Abstract

In necropsies performed on dead or moribund crayfish, where the crayfish plague fungus Aphanomyces astaci was not diagnosed, the causes of death were investigated. Bacteriological and histological studies were performed. Parasites were present in some animals at low infestation levels which were not considered to be responsible for their deaths. Bacteriology was performed in 39 specimens. The crayfish species investigated were Astacus astacus (32 specimens), Austropotamobius torrentium (1), Cherax destructor (3), Pacifastacus leniusculus (1) and Orconectes limosus (2). Most Gram-negative bacteria were determined to species level, 21 different species being isolated. Gram-positive bacteria were only determined as being either cocci or rods. It was found that the bacteria most frequently isolated were Vibrionaceae (Aeromonas hydrophila/caviae, 21 isolates; Aeromonas sobria, 6), Enterobacteriaceae (Citrobacter freundii, 9; Hafnia alvei 1, 13), Pseudo-monaceae (Sphingomonas paucimobilis, 7; various Pseudomonas spp., 13) and Shewanella/Pseudomonas putrefaciens (16). Gram-positive cocci and Gram-positive rods were found in eight and nine cases respectively. Mould fungi were observed in three cases and yeasts in one case. Citrobacter freundii infections were associated with elevated mortalities.

Supplemental Documents

• There are no supplementary documents for this article

Cited By

Citations: