AN EPIZOOTIC OF NECROTIZING HEPATOPANCREATITIS IN CULTURED PENAEID SHRIMP (CRUSTACEA, DECAPODA) IN NORTHWESTERN PERU

In January and February of 1993 a severe epizootic of necrotizing hepatopancreatitis (NHP) began to affect a number of commercial penaeid shrimp farms in the Tumbes area of northwestern Peru and adjacent areas of Ecuador. Histological and transmission electron microscopical (TEM) examination of affected juvenile Penaeus vannamei showed massive infections of the hepatopancreas by a pleomorphic intracellular Gram-negative bacterium. The agent was named Peru NHP (PNHP) for its geographical occurrence and for the type of lesion with which it was associated. A very similar bacterium (TNHP) has been found to be associated with a serious epizootic disease in shrimp farms in Texas. Before the cause of the Peru epizootic of PNHP was determined and corrective measures were taken, nearly half of Peru's 44 active shrimp farms had been so seriously affected that they were closed by June of 1993.