Lassa fever

Lassa fever is a notifiable condition. Early recognition, isolation of the patient, and appropriate infection control measures are a critical part of management.

Asymptomatic or mild febrile illness presents 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.

BMJ talk medicine podcast: recognise, refer and report Lassa fever, with John Schieffelin Opens in new window