However, the article alleges that the best cure rates occurred in facilities that solved the problem with natural remedies, as opposed to allopathic facilities. Maybe it's just author's bias, or maybe it's true. But it's a pretty safe bet that hygiene and sanitation go a long way toward stopping the spread of disease. The difference between a somewhat more sanitary America [especially medical clinics...] and its 1918 flu crisis versus the less sanitary regions you mentioned and their flu crises could have a lot to do with the outcomes in the different areas.
In other words... by changing other variables in the biological equation, direct comparisons are impossible. Make the case with American data, and you'll win me over.