Any chance that this is proof to get back on the Lamictal? I know that it was working for you and at one point you were not sure if it was the Lamictal or a family "bug".

While bathing in Lysol would work... not very practical. Make sure though that you are washing linens like every day or every other day. This will help prevent re-contamination when everyone goes to sleep. Also, some lysol on telephones (cell and home) and doorknobs is also a very good simple thing that could help everyone out.

Make it a rule also that everyone wash there hands before going into common spaces, such as a silverware drawer or the refridgerator. This could help with cross-contamination. One other thing is to make sure that everyone in the house gets new toothbrushes. Probably already thought of all this, but hopefully it can get your family bug free.