WHO: Tropical Diseases, No Longer Tropical Indeed

In medical school, we were taught that there are some diseases peculiar to the tropics.
The tropics is a geographical region as delineated by latitudes and longitudes. Generally, sub saharan Africa falls within this region, same for some Asian and South American countries.

In the past, some diseases seen and reported, predominantly in this region, were called Tropical Disease. But at the moment, tropical disease do not seem to be strictly tropical any longer. The World Health Organisation (WHO), agrees with this position in this tweet;

Oh my!! We need to pay more attention!!