According to a new study out of China
There have recently been reported multiple new deadly viruses that threaten the shrimp farming industry, such as the iridovirus, and hemocyte iridescent virus, which have been destroying farmed Pacific white shrimp, as well as other shrimp species. A new type of white spot virus has an 80% mortality rate.
A method to control the virus outbreaks was developed, stocking the farms in polyculture mode of different species, especially with M. rosenberqii, because of it's tolerance to white spot virus, but the emergence of the new viruses has negated this approach, because the newer viruses have found their way into the polyculture farms and attacked all the varied species, causing the die-off of the entire stocked species. This has validated the warnings of specialists that polyculture of different species of crustaceans brings the risk of the spread of other diseases and viruses, based on the observance of shrimp epidemiology.
The only sustained answer to these, and future new viruses, is the development of a method of raising shrimp that kills viruses and other pathogens.