“We’re dealing with the animal-human interface being quite instable,’’ said Ryan in Geneva.

However, other diseases originating in animals such as Lassa fever and Ebola were also increasingly spreading to humans.

In the last several weeks, the UN agency had recorded over 550 cases of monkeypox in 30 countries where the virus is not usually found.

These numbers do not contain infections in the African countries where the virus is considered endemic.

Carriers of the monkey pox include various primates and rodents.

The latest wave of infections, reported largely in Western countries, appears, however, to show human-to-human transmission.

“We don’t really know whether it’s too late to contain,’’ said WHO expert, Rosamund Lewis about the virus.

However, she was optimistic that its spread could be curtailed with conventional hygiene measures.