Abstract

Spontaneous and experimentally reproduced fungal infections of gills have been investigated in the crayfish Astacus leptodactylus and Austropotamobius pallipes. These diseases are caused by Fusarium oxysporum. The study of pathogenesis by means of histological and ultrastructural methods has shown that the penetration of the fungus depends on integumentary wounds, and that the pathogen triggers strong but weakly efficient defence reactions in the haemocoel. The development of the hyphae provokes a localized necrosis in the invaded area as well as generalized alterations of the gills. Biochemical analyses have revealed that the fungal attack is also at the origin of disturbances of physiology of the host, characterized essentially by a decrease of the osmotic pressure and of the concentration of Na+ and Cl- ions in the haemolymph. Such results have demonstrated that the infection caused by F. oxysporum is a complex syndrom, and have emphasized the importance of this fungus as a factor of regulation of crayfish populations.

Supplemental Documents

• There are no supplementary documents for this article

Cited By

Citations: