#16,559
While we remain focused on our COVID pandemic there are other public health threats out there that deserve our attention. Viruses with pandemic potential - like MERS-CoV, Nipah, Monkeypox and multiple subtypes of avian influenza (to name but a few) - still circulate, and evolutionary processes continue to propel them, and others, towards greater human impact.Admittedly very low on our pandemic worry list, every year Lassa fever - which is endemic to a handful of West African Nations (see map above) - sparks sporadic local outbreaks, mainly during their dry season (Nov-May).
Lassa fever is a Viral Hemorrhagic Fever (VHF) commonly carried by multimammate rats - a local rodent that often likes to enter human dwellings. Exposure is typically through the urine or dried feces of infected rodents, and roughly 80% who are infected only experience mild symptoms.
Like many other hemorrhagic fevers, person-to-person transmission may occur with exposure to the blood, tissue, secretions, or excretions of an individual (cite CDC Lassa Transmission).
Over the past decade we've followed a small number exported cases turning up outside of Western Africa, including in the United States, Germany, and Sweden. Luckily, secondary transmission is far less common with Lassa than with many of the other Viral Hemorrhagic Fevers (VHF), including Ebola.
In 2018, the World Health Organization included Lassa Fever in their short List Of Blueprint Priority Diseases, for which there is an urgent need for additional research and drug development.
- Crimean-Congo haemorrhagic fever (CCHF)
- Ebola virus disease and Marburg virus disease
- Lassa fever
- Middle East respiratory syndrome coronavirus (MERS-CoV) and Severe Acute Respiratory Syndrome (SARS)
- Nipah and henipaviral diseases
- Rift Valley fever (RVF)
- Zika
- Disease X
Yesterday the UK's Health Security Agency announced two confirmed cases - and a 3rd case under investigation - in a family with recent travel links to West Africa.
This press release is long on reassurances - and short on specifics (including dates of travel, and itinerary) - but we'll probably get additional details from the ECDC and/or Eurosurveillance in the days to come.
In the meantime, we have the following:
Two people have been diagnosed with Lassa fever in England, confirms the UK Health Security Agency.
Published 9 February 2022 Last updated 9 February 2022 — See all updates
A further probable case of Lassa fever is under investigation. The cases are within the same family in the East of England and are linked to recent travel to West Africa.
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.
