Plebejus baculovirus and other MBV-related viruses have been found in Penaeus plebejus, P. monodon and P. merguiensis . They appear highly pathogenic in certain situations currently undefined. We have found Hepatopancreatic Parvo-like Virus (< hpv) in wild P. esculentus and P. merguiensis but not yet in cultured prawns. The amphophilic intranuclear inclusion bodies we find in P. esculentus do not appear to have a viral cause.