Mpox was first detected in humans in neighbouring Democratic Republic of Congo in 1970, according to the WHO.
Republic of the Congo has declared an epidemic of mpox after 19 cases were confirmed across five departments, including the capital Brazzaville.
No deaths have yet been recorded, Health Minister Gilbert Mokoki said in a statement on Tuesday.
He called on the public to take precautions including avoiding close contact with suspected cases, avoiding contact with animals and avoiding handling game meat with bare hands.
The World Health Organisation (WHO) has named the virus mpox to replace the older term monkeypox, citing concerns of stigma and racism associated with the name.
Mpox was first detected in humans in neighbouring Democratic Republic of Congo in 1970, according to the WHO.
Symptoms include fever, aches and skin lesions.
In 2022, the WHO declared an outbreak that spread to Europe and North America a global health emergency.