Development and application of a simple and rapid diagnostic method to studies on hepatopancreatic parvovirus of penaeid shrimp

Hepatopancreatic parvovirus (HPV) is one of about a dozen viruses known to infect penaeid shrimps. HPV is apparently cosmopolitan in distribution, having been reported from wild and/or cultured penaeid shrimp in Asia, Africa, Australia and North and South America. However, the importance of the virus as a pathogen remains poorly understood, possibly due in part to the relative difficulty of diagnosis of HPV infections and to the possibility that HPV infections may be masked in multiple infections with other pathogens. Until now diagnosis of HPV has been dependent upon the histological demonstration of pathognostic Feulgen positive, basophilic intranuclear inclusion bodies in hepatopancreatic epithelial cells, which has limited diagnostic capability for HPV to suitably equipped laboratories. A rapid field diagnostic method for HPV infections was developed that uses Giemsa-stained impression smears of the hepatopancreas. The impression smear method was shown to compare favorably in diagnostic sensitivity to the standard histopathological method for HPV when applied to the diagnosis of HPV infections in postlarval and juvenile Penaeus chinensis (Osbeck).