This study was funded by grants FIS-PI-02/00017 and FIS-PI-05/00047 from the Spanish Ministry of Health. The authors are grateful to O. Donoso-Mantke for critical reading of the manuscript, to R. Schädler for assistance in the preparation of the manuscript, and to L. Puyol for technical assistance PLX-4720 nmr in sample management. C. D., M. N., D. S., L. V., M. V. E., I. S., M. G., and A. T. belong to the ENIVD network. J. G., O. W., M. S., R. L.-V., and S. P. belong to the TropNetEurop Network. The authors state they have no conflicts of interest to

declare. Supporting Information Additional Supporting Information may be found in the online version of this article: The following supporting information is available for this article: Table S1 Primers used for the sequencing of the complete E gene Table S2 DENV strains detected in European travelers Fig. S1 DENV-1 phylogenetical analysis and characterization PD-0332991 nmr of DENV-1 strains detected in European travelers using the carboxyl-terminal fragment of the E gene (264 sequences). The Neighbor-joining method (Tamura-Nei) was used for the analysis. Strains are denoted by name/number, country, and year of isolation. Strains detected on

this study are marked with a dot in the general tree and in bold in the individual genotype images. DENV = dengue viruses. Fig. S2 DENV-2 phylogenetical analysis and characterization of DENV-2 strains detected in European travelers using the carboxyl-terminal fragment of the E gene (340 sequences). The Neighbor-joining method (Tamura-Nei) was used for the analysis. Strains are denoted by name/number, country, and year of isolation. Strains detected on this study are marked with a dot in the general tree and in bold in the individual genotype images. DENV = dengue viruses. Fig. S3 DENV-3

phylogenetical analysis and characterization of DENV-3 strains detected in European travelers using the carboxyl-terminal fragment of the E gene (333 sequences). The Neighbor-joining method (Tamura-Nei) was used for the analysis. Strains are denoted by name/number, country, and year of isolation. Strains detected on this study are marked with a dot in the general tree and in bold in the individual genotype images. DENV = dengue viruses. Olopatadine Fig. S4 DENV-4 phylogenetical analysis and characterization of DENV-4 strains detected in European travelers using the carboxyl-terminal fragment of the E gene (243 sequences). The Neighbor-joining method (Tamura-Nei) was used for the analysis. Strains are denoted by name/number, country, and year of isolation. Strains detected on this study are marked with a dot in the general tree and in bold in the individual genotype images. DENV = dengue viruses. Fig. S5 Dengue serotype 1 complete E gene analysis. The phylogeny was inferred by Neighbor-joining method. The optimal tree is shown.