Analysis suggests that both factors are at work.
As a result, much of the Americas became free of dengue. As a consequence, dengue spread throughout the region, causing severe epidemics or even pandemics during the 1970s and 1980s. Currently, dengue is endemic in virtually all countries with Ae. After the 1981 DHF outbreak in Cuba, reports of DHF in the Americas markedly increased. The Cuban authorities implemented a successful vector control program and the country is still virtually free of Ae. aegypti .