Lassa fever in Nigeria

The Nigeria Centre for Disease Control and Prevention (NCDC) has reported continuous occurrence of Lassa fever throughout 2023. From the beginning of 2023 to the middle of December there were 1201 confirmed cases, including 210 deaths. A further 8800 suspected cases were reported.

During 2023, 28 States recorded at least one confirmed case. Seventy-six percent (76%) of all confirmed Lassa fever cases were reported from Ondo, Edo and Bauchi States.

Lassa fever is a type of viral haemorrhagic fever (VHF) endemic in parts of West Africa. Lassa virus is transmitted via the urine or droppings from infected rodents (Mastomys rats). Transmission can also occur via body fluids of infected people.

Advice for Travellers

The risk to travellers becoming infected or developing Lassa fever is extremely low, unless living in conditions of poor sanitation and overcrowding in rural areas where these rodents are usually found.

Travellers to known Lassa fever outbreak areas must be made aware of the risk of infection and transmission routes of Lassa virus which is most commonly through:

• ingesting or breathing in tiny particles in the air if it has been contaminated with infected rodent excretions, for example during cleaning activities such as sweeping
• touching objects soiled with infected rat excretions, and infecting open cuts or sores
• eating food which has been contaminated with rat excretions

Medical personnel travelling to work in an outbreak region must follow strict infection prevention control guidance.

Travellers returning from a Lassa fever outbreak area should seek rapid medical attention by contacting NHS 24 (Scotland) or NHS 111 (rest of UK) for advice prior to attending UK medical facilities if they develop fever and have:

• returned to the UK within 21 days from a region or area with a known outbreak of Lassa fever
• had contact with individuals infected with a VHF

For further information, see the TRAVAX Viral Haemorrhagic Fever page.