Dust Storm good friend
I believe,(and I am sure Father Rob), that infant baptism has infused virtues....
The question comes in as to a person's ability to reason at infancy, and therefore the effects of the infused cardinal virtues are difficult to realize see.
Infants display cardinal virtues of faith, hope, love, especially towards their parents, which is easily seen. But do not display for instance prudence, justice, temperance, fortitude until years later. And for all purposes the age of reason is a good place that they seem to begin in an affective way(IMHO).
A baby/infant/small child is not yet able to believe/faith or to make a personal decision to follow Christ and take up his cross.