The Nigeria Centre for Disease Control and Prevention (NCDC) says Lassa fever has claimed 195 lives across 21 states by Epidemiological Week (Epi Week) 49 of 2025, representing a case fatality rate (CFR) of 18.2 per cent.
The NCDC disclosed this in its latest Lassa Fever Situation Report for Epi Week 49, covering Dec. 1 to Dec. 7, 2025, released on its official website on Sunday.
According to the report, 33 new confirmed cases and eight deaths were recorded during the reporting week, up from 24 confirmed cases reported in Epi Week 48.
The newly confirmed cases were reported from Bauchi, Ondo, Edo and Taraba states as part of ongoing national disease surveillance.
Cumulatively, as of Week 49 in 2025, Nigeria recorded 9,041 suspected cases, 1,069 confirmed cases, seven probable cases and 195 deaths.
The agency noted that the 2025 CFR of 18.2 per cent was higher than the 16.5 per cent recorded during the same period in 2024, when 190 deaths were reported.
The report showed that 89 per cent of confirmed cases originated from four states: Ondo (36 per cent), Edo (24 per cent), Bauchi (12 per cent) and Taraba (12 per cent).
Overall, 21 states and 103 Local Government Areas (LGAs) recorded at least one confirmed case in 2025, compared with 28 states and 137 LGAs during the same period in 2024.
The NCDC observed that although suspected and confirmed cases declined compared to 2024, fatalities remained high, largely due to late presentation of cases and poor health-seeking behavior in affected communities.
The most affected age group was young adults aged 21 to 30 years. Cases ranged from one to 96 years, with a median age of 30 years. The male-to-female ratio was 1:0.8.
The report noted that no healthcare worker was infected during the reporting week, although 24 healthcare workers had been affected cumulatively in 2025.
The NCDC said the National Lassa Fever Multi-sectoral Technical Working Group continued to coordinate response efforts nationwide, with support from partners including the World Health Organization (WHO), UNICEF, the United States Centres for Disease Control and Prevention (US CDC), the Coalition for Epidemic Preparedness Innovations (CEPI) and other stakeholders.
Response activities during the week included the deployment of National Rapid Response Teams to 10 states, strengthening infection prevention and control measures, training of clinicians, conducting After Action Reviews and commencing the INTEGRATE trial.
Other interventions included community risk communication, distribution of Ribavirin, personal protective equipment and information, education and communication materials, environmental sanitation campaigns, and the launch of the NCDC infection prevention and control e-learning platform for health workers nationwide.
However, the agency identified key challenges such as late case presentation, high treatment costs, poor environmental sanitation and low awareness in high-burden communities.
The NCDC urged states to intensify year-round community engagement on Lassa fever prevention and advised healthcare workers to maintain a high index of suspicion to ensure timely referral and treatment of suspected cases.
It also called on partners to strengthen state capacity for early detection and rapid response to curb transmission and reduce Lassa fever-related deaths.
Lassa fever, first identified in Nigeria in the late 1960s, remains endemic in West Africa and continues to cause recurrent outbreaks with high morbidity and mortality.
The virus, which is primarily spread by rodents, can lead to severe complications including bleeding, deafness and death, especially in settings with poor sanitation and delayed access to medical care.
