1992 Volume 45 Issue 3 Pages 203-206
In August 1990, vibriosis of wild ayu began occurring suddenly in the Nakagawa River, Tochigi Prefecture. It was caused by Vibrio cholerae serogroup 09. A great number of ayu died, as ayu are easily infected with V. cholerae serogroup 09. The ornithin decarboxylase reaction was negative for isolates from ayu. The isolates were superier in lethality for mouse and productions of hemolysin and Vero toxin to V. cholerae non-01 isolated from water of other rivers.
This ayu case did not seen to correlate to the rate of incidence of human cases caused by V. cholerae non-01.