The death toll from Lassa fever outbreak in Nigeria has hit 103 in 2025, with a case fatality rate (CFR) of 18.3 per cent.
The Nigeria Centre for Disease Control (NCDC) record indicates that this is slightly lower than the CFR of 18.9 per cent recorded during the same period in 2024.
In epidemiological (epi) week 10 of 2025, between 3 and 9 March, the number of new confirmed cases dropped slightly from 29 in the previous week to 28.
These cases were reported across Bauchi, Ondo, Edo, Plateau, Delta, Anambra, Kogi, and Taraba states.
Breakdown
As of 9, March, Nigeria had recorded 232 new suspected cases of Lassa fever, 28 newly confirmed cases and three new deaths, with 14 states and 78 local government areas affected.
Cumulatively, the total number of confirmed cases in 2025 has risen to 563, with the death toll reaching 103.
Ondo, Bauchi, and Edo remain the most affected states, accounting for 73 per cent of all confirmed cases.
According to the data, Ondo recorded the highest share with 31 per cent, followed by Bauchi at 25 per cent, and Edo at 17 per cent. The remaining 27 per cent of cases were reported from eleven other states.
Of the 36 states in Nigeria, only Jigawa, Akwa Ibom and Niger have the lowest number of suspected cases of one each. At the same time, the three new deaths in the week under review were recorded in Bauchi, Plateau, and Delta states.
Epidemiological data further shows that individuals aged 21 to 30 years are the most affected, with cases ranging from one to 94 years and a median age of 30 years.
The male-to-female ratio among confirmed cases stands at 1:0.8 while no new healthcare worker was affected in the reporting week 10.
To manage the outbreak, NCDC said the National Lassa fever multi-partner, multi-sectoral Incident Management System (IMS) has been activated to coordinate the response activities at all levels.
Lassa fever symptoms, transmission
Lassa fever is an acute viral haemorrhagic fever (VHF) caused by the Lassa virus.
The natural reservoir for the virus, according to NCDC, is the multimammate rat (also known as the African rat). However, other rodents can also act as carriers of the virus.
This zoonotic disease was first reported in the Lassa community in Borno State, Nigeria, when two missionary nurses died from an unusual febrile illness. Since then, cases and outbreaks continue to be reported in Nigeria.
NCDC explained that Lassa fever is transmitted through direct contact with or ingesting food and drinks contaminated with the urine, faeces, saliva, or blood of infected rodents.
It can also be contracted through contact with contaminated objects, household items, or surfaces.
Person-to-person transmission is possible through exposure to the blood, urine, faeces, vomitus, or other body fluids of an infected individual, particularly in hospital settings with inadequate infection prevention and control measures.
On how it presents, NCDC explained that Lassa fever initially presents like other common illnesses accompanied by a fever, such as malaria.
Other symptoms may include headache, general body weakness, cough, nausea, vomiting, diarrhoea, muscle pains, chest pain, sore throat, and, in severe cases, bleeding from ears, eyes, nose, mouth, and other body openings.
