The Nigeria Centre for Disease Control and Prevention (NCDC) has said the country’s Lassa fever outbreak has become deadlier this year, with 221 deaths recorded and the case fatality rate rising to 24 per cent, compared with 18.7 per cent during the corresponding period in 2025.
The agency disclosed this in its Lassa fever situation report for epidemiological week 26, released on Friday.
The report also showed that confirmed infections increased during the week, with 31 new cases recorded, up from 22 in the previous reporting week.
A total of 23 states have recorded at least one confirmed case across 111 local government areas this year, highlighting the continued spread of the disease across the country.
Five states account for most infections
The NCDC reported that 85 per cent of all confirmed cases originated from Ondo, Bauchi, Taraba, Edo and Benue states, while the remaining 15 per cent were reported elsewhere.
Ondo accounted for the largest share of confirmed infections at 30 per cent, followed by Bauchi (26 per cent), Taraba (14 per cent), Edo (nine per cent) and Benue (six per cent).
People aged 21 to 30 years remained the most affected group, although confirmed cases ranged from one to 93 years.
The male-to-female ratio among confirmed cases stood at 1:0.9, indicating nearly equal infection rates between men and women.
Why deaths remain high
The NCDC attributed the elevated fatality rate to several persistent challenges, including late presentation of cases, poor health-seeking behaviour driven by the high cost of treatment, inadequate environmental sanitation in high-burden communities, low public awareness, and infections among healthcare workers.
The agency disclosed that one healthcare worker was infected during week 26.
Response efforts intensified
To contain the outbreak, the NCDC said the National Lassa Fever multi-partner, multi-sectoral Incident Management System remains activated to coordinate surveillance, case management, risk communication and response activities nationwide.
During the reporting week, the agency and its partners supported case management training for healthcare workers, active case search and contact tracing, infection prevention and control (IPC) training, community engagement activities, distribution of personal protective equipment, laboratory testing, and high-level field missions to affected states.
The NCDC urged state governments to sustain year-round community engagement on Lassa fever prevention, while healthcare workers were advised to maintain a high index of suspicion for the disease, initiate timely referral and treatment, and adhere strictly to infection prevention and control procedures.
Lassa fever
Lassa fever is an acute viral haemorrhagic illness caused by the Lassa virus, which is transmitted to humans primarily through contact with food or household items contaminated by the urine or faeces of infected rats.
It can also spread from person to person through contact with bodily fluids.
The disease often begins with fever, weakness, and headache, and may progress to more severe symptoms such as bleeding, difficulty breathing, swelling, and organ failure.
Early diagnosis and prompt treatment with Ribavirin are critical for improving survival.