Dengue fever outbreaks have been repeatedly reported in Cote d'Ivoire. In 2019 outbreak, DENV-1 was predominant and phylogenetic analysis of the DENV-1 strain detected in a present patient who returning to Japan in January 2019 revealed high homology with the 2013-2014 Southeast Asian strains. Previous outbreak in 2017, DENV-1 accounted for 5% of the DENV serotypes. The endemic DENV-1 strain in Abidjan in 2019 could be a strain that was imported from Southeast Asia. Dengue virus spreads intercontinentally and imported dengue fever case could be an alert for the outbreaks in the exporting country.