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.