A shrimp hatchery manager notices unusually high mortality among post-larvae in one of his rearing tanks, along with lethargic behaviour, reduced feeding and a whitish discolouration of the shell in affected shrimp. On sending samples for laboratory testing, the pathogen is confirmed to be a virus rather than a bacterium or fungus, and the disease is known to spread rapidly in dense culture systems, often causing near-total crop loss within days if not managed through strict biosecurity measures. Which of the following viral diseases of farmed shrimp matches this description?