Yes, that could be the case:
bats are reservoirs for more than 60 viruses that can infect people, according to a 2013 study. The animals host more viruses per species than rodents.
When they fly, bats increase their energy expenditure (metabolic rate) and body temperature, resulting in body temperatures similar to those seen in other mammals that have a fever (100 to 105 degrees Fahrenheit), the researchers said. This suggests that flight protects bats from infection in the same way that fever protects mammals — by boosting their immune response, the researchers said.
If the high metabolic rates and high body temperatures that accompany flight activate the immune system, then flight could be the ultimate explanation “for the evolution of viral infections without overt signs of illness in bats,” the researchers wrote in a paper in the May issue of the journal Emerging Infectious Diseases.
https://www.livescience.com/44870-bats-viruses-flight.html
There was an intermediate host however. They’re speculating it was civets cats.