A novel bacterial disease of the European shore crab, Carcinus maenas - Molecular pathology and epidemiology

Fiona Eddy, Adam Powell, Simon Gregory, Linda M. Nunan, Donald V. Lightner, Paul J. Dyson, Andrew F. Rowley, Robin J. Shields

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


Several rickettsia-like diseases have been reported in arthropods (insects and crustaceans), some of which result in significant losses of economically important species such as shrimp and crabs. This study reports on the molecular pathology of a recently emerged disease of the European shore crab, Carcinus maenas, termed milky disease - named as a result of the unusual milky appearance of the haemolymph (blood). This disease was more prevalent (>26 %) during summer months when the water temperature in a pilot crab farm was approximately 19 °C. The putative causative agent of the disease was a Gram-negative bacterium that could not be cultured on a range of agar-based growth media. Diseased crabs showed significant reductions in free blood cell numbers and total serum protein. Such animals also displayed raised levels of glucose and ammonium in blood. Ultrastructural and in situ hybridization studies revealed that the causative agent associated with milky disease multiplied in the fixed phagocytes of the hepatopancreas (digestive gland), ultimately to be released into the haemolymph, where the circulating blood cells showed little response to the presence of these agents. Attempts to induce the infection by short-term temperature stress failed, as did transmission experiments where healthy crabs were fed infected tissues from milky disease affected individuals. Sequence analysis of the 16S rRNA gene from the milky disease bacteria indicated that they are a previously undescribed species of α-proteobacteria with little phylogenetic similarity to members of the order Rickettsiales.

Original languageEnglish (US)
Pages (from-to)2839-2849
Number of pages11
Issue number9
StatePublished - Sep 2007
Externally publishedYes

ASJC Scopus subject areas

  • Microbiology


Dive into the research topics of 'A novel bacterial disease of the European shore crab, Carcinus maenas - Molecular pathology and epidemiology'. Together they form a unique fingerprint.

Cite this