Hepatopancreatic rickettsial infection of the penaeid shrimp, <em>Penaeus marginatus</em> (Randall), from Hawaii.

The article reports on the Hepatopancreatic rickettsial infection of the penaeid shrimp. Frozen Penaeus (P.) marginatus tissues were screened for pathogens by shrimp bioassay. Preserved shrimp were processed for routine histopathology and stained with haematoxyiin and eosin. The rickettsial agent from P. marginatus was found to be highly infectious for juvenile P. stylirostris. Based on the data presented, P. stylirostris bioassay would appear to be of use as a method to determine the presence of this rickettsia in wild-caught P. marginatus, and juvenile P. stylirostris could be used as a suitable host for experimental culture of this rickettsia under laboratory conditions.