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
The Nigeria Centre for Disease Control and Prevention (NCDC) says 215 deaths were recorded from Lassa fever in 2025, with the case fatality rate (CFR) rising to 18.7 per cent, higher than the 16.3 per cent recorded during the same period in 2024.
The NCDC disclosed this via its official website in its Lassa Fever Situation Report for Epidemiological Week 52 (Dec. 22–28, 2025), noting that the country recorded 1,148 confirmed cases out of 9,389 suspected cases during the year.
According to the report, 22 states and 107 Local Government Areas were affected by confirmed cases in 2025, underscoring the continued public health threat posed by the viral haemorrhagic disease.
The agency said that while the number of suspected and confirmed cases declined compared to 2024, the higher fatality rate remained a major concern.
“In week 52 alone, 27 new confirmed cases and nine deaths were reported across Bauchi, Ondo, Ebonyi, Taraba and Nasarawa states,” the NCDC stated.
It added that the increase from 21 cases in the previous week signalled sustained transmission in hotspot areas.
The report revealed that four states, Ondo, Bauchi, Edo and Taraba, accounted for 89 per cent of all confirmed cases recorded nationwide.
“Ondo state led with 35 per cent, followed by Bauchi with 26 per cent, Edo with 16 per cent and Taraba with 12 per cent,” it said.
On demographics, the NCDC said young adults aged 21 to 30 years were the most affected, with cases ranging from one to 96 years and a median age of 30 years.
It added that the male-to-female ratio stood at 1:0.8 among confirmed cases.
The agency attributed the rising fatality rate largely to late presentation of cases at health facilities, poor health-seeking behaviour and the high cost of treatment, especially in high-burden communities.
It also listed poor environmental sanitation and low awareness levels as persistent challenges fueling the spread of the disease.
The NCDC, however, said it had intensified response efforts through a multi-partner, multi-sectoral approach, including the deployment of 10 National Rapid Response Teams to affected states.
Other interventions included training of healthcare workers, strengthening of infection prevention and control (IPC) measures, distribution of Ribavirin, personal protective equipment (PPEs) and other response commodities, as well as expanded risk communication and community engagement activities.
The public health agency said no new healthcare worker infection was recorded in week 52, attributing this to improved IPC compliance in treatment centres.
Looking ahead, the NCDC urged states to sustain year-round community engagement on Lassa fever prevention, particularly as the country prepared for a new outbreak season.
It also advised healthcare workers to maintain a high index of suspicion and ensure timely referral and treatment of suspected cases, while calling on partners to continue strengthening state capacity to prevent, detect and respond promptly to outbreaks.
Nigeria recorded cases throughout the year, although transmission is usually higher during the dry season.
Symptoms range from fever, weakness and headache to vomiting, diarrhoea, bleeding and organ complications in severe cases.
Early diagnosis and prompt treatment with antiviral medication improved survival outcomes.
The NCDC advised the public to maintain good hygiene, ensure proper food storage, keep homes rodent-free and seek early medical attention if symptoms developed.
