molecular and histopathological investigation of carp edema virus in fish farms mortality in khuzestan province

In recent years, the carp fish industry in khuzestan province has faced significant losses, especially in spring and summer. among the infectious pathogens, viruses are the most transformed and cause fatal diseases. the role of viral agents is much more important than other pathogens due to their incurable, speed of transmission, severity of pathogenicity and difficulty of diagnosis. carp edema virus is the cause of koi sleepiness disease, an emerging problem that is detrimental to cultured carp and ornamental koi carp. as the existence of infection with this virus is not investigated, the aim of this study is molecular detection of carp edema virus in khuzestan province and also histopathological study of accompanying lesions. for this purpose, 60 pieces of common carp from farms with losses and farms from khuzestan province that reported losses in the last few years were sampled during 2017 to 2022 by molecular and histopathological methods. 10 apparently healthy fish samples were also prepared from farms without loss reported as control samples. the results of the molecular study showed that the number of 22 samples was determined positive by creating the expected 327 nucleotide bands in terms of the presence of carp edema virus. the results of microscopic examination of positive samples of cev disease, showed the widespread necrosis with hyperplasia of epithelial cells, with connecting the secondary lamellae of the gills. also, eosinophilic intracytoplasmic inclusions were observed in respiratory epithelial cells and hematopoietic cells of kidney tissue. the results of this study showed the presence of cev in khoozestan fish farms. the results insisted on more attention for the detection and prevention of carp edeme virus.