Rickettsia-like Organisms in the Cytoplasm of Gill Epithelial Cells of the Pacific Oyster Crassostrea gigas

Rickettsia-like organisms are reported only into the cytoplasm of gill epithelial cells of the oyster Crassostrea gigas (Mollusca, Bivalvia) from the French Atlantic coast. These rickettsia-like procaryotes are pleomorphic with a maximum length of 4 mu m. The internal elements are ribosome-like particles and DNA strands are distributed in some light areas. Only reduced cytopathological effects are visible in this infection, although the intensity of infection suggests that gill functions could be compromised. This is believed to be the first description of rickettsia-like organisms infecting gill epithelial cells of the Pacific oyster C. gigas.