[Histopathological research and immunofluorescence of AVND virus infection in cultured scallop Chlamys farreri].

The naturally infected scallops Chlamys farreri sampled during mass mortality in summer of 2003 was detected by means of histopathological and MAb-based immunofluorescence assay (IFA). The results of histological examination demonstrated that a series of histopathological changes including cell swelling, basophilic increase, disorder, partial sloughing and excessive sloughing were always observed in epithelia of many different organs, e.g. mantle, gills, stomach, intestine and kidney. Additionally, the infected tissues were applied for in situ detection of the "acute virus necrobiotic disease" (AVND) virus by means of specific MAb-based IFA, and the result demonstrated that this pathological changes or lesions were perfectly coincident with the positive cells (fluorescencing cells) . The positive cells were denser in some local area of epithelia, and exhibited serious pathological lesions, which would reveal the roles of this virus in pathogenesis and further confirm that the AVND virus is the main causative agent of mass mortalities among cultured scallop Chlamys farreri farmed in northern coast of China.