A viral disease occurring in cultured carp Cyprinus carpio in Korea

A new disease with high mortalities has been occurring in summer scince 199 8 in different ages of carp Cyprinus carpio cultured in Korea. The clinical signs of the disease included erratic swimming of moribund fish at the wat er surface, respiratory distress, presence of thick and foggy mucus coverin g the body and gills, Dermal ulcers were also noticed in a few cases. Micro biological, parasitological and virological investigations were carried out on the fish samples collected from various localities. Although bacteria a nd a protozoan parasite were recovered from some fish, their occurrences we re not consistent. Histologically, the kidney and spleen showed discernible changes. Inoculation of tissue filtrates from affected fish to various fis h cell lines showed cytopathic effects only in FHM. Ultra-thin sections of the infected FHM cells under an electron microscope revealed distinct cytop lasmic virus-like particles with a diameter of 70-80 nm. Immersion infectio n trials, using a viral suspension of 10(3.0)TCID(50)/mL obtained from the infected FHM cells, produced 100 and 80% mortalities in Israel carp and com mon carp, respectively. This is the first epizootic of viral disease report ed among cultured carp in Korea.