Cases of the new mpox variant, which kills up to one in ten people it infects, may have reached three countries outside Africa.
Sweden has become the first country outside the continent to confirm a case of the new mpox strain, dubbed clade 1b, which has swept through central Africa killing hundreds of people since the outbreak began.
Now Pakistan and the Philippines have reported suspected cases, though they are awaiting test results to confirm whether the mpox case is specifically linked to the strain that is raising the alarm.
And experts suspect the new variant is already in Britain.
Infectious disease specialists told MailOnline that since symptoms can take up to 17 days from infection to appear, there is a strong chance that Britain’s first case could be confirmed within just a few days or weeks.
This long incubation time also means that border officials are unlikely to detect such cases, meaning that screening at airports is incredibly unlikely to be effective, they added.
To add to the confusion, another type of mpox, formerly called monkeypox, is making a resurgence in the UK.
The latest official data show that twice as many less fatal clade 2 mpox cases were recorded in July this year compared to the previous month.
The total of more than 40 cases in July is the highest number recorded in more than a year.
And as the maps on this website show, cases of the clade 2 variant, which is much less lethal than the clade 1 variant of global concern, are also being reported around the world.
The World Health Organization (WHO) last week declared the current outbreak of mpox in several Central African nations a “public health emergency of international concern.”
In the 2022 outbreak, thousands of cases were recorded in the UK, mainly in London.
This is the same designation the WHO gave to Covid in late January 2020, just weeks before the virus spread around the world, and some scientists have compared the current outbreak to the “early days of HIV.”
Now, within days, the first case of the new mpox variant outside the continent has been detected in Sweden, prompting the European Centre for Disease Prevention and Control to raise its risk level.
Suspected cases of the new variant have also been detected in two patients, in Pakistan and the Philippines.
However, local health authorities have said that although both patients have MPOX tests, they are still ongoing to establish whether these patients were indeed infected with the new strain.
Monkeypox, formerly known as Mpox, is a rare viral infection that is usually contracted in tropical areas of West and Central Africa. Pictured here, a coloured transmission electron micrograph of monkeypox particles (green) found inside an infected cell (pink and purple).
The UK’s Health Security Agency has said no cases have yet been detected in Britain and the risk to the public remains “low”.
But rapid tests are being made available and GPs and hospitals have been told to isolate those with potential symptoms.
The government is said to have enough vaccines and treatments to deal with a potential outbreak.
Professor Paul Hunter, an infectious diseases expert at the University of East Anglia, told MailOnline that the new strain of mpox was likely already in the UK.
“Given that symptoms can take up to 17 days to develop and then another week to confirm the diagnosis, it is highly likely, though not certain, that we already have this clade here,” he said.
He added that, similar to the clade 2 variant, sexual contact remains the main way the new strain spreads and therefore groups such as men who have sex with men would be at higher risk.
‘The 1b virus was first detected in sex workers and is spread primarily through sexual contact,’ she explained.
“So I think it’s likely that this new clade will spread more efficiently in the same population.”
An mpox clade 2 outbreak that swept across Europe in 2022 spread primarily through sexual contact, particularly among gay and bisexual men.
This led to the NHS offering these groups an mpox vaccine, along with other at-risk groups such as those working in venues where sex on-site takes place, as well as NHS workers who might be treating potential patients.
Nearly 100,000 people were infected in 2022 during the global outbreak of the disease.
The United States reported as many as 32,063 cases, with 58 deaths during the period, as cases were reported in significant numbers in North, Central and South America, Europe, Africa, Asia and Australasia.
However, the outbreak only killed about 183 people, and this strain has an estimated mortality rate of only one in every 500 people infected.
By comparison, the new strain 1b kills about one in 20 adults and one in 10 children.
But experts have said these mortality rates, which are seen in central Africa, are unlikely to be replicated in developed countries because of better access to higher quality healthcare.
However, cases of the mpox 2022 strain continue to circulate, with more than 5,000 cases reported worldwide since the beginning of the year.