Dengue, a Spanish alteration of the Swahili word Ki-dinga, is the most common mosquito-borne viral illness in humans. The earliest known documentation of denguelike symptoms was recorded in the Chinese Encyclopedia of Symptoms during the Chin Dynasty (AD 265-420). The illness was called "the water poison" and was associated with flying insects near water. Today, dengue is known to be caused by a single-stranded RNA virus (approximately 11 kilobases long) with an icosahedral nucleocapsid and covered by a lipid envelope. The virus is in the family Flaviviridae (of the genus Flavivirus), and the type-specific virus is yellow fever.
The dengue virus has 4 closely related but distinct serotypes, DEN1-DEN4.[1]It maintains an infection cycle that uses mosquitoes, mostly the Aedes aegypti mosquito[2] and rarely the Asian tiger mosquito (Aedes albopictus), as vectors to human hosts, who also serve as sources of viral amplification. A aegypti is a small, highly domesticated, black-and-white tropical insect that prefers to feed on humans (favoring ankles and the back of the neck). See the images below.
The insect typically lays its eggs in artificial containers that contain water, and, as a consequence, dengue is frequently an urban-acquired disease.
Worldwide distribution of dengue in 2003. Picture from the Centers for Disease Control and Prevention (CDC) Web site.
In 1779-1780, the first reported outbreak of dengue fever (DF) occurred almost simultaneously in Asia, North America, and Africa. This indicates that the virus and its vector have a worldwide distribution in the tropical regions of the world (see the images below).
Worldwide distribution of dengue in 2000. Picture from the Centers for Disease Control and Prevention (CDC) Web site.Worldwide distribution of dengue in 2005. Picture from the Centers for Disease Control and Prevention (CDC) Web site
The clinical presentation of dengue infection involves a wide spectrum of findings, from asymptomatic or mild self-limiting infection of dengue fever to potentially fatal hemorrhage and shock (dengue hemorrhagic fever [DHF], dengue shock syndrome [DSS]).
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