The Nigeria Centre for Disease Control and Prevention (NCDC) disclosed this in its latest situation report for Epidemiological week 11, spanning 9 to 15 March.
The infectious disease agency said 38 health workers have also been infected so far this year, highlighting ongoing risks within healthcare settings.
The report shows that 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.
During the reporting week, confirmed cases rose from 40 in week 10 to 66, with new infections recorded in Bauchi, Ondo, Taraba, Plateau, Edo, Benue, Kogi, Gombe and Niger states.
Cumulatively, 21 states and 82 local government areas have recorded at least one confirmed case in 2026.
According to the NCDC, 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), Taraba (20 per cent), while Benue and Edo each account for eight per cent. The remaining 15 per cent of cases are distributed across 16 other states.
More details
NCDC noted that young adults aged 21 to 30 years remain the most affected group, although cases have been recorded across a wide age range, from 1 to 90 years.
Despite the rise in weekly cases, the NCDC said no new infections among health workers were recorded in week 11.
However, the cumulative figure of 38 infections among frontline workers highlights the persistent gaps in infection prevention and control measures.
Infections among health workers have consistently been attributed 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.
NCDC noted that young adults aged 21 to 30 years remain the most affected group, although cases have been recorded across a wide age range, from 1 to 90 years.
Despite the rise in weekly cases, the NCDC said no new infections among health workers were recorded in week 11.
However, the cumulative figure of 38 infections among frontline workers highlights the persistent gaps in infection prevention and control measures.
Infections among health workers have consistently been attributed 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.
Contributing factors
The report also indicates that while the number of suspected and confirmed cases is lower compared to the same period in 2025, the proportion of deaths remains high, suggesting continued 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 challenges continue to hinder effective control of the outbreak. These include 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 year-round, 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.
The report also indicates that while the number of suspected and confirmed cases is lower compared to the same period in 2025, the proportion of deaths remains high, suggesting continued 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 challenges continue to hinder effective control of the outbreak. These include 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 year-round, 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.
About Lassa Fever
Lassa fever is a viral haemorrhagic disease transmitted primarily 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.
Lassa fever is a viral haemorrhagic disease transmitted primarily 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.
