Re: What my vet said...

Fungi being highly infectious through contact is just so common-knowledge where I'm coming from that I can't really say... Russians have a habit of removing their shoes indoors and wearing slippers, and it's always been standard practice in any house to not give guest slippers to people with toenail fungus. And docs tell you not to share towels. And to rinse off any shower/bath you use that others with fungi may have used.

Don't know what the original source was, it's just really standard practice.