Differences in the susceptibility of some penaeid prawn species to gill-associated virus (GAV) infection

Four species of penaeid prawn cultured in Australia (Penaeus monodon, Penae us esculentus, Marsupenaeus japonicus and Fenneropenaeus merguiensis) were injected with a virulent preparation of gill-associated virus (GAV). P. mon odon (average weight = 8.9, 13,9 and 19.2 g), P. esculentus (average weight = 19.5 g), F, merguiensis (average weight = 10.5 g), and small (average we ight = 5.8 g) M. japonicus displayed overt signs of disease and mortalities which reached 82 to 100% within 23 d post-injection. Cumulative mortalitie s in P. esculentus and F, merguiensis were significantly lower than for P, monodon of the same size class. Medium (average weight = 13.0 g) M. japonic us also developed overt signs of disease but cumulative mortalities were no t significantly higher than uninfected controls. Large (average weight = 20 .3 g) M. japoncius did not display symptoms of disease and there were no si gnificant mortalities up to 23 d post-injection.