Koi herpesvirus disease (KHVD) is an emergent cyprinid herpesvirus disease causing mass mortalities in koi and common carp Cyprinus carpio worldwide since 1998. In Japan, KHVD broke out in Autumn 2003 and has caused mass mortalities in farmed fish as well as wild fish all over Japan. Establishment of control measures against KHVD is the urgent theme, and in order to address this issue many scientists belonging to universities, national and prefectural research institutes, and pharmaceutical companies have studied on KHVD and produced excellent results. Not only scientists but also fish farmers are eager to know the results. This context motivated the author to organize a symposium in Mie. The symposium focused on the up-to-date results of studies on KHVD: KHV genome analysis, methods to inactivate KHV in the environmental water, ways to coexist with KHV, development of a delivery system for oral vaccination using liposome, and successful oral vaccination with liposomes entrapping KHV antigens.