Characteristics of infectious dropsy from an epizootic of cultured common carp (Cyprinus carpio L.)‎ with special investigation to swim-bladder lesions

Abstract EN

Infectious dropsy was recorded in 2015 among a group of Common carp (Cyprinus carpio L.) collected from several private fish farms at Sharkiya Province, Egypt.

Out of 200 clinical cases, 180 (90%) Common carp were found infected by bacteria.

The bacterial isolates revealed a mixed infection with Aeromonas hydrophila and Pseudomonas fluorescens.

The affected fish presented typical signs of infectious dropsy including hemorrhagic lesions in the skin, fin, tail, and eye.

Loss of scale with sluggish movement and imbalance were also observed in some fish.

Grossly, the diseased fish exhibited symptoms of septicemia such as congestion and hemorrhages in the skin and internal organs with distended anus, exophthalmia and ascites.

The antimicrobial resistance of the isolated bacteria was higher with Oxytetracycline (OX) and lower with Ciprofloxacin (CIP).

The other used antimicrobials showed variable resistance to both bacterial isolates.

Experimental infection was done on 100 Common carp and revealed same clinical findings and gross lesions of the field study with 76 % mortality.

Microscopically, the internal organs showed degenerative changes, focal necrosis, circulatory disturbances and inflammatory reactions.

The swim bladder mucosa of infected carp exhibited necrosis, epithelial sloughing with congestion and lymphocytic infiltration.

This study describes Infectious dropsy among cultured carp in Egypt and highlighted the importance of implementing preventive measures to control this infection.