抄録
Viral endothelial cell necrosis of eel (VECNE) is a disease caused by the Japanese eel endothelial cells-infecting virus (JEECV) and significantly impacts the eel aquaculture in Japan. Although Japanese eel Anguilla japonica are often exposed to virus-contaminated water during aquaculture operations, the risk of infection via rearing water has not been well-studied. Using a waterborne challenge test, we showed JEECV could be transmitted via rearing water. Additionally, we examined the effects of water temperature on JEECV infection. The challenged eels started to die on day 18, and the cumulative mortality during the experiment was 32%, 15%, and 0% at 30°C, 32.5°C, and 35°C, respectively. Eels that died on day 18–20 showed high viral loads and typical symptoms of VECNE. Eels that survived the challenge test at 30°C and 32.5°C were also positive for JEECV, whereas no viral DNA was detected in eels at 35°C. The serum antibody titers against JEECV were high and moderate in the surviving eels at 30°C and 32.5°C, respectively. The titers in those at 35°C were low and not significantly different from those in the uninfected control. These imply that JEECV remains infectious outside of a host and that high water temperatures of approximately 35°C prevent its transmission.
