A person in England has been diagnosed with the rare viral infection monkeypox, Public Health England (PHE) has said.
The patient is believed to have contracted the infection while visiting Nigeria and is currently being treated at the specialist high consequence infectious disease centre at Guy's and St Thomas' NHS Foundation Trust in London.
Close contacts of the patient, including those who travelled in close proximity to them on the flight from Nigeria to the UK, are being contacted.
PHE said monkeypox "is a rare viral infection that does not spread easily between people and the risk to the general public in England is very low.
"It is usually a self-limiting illness and most people recover within a few weeks.
"However, severe illness can occur in some individuals."
PHE said the patient was staying in south-west England before they were transferred to Guy's and St Thomas'.
It said it is working with the NHS to implement "rapid infection control procedures, including contacting people who might have been in close contact with the individual".
Dr Meera Chand, consultant microbiologist at PHE, said: "Monkeypox does not spread easily between people and the overall risk to the general public is very low.
"We are following up with those who have had close contact with the patient to offer advice and to monitor them as necessary.
"PHE and the NHS have well established and robust infection control procedures for dealing with cases of imported infectious disease, and these will be strictly followed to minimise the risk of transmission."
This is not the first time that the virus has been detected in the UK. PHE reported three cases of monkeypox in the UK in September 2018.
The first two were in people who had travelled from Africa and the third was a healthcare worker who cared for one patient. The worker became infected before monkeypox was suspected.
In most cases, monkeypox will resolve on its own and have no long-term effects on a person's health.
Initial symptoms include a fever, headache, muscle aches, backache, swollen lymph nodes, chills and exhaustion.
People can suffer a rash, which often begins on the face before spreading to other parts of the body.
The rash changes from raised red bumps to spots filled with fluid. The spots eventually form scabs which later fall off, according to the NHS website.
What is monkeypox?
Monkeypox is a rare viral infection, which does not spread easily among people and the general risk to the public is low.
The majority of recent cases have been reported in central and west African countries. Generally, it is a mild condition which resolves itself and has no long-term impact on a person's health. Usually, a sufferer fully recovers within a few weeks.
Early symptoms include fever, headache, muscle aches, backache, swollen lymph nodes, chills and exhaustion.
In certain cases, a rash develops - often on the face - and spreads to other parts of a person's body.
This rash will change colour over time, before finally forming into a scab, which will ultimately fall off.
How can you get monkeypox?
The orthopoxvirus is most often found in monkeys and rodents but can be passed to humans.
The death rate is much lower than other similar diseases, such as smallpox.
A person can get it by coming into contact with items used by an infected person or touching the spots or scabs of the sufferer.