Dengue is caused by a virus spread by Aedes (Stegomyia) mosquitoes. Over the past two decades there has been a dramatic global increase in the frequency of dengue fever (DF) dengue haemorrhagic fever (DHF), and dengue shock syndrome (DSS) and their epidemics, with a concomitant increase in disease incidence. The World Health Report 1996 stated, that the "re-emergence of infectious diseases is a warning that progress achieved so far towards global security in health and prosperity may be wasted." The report further indicated that "infectious diseases range from those occurring in tropical areas (such as malaria and DHF which are most common in developing countries) to diseases found worldwide (such as hepatitis and sexually transmitted diseases, including HIV/AIDS) and food-borne illnesses that affect large numbers of people in both the richer and poorer nations."
Dengue epidemics are known to have occurred over the last three centuries in tropical, subtropical and temperate areas of the world. The first epidemic of dengue was recorded in 1635 in the French West Indies, although a disease compatible with dengue had been reported in China as early as 992 AD. During the 18th, 19th and early 20th centuries, epidemics of dengue-like diseases were described globally in the tropics as well as in some temperate regions. Rush was probably describing dengue when he wrote of "break-bone fever" occurring in Philadelphia in 1780. Most of these epidemics were clinical dengue fever, although some were associated with the severe haemorrhagic form of the disease. Efforts to control Aedes aegypti and economic development have markedly reduced the threat of epidemic dengue in temperate countries during the past 50 years.
The first recorded outbreak of a dengue disease compatible with DHF occurred in Australia in 1897. A similar haemorrhagic disease was recorded in 1928 during an epidemic in Greece and again in Taiwan in 1931. The first confirmed epidemic of DHF was recorded in the Philippines in 1953-1954. Since then, major outbreaks of DHF with significant mortality have occurred in most countries of the South-East Asia Region, including India, Indonesia, Maldives, Myanmar, Sri Lanka, and Thailand, as well as in Singapore, Cambodia, China, Laos, Malaysia, New Caledonia, Palau, Philippines, Tahiti and Vietnam in the Western Pacific Region. Over the past 20 years, there has been a dramatic increase in the incidence and geographical distribution of DHF, and epidemics now occur each year in some South-East Asian countries.