Development of a standardized Sanger-based method for partial sequencing and genotyping dengue viruses.

The global expansion of dengue viruses (DENV-1-4) has contributed to the divergence, transmission, and establishment of genetic lineages of epidemiological concern; however, tracking phylogenetic relationships of these virus is not always possible due to inability of standardized sequencing procedures in resource-limited public health laboratories Consequently, public genomic data banks contain inadequate representation of geographical regions and historical periods. In order to improve detection of DENV-1-4 lineages, we report the development of a serotype-specific Sanger-based method standardized to sequence DENV-1-4 directly from clinical samples using universal primers that detect most DENV genotypes. The resulting envelope protein coding sequences are analyzed for genotyping with phylogenetic methods. We evaluated the performance of this method by detecting, amplifying, and sequencing 54 contemporary DENV isolates, including 29 clinical samples, representing a variety of genotypes of epidemiological importance and global presence. All specimens were sequenced successfully and phylogenetic reconstructions resulted in the expected genotype classification. To further improve genomic surveillance in dengue endemic regions, this method was transferred to 16 public health laboratories in 13 Latin American countries, to date. Our objective is to provide an accessible method that facilitates the integration of genomics with dengue surveillance.