Amoebiasis of Cockles


Category 3 (Host Not in Canada)

Common, generally accepted names of the organism or disease agent

Amoebiasis of cockles.

Scientific name or taxonomic affiliation

Amoeba of unknown identity.

Geographic distribution

Estuarine region of Aveiro, Portugal.

Host species

Cerastoderma edule.

Impact on the host

Observed on the gills of gaping specimens of C. edule sampled for other investigations. Histopathology of haemocytic infiltration and the presence of necrotic cells associated with massive concentrations of the amoeba in the gill tissues were interpreted as a sign that this parasite was pathogenic to the cockles. The prevalence of infection was described as being infrequent.

Diagnostic techniques

Wet Mounts: Examine gill tissues microscopically for amoeboid protozoa (about 19 µm in diameter).

Histology: Isolated and massive concentrations of the amoeba (8 to 20 µm in diameter) occurred in the internal tissues of the gill filaments. The amoeba has a single spherical nucleus (5 µm in diameter) which contains a prominent nucleolus (3 µm in diameter).

Electron Microscopy: The nucleolus is composed of compact fibrillar and granular components. Several dense bodies occur at the periphery of the nucleus, on both sides and in close contact with the nuclear envelope.

Methods of control

No known methods of prevention or control.


Azevedo, C. 1997. Some observations on an amoeba, destructive agent of the gills of Cerastoderma edule (Mollusca, Bivalvia). Diseases of Aquatic Organisms 30: 223-225.

Citation Information

Bower, S.M. (2002): Synopsis of Infectious Diseases and Parasites of Commercially Exploited Shellfish: Amoebiasis of Cockles.

Date last revised: March 2002
Comments to Susan Bower

Date modified: