Necrosis of the hepatopancreas in Penaeus monodon and P, stylirostris (Arthropoda, Decapoda) with red disease

Abstract The histopathology of red disease was studied in samples of Penaeus monodon from a commercial prawn farm in the Philippines and in a single pond–reared adult P. stylirostris from Hawaii. The principal lesion type observed in prawns from both locations was a marked atrophy and necrosis of the hepatopancreas that was accompanied by an intense cellular inflammatory response. Less commonly, melanized cellular inflammatory lesions were observed in the antennal gland, mandibular organ, gonads, midgut and gills. The aetiology of red disease is unknown, but because of the similarity of hepatopancreatic lesions in red disease to those observed in aflatoxicosis, mycotoxins (or other microbial toxins) present in rancid or spoiled feeds or in the detritus of organically rich ponds are suggested as its cause.