Lassa fever is an acute viral haemorrhagic illness caused by Lassa virus. People usually become infected with Lassa virus 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. The virus can also be spread through infected bodily fluids.
Most people with Lassa fever will make a full recovery, however severe illness can occur in some individuals. One of the cases has recovered, while the other will receive specialist care at the Royal Free London NHS Foundation Trust.
The probable case is receiving care at Bedfordshire Hospitals NHS Foundation Trust. The High Consequence Infectious Disease Network is engaged with their ongoing care.
Dr Susan Hopkins, Chief Medical Advisor at UKHSA said:
We can confirm that 2 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 8 cases of Lassa fever imported to the UK since 1980. The last 2 cases occurred in 2009. There was no evidence of onward transmission from any of these cases.
Dr 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.
People living in endemic areas of West Africa with high populations of rodents are most at risk of Lassa fever. Imported cases rarely occur elsewhere in the world. Such cases are almost exclusively in people who work in endemic areas in high-risk occupations, such as medical or other aid workers