2. Dengue fever, transmitted by tropical mosquitoes, affects tens, if not hundreds, of millions of people per year, with limited treatment and vaccination options available
A mosquito-borne tropical disease, dengue fever induces an extreme fever, vomiting, muscular spasms, and severe skin rashes. Taking between three and fourteen days for symptoms to appear, in a small percentage of cases the disease compounds into dengue hemorrhagic fever, causing bleeding, blood leakage, and dangerously low blood pressure. First recorded in China during the Jin Dynasty (265-420 CE), the present strains of the disease are believed to have originated in Africa before proliferating throughout the globe via the slave trade between the 15th and 19th centuries. Despite being prevalent during and after the Second World War, a vaccine, only partially effective, was not discovered until 2016.
Due to the lack of preventative medicine concerning dengue fever, the disease continues to ravage the developing tropics. An estimated 50 to 528 million people are infected by dengue fever each year. Of these, a significant proportion requires medical attention and approximately ten to twenty thousand die as a direct consequence. Recommended treatments are limited and mostly palliative, including fluid replenishment and paracetamol. Even the developed world has not escaped the long-lasting disease. Hawaii, in the United States, is experiencing the largest outbreak of dengue fever since it obtained statehood in 1959, with 261 confirmed cases on the islands.