Which historical period are you talking about? Before quinine, the death rate from disease is too high for any sustained development. After quinine, this is the era of High Imperialism even in other parts of the world, so the regimes in charge (i.e. European colonialists) care fuck all about infrastructure development except for resource extraction. Even in self-governing areas, areas with a resource extraction economy have terrible infrastructural development - for example, railroads in the Western US were built to very poor standards, unlike in the Eastern US or in Europe.
To the extent your question is "AHC: more development in Africa with a post-medieval POD," probably the only option is to figure out a way to butterfly High Imperialism. This isn't as silly as it sounds, because evidently in China, Europeans were okay with the open door model proposed by the US, in which China remains intact and Europeans (and Japanese) get to humiliate the natives collectively at treaty ports. But this by itself doesn't develop Africa. Developmental states like Egypt still get shelled if they can't pay their debts. It just means that, eventually, Africa ends up with somewhat better institutions than the extractive ones created by European colonialists everywhere between the Sahara and the Kalahari, so in the second half of the 20th century it can develop its own infrastructure better. (P.S. I'm writing that TL.)