Nocardia sp. (Bacterial Disease) of Crayfish


Category 3 (Host Not in Canada)

Common, generally accepted names of the organism or disease agent

Nocardiosis, Bacterial disease.

Scientific name or taxonomic affiliation

Nocardia sp.

Geographic distribution

United Kingdom.

Host species

Austropotamobius pallipes.

Impact on the host

Melanized nodules (2-3 mm) throughout tail musculature beneath a fracture in the exoskeleton. Abnormal behaviour.

Diagnostic techniques

Gross Observations: Examine musculature for nodules.

Histology: Transverse section reveals branched, Gram positive, acid fast Nocardia bacteria that also stain darkly with Grocott methenamine silver but are not evident with haematoxylin and eosin stain.

Methods of control

No known methods of treatment or control.


Alderman, D.J., Feist, S.W. and Polglase, J.L. 1986. Possible nocardiosis of crayfish Austropotamobius pallipes. Journal of Fish Diseases 9: 345-347.

Alderman, D.J. and J.L. Polglase. 1988. Pathogens, parasites and commensals. In: D.M. Holdrich and R.S. Lowery (eds.). Freshwater Crayfish ­ Biology, Management and Exploitation. Timber Press, OR., p. 168-171.

Citation Information

Bower, S.M., McGladdery, S.E., Price, I.M. (1994): Synopsis of Infectious Diseases and Parasites of Commercially Exploited Shellfish: Nocardia sp. (Bacterial Disease) of Crayfish.

Date last revised: Fall 1994
Comments to Susan Bower

Date modified: