Significant number, maybe. Penetration of medical services in these countries has increased quite a lot in the same time span. But, impact of this depends on the type of disease.
Significant increase in breast cancer cases for example is I believe a direct result of increased diagnosis.
But, for the increase in cases of viral diseases, I believe the majority cause is due to things like more dense population, unsanitary conditions and poor infrastructure.
I'd exclude breast cancer because it's detectable with non-medical means before it becomes fatal. I also wasn't speaking so much about medical incidence statistics, but more about perceptions.
Diseases like this are something that forces you go to the doctor, where its gonna gain a diagnosis. With diseases like Zika and Chikungunya the big problem is globalization and air travel.
How is a doctor supposed to diagnose a Virus like Zika without advanced lab tests? The symptoms are non-specific and often non-obvious. In fact, I doubt Zika virus was regularly tested for.
Significant increase in breast cancer cases for example is I believe a direct result of increased diagnosis. But, for the increase in cases of viral diseases, I believe the majority cause is due to things like more dense population, unsanitary conditions and poor infrastructure.