Mpox clade Ib is now circulating locally among men WHO have sex with men in Europe with no African travel history, continuing the local clade Ib spread that ECDC first reported in Spain, Italy, Portugal and the Netherlands in October 20251. mpox, formerly called monkeypox, comes in genetic lineages called clades; clade I has historically been the more severe and was confined to central Africa until recently. Local transmission means European cases are catching the virus from each other rather than importing it from abroad, an advance on the recombinant clade Ib/IIb strain tracked across four countries in May.
In the United States, all 23 confirmed clade I cases remain travel-linked, and the CDC expects numbers to rise with World Cup travel as crowds gather across the host nations from mid-June. The ECDC and UK Health Security Agency are watching whether existing Jynneos vaccine stocks, validated against earlier strains, hold against clade Ib.
This mpox signal and the Dermatophilus congolensis cluster surface in the same surveillance window and the same community, but they are independent pathogens, a virus and a bacterium, with no causal link between them. Both appear here because sexual-health screening in this community is among the densest anywhere, not because they share an outbreak or a cause. Reading them as one phenomenon would be a category error.
