Dengue virus (DENV) is the cause of dengue fever. It is a mosquito-borne single positive-stranded RNA virus of the family Flaviviridae; genus Flavivirus. Five serotypes of the virus have been found, all of which can cause the full spectrum of disease. Non-structural protein 1 is involved in immune evasion, pathogenesis and viral replication. Once cleaved off the polyprotein, NS1 is targeted to three destinations: the viral replication cycle, the plasma membrane and the extracellular compartment. It may plays a role in viral genome replication.