The UN health agency said on Friday that it had approved the use of the first diagnostic test for mpox, a key tool in countries battling outbreaks.

More than 800 people have died across Africa from mpox, where the disease has been officially detected in 16 countries, according to the African Union's disease control centre.

"The approval for emergency use" of the test "will be pivotal in expanding diagnostic capacity in countries facing mpox outbreaks, where the need for quick and accurate testing has risen sharply", the World Health Organization said in a statement.

The test, called the Alinity m MPXV assay and manufactured by Abbott Molecular Inc., enables the detection of the mpox virus from swabs taken from human lesions.

"By detecting DNA from pustular or vesicular rash samples, laboratory and health workers can confirm suspected mpox cases efficiently and effectively", the WHO said.

"Limited testing capacity and delays in confirming mpox cases persist in Africa, contributing to the continued spread of the virus", it said.

The approval of the test "represents a significant milestone in expanding testing availability in affected countries," the statement quoted Yukiko Nakatani, an assistant director-general of WHO, as saying.

"Increasing access to quality-assured medical products is central to our efforts in assisting countries to contain the spread of the virus and protect their people, especially in underserved regions", Nakatani said.

Mpox, previously known as monkeypox, is caused by a virus transmitted to humans by infected animals but can also be passed from human to human through close physical contact.

It causes fever, muscular aches and large boil-like skin lesions, and can be deadly.