So I’ve been thinking about this recently...
When the Flood landed on Earth, the Elites took it upon themselves to purge the Flood from Earth. Is there anymore detail or lore on this?
How could they be sure they killed every infection form and what not. Was all of Africa placed on Quarantine?
Did any civilians succumb to the Flood? Did they ever find out that the Flood attacked?
(See video above)
Lord Hood's comment about the Elites glassing half of Africa isn't an exaggeration. However, it was in regards to population, not of geography.
While the area surrounding the crash site was extensively glassed, to ensure that nothing was missed, all surrounding population centers were glassed as well.
It's unknown if any civilians succumbed. It's entirely possible that civilian survivors at Voi could have been infected.