Kenya and the Central African Republic have declared new outbreaks of mpox as Africa’s health officials race to contain the spread of the disease in a region lacking vaccines.

Nairobi announced the outbreak on Wednesday, after a case was detected in a passenger traveling from Uganda to Rwanda at a border crossing in southern Kenya. The Central African Republic was the first to declare a new outbreak on Monday, saying it extends to its capital of Bangui.

Mpox, previously known as monkeypox, is caused by a virus that originates in wild animals and occasionally jumps to people, who can spread it to others.