Phylogeographic analysis of dengue virus serotype 1 and cosmopolitan serotype 2 in Africa

Objectives: The origin and spread of dengue virus (DENV) circulating in Africa remain poorly character-ized, with African sequences representing < 1% of global sequence data. Methods: Whole genome sequencing was performed on serum samples (n = 29) from an undifferentiated fever study in 2016 in the Democratic Republic of Congo (DRC), and from febrile travelers returning from Africa. The evolutionary history of the newly acquired African DENV-1 (n = 1) and cosmopolitan genotype DENV-2 (n = 18) genomes was reconstructed using a phylogeographic, time-scaled Bayesian analysis on a curated DENV panel including all known African sequences. Results: A minimum of 10 and eight introductions could be identified into Africa for DENV-1 and cos-mopolitan DENV-2, respectively, almost all originating from Asia. Three introductions were previously unknown. The currently circulating virus comprises mainly the recently introduced clades and one long-established African clade. Robust geographical clustering suggests limited spread of DENV after each in-troduction. Our data identified the DRC as the source of the 2018 Angolan DENV-2 epidemic, and simi-larly, the 2013 Angolan DENV-1 outbreak as the origin of our DRC study. Conclusion: Active genomic surveillance of DENV in Africa at the portals of entry might help early out-break response and limit sero-and genotype spread and human disease burden. (c) 2023 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )

Automated summary

The origin and spread of dengue virus (DENV) circulating in Africa were studied by sequencing serum samples from the Democratic Republic of Congo and febrile travelers returning from Africa. The results showed that DENV in Africa mainly originated from Asia through multiple introductions. Genomic surveillance of DENV in Africa can help with early outbreak response and limit virus spread and human disease burden.