IL6 and infection: Interleukin-6, which encodes one of the most important cytokines during infection (Velazquez-Salinas et al. 2019), showed 6 sites predicted to be positively selected in bats and a high ratio of nonsynonymous substitutions per nonsynonymous site to the number of synonymous substitutions per synonymous site on the bat MRCA branch (dN/dS = 2.72).