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Volume 31, Number 9—September 2025

Research Letter

Monkeypox Virus Clade IIa Infections, Liberia, 2023–2024

Dougbeh Chris Nyan1, Irina Maljkovic Berry1, Bode I. Shobayo, Monika Mehta, Gabriella Worwa, Shawn Hirsch, Sarah E. Klim, Fahn Taweh, Kalilu S. Donzo, B.M. Freeman, Alberta B. Corvah, Francis Jaryan, Julius S.M. Gilayeneh, Ian Crozier, Courtney Renken, Laura McNay, J. Soka Moses, Jens H. Kuhn, Lisa E. Hensley, and Sara E. ZufanComments to Author 
Author affiliation: National Public Health Institute of Liberia, Monrovia, Liberia (D.C. Nyan, B.I. Shobayo, F. Taweh, K.S. Donzo, B.M. Freeman, A.B. Corvah, F. Jaryan, J.S.M. Gilayeneh, J.S. Moses); National Institutes of Health, Frederick, Maryland, USA (I. Maljkovic Berry, M. Mehta, G. Worwa, S. Hirsch, S.E. Klim, J.H. Kuhn, S.E. Zufan); Clinical Monitoring Research Program Directorate, Frederick National Laboratory for Cancer Research, Frederick (I. Crozier); National Institutes of Health, Bethesda, Maryland, USA (C. Renken, L. McNay); US Department of Agriculture, Manhattan, Kansas, USA (L.E. Hensley)

Main Article

Figure

Sequencing characteristics of monkeypox virus clade IIa infections, Liberia, 2023–2024. A) Ancestral state reconstruction of the clade II phylogeny comparing the 5 new sequences against all publicly available clade IIa genomes (n = 27) and a subset of clade IIb sequences for context (n = 7), including hMPXV-1. Mutations are annotated along each branch with circles colored by whether it is an APOBEC3-like signature (TC→TT and GA→AA; dark orange) or whether it is another mutation type (light orange). Branch tips show circles colored by host (human, dark blue; NHP, turquoise; other, yellow). The sequences generated from this study are displayed in the green box. A large clade from Côte d'Ivoire NHPs is collapsed (turquoise funnel). Ultrafast bootstrap support is indicated only at nodes for which support <0.75. B) Number of APOBEC3-like SNPs of all mutations for subclade hMPXV-1, prior clade IIa sequences, and the new clade IIa found in Liberia. C) Comparison of the evolutionary clock rate of the prior clade IIa and new Liberian clade IIa sequences estimated under the local clock model. APOBEC3, apolipoprotein B mRNA editing enzyme catalytic subunit 3; hMPXV-1, sustained human monkeypox virus outbreak; NHP, nonhuman primate; SNP, single-nucleotide polymorphism.

Figure. Sequencing characteristics of monkeypox virus clade IIa infections, Liberia, 2023–2024. A) Ancestral state reconstruction of the clade II phylogeny comparing the 5 new sequences against all publicly available clade IIa genomes (n = 27) and a subset of clade IIb sequences for context (n = 7), including hMPXV-1. Mutations are annotated along each branch with circles colored by whether it is an APOBEC3-like signature (TC→TT and GA→AA; dark orange) or whether it is another mutation type (light orange). Branch tips show circles colored by host (human, dark blue; NHP, turquoise; other, yellow). The sequences generated from this study are displayed in the green box. A large clade from Côte d'Ivoire NHPs is collapsed (turquoise funnel). Ultrafast bootstrap support is indicated only at nodes for which support <0.75. B) Number of APOBEC3-like SNPs of all mutations for subclade hMPXV-1, prior clade IIa sequences, and the new clade IIa found in Liberia. C) Comparison of the evolutionary clock rate of the prior clade IIa and new Liberian clade IIa sequences estimated under the local clock model. APOBEC3, apolipoprotein B mRNA editing enzyme catalytic subunit 3; hMPXV-1, sustained human monkeypox virus outbreak; NHP, nonhuman primate; SNP, single-nucleotide polymorphism.

Main Article

1These first authors contributed equally to this article.

Page created: July 10, 2025
Page updated: August 04, 2025
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