Tropical diseases have been all over the news recently, first with the rise and fall of Ebola in west Africa and now with the outbreak of Zika in the Caribbean. Part of what makes these outbreaks so severe is that these diseases are not very well researched. There are no vaccines against them, and, since they are caused by viruses, there is no treatment for infected individuals.
The World Health Organization (WHO) has a list of diseases called the Neglected Tropical Diseases (NTDs). NTDs are diseases that are known to affect tropical areas of the world, which scientists don't often research. Examples of NTDs include rabies, dengue and sleeping sickness. These are diseases that may be caused by bacteria, viruses, fungi or eukaryotic parasites. They often affect individuals in the Caribbean and Africa.
Part of what makes these diseases so hard to contain is that they are often vector-borne, which means you can get them from an insect like a mosquito, or another arthropod-like a tick. It is very hard to control vector-borne diseases. There have been talks of genetically engineering Aedes aegypti mosquitos so they cannot carry Zika, but there has been a lot of pushback to that idea.
Also, there are many important diseases that are not on the official NTD list. The diseases on the NTD list get a special signal boost by the WHO, and a financial incentive to research them. Zika and Ebola are not even on the list.
Science is performed in places of wealth. Scientists who study infectious diseases often study diseases that have impact close to their home, and that they and their loved ones may have experienced. Diseases like smallpox, polio, and cholera have been all but eliminated from the developed world, thanks to scientists that have dedicated their lives to fighting them. Infectious diseases used to be rampant causes of death; even as recently as 1900, the top three causes of death in the United States were all infectious diseases. The death rate from influenza and pneumonia was over 10 times higher then than it is now. Now, infectious diseases don't even break into the top five in developed countries like the United States, and influenza and pneumonia are only the 7th leading cause of death here.
In order to prevent the spread of tropical diseases, we have to expand the scope of our scientific study. This will, in turn, prevent them from breaking into the US, like Zika is doing right now. Scientists in places of privilege must work on understanding and eradicating diseases that may not affect them and their country, so that we can help those less fortunate than us. This is the only way we can prevent disasters like the unprecedented spread of Ebola and Zika from happening in the future.
