Experts fear Mpox could be quietly spreading in Britain as officials scramble to curb a potential crisis.
One Briton has already fallen ill with a disease never before seen in this country, which is killing one in 10 infected people.
The mutation, called clade 1b, was discovered after the unknown patient traveled to Britain from a holiday in Africa on October 21 before developing symptoms a day later.
The patient has been moved to a high-quality isolation unit at the Royal Free Hospital in North London.
But top virus doctors have told MailOnline that the first patient is likely to be one of many.
‘It is very likely that there are undetected cases of mpox clade 1b in the UK,” said Dr Azeem Majeed, a public health expert at Imperial College London.
Meanwhile, other specialists described the uncontrolled spread of the virus as ‘inevitable’, adding that it is ‘highly likely’ that several cases in Britain have gone undetected for weeks.
Yesterday, bosses at the UK Health Security Agency (UKHSA) revealed they do not know how the person with the diagnosed illness contracted the strain, but investigations are ‘ongoing’.
They urged Britons not to panic, saying the threat clade 1b poses to the public was ‘low’.
Dr. Majeed said MPox can fly under the radar because symptoms can be nonspecific or mild, and the rash can be confused. with rashes due to other diseases.
“It can even be asymptomatic,” he added.
It is “essential”, he said, that there is “rigorous surveillance” to identify potential cases early and “prevent the further undetected spread of MPox”.
Meanwhile, Dr Simon Clarke, an infectious disease expert at the University of Reading, told MailOnline: ‘It is certainly possible for the disease to spread unnoticed.
“If there are asymptomatic cases, there is always the possibility of spread that we don’t know about.
‘Unless there is systematic checking of everyone at the border – which there isn’t – then you won’t know until people come to the NHS through the hospital or their GP.
‘Inevitably, people traveled from the region in Africa where it was located, so there is a good chance it spread across Europe.
‘Cases have been picked up in Germany and Sweden, so of course anyone who traveled there could have picked it up too.’
Professor Paul Hunter, an infectious disease expert at the University of East Anglia, said he was “surprised” that the first clade1b case in Britain had not been discovered earlier.
Mpox is not classified as a sexually transmitted infection, although it can be transmitted through direct contact during sex.
The unnamed patient had traveled back to Britain from a holiday in Africa on an overnight flight on October 21
‘The fact that no reports have been made does not necessarily mean that there have been none.
“It is absolutely plausible that there have been more infections in Europe than we know.”
However, he warned: “I don’t think it will be as big of a problem as we saw two years ago.”
The clade 2 mpox strain spread worldwide in 2022, mainly affecting gay and bisexual men.
But Professor Hunter noted that the new strain “could pose a major problem” if it spreads among female sex workers in Britain.
Mpox is not classified as a sexually transmitted infection, although it can be transmitted through direct contact during sex.
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Infectious lesions, through which infections are most likely to be passed on, can occur on any part of the body.
The infection can also be transmitted through contact with clothing or bedding used by an infected person.
Professor Hunter added: ‘Female sex workers can have multiple partners themselves, so if she were under pressure she could potentially infect quite a few of the men who use her services.
‘They could then spread it among their own families.
“If we see such spread, we have to change our strategy.”
The clade 1b mutation, which experts have previously called ‘the most dangerous yet’, is believed to be the cause of a spate of miscarriages.
Since the outbreak began, the disease has spread through Central Africa, killing at least a thousand people.
Countries such as the Democratic Republic of Congo have been hit particularly hard, with cases also seen in Burundi, Rwanda, Uganda and Kenya.
Although designed for smallpox, Imvanex provides recipients with cross-protection because the virus is from the same orthopoxvirus family
However, experts say the death rate of clade 1b from Central Africa is unlikely to be repeated in developed countries such as Britain, due to greater access to higher quality healthcare.
Britain’s first case now means the country joins countries such as Sweden, Thailand, India and Germany in cases outside Africa.
The An unnamed patient had traveled back to Britain from a holiday in Africa on an overnight flight on October 21.
They developed flu-like symptoms 24 hours later, followed by a rash, and went to the emergency room on October 27 where they were tested for MPox.
Fewer than 10 people are now being contacted, although authorities are “still working” on how many people they may need to monitor, the UKHSA said.
Officials do not currently suspect the patient was contagious during the flight back from the as-yet-unnamed African country where they contracted the disease.
UKHSA also said they are securing more supplies of MPox vaccines as part of the jab’s further rollout.
The current MPOX vaccines were used against the milder variant during the 2022 global outbreak.
It is a far cry from the 2022 outbreak, when thousands of cases were recorded, mainly in London
Although it is designed for smallpox, Imvanex provides recipients with cross-protection because the virus is from the same family of orthopoxviruses.
The vaccine, believed to cost £20 per dose, contains a modified vaccinia virus, which is similar to both smallpox and mpox but does not cause disease in humans.
Experts today warned that despite the emergence of the new strain, Britain’s current targeted vaccine strategy ‘remains the best policy for Britain’ and that all ‘risk groups are covered’.
Dr. Majeed told MailOnline: ‘The targeted vaccination program during the 2022 outbreak in Britain was effective in reducing the number of cases.
‘For now, I think a targeted vaccine strategy remains the best policy for Britain.
‘The targeted approach to vaccination is in line with patterns observed in previous outbreaks, with most cases occurring in groups such as gay men.’
Common symptoms of MPOX include a rash or pus-filled lesions that can last for two to four weeks.
In a small number of cases, the infection can invade the blood and lungs, as well as other parts of the body such as the brain, making it life-threatening.
Anyone with symptoms should continue to avoid contact with other people while symptoms persist.
It can also cause fever, headache, muscle aches, back pain, low energy, and swollen lymph nodes.