Using Background Sequencing Data to Anticipate DENV-1 Circulation in the Lao PDR

Elodie Calvez (1) , Phaithong Bounmany (1) , Charlotte Balière (2) , Somphavanh Somlor (1) , Souksakhone Viengphouthong (1) , Thonglakhone Xaybounsou (1) , Sitsana Keosenhom (1) , Kitphithak Fangkham (1) , Paul Brey (1) , Valérie Caro (2) , Vincent Lacoste (1) , Marc Grandadam (1)

1 Institut Pasteur du Laos
2 ERI - Environnement et Risques infectieux - Environment and Infectious Risks

Since its first detection in 1979, dengue fever has been considered a major public health issue in the Lao People’s Democratic Republic (PDR). Dengue virus (DENV) serotype 1 was the cause of an epidemic in 2010–2011. Between 2012 and 2020, major outbreaks due successively to DENV-3, DENV-4 and recently DENV-2 have been recorded. However, DENV-1 still co-circulated in the country over this period. Here, we summarize epidemiological and molecular data of DENV-1 between 2016 and 2020 in the Lao PDR. Our data highlight the continuous circulation of DENV-1 in the country at levels ranging from 16% to 22% among serotyping tests. In addition, the phylogenetic analysis has revealed the circulation of DENV-1 genotype I at least since 2008 with a co-circulation of different clusters. Sequence data support independent DENV-1 introductions in the Lao PDR correlated with an active circulation of this serotype at the regional level in Southeast Asia. The maintenance of DENV-1 circulation over the last ten years supports a low level of immunity against this serotype within the Lao population. Thereby, the risk of a DENV-1 epidemic cannot be ruled out in the future, and this emphasizes the importance of maintaining an integrated surveillance approach to prevent major outbreaks

Mots clés: dengue; DENV-1; epidemiology; phylogeny; Lao PDR

Domaines: Maladies infectieuses; Systématique, phylogénie et taxonomie; Maladies émergentes; Virologie; Santé publique et épidémiologie

Elodie Calvez, Phaithong Bounmany, Charlotte Balière, Somphavanh Somlor, Souksakhone Viengphouthong, et al.. Using Background Sequencing Data to Anticipate DENV-1 Circulation in the Lao PDR. Microorganisms, 2021, 9 (11), pp.2263. ⟨10.3390/microorganisms9112263⟩. ⟨hal-03690926⟩