New detection of Cyprinid herpesvirus 2 associated with mass mortality in colour crucian carp ( Carassius auratus ), in China

During October 2016, a mass mortality of colour crucian carp (Carassius auratus), which the affected fish were lethargic, inappetence and anoxic, was occurred in a fish farm located in Chengdu, Sichuan province, China. To elucidate the aetiology of this outbreak, histological and electron microscope examination, molecular investigation were conducted. Pathologic examination revealed multi foci necrosis on haematopoietic organs, gills, hearts and pancreas. Transmission electron microscopy observations exhibited sphere herpesvirus‐like particles distributed amongst the tissues of gill, spleen and kidney. Molecular analysis is verified that the causative agent of this outbreak was Cyprinid herpesvirus 2 (CyHV‐2). This report first report CyHV‐2 in colour crucian carp, which increases the concern about damage of CyHV‐2 and its potential role in species.