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Nigeria recorded 109 deaths from Lassa fever in the first nine weeks of 2026, the Nigeria Centre for Disease Control and Prevention reported on Monday, with the case fatality rate rising to 23.2 percent — significantly above the 18.7 percent recorded in the same period last year and a level that health experts say reflects a combination of delayed hospital presentation, strained treatment infrastructure, and growing occupational exposure among frontline healthcare workers.
The NCDC’s Lassa Fever Situation Report for Epidemiological Week 9, covering February 23 to March 1, 2026, showed that 65 new confirmed cases were recorded during the week, a decline from the 77 cases reported in Week 8. While the week-on-week reduction in new confirmed cases is a cautiously positive signal, the accumulating death toll and the deteriorating fatality ratio indicate that the cases reaching medical attention are increasingly severe, and that the gap between reported and total actual infections remains wide.
Cumulatively, Nigeria has recorded 2,446 suspected cases and 469 confirmed cases of Lassa fever in 2026, with 109 deaths reported so far. The confirmed case count represents just over 19 percent of all suspected cases, a proportion that reflects both the limited diagnostic laboratory capacity available in most high-burden states and the high rate of mild or asymptomatic infection that characterizes the disease in populations with some endemic exposure.
For the fraction of infected individuals who do develop severe hemorrhagic illness, however, the case fatality rate in the current season is markedly higher than recent years would suggest.
Six healthcare workers were confirmed infected with the virus during Week 9 alone, bringing the cumulative total for the year to 37 as of March 1. The development raised fresh concerns about occupational exposure among frontline health personnel. Healthcare worker infections in Lassa fever outbreaks typically arise from lapses in infection prevention and control protocols — in particular, inadequate use of personal protective equipment during blood or bodily fluid contact, delays in recognizing Lassa presentation in patients who initially appear to have malaria or typhoid, and aerosol exposure during clinical procedures such as intubation or suctioning. At 37 confirmed healthcare worker infections in nine weeks, the rate exceeds levels recorded in comparable periods during previous outbreak seasons, a pattern the NCDC attributed partly to the increasing geographic spread of the current outbreak and partly to inconsistent PPE adherence.
The burden of the outbreak remains heavily concentrated in five states. Bauchi, Ondo, Taraba, Benue, and Edo collectively account for 86 percent of all confirmed infections, with the remaining 14 percent distributed across 13 other states. Eighteen states and 69 local government areas have now recorded at least one confirmed case, the widest geographic spread of the disease recorded in any comparable period. The predominant age group affected is 21 to 30 years, and the male-to-female ratio among confirmed cases stands at 1:0.8 — patterns consistent with occupational and behavioral exposure profiles in which younger men, who are more likely to engage in activities involving contact with agricultural settings or rat-contaminated spaces, bear a disproportionate share of infections.
Late presentation of cases at health facilities — often occurring after the optimal therapeutic window for ribavirin treatment has closed — was cited as the primary factor. This reflects a complex interaction of factors including limited public awareness of Lassa fever’s distinctive early symptoms, financial barriers to hospital attendance, distrust of formal health services in some high-burden communities, and the disease’s deceptive resemblance in its early stages to malaria, a condition with which it shares fever, headache, and body weakness but which responds to entirely different treatment. Cost was specifically cited as a barrier: ribavirin, the antiviral treatment used for Lassa fever, is not available through primary health care facilities in most affected states and must be obtained at secondary or tertiary centers, where the associated treatment costs are beyond the means of many affected households.
Read Also: 4 Health Workers Infected As Benue Records Fresh Lassa Fever
Healthcare facility inadequacy in affected communities was an additional challenge identified by the report. Several local government areas with confirmed cases lack functional Lassa fever isolation and treatment units, forcing referral over long distances and further extending the time between symptom onset and effective treatment. Rodent control in rural communities — the fundamental environmental intervention that would reduce transmission from the primary reservoir, the multimammate rat Mastomys natalensis — remains grossly inadequate across high-burden zones, where grain storage practices, housing construction, and seasonal rodent population dynamics create near-continuous exposure risk.
In response to the current season, the NCDC said it had activated its Lassa Fever Incident Management System to coordinate multi-partner response efforts nationwide. Activities include active case searches and contact tracing in collaboration with RTI International through CDC funding, distribution and pre-positioning of personal protective equipment in health facilities, deployment of national rapid response teams to seven high-burden states, and a high-level field mission to Bauchi State conducted with support from Medecins Sans Frontieres to strengthen outbreak control efforts.
In Benue State, the NCDC and the World Health Organization launched a targeted infection prevention and control ring strategy, concentrating resources around confirmed cases to interrupt transmission chains before they can expand.
Read Also: Nigeria Records Fewer Lassa Fever Cases But More Deaths – NCDC
Lassa fever is an acute hemorrhagic illness caused by the Lassa arenavirus, first identified in 1969 in the town of Lassa in what is now Borno State. It is endemic across Nigeria’s southern and central zones and in parts of Sierra Leone, Guinea, and Liberia. The virus is shed in the urine and feces of the multimammate rat, a rodent species that commonly cohabits with humans in rural and peri-urban settings across West Africa and that enters homes in search of food stores.
Human-to-human transmission occurs in healthcare settings through direct contact with infected blood or bodily fluids. The WHO estimates that approximately 80 percent of infections are mild or subclinical, but the 20 percent that develop into severe disease carry a case fatality rate that varies by season and access to treatment, typically ranging between 15 and 25 percent in outbreak contexts.
No WHO emergency designation has been issued for the current season. The NCDC’s Week 10 situation report, covering March 2 to 8, is expected to be released in the coming days.
