From the past as you know there were a lot of unknown diseases which had no cures for those days but by time science has been developed and there are cures for a lot of illnesses for people and also you wrote about birth deaths are decreased and even finished.
Anyway I can write a lot of thing about this subject but actually I am at work so that is all for now .
Thank you for sharing and have a nice day ...
Meanwhile if you have some time visit my page I have a lot of new stuff...