Effectiveness of increasing temperature of rearing water and non-feeding against viral endothelial cell necrosis of eel

Viral endothelial cell necrosis of eel (VECNE) of Japanese eel Anguilla japonica, caused by an adenovirus (JEAdV), has been a serious problem of aquaculture industry in Japan. In the present study, effectiveness of increasing water temperature and non-feeding against VECNE was evaluated. Cumulative mortalities of fish intraperitoneally injected with 105.05 TCID50/fish of JEAdV increased with elevating water temperature in the range between 20°C and 31°C, but mortality at 35°C was as low as that at 20°C. Rearing infected fish under the non-feeding condition further enhanced the effect of treatment at 35°C. The effectiveness was dependent on rearing periods at the high temperature; more than 3 days at 35°C were needed to reduce mortality. Fish, which survived the primary challenge with JEAdV at 35°C, showed high resistance to re-challenge with JEAdV. From these results, the treatment of fish under the non-feeding condition at 35°C is useful to control VECNE.