Dengue fever is a viral disease spread by mosquito of Flaviviridae family.1,2 Antigenically, four different serotypes of the dengue virus with 65% genomic similarity exist.3,4 Commercially available kits use mixes of inactivated viral preparations or recombinant envelope proteins, so detection of anti-dengue antibodies is problematic.5 Here, ERVW-1 is linked to dengue disease.