Ebola

More specifically, there is no record (AFAIK) of any virus in vivo evolving mechanisms for airborne transmission.But this possibility is not so remote that we shouldn't give it some consideration.We know that there are evolutionary pathways that can readily make a viral strain airborne. See the laboratory work by Herfst et al., 2012 ("Airborne transmission of influenza A/H5N1 virus between ferrets").Additionally, Ebola (specifically, the ZEBOV strain) has shown evidence of airborne transmission, albeit under carefully controlled laboratory conditions (see "Transmission of Ebola virus from pigs to non-human primates," in Scientific Reports).So is it likely that the airborne transmission of Ebola will occur? Not really -- not at this point -- but the longer we take to bring this current outbreak under control, the greater chance of something like this happening.Ebola is nasty, and evolution can be, too.