Flexibacter columnaris was isolated from 13 cultured Oreochromis niloticus showing respiratory disorders. The isolates developed typical swarming rhizoid colonies on Cytophaga agar medium. Antibiotic sensitivity test revealed the susceptibility of F. columnaris isolated to oxytetracycline, chloramphenicol and erythromycin. A marked difference in the pathogenicity of seven tested isolates was observed: two were highly virulent, one was moderately virulent and four were avirulent. No experimental infection could be induced with the highly virulent isolates except after injuring one of the natural barriers of the fish body. The severity of the disease and the increased median death time shortened by keeping infected fishes with injured gills in water containing ammonia. In naturally infected O. niloticus, the disease became chronic as indicated by the presence of excessive proliferative and necrotic changes. On the other hand, severe dilatation of branchial blood vessel, oedema and round cell infiltration proved that, the disease among experimentally infected tilapias was acute.

About 400 m3/d of raw sewage from the City of Suez were diverted and treated by two parallel pond systems. The first treatment system was conventional Waste Stabilization Ponds which included anaerobic, facultative, and maturation compartments for a total residence time of 21 days. The second system included a series of four plankton ponds with a total residence time in the order of 26 days. The effluent from these inexpensive, but yet effective treatment technologies, was found to conform to the World Health Organization (WHO) standards for unrestricted agricultural and aquacultural applications. The treated waste effluent was successfully used to grow two types of local fish, i.e.Oreochromis niloticus and Mugil sehli. Fish production, without supplemental feeding or pond aeration, reached 5-7 metric tons/hectare/year. Furthermore, the fish were found to be free from human parasites and safe for human consumption. The nutrient rich effluent from the fish pond was further used to grow trees and cultivate certain types of crops, i.e. barley, maize, beets and ornamental plants. This study clearly demonstrates the effectiveness and benefits of waste stabilization ponds systems for low cost treatment of domestic waste and the combined reuse in aquaculture and agriculture applications. In addition, the unique treatment/reuse facilities constructed at Suez will continue to function as an experimental station and serve scientists and engineers to study and to plan applications in Egypt and the region.

This is the first report of lipoma in the European eel Angudla an udla. In a single eel that was obtained from a polyculture fish farm in northern Egypt, a yellowish swelfing (10 mm in diameter) was observed near the ti of the lower lip. The tumor was composed of mature Iipocytes that occasionally fused into an unlinelcystic space. Resume Une Lipome Pseudocystique chez l'anguille europeine (Anguilla anguilkz)C'est le premier rapport d'un lipome chez I'anguille europetne Anguilla anguilla. Dans une seule anguille qui fut obtenut dam une ferme polyculture de poisson en kgypte du nord, une masse jeune (10 mm de diametre) fut o b s e d e pres de l'extrtmite de la levre inftrieure. La tumuear A t composte de lipocite mature qui occasionellement out fait fusion avec un espace cysrique a c e h e .

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