Lassa fever in Nigeria

Public health authorities in Nigeria have reported continuing widespread transmission of Lassa fever in the country. In the first two weeks of 2022, 96 cases, including 11 deaths, have been reported from Bauchi, Benue, Cross River, Ebonyi, Edo, Kaduna, Kogi, Ondo, Oyo, Plateau, and Taraba states, with three-quarters of these cases recorded in the Edo, Bauchi, and Ondo states.

Lassa fever is a type of viral haemorrhagic fever (VHF) endemic in parts of West Africa and 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 a 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

Further information and advice on VHFs, including Lassa fever, is available on the TRAVAX (for health professionals) and fitfortravel (for the general public) websites.

Source: TRAVAX, 27 January 2022