'In orders such as Chiroptera (bats), in which the authors infer a high tolerance to immunopathology and high levels of constitutive immunity, the expected (and observed) virulence is high. The expected virulence could be even higher in Monotrema (suggesting that you definitely should not kiss a platypus), but there currently is no data on emerging viruses from this order.'

https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3002286