Contribution to motile aeromonas septicemia in some cultured and wild freshwater fishes

This study was carried out to gain more information about the prevalence of motile aeromonas septicemia [MAS] in both cultured and wild Nile tilapia and karmout catfish. The clinical signs and PM lesions were pronounced in cultured fish. Aeromonas hydrophila was recovered from all MAS affected fish. The incidence of MAS in cultured and wild Nile tilapia was 10% and 2.5%, respectively, while it was 18.75% and 6.25% in cultured and wild karmout catfish, respectively. Reisolation of A. hydrophila was recovered after experimental infection of karmout catfish by i.p. and s.s. revealing the same clinical signs and lesions. The histopathological pictures produced by such microorganisms along the course of experimental infection were discussed. Besides, A. hydrophila isolated from cultured fish were more resistant to antibiotic sensitivity test than those isolated from wild fish

Studies on saprolegniasis among cultured mullet fingerlings

In this work, two mullet species, Mugil cephalus and Mugil capito fingerlings naturally infected with saprolegnia were examined and controlled. Saprolegnia parasitica was isolated from the characteristic brownish cotton wool like lesions covering the body surface and penetrating into some internal organs. The infection trials with isolated Saprolegnia parasitica in apparently healthy mullet spp. via skin scarification revealed the same clinical signs and postmortem lesions. For controlling this serious disease, proper management and treatment by bathing the diseased mullet fingerlings in sodium chloride solution were used

Some studies on emphysematous putrefactive disease among catfish clarias lazera in lake Manzala

Lake Manzala, the most important and largest brackish water lake in Egypt, suffers from water pollution induced by agricultural drainage, industrial wastes, sewage, and invasion of Mediterranean Sea water. Besides, high temperature plays a great role for appearance of some temperature dependent bacterial disease such as emphysematous putrefactive disease [EPD] or what is called Edwardsiella septicaemia. Catfish [Clarias lazera] showing the characteristic pathognomonic signs and lesions of EPD were subjected to organoleptic examination, clinical, postmortem and bacteriological examination. The bacterial isolates [11%] were morphologically and biochemically related to Edwardsiella tarda. Reisolation of E. tarda was recovered after the experimental infection of the healthy Clarias lazera by intraperitoneal and intramuscular routes revealing the same clinical signs and lesions. After using drug sensitivity tests, E. tarda was highly sensitive to oxytetracycline, chloramphenicol and kanamycin. The organoleptic examination and measurement of pH revealed the unpleasant and nauseating characters of catfish Clarias lazera infected with EPD either naturally or experimentally which was absolutely unfit for human consumption

Bacterial disturbances implicated in naturally and experimentally infected fresh water fishes

Motile aeromonad organisms have been isolated in high incidence among examined fish species. A. hydrophila was recovered in an incidence of 6.4%, 4.8% and 6.4% from tilapia nilotica, clarias lazera and mugil species respectively. Other aeromonads were A. punctata, A. salmonicida and A. anaerogenes in an incidence extended between 0.00% up to 4.0%. A. salmonicida was the first to be recovered from fresh water fish. Ps. fluorescens, Citr. diversus, Citr. Freundii, capital later U enterocolitica, S. marcescens and Enterbacter species were the most bacterial pathogens isolated from different kinds of fish. Experimental studies on the pathogenicity of A. hydrophila, Ps. fluorescens and A. punctata in clarias species were discussed in details