Notifiable condition. Early recognition, isolation of the patient, and appropriate infection control measures are a critical part of management.
Asymptomatic or mild febrile illness in approximately 80% of patients, which can make diagnosis difficult. Severe symptoms such as haemorrhage, respiratory distress, repeated vomiting, facial swelling, and shock occur in approximately 20% of patients.
Can be particularly difficult to distinguish from malaria and typhoid fever; therefore, all should be considered in people returning from endemic areas with an appropriate history.
Management involves early initiation of ribavirin with supportive care in a hospital setting. Ribavirin is occasionally used for post-exposure prophylaxis.
An acute zoonotic viral haemorrhagic fever endemic to West Africa. It is caused by infection with the Lassa virus, a single-stranded RNA virus that belongs to the Arenaviridae family of viruses (genus: Mammarenavirus). The natural reservoir is the multimammate rat (Mastomys natalensis), a rodent found commonly in rural areas of tropical Africa that often colonises in or around human homes where food is stored. The clinical disease is variable, ranging from mild non-specific symptoms (e.g., fever, malaise) to haemorrhagic fever and death.
History and exam
Key diagnostic factors
- presence of risk factors
- fever ≥37.5°C
- elevated respiratory rate
- low systolic blood pressure
- sore throat/pharyngitis
- chest pain/cough
- deafness (sensorineural)
- facial oedema
Other diagnostic factors
- abdominal pain
- confusion and altered Glasgow Coma Scale or seizures
- occupational exposure
- living/working in, or arrival from, endemic area
- contact with infected body fluids
- butchering and/or eating rodent meat
1st investigations to order
- reverse transcription-polymerase chain reaction (RT-PCR)
- rapid diagnostic lateral flow assay
- rapid diagnostic test for malaria
- blood culture for typhoid
Investigations to consider
- renal function
- serum electrolytes
- blood lactate/ABG
- coagulation studies
- chest x-ray
- blood cultures
- lumbar puncture
- abdominal ultrasound
suspected infection or symptomatic
Catherine Houlihan, MBChB, PhD
Clinical Lecturer in Infectious Diseases/Virology
University College London
CH declares that she has no competing interests.
Ron Behrens, MD, FRCP
Consultant in Tropical and Travel Medicine
Hospitals for Tropical Diseases
London School of Hygiene and Tropical Medicine
RB has provided expert testimony to the courts, on behalf of the Crown, regarding Q fever. RB has been a paid member of the Advisory Board for Takeda regarding Dengue vaccine. He has been a paid member of the Advisory Board for Valneva UK regarding Ixiaro, a vaccine for Japanese encephalitis.
John S. Schieffelin, MD, MSPH
Assistant Professor of Medicine & Pediatrics
Tulane University School of Medicine
JSS is a paid reviewer and author of articles on UpToDate.
Michael Brown, BA, BM, BCh, FRCP, PhD, DTM&H
Hospital for Tropical Diseases
University College London Hospitals
MB is Clinical Lead of the Hospital for Tropical Diseases, a contributing partner to the PHE Imported fever service that co-ordinates testing of samples from UK patients for viral haemorrhagic fevers.
Stephen Gluckman, MD
Professor of Medicine
Perelman School of Medicine at the University of Pennsylvania
SG declares that he has no competing interests.
- Malaria infection
- Typhoid infection
- Ebola virus infection
- CDC health information for international travel (the yellow book): viral hemorrhagic fevers
- Lassa fever: origins, reservoirs, transmission and guidelines
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