One part he doesn't go into too much is the effect of malaria on culture.

Because malaria was so rife any large settlements would be built away from water sources, the opposite as happened the rest of the world. This then both limited the size those settlements could grow to and encouraged slavery because someone had to go and fetch the water everyday.

For decades we've been seeing charity ads along the lines of "poor little Abi has to walk 9 miles everyday twice a day just to fetch clean water for her family" and no one ever stopped to ask why all these villages were build miles away from basic essentials.

I think the charities have worked it out now because they build these completely sealed pumps so there's no standing water.

But they still sell the idea this situation is down to poverty and inequality rather than being done by design and actually a practical solution to the threats in the local environment.