Dengue is an arbovirus disease caused by any one of four closely related viruses that do not provide cross-protective immunity; a person can be infected as many as four times, once with each serotype. Dengue viruses are transmitted from person to person by the Aedes aegypti mosquito in the domestic environment. Periodic epidemics have occurred in the Western Hemisphere for over 200 years. In the past 20 years, however, dengue transmission and frequency of epidemics have increased greatly in most tropical countries of the American, African and Asian region. As this has occurred, dengue hemorrhagic fever (DHF) has emerged and produced epidemics in many countries of the region.
What is Dengue?
The first reported epidemics of dengue fever occurred in 1779-1780 in Asia, Africa, and North America; the near simultaneous occurrence of outbreaks on three continents indicates that these viruses and their mosquito vector have had a worldwide distribution in the tropics for more than 200 years. During most of this time, dengue fever was considered a benign, nonfatal disease of visitors to the tropics. Generally, there were long intervals (10-40 years) between major epidemics, mainly because the viruses and their mosquito vector could only be transported between population centers by sailing vessels.
A global pandemic of dengue began in Southeast Asia after World War II and has intensified during the last 15 years. Epidemics caused by multiple serotypes (hyperendemicity) are more frequent, the geographic distribution of dengue viruses and their mosquito vectors has expanded, and DHF has emerged in the Pacific region and the Americas. In Southeast Asia, epidemic DHF first appeared in the 1950s, but by 1975 it had become a leading cause of hospitalization and death among children in many countries in that region
In 1997, dengue is the most important mosquito-borne viral disease affecting humans; its global distribution is comparable to that of malaria, and an