Rapid diagnosis, genome sequencing and culture isolation of a monkeypox virus of clade Ib from a Ugandan during a professional stay in France.

A new monkeypox virus (MPXV) lineage, clade Ib, was first identified in September 2023 in South Kivu, Democratic Republic of the Congo. Here, we report the fourth imported case of MPXV clade Ib identified in France and the first publicly available French genome sequence and culture isolate. MPXV clade Ib infection was detected by quantitative polymerase chain reaction (qPCR) and confirmed by a clade Ib-specific qPCR. Whole-genome sequencing using Oxford Nanopore technology and viral culture on Vero E6 cells were both performed in a biosafety level 3 laboratory. Genome classification used Nextclade. Clinical presentation and outcome were without particularities or complications. This case highlights the ongoing international dissemination of MPXV clade Ib and underscores the importance of genomic surveillance and viral isolation for monitoring emerging MPXV lineages in non-endemic countries.