Nigeria has recorded six monkeypox cases in May from four states, the country's Centre for Disease Control (CDC) said late on Sunday.
The cases were reported in the states of Bayelsa (two), Adamawa (two), Lagos (one) and Rivers (one).
In total, the country has confirmed 21 cases since the start of the year with one death reported - a 40-year-old patient.
The cases were reported in nine states and the capital, Abuja.
The CDC said there was a case of a visitor who "exported monkeypox from Nigeria" to the UK. The case was detected on 6 May by British authorities.
Outbreaks of the virus have been found in Europe, Australia and America.
The symptoms often include a fever and rash - but the infection is usually mild.