A patient with Lassa fever has been placed in the Royal Free Hospital's high level isolation unit (HLIU).

Two cases of the infectious disease have been identified in the UK, both in the same family and linked to recent travel to West Africa.

One patient has recovered while the other is at the Royal Free. A further probable case is under investigation in Bedfordshire.

Lassa fever is an 'acute viral haemorrhagic illness' caused by Lassa virus. People usually become infected through exposure to food or household items contaminated with urine or faeces of infected rats – present in a number of West African countries where the disease is endemic.

Most people make a full recovery, however severe illness can occur in some individuals.

Sir Michael Jacobs, consultant in infectious diseases at the Royal Free London, said: “The Royal Free Hospital is a specialist centre for treating patients with viral haemorrhagic fevers, including Lassa fever.

"Our secure unit is run by a highly trained and experienced team of doctors, nurses, therapists and laboratory staff and is designed to ensure our staff can safely treat patients with these kind of infections.”

Dr Susan Hopkins, chief medical advisor at the UK Health Security Agency said: "We can confirm that two cases of Lassa fever have been identified in England, and a further probable case is under investigation. The cases are within the same family and are linked to recent travel to West Africa.

"Cases of Lassa fever are rare in the UK and it does not spread easily between people. The overall risk to the public is very low. We are contacting the individuals who have had close contact with the cases prior to confirmation of their infection, to provide appropriate assessment, support and advice."

"UKHSA and the NHS have well established and robust infection control procedures for dealing with cases of imported infectious disease and these will be reinforced."

Prior to these cases, there have been eight cases of Lassa fever imported to the UK since 1980. The last two occurred in 2009. There was no evidence of onward transmission.