DENGUE

Dengue fever and dengue hemorrhagic fever (DHF) are acute febrile diseases which occur in the tropics can be life-threatening, and are caused by four closely related virus serotypes of the genus Flavivirus, family Flaviviridae. It is also known as breakbone fever. It occurs widely in the tropics, including northern Argentina, northern Australia, the entirety of Bangladesh, Barbados, Bolivia, Brazil, Cambodia, Costa Rica, Dominican Republic, Guatemala, Guyana, Honduras, India, Indonesia, Jamaica, Laos, Malaysia, Mexico, Micronesia, Pakistan, Panama, Paraguay, Philippines, Puerto Rico, Samoa, Singapore, Sri Lanka, Suriname, Taiwan, Thailand, Trinidad, Venezuela and Vietnam, and increasingly in southern China. Unlike malaria, dengue is just as prevalent in the urban districts of its range as in rural areas. Each serotype is sufficiently different that there is no cross-protection and epidemics caused by multiple serotypes (hyperendemicity) can occur. Dengue is transmitted to humans by the Aedes aegypti or more rarely the Aedes albopictus mosquito, which feed during the day.
The WHO says some 2.5 billion people, two fifths of the world's population, are now at risk from dengue and estimates that there may be 50 million cases of dengue infection worldwide every year. The disease is now endemic in more than 100 countries.