Why not parasites causing both poverty and authoritarianism? A big part of the reason Bill Gates is so committed to fighting parasite diseases like Malaria is that there's strong evidence that this alleviates poverty. After all, it makes sense when you consider the effects a case of Malaria would have on a family: children unable to go to school, adults unable to work. If the baseline load of Malaria cases is high enough then it's not hard to see how that would continually depress the economy.