A second strain of monkeypox has been detected in the UK, health officials have confirmed.
A person who recently travelled to West Africa has been diagnosed with a different strain of monkeypox to the one circulating during the current outbreak, the UK Health Security Agency (UKHSA) announced.
The agency said the variant may have been seen in the UK before and that tests are being done to establish this.
The unnamed person has been admitted to the High Consequence Infectious Disease (HCID) unit at the Royal Liverpool University Hospital.
Contact tracing is now being done to establish if there are any further linked cases.
No cases had yet been identified as of Thursday, the UKHSA said.
Dr Sophia Maki, its incident director, said: “We are working to contact the individuals who had close contact with the case prior to confirmation of their infection, to assess them as necessary and provide advice.”
The risk to the public is “very low” due to “well established and robust” infection control procedures, which will be strictly followed, she added.
Anyone who is travelling to West and Central Africa is urged to be alert for the symptoms of monkeypox, which include a high temperature, headache, muscle and backache, swollen glands, shivering and exhaustion.
Single genital lesions and sores on the mouth or anus have also been identified as symptoms of the virus by an international collaboration of clinicians across 16 countries.
Some of the symptoms were so severe they required patients to be admitted to hospital.
Gay and bisexual men are disproportionately affected by the spread of the disease, with sexual closeness the most likely route of transmission.
However, it can be spread via any close contact, the scientific research revealed.
Chloe Orkin, professor of HIV Medicine at Queen Mary University of London, where the data was collated, said in July: “Viruses know no borders and monkeypox infections have now been described in 70 countries and more than 13,000 people.”
Anyone returning to the UK with monkeypox symptoms is urged to call 111.
The discovery of a new strain comes days after it emerged the UK is facing a 100,000 shortfall of monkeypox vaccine doses because the UKHSA grossly underestimated how many were required.
An NHS pilot scheme is now under way offering “fractional” doses to stretch stocks of the jab in a bid to protect five times as many people.