In my experience, I have Never heard of a bird with ILT surviving and being a carrier. It is a death sentence.
I am very sorry you experienced this with your first birds.
I personally would follow the advice of Pips and Peeps.
K.
Stress can bring on conditions that are otherwise go unnoticed, or lay dorment. Keep a very close eye on the sneezing and coughing and for any other signs of illness.
K.