Pathological investigation on crayfish (Procambarus clarkii, Girard 1852) from canals in Padana Plain.

Several populations of allochthonous crayfish Procambarus clarkii (Girard, 1852) were studied in order to observe the presence and effects of pathogenic organisms. A total of 178 animals were analysed over a 3 year period. The specimens were collected from the canals and the ditches of Rena Land Reclamation Consortium (Province of Bologna) during the summer seasons from 2001 to 2003. The study involved mycological, parasitological, bacteriological and histopathological investigations. At mycological examination, 95.51% of the samples were infected and Fusarium sp. was the most frequently isolated fungus (27.52%). During parasitological investigation, Epistylis spp. and Cothurnia spp. were frequently isolated from the gills and the cuticle of the exoskeleton. One commensal Nematode in the gills and four intestinal Nematodes whose determination is still under study were found. Bacteriological examination of crayfish which died during transport and in laboratory tanks led to the isolation of Citrobacter freundii and Pseudomonas sp. Histopathological investigation is described.