Rickettsia-like organisms from cultured aquatic organisms, with emphasis on necrotizing hepatopancreatitis bacterium affecting penaeid shrimp: an overview on an emergent concern.

Aquaculture has expanded significantly in the last two decades. However, mass mortalities of cultured organisms have occurred, sometimes caused by intracellular prokaryotic organisms such as rickettsial-like organisms ( RLO). Different species of bivalves, fish and crustacean considered as commercially important have been affected by RLO. In particular, there are scarce reports of RLO affecting crustaceans; however, the necrotizing hepatopancreatitis ( NHPB) bacterium has emerged as a pathogen of concern during the last decade. NHPB thrives in shrimp hepatopancreas, causing physiological alterations and inclusively massive mortalities. In spite of the above, there is still scarce information regarding NHPB and its molecular characterization. The review is focused on the recent advances in the knowledge of RLO of mollusc and fish, with special emphasis on the intracellular necrotizing hepatopancreatitis bacterium ( NHPB) of penaeid shrimp. [ABSTRACT FROM AUTHOR]