Four people in England have been diagnosed with the rare viral infection monkeypox.
Three of the cases have been detected in London and one in the north east of England, the UK Health Security Agency (UKHSA) announced on Monday.
The UKHSA has said it is currently investigating connections between the four patients, who are all believed to have contracted it in the capital, although the virus is mainly spread by wild animals in areas of western and central Africa.
The new cases are not thought to be related to the two previously reported on 14 May and another isolated case discovered on 7 May.
So what precisely is monkeypox and how much danger does it pose to the public?
Where did monkeypox originate?
The World Health Organisation (WHO) traced the sickness to the tropical rainforests of Central and West Africa and defines it as a viral zoonotic (meaning it can be transmitted from animals to humans) disease akin to smallpox, itself eradicated in 1980.
The first recorded case of monkeypox was identified in what is now the Democratic Republic of Congo in 1970.
While it would have initially been transmitted to humans by contact with the blood or bodily fluids of contaminated primates (or rodents such as tree squirrels and Gambian rats), it is an infectious disease so is much more likely to be caught from fellow human sufferers.
What are the symptoms?
The disease has a six to 16 day incubation period. In its opening stages, patients first suffer fever, headaches, swellings, back pain, aching muscles and a general listlessness.
Once the fever breaks, the sufferer’s body will face a skin eruption, in which a rash spreads across the face, followed by the rest of the body, most commonly the palms of the hands and soles of the feet.
The blemishes evolve from lesions into crusted blisters, which can then take three weeks to heal and disappear.
The virus can be difficult to diagnose without the aid of laboratory analysis because of its superficial similarity to other afflictions that result in a rash, such as chickenpox, measles, scabies and syphilis.
How dangerous is it?
Dr Colin Brown, director of clinical and emerging infections at the UK Health Security Agency, said monkeypox “does not spread easily between people and the overall risk to the general public is very low”.
Although this strand of orthopoxvirus is much milder than smallpox, fatalities have been recorded, particularly among the young. WHO lists the case fatality rate as less than 10 per cent.
In Nigeria’s 2017 outbreak, the largest ever seen, 172 suspected cases of monkeypox were identified and 61 confirmed cases were reported across the country. Seventy-five per cent of sufferers were male and aged between 21 and 40 years old.
At present there is no vaccine or specific treatment available but the pre-existing smallpox has proven to be 85 per cent effective at combatting the disease.
Professor Jimmy Whitworth, of the London School of Hygiene and Tropical Medicine, stressed that while monkeypox is “usually mild... it is a sensible precaution that those people who may have come into contact with these two recent cases [in the UK] are being traced and followed up”.
How many cases have been detected in the UK?
The UK is one of only a handful of countries outside of Africa where monkeypox has been detected.
The first four infections were reported in Britain in 2018 and 2019. There was a second outbreak in 2021, in which three family members were diagnosed with the virus after travel to Nigeria.
The cases spotted in May double the UK’s total from seven to 14.
Those currently infected are being treated at specialist infectious disease units of the Royal Free Hospital and Guys' and St Thomas' in central London and at the Royal Victoria Infirmary in Newcastle upon Tyne.
