The World Health Organization has called on authorities in Cameroon and Gabon to immediately strengthen their health systems to detect, test and isolate cases of the Marburg virus.
The agency further urged preventative measures.
WHO made the call after Equatorial Guinea, reported its first case of the viral disease that has so killed nine people with sixteen others receiving medical attention.
Highly fatal, Marburg belongs to the family of Ebola virus that causes haemorrhagic fever, bleeding and vomiting and kills about 7 days after infection.
Across the world, the UN health body says M-pox remains public health emergency of international concern.
More than thirty countries are still reporting cases.