The first description of histopathology of Lates calcarifer herpesvirus (LCHV) infection in barramundi (Lates calcarifer)

Abstract

Barramundi (Lates calcarifer), an economically important species for mariculture in the Asia-Pacific region, has been threatened by various infectious diseases. Lates calcarifer herpes virus (LCHV) is a newly emerging virus which was first reported in farmed barramundi in 2015. Up to now, the pathognomonic histopathological lesion of this disease has not yet been described for the purpose of disease diagnosis. This study investigated the histology of five natural LCHV outbreaks throughout a year and consistently detected the presence of a typical type of intra-nuclear inclusion bodies (IIBs) in various organs of infected fish. Experimental infection was conducted by injecting the healthy fish with filtered supernatant of crude extract from the LCHV-positive barramundi from the field. Histological examination of experimentally infected barramundi clearly indicated the presence of the same type of IIBs in multiple organs, including the liver, pancreas, kidney, eyes, gills, and adipose tissue. The presence of IIBs in barramundi infected with LCHV was a pathognomonic feature that can be used for the histological diagnosis and particularly for surveillance of this emerging viral disease in barramundi farming countries.