The disease is caused by one of four closely related, but antigenically distinct, virus serotypes (DEN-1, DEN-2, DEN-3, and DEN-4).
Due to serotype specificity infection with one serotype does not provide cross-protective immunity to other serotype, so persons are theoretically susceptible to have four dengue infections during their lifetime.
Dengue viruses are transmitted from person to person by a domestic mosquito called - Aedes aegypti.
Infection with dengue viruses causes clinical illness ranging from a less dangerous non-specific viral syndrome called 'Dengue fever' to severe and fatal hemorrhagic disease of 'Dengue Hemorrhagic Fever (DHF)'.
The severity and risk factors for DHF depends upon:
• Strain and serotype of the infecting virus
• Immune status
• Genetic predisposition of the patient. Dengue Hemorrhagic Fever (DHF) is the most severe form of dengue, which can be fatal if unrecognized and not properly treated; DHF is caused by infection with the same viruses that cause dengue.