It spreads if there are insects, even house flies can land on an infected plant and spread it to a healthy plant, humans do it too by touching foliage. Viruses like in people cannot be cured in plants. The thing I found out is this virus starts out strong and gets weaker as the plant gets bigger and stronger, I would recommend a longer veg period, cut off infected leaves and leave the newer more vibrant leaves, also move the light back a bit, the chlorophyll that is affected can't handle too much intense light, that's why the blotches appear to be bleached.