In Ethiopia, dengue virus (DENV) infections have been reported in several regions; however, little is known about the genetic diversity of circulating viruses. We conducted clinical surveillance of DENV during the 2023 nationwide outbreak in Ethiopia. We enrolled patients at 3 sentinel hospital sites. Using reverse transcription PCR, we screened serum samples for 3 arboviruses and then serotyped and whole-genome sequenced DENV-positive samples. We detected DENV-1 and DENV-3 serotypes. Phylogenetic analysis identified 1 transmission cluster for DENV-1 (genotype III major lineage A) and 2 clusters for DENV-3 (genotype III major lineage B). The first DENV-3 cluster was closely related to an isolate from a 2023 dengue outbreak in Italy; the second cluster was related to isolates from India. Co-circulation of DENV-1 and DENV-3 in Ethiopia highlights the potential for severe dengue. Intensified surveillance and coordinated public health responses are needed to address the threat of severe dengue outbreaks.
Keywords: DENV; Ethiopia; dengue; dengue virus; genotype; human mobility; phylogenetic analysis; seasonality; serotype; vector-borne infections; viruses; zoonoses.