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Volume 32, Number 10—October 2026

Research Letter

Cocirculation of Human Monkeypox Virus Clade 1b with Varicella Zoster Virus, Uganda

Nicholas BbosaComments to Author , Alfred Ssekagiri, Hamidah S. Namagembe, Stella E. Nabirye, Ronald Kiiza, Danstan Kabuuka, Stephen Balinandi, Tom Lutalo, John Kayiwa, Henry Kyobe Bosa, Robert Downing, Michael G. Berg, Mary A. Rodgers, Gavin A. Cloherty, Pontiano Kaleebu, and Deogratius Ssemwanga
Author affiliation: Uganda Virus Research Institute, Entebbe, Uganda (N. Bbosa, A. Ssekagiri, S.E. Nabirye, D. Kabuuka, S. Balinandi, T. Lutalo, J. Kayiwa, R. Downing, P. Kaleebu, D. Ssemwanga); Medical Research Council/Uganda Virus Research Institute and London School of Hygiene and Tropical Medicine Uganda Research Unit, Entebbe (N. Bbosa, H.S. Namagembe, R. Kiiza, P. Kaleebu, D. Ssemwanga); Abbott Pandemic Defense Coalition, Abbott Park, Illinois, USA (N. Bbosa, M.G. Berg, M.A. Rodgers, G.A. Cloherty); Uganda Ministry of Health, Kampala, Uganda (H.K. Bosa); Uganda People’s Defence Forces, Kampala (H.K. Bosa); Makerere University Lung Institute, Kampala (H.K. Bosa); Abbott Diagnostics, Abbott Park (M.G. Berg, M.A. Rodgers, G.A. Cloherty)

Main Article

Figure 1

Phylogenetic and mutational characterization of Uganda monkeypox virus (MPXV) strains in study of cocirculation of human MPXV clade 1b with varicella-zoster virus, Uganda. A) Maximum-likelihood phylogenetic tree of MPXV sequences generated with 1,000 bootstrap resampling. Tree includes 115 new sequences from Uganda (highlighted with a gray rectangular background) and 37 clade 1B reference sequences retrieved from GenBank and GISAID (https://www.gisaid.org) (accession numbers provided). Highly similar sequences have been collapsed (denoted by triangle). Scale bar indicates number of nucleotide substitutions per site. B) New (n = 115; red squares) and previously reported (n = 22; blue squares) Uganda sequences were aligned, and Squirrel software was used to infer the maximum-likelihood phylogeny and map APOBEC (brown circle) and non-APOBEC (yellow circle) mutation events. The number of unique mutations from this study and shared mutations distinct from the DQ011155.1 clade I archetype are listed.

Figure 1. Phylogenetic and mutational characterization of Uganda monkeypox virus (MPXV) strains in study of cocirculation of human MPXV clade 1b with varicella-zoster virus, Uganda. A) Maximum-likelihood phylogenetic tree of MPXV sequences generated with 1,000 bootstrap resampling. Tree includes 115 new sequences from Uganda (highlighted with a gray rectangular background) and 37 clade 1B reference sequences retrieved from GenBank and GISAID (https://www.gisaid.org) (accession numbers provided). Highly similar sequences have been collapsed (denoted by triangle). Scale bar indicates number of nucleotide substitutions per site. B) New (n = 115; red squares) and previously reported (n = 22; blue squares) Uganda sequences were aligned, and Squirrel software was used to infer the maximum-likelihood phylogeny and map APOBEC (brown circle) and non-APOBEC (yellow circle) mutation events. The number of unique mutations from this study and shared mutations distinct from the DQ011155.1 clade I archetype are listed.

Main Article

Page created: August 13, 2026
Page updated: September 21, 2026
Page reviewed: September 21, 2026
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