A Study on the Pathogenicity of Hepatopancreatic Parvo-like Virus in Chinese Prawn, Penaeus chinensis

Abstract

Hepatopancreatic parvo-like virus (HPV) is a kind of virus detected from the epithelial cells of the mucosa of the fore-midgut and those of the hepatopancreas of the Chinese prawn, Penaeus chinensis. In order to verify its pathogenicity, experimental infections were made in healthy larva and adults by the immersion and oral feeding methods, respectively. The results indicated that Z-3, P-7, and adults can all be infected. The mortalities caused by HPV infection were highest in Z-3 followed by P-7 and lowest in adults. These results consistent with mortalities due to HPV in natural pathogenesis. Histopathological changes in the infected prawns were similar to those of naturally infected prawns, which are the occurrence of basophilic or acidophilic inclusion bodies in the nuclei of the epithelial cells of hepatopancreas or in the mucosa of the fore-midgut. Electron microscopic observations showed that there were large numbers of virions, 22-24 nm in diameter, in the virogenic stroma. The above results prove that HPV is a pathogen responsible for the pathological changes in the hepatopancreas and fore-midgut and consequently for the death of Penaeus chinensis.