Sweden reports 1st case of deadlier mpox outside Africa

Illustration of blocky, roughly rectangular viral particles with bumps on their surfaces.

Sweden has just announced the country's first case of clade 1 mpox, a deadlier version of mpox that previously had been reported only in Africa.

Mpox, formerly known as monkeypox, is caused by a group of viruses with two main branches in their family tree: clade 1 and clade 2. The latter caused the global mpox emergency in 2022 and 2023, which affected countries all over the world, including the U.S., the U.K. and Sweden. In comparison, clade 1 mpox viruses cause more severe disease and death and had never been seen outside Africa — until now.