How did they treat malaria back in the old days in the jungle?

Not. For years the only therapy was quinine and before that nothing. This is why the childhood mortality rate is so high in malarious countries, and why genetic mutations (i.e. Sickle trait and others), have occurred in humans to create resistance to infection by the parasite. But even today, keeping up with resistance development and the cost of medicines, there is still a high death rate.