This virus literally destroyed the Chilen farm fish market just a few years ago when I was visiting in 2007. A volcano eruption in the same area added the the disaster. Chile was posied to make quite a comeback, but this news shows the danger of farmed fish and their general lack of good health. The photo links to an article that explains the ISA virus a bit more.
The ISA virus was detected last Thursday in three of the ten cages installed in the center at Perales Bay. The company began the harvest of salmon with weights ranging from 800 grams to 1.5 kilograms, far below what would be ideal (which is between 4 and 5 kg) to get good values on the market.