This is just an anecdote from my past.  When I was tandem nursing a
three year old and an infant, at one time everyone in my family came down
with strep throat (my husband, 6 year old, 3 year old, and myself) except
the nursing infant.  I remember worrying about it because before knowing
we were all sick, I had allowed the 3 year old to nurse and then the
infant immediately after her on the same side even.  However, even with this
close contact, the baby's culture came back negative although everyone else
was positive.
This really doesn't have anything to do with kissing dogs, but
nevertheless, I was pretty impressed with the power of breast milk!

Kris Rogers, RN, BSN, IBCLC   Crystal Lake, Il
(P.S.  For whomever asked, my kids' code words were "nurnee" or "neenee".)