Africa, as a continent, is almost totally ravaged. There are a billion people there, and probably 900 million are less than a month from starvation. The tribal wars have been devastating, the fall of European colonialism in Africa doomed them.
There is little doubt that Ebola and Marburg started there. The congo and central africa is still the place that has the highest genetic diversity on earth.
Only the Amazon basin might compare. And there's alot of nastys there too.
In case anyone is interested, I've located the report which speculates about bats as a disease vector:
http://www.promedmail.org/pls/askus/f?p=2400:1001:1259399917138472079::NO::F2400_P1001_BACK_PAGE,F2400_P1001_PUB_MAIL_ID:10002,28540
The reference is the 3rd posting on the page.