This same thing happen a few years back. At that time it took about 2 or 3 weeks for the outbreak to pass. Mother Nature always wins when it comes to selection so I just do what I can to help her stay healthy. I have found two dead Pine Siskins today and know over the next couple of weeks there will be a few more. I belive this natural selection will happen if I feed the birds or don't. Keeping the feeding areas and feeders clean should be a normal action all the time not just during an ourbreak.
Best to you all. Good Birding.