HTLV-1 genetic diversity of 52 complete sequences from 14 African countries reveals novel variants and a lack of typical P12/P8 and P30 accessory proteins in HTLV-1b, d, and f genotypes
Author(s)
Cassar, Olivier
Djuicy, Délia Doreen
Begliomini, Giovanni
Ramassamy, Jill-Léa
Oloumbou, Eldridge Fredricksen
Type
Journal Article
Abstract
Central Africa is the largest region of human T-cell Leukaemia virus (HTLV-1) endemicity with several million people estimated to be infected. Based on the study of the LTR region, it is also the region with the highest HTLV-1 diversity, with the presence of genotypes a-b and d-g. However, complete genomic sequences are still lacking for Central African genotypes. Here, we report the first large collection of complete HTLV-1 sequences for genotypes b, d and f from Central Africa and neighbouring countries. We identified substantial diversity within the HTLV-1b genotype, including a newly defined clade that we designated HTLV-1b-del. It mainly comprises strains from the Democratic Republic of the Congo (COD) and neighbouring countries and is characterized by a distinctive 12-bp-long deletion. We also generated the complete sequence of the STLV-1 strain from Allenopithecus nigroviridis from the COD. This strain belongs to the PTLV-1b genotype and carries a 12-bp duplication in the pX region. Lastly, we found that, except for HTLV-1a strains, HTLV-1 genomes generally lack open reading frames encoding the canonical accessory protein P12; instead, they encode either shorter versions of the protein or an ORF lacking a start ATG codon. This work substantially expands the genomic landscape of HTLV-1 in Central Africa and provides a critical resource for understanding viral diversity.
Date Issued
2026-12-31
Date Acceptance
2026-03-23
Citation
Emerging Microbes and Infections, 2026, 15 (1)
ISSN
2222-1751
Publisher
Taylor & Francis Group
Journal / Book Title
Emerging Microbes and Infections
Volume
15
Issue
1
Copyright Statement
© 2026 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group, on behalf of Shanghai Shangyixun Cultural Communication Co., Ltd This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The terms on which this article has been published allow the posting of the Accepted Manuscript in a repository by the author(s) or with their consent.
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/41879736
Subjects
Africa
HTLV
STLV
accessory proteins
molecular epidemiology
Human T-lymphotropic virus 1
Humans
Genetic Variation
Genotype
HTLV-I Infections
Phylogeny
Genome, Viral
Animals
Africa
Open Reading Frames
Publication Status
Published
Coverage Spatial
United States
Article Number
2651463
Date Publish Online
2026-04-07