An ecologist extracts a sample of blood from a Mastomys Natalensis rodent in the village of Jormu in southeastern Sierra Leone February 8, 2011. Lassa fever, named after the Nigerian town where it was first identified in 1969, is among a U.S. list of "category A" diseases -- deemed to have the potential for major public health impact -- alongside anthrax and botulism. The disease is carried by the Mastomys Natalensis rodent, found across sub-Saharan Africa and often eaten as a source of protein. It infects an estimated 300,000-500,000 people each year, and kills about 5,000. Picture taken February 8, 2011. To match Reuters-Feature BIOTERROR-AFRICA/ REUTERS/Simon Akam (SIERRA LEONE - Tags: HEALTH SOCIETY ANIMALS) - GM1E72F07HC01
Dec. 19, 2025
The Nigeria Centre for Disease Control and Prevention (NCDC) says Lassa fever claimed 195 lives across 21 states by Epidemiological Week 49 of 2025, representing a case fatality rate of 18.2 per cent.
The NCDC disclosed this in its latest Lassa Fever Situation Report for Epi Week 49, covering Dec. 1 to 7, 2025, released on its official website on Sunday nationwide online.
According to the report, 33 new confirmed cases and eight deaths were recorded during the reporting week, rising from 24 confirmed cases reported in Epidemiological Week 48 across affected states nationwide.
The new confirmed cases were reported from Bauchi, Ondo, Edo and Taraba states during the epidemiological reporting period as part of ongoing national surveillance efforts coordinated by health authorities nationwide daily.
Cumulatively as at week 49 of 2025, Nigeria recorded 9,041 suspected cases, 1,069 confirmed cases, seven probable cases and 195 deaths, the NCDC stated in its official situation report released Sunday.
The agency noted that the CFR of 18.2 per cent in 2025 was higher than the 16.5 per cent recorded during the same period in 2024, when 190 deaths were reported nationwide.
The report showed that 89 per cent of confirmed Lassa fever cases in 2025 came from four states: Ondo 36 per cent, Edo 24 per cent, Bauchi 12 per cent and Taraba 12 per cent combined.
Overall, 21 states and 103 Local Government Areas (LGAs) recorded at least one confirmed Lassa fever case in 2025, compared with 28 states and 137 LGAs during the same period in 2024.
The NCDC noted that, although suspected and confirmed cases declined compared to 2024, fatalities remained high largely due to late presentation of cases and poor health-seeking behaviour nationwide among affected communities.
The agency identified young adults aged 21–30 as the most affected group, with cases ranging from one to 96 years and a median age of 30, with male-to-female ratio of 1:0.8.
Encouragingly, the report stated that no healthcare worker was infected during the reporting week, although 24 healthcare workers had been affected cumulatively in 2025 nationwide so far officially recorded nationally overall.
The NCDC said the National Lassa Fever Multi-sectoral Technical Working Group continued coordinating nationwide response efforts, supported by partners including WHO, UNICEF, US CDC, CEPI and other key public health stakeholders.
Response activities during the week included deploying National Rapid Response Teams to 10 states, strengthening infection prevention and control measures, training clinicians, conducting After Action Reviews and commencing the INTEGRATE trial.
Other interventions involved community risk communication, distribution of Ribavirin, personal protective equipment and IEC materials, environmental sanitation campaigns, and launching the NCDC infection prevention and control e-learning platform nationwide for workers.
However, the agency listed key challenges as late case presentation, high treatment costs, poor environmental sanitation, and low awareness in high-burden communities across affected states nationwide currently hindering effective response efforts.
It also called on partners to strengthen state capacity for early detection and rapid response systems to better curb transmission and reduce Lassa fever mortality nationwide sustainably going forward collectively together.
