Anuj Kumar, Dalhousie University, Halifax, Canada

Anuj Kumar1, Gustavo Sganzerla Martinez1, Mansi Dutt1, Ali Toloue Ostadgavahi1, Alyson Kelvin2, Luis Flores3,4,5,6, Prince Kaleme Kiswele3,5, Christopher D. Richardson1, David J Kelvin1,7,8 1Department of Microbiology and Immunology, Canadian Center for Vaccinology (CCfV), Faculty of Medicine, Dalhousie University, Halifax, NS B3H 4H7, Canada 2Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada 3Centre de Recherche en Sciences Naturelles de Lwiro, South Kivu, Democratic Republic of the Congo 4Volunteers for the Conservation of Fauna and Flora (VCFF) 26 5One Health Conservation Initiative, Katana, Kabare, South Kivu, Democratic Republic of the Congo 6Centre de Rehabilitation des Primates de Lwiro, Lwiro, South Kivu, DS Bukavu, Democratic Republic of the Congo 7Department of Paediatrics, Dalhousie University, Halifax, NS B3H 4R2, Canada 8Laboratory of Immunity, Shantou University Medical College, Jinping, Shantou, Guangdong, China

Damaging & Spreading

Mpox, formerly known as monkeypox, is a viral infectious disease caused by the monkeypox virus (MPXV), a member of the Orthopoxvirus genus of the Poxviridae family. Phylogenetically, MPXV is classified into two main clades: Clade I and Clade II. The Clade Ib mpox virus (MPXV) was first reported in September 2023 in eastern Democratic Republic of Congo. Importantly, travel-associated cases of Clade Ib have been documented in other African countries, as well as in Europe, Asia, North America, South America, and Oceania, highlighting its global spread. In this study, we sequenced 17 new MPXV genomes and also analyzed a total of 608 Clade Ib MPXV sequences (available from GISAID) reported from 22 countries as of December 2025. Our analysis reveals partial deletion of the OPG164 and OPG153 proteins. Based on the variant calling, we noted that three important MPXV genes, including A24R (OPG150), B4R (OPG188), and E8L (OPG120), harbor emerging variants. Sequences reported from Africa were found to possess a high rate of APOBEC3 (apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like 3) mutations compared to the global sequences. Phylogenetic analysis demonstrated that most sequences from Uganda and Burundi formed two distinct clusters. Moreover, travel-associated cases clustered with multiple sub-lineages but showed a closer association with Uganda sequences than with others. Our study suggests multiple spillover events from animals (e.g., Rope Squirrels) to humans of Clade Ib/sh2023 viruses and indicates that multiple strains are circulating globally from different locations.