I'll go out on a limb and suggest that the African mortality rates are exaggerated, but, again going to teh Spanish Flu, there were situations in Alaska where it'd hit a village, the natives had no defenses, and while not everyone would fall down and die, everyone *would* become bedridden and sick. And after four to six days of not being cared for or fed, the dogs would break in and find no one able to defend themselves.
When rescue teams/medical personnel finally made it up there, they'd find whole communities without a single living person and only 1-3 dogs left, tugging over bones and scraps.
Africa likely saw some similar results, and also had a large exodus situation, where rumors of safe places would cause a lot of movement.
That said, I hope to explore the Ethomalian Territories more about this in the future. There, the plagues had lasting psychological effects where people retreated from flesh and the shamans who were able to use magic to cur ethings became modern priest-kings. Now you have a society where the less flesh you have, the more 'holy' you are, with cybernetic replacements seen as a GOOD thing, and the top of society are these people who dress in long black attire topped with spooky masks.(You can see more about it in Chrome Flesh, plug plug.)
I'm a comedy guy, so I don't get to bust out the horror writing very often, but it's a nice change-up every now and then.