What kind of virus passes through an infant for a few hours with only fever and otherwise my daughter seems fine just slight temp of 100.5 earlier?

Too fast: Viruses generally have a longer effect upon their hosts (your daughter), I do not know of one that would initiate and be shed so quickly. Perhaps it is a minor reaction to a mild virus, or just as easily be food related or environmentally induced. Take temp several ways and see, orally, basally, by ear, armpit. If she starts to really feel unwell consult with an md.