Due to the small size of the juvenile prawns, the inoculum was both diluted and reduced in volume so that the mortality due to the injection procedure would be minimised. This may have reduced the mortality rate and the number of positive PCRs from the experimental groups. Other explanations for the limited effect of the inoculum are possible, such as the life the age of the prawns involved. Most previous reports have involved postlarvae or very young juveniles,
whereas this case involved adults and older juveniles.The gross signs, the histopathological lesions in muscle and the confirmatory genome sequence are all consis-tent with the OIE definitions. The mortality in experi-mental prawns was chronic and limited over the time frame of the study, and inclusion bodies were not seen in connective tissue but rather in the muscle, staining more like RNA (pyroninophilic). Based on the findings in this case, perhaps the OIE definition needs to be broadened somewhat to include adult life stages, and the staining characteristics should be reevaluated