggestive of an actinomycete. Clusters of the bacteria elicit a marked inflammatory response. Glycogenic degeneration of host vesicular cells occurs in the advanced infections and results in the formation of the characteristic nodules comprised of lipid filled cells. The disease is, thus, significant to the health of individual oysters and also appears to be an important factor in the historically observed phenomenon of summer mortality in certain areas of Puget Sound.