Cull and start again?

I would whack them and freeze them for food.

Clean everything and get your stock from someplace reputable.

I have only had one animal that had the sneezes and I eliminated it immediately.

I wouldn't risk it. It takes so long to get the stock that you want to breed that you should only introduce new stock from someplace that you really trust.

Just recently, one of my rats (and a few of my sister's rats) had an RI. Now, these were not bad cases, and using tetracycline seems to have worked. I found dosing instructions here...

http://www.rmca.org/Articles/dchart.htm

If you go all the way down to tetracycline and use the soluble powder dosages. I supplemented Yoshi's food with fresh foods, quality lab block and made sure her bedding, water, and food was checked and refreshed daily. She was also weighed several times a week. My sister did this with her rats as well and all of them have recovered from their RIs. No sneezes in a while.

You could try this and if it does not work, then I would consider culling, but I always try and give an animal a chance at life if I can.