Amplification of viruses in maternal colonies?

The paper here
Amplification of Emerging Viruses in a Bat Colony

describes a first wave of infection. Since the bats were probably all born in similar colonies, wouldn’t they very likely already have been previously infected? That would mean that the female bats arrived at the colony with a persistent infection.

Female bats of species normally go into a daytime torpor will maintain high daytime temperatures during reproduction. Could a rise in body temperature be the cause of the virus spike?

With a captive colony, if the droppings could be regularly checked for viruses, what’s known about persistence of viruses in bats will
become a lot less nebulous. And perhaps with infrared thermometers,
the resting temperatures might be taken without disturbing the bats.
It will be interesting to see if there’s any correlation between the
bat’s resting body temperature and the presence of viruses.

Experiment DID NOT show that bats are asymptomatic carriers of rabies

Bats, emerging infectious diseases, and the rabies paradigm revisited

It is stated that:
“More recently, the asymptomatic excretion of RABV in the saliva of
experimentally infected vampire bats, which survived the challenge
during at least 2 years of observation, was documented again (18).”

But the cited research — despite what one might expect from the title
Salivary excretion of Rabies virus by healthy vampire bats

states that
“Rabies virus was not detected in the saliva of any of the 11 animals
that succumbed (somewhat early) to rabies challenge, nor in the
control bats. In contrast, virus was detected early, and only once
(days 6, 6 and 21) in each of the three animals that survived rabies
challenge and remained healthy for at least 2 years after challenge.
At that time even vigorous dexamethasone and cyclosporine
administration failed to provoke further viral excretion.”

This seems to show that bats once recovered are no longer carriers and not that apparently healthy ones are.