Two individuals have been diagnosed with monkeypox virus in London, the UK Health Security Agency (UKHSA) confirmed on Saturday.
The cases are from the same household and are not linked to a previous infection confirmed by the agency last week, which had been linked with recent travel history to Nigeria where they are believed to have caught it.
Where and how the two new cases acquired their infection remains under investigation.
We have confirmed two new monkeypox cases in England that are not linked to the case announced on May 7, said Dr. Colin Brown, UKHSA Director of Clinical and Emerging Infections.
While investigations remain ongoing to determine the source of infection, it is important to emphasise it does not spread easily between people and requires close personal contact with an infected symptomatic person. The overall risk to the general public remains very low, he said.
UKHSA said they are contacting any potential friends, family, or contacts in the community and are also working with the National Health Service (NHS) to reach any healthcare contacts who have had close contact with the cases prior to confirmation of their infection, to assess them as necessary and provide advice.
UKHSA and NHS have well-established and robust infection control procedures for dealing with cases of imported infectious disease and these will be strictly followed, added Brown.
One of the cases is receiving care at the expert infectious disease unit at St. Mary's Hospital, Imperial College Healthcare NHS Trust, London. The other case is isolating and does not currently require hospital treatment.
We are caring for a patient in our specialist high consequence infectious diseases unit at St. Mary's Hospital. All of the necessary infectious control procedures have been followed and we are working closely with UKHSA and NHS England, said Professor Julian Redhead, medical director at Imperial College Healthcare NHS Trust.
Monkeypox is a rare viral infection that does not spread easily between people. It is usually a mild self-limiting illness and most people recover within a few weeks.
However, severe illness can occur in some people. The infection can be spread when someone is in close contact with an infected person, however, experts believe there is a very low risk of transmission to the general population.
Initial symptoms of monkeypox include fever, headache, muscle aches, backache, swollen lymph nodes, chills, and exhaustion.
A rash can develop, often beginning on the face, then spreading to other parts of the body, particularly the hands and feet.
The rash changes and goes through different stages before finally forming a scab, which later falls off.
It can be spread when someone is in close contact with an infected person. The virus can enter the body through broken skin, the respiratory tract, or through the eyes, nose, or mouth.
The NHS said the infection could be caught from infected wild animals in parts of west and central Africa and was believed to be spread by rodents.
The UKHSA said people without symptoms are not considered infectious but, as a precaution, those who have been in close proximity of the infected patients are contacted to ensure that if they do become unwell they can be treated quickly.
The first-ever recorded occurrence of the monkeypox virus in the UK was in 2018, and since then a handful of cases have been confirmed by health authorities.