Another case of the new deadly mpox strain has been detected in the UK, health officials confirmed today. 

The clade 1b mutation, which experts have called ‘the most dangerous one so far’ kills one in ten of those infected and is believed to be behind a wave of miscarriages.

It takes the total number of confirmed cases in Britain now to five. The unidentified patient, from Leeds, had no links to the previous four cases.

Officials don’t yet know how they became infected with the strain.

But they had ‘recently’ travelled back to the UK from Uganda, the UK Health Security Agency (UKHSA) said. 

The latest patient is under specialist care at Sheffield Teaching Hospitals NHS Foundation Trust, 160 miles from where the first four cases were identified in London. 

However, health chiefs say they still consider the threat clade 1b poses to the public as ‘low’. 

Professor Susan Hopkins, chief medical adviser at UKHSA, said: ‘It is thanks to clinicians rapidly recognising the symptoms and our diagnostics tests that we have been able to detect this new case. 

‘The risk to the UK population remains low following this fifth case, and we are working rapidly to trace close contacts and reduce the risk of any potential spread. 

‘In accordance with established protocols, investigations are underway to learn how the individual acquired the infection and to assess whether there are any further associated cases.’

The UKHSA said all contacts of this fifth case will be offered testing and vaccination as needed and advised on any necessary further care if they have symptoms or test positive.

The UK’s first mpox case was detected after the unidentified patient developed flu-like symptoms, followed by a rash and attended A&E on October 27 where they were tested. 

They were then transferred to a high-level isolation unit at the Royal Free Hospital in North London — the same facility where imported cases of Ebola were treated in 2015.    

Earlier this month, officials confirmed a further three patients were being treated at Guy’s and St Thomas’ NHS Foundation Trust with the strain. 

But all four cases, who were from the same household, have now all fully recovered, the UKHSA said today. 

A global outbreak of mpox, previously known as monkeypox, began in Africa in May 2022.

But the latest Clade 1b strain is considered far deadlier. 

It has swept through central Africa killing at least 1,000 people, since the outbreak began.

Countries like the Democratic Republic of Congo have been hit especially hard with cases also spotted in Burundi, Rwanda, Uganda, Kenya.

However, experts say fatality rates of clade 1b from central Africa are unlikely to be replicated in developed nations like the UK due to better access to higher quality healthcare. 

Britain’s five cases means it joins countries including the US, Sweden, Thailand, India and Germany in having cases outside of Africa. 

In July, the World Health Organization (WHO) declared an ongoing mpox outbreak across several central African nations as a ‘public health emergency of international concern’.

This is the same designation the WHO gave Covid in late January 2020, just a few weeks before the virus ripped across the world, and some scientists have compared the current outbreak to the ‘early days of HIV’.

Mpox causes characteristic lumpy lesions, as well as a fever, aches and pains and fatigue.

However, in a small number of cases, it can enter the blood and lungs, as well as other parts of the body, when it becomes life-threatening.

Current mpox vaccines, which are designed to work on smallpox a close relative of the mpox virus, were used during the 2022 outbreak against the milder strain.

But they have yet to be widely tested against the more potent clade 1b strain.

The WHO and the NHS recommends a vaccine within four days of contact with someone who has the virus or within up to 14 days if there are no symptoms.

Healthcare workers and men who have sex with men are advised to receive a vaccine even if they have had no mpox exposure.

There are no direct treatments available with medics focused instead on supporting a patient to help their body fight off the virus.