Scientists studying the new mpox strain that has spread out of Democratic Republic of Congo say the virus is changing faster than expected, and often in areas where experts lack the funding and equipment to properly track it.

That means there are numerous unknowns about the virus itself, its severity and how it is transmitting, complicating the response, half a dozen scientists in Africa, Europe and the United States said.

Mpox, formerly known as monkeypox, has been a public health problem in parts of Africa since 1970, but received little global attention until it surged internationally in 2022, prompting the World Health Organization to declare a global health emergency. That declaration ended 10 months later.