I had a dwarf gourami in my tank for several weeks and it was healthy, as were the rest of my fish, including regular gouramis. I decided to add another dwarf gourami. I purchased another one from the local pet megamart. My quarantine tank had an algae explosion and I hadnt dealt with it, so I stupidly decided to put the new dwarf in the tank. For a few days everything was fine, but one morning I looked in and saw one of the dwarfs lying on the substrate gasping. There really wasnt anything I could do, as I still hadnt taken care of the quarantine tank. I thought, well if he dies, I can return him and get a new one. Later that day, my other dwarf was dying as well. My non-dwarf gouramis were doing fine; and still are several days later. I thought this could not be a coincidence and started researching online in forums and sites. It would appear that the new dwarf had Dwarf Gourama Indovirus (DGIV) and passed it to the other dwarf. It is a dwarf only disease, which makes sense, as my other gouramis are fine. I tested my water and it was acceptable, so thats a plus. I brought the dead dwarfs back to the store and they refunded my money. I looked at the remaining dwarfs and they looked sickly as well. This observation makes me feel fairly confident if was DGIV.

If I were to get more dwarf gouramis (I found a better non-chain store), do I need to wait a specific period before the virus dies out? I do weekly water changes of 12.5% and I have a small UV filter running.

I definitely prefer answers with sources to back them up.