STAT | A Niedringhaus/AP
Mpox is caused by a virus in the same family as smallpox, a virus that was declared eradicated in 1980. The virus, which is believed to be carried by small rodents in some countries in Africa, causes painful scarring rashes when contracted by people. People with mpox can also experience fever, muscle aches, headaches, and respiratory symptoms. The infection is especially dangerous in young children — most mpox deaths occur in young children — and people with compromised immune systems.