To clarify whether the "mucus sloughing and hemorrhagic septicemia disease" of cultured European eels,Anguilla anguilla,is related with virus,the internal organs of the diseased European eel were extracted and homogenized,and virions were purified by sucrose density gradient centrifugation;then EO cells were incubated with the supernatant of the tissue homogenate,and the cytopathic effects of cell fusion appeared.In addition,the virus infected cells were thin sectioned,also the negatively stained purified virions were observed by electron microscope to photograph the virus morphology.It showed that the virus was enveloped with size in about 200 nm.Furthermore,DNA were extracted from the supernatant of the infected cells,and used for Anguillid herpesvirus(AngHV)PCR detection,and then the amplified fragment was sequenced and alignment analyzed.The results showed that it was exactly the same sequence with the AngHV European strain,AngHV-1.Therefore,the observation by electron microscope and DNA polymerase gene sequencing confirmed that the isolated virus is an AngHV strain,named AngHV-FJ,which is the first cell isolation in China mainland.The research has laid an important foundation for the study of the pathogenic mechanism of AngHV-FJ and the prevention and control of eels "mucus sloughing and hemorrhagic septicemia disease".