The UK Health Security Agency (UKHSA) announced on Friday that it has identified a second monkeypox strain in a hospitalized individual who has recently traveled to west Africa.

"Preliminary genomic sequencing conducted by the UKHSA indicates that this case does not have the current outbreak strain circulating in the UK," the UKHSA said.

The agency said contact tracing is being conducted to establish if there are any further linked cases, though it did not reveal whether the case involves a new strain of monkeypox, or one that has previously been identified.

"The UKHSA and the NHS have well-established and robust infection control procedures for dealing with cases of imported infectious disease and these will be strictly followed. The risk to the general public is very low," said Dr. Sophia Maki, incident director at the UKHSA.

Monkeypox is endemic in animals in parts of west Africa and has caused outbreaks in humans there. The virus lasts for two to four weeks and is mild in most cases, but can prove fatal for children and the immunocompromised. Initial symptoms are fever and muscle aches followed by a skin rash and lesions. 

The monkeypox outbreak that is concentrated among men who have sex with men has affected over 53,000 cases in 100 places globally, according to the Centers for Disease Control and Prevention as of 5:00 p.m. EDT, September 2.