LONDON, June 25 (Reuters) - The spread of mpox in Africa needs to be addressed urgently, the World Health Organization said on Tuesday, as scientists warned separately of a dangerous strain in the Democratic Republic of Congo.

"There is a critical need to address the recent surge in mpox cases in Africa," Rosamund Lewis, the WHO's technical lead for mpox, said in a briefing note to journalists.

In a separate briefing, John Claude Udahemuka of the University of Rwanda, who has been working on an outbreak in Congo's hard-to-reach South Kivu province, said the strain spreading there - a mutated version of the clade I mpox endemic in Congo for decades - was extremely dangerous. It has fatality rates of around 5% in adults and 10% in children.

This year, roughly 8,600 mpox cases have been reported in Congo, and 410 deaths, Cris Kacita, the doctor in charge of operations in the country's mpox control programme, told Reuters last week.

Mpox is a viral infection that spreads through close contact, causing flu-like symptoms and pus-filled lesions. Most cases are mild but it can kill.