Nigeria has recorded 146 deaths from Lassa fever between January and mid-March, as infections continue to spread across the country.
The Nigeria Centre for Disease Control and Prevention (NCDC) disclosed this in its latest situation report for Epidemiological Week 11, covering March 9 to 15.
The agency said 38 health workers have also been infected so far this year, underscoring ongoing risks within healthcare settings.
According to the report, the case fatality rate (CFR) stands at 25.1 per cent, significantly higher than the 18.7 per cent recorded during the same period in 2025.
Within the reporting week, confirmed cases increased from 40 in week 10 to 66, with new infections recorded in Bauchi State, Ondo State, Taraba State, Plateau State, Edo State, Benue State, Kogi State, Gombe State and Niger State.
In total, 21 states and 82 local government areas have reported at least one confirmed case in 2026.
The NCDC noted that five states — Bauchi, Ondo, Taraba, Benue and Edo — account for 85 per cent of all confirmed cases.
Bauchi leads with 28 per cent of infections, followed by Ondo (21 per cent) and Taraba (20 per cent), while Benue and Edo each account for eight per cent. The remaining 15 per cent of cases are spread across 16 other states.
The agency added that young adults aged 21 to 30 years remain the most affected group, although cases have been recorded across a wide age range, from one to 90 years.
Despite the rise in weekly infections, the NCDC said no new cases among health workers were recorded in week 11. However, the cumulative figure of 38 infections among frontline workers points to persistent gaps in infection prevention and control measures.
Infections among health workers have consistently been linked to inadequate use of personal protective equipment (PPE), low suspicion for Lassa fever during early patient contact, and weak infection control practices in some facilities.
The report further shows that although suspected and confirmed cases are lower compared to the same period in 2025, the proportion of deaths remains high, suggesting ongoing challenges with late presentation and case management.
To strengthen response efforts, the NCDC said the national multi-partner, multi-sectoral Incident Management System has been activated to coordinate interventions across affected states.
However, several factors continue to hamper effective control of the outbreak, including poor health-seeking behaviour driven by the high cost of treatment, low awareness in high-burden communities, and poor environmental sanitation, which contributes to the spread of the virus.
The agency urged state governments to intensify community engagement and prevention efforts throughout the year, particularly in high-risk areas.
It also advised healthcare workers to maintain a high index of suspicion for Lassa fever, ensure early diagnosis and referral, and strictly adhere to infection prevention and control protocols.
Lassa fever is a viral haemorrhagic disease primarily transmitted through contact with food or household items contaminated by the urine or faeces of infected rodents. Human-to-human transmission can also occur through contact with bodily fluids.
Symptoms typically begin with fever, weakness and headache, but can progress to severe complications, including bleeding, respiratory distress and organ failure if not treated early.