Lassa fever is a viral haemorrhagic disease endemic to West Africa, caused by the Lassa virus and primarily transmitted through exposure to food or surfaces contaminated by infected rodents. Human-to-human transmission can also occur, particularly in healthcare settings without adequate infection control. Symptoms range from mild fever and weakness to severe complications such as bleeding, organ failure, and, in some cases, death.
Nigeria continues to experience seasonal outbreaks, and recent data from the Nigeria Centre for Disease Control and Prevention shows that 2026 is following a concerning trajectory.
As of Epidemiological Week 8 (February 2026):
- 404 confirmed cases have been recorded
- 99 deaths, with a case fatality rate (CFR) of 24.5%
- Cases have spread across 18 states and 67 Local Government Areas
While weekly confirmed cases have slightly declined (77 new cases in Week 8 compared to 82 in Week 7), the rising fatality rate higher than 18.8% in 2025 signals ongoing gaps in early detection and treatment access.
More recent updates suggest the trend persists. By March 2026, Nigeria had recorded over 580 confirmed cases and more than 140 deaths, maintaining a high fatality rate above 24%.
Geographic and Demographic Trends
The outbreak remains highly concentrated:
- Bauchi (30%), Ondo (21%), and Taraba (19%) account for the majority of cases
- Together with Edo and Benue, these states contribute 84% of all confirmed infections
The most affected group is young adults aged 21–30, although cases span from infants to older adults. Men are slightly more affected than women (ratio 1:0.8).
Healthcare workers also remain at risk, with new infections recorded among frontline responders highlighting persistent vulnerabilities in infection prevention systems.
Treatment Gaps and a New Breakthrough
Currently, treatment options for Lassa fever are limited. The antiviral drug ribavirin is widely used but is most effective only when administered early, which is often not the case due to delayed diagnosis.
However, new research published in Nature introduces a promising development. Scientists have identified an oral antiviral drug, 4′-fluorouridine (4′-FIU), that demonstrated strong efficacy in treating Lassa fever in nonhuman primates.
Key findings from the study include:
- Effectiveness even when treatment begins several days after infection
- Significant reduction in viral load
- Improved survival outcomes
This is particularly important because Lassa fever is often diagnosed late, when existing treatments are less effective. An oral drug also offers practical advantages for deployment in rural and resource-limited settings.
What This Means for Public Health in Africa
The combination of rising fatality rates and continued geographic spread underscores the urgency of improving surveillance, diagnostics, and treatment access.
At the same time, advances like 4′-FIU highlight the role of genomics, antiviral research, and global collaboration in addressing endemic diseases.
While the drug is still in the experimental stage and requires human clinical trials, it represents a potential shift in how Lassa fever is treated especially in regions where early intervention is difficult.
Lassa fever remains a persistent and evolving public health challenge in Nigeria. But with improved data tracking and emerging therapeutic innovations, there is a clear pathway toward better outcomes and reduced mortality if investments in research, healthcare systems, and community awareness continue.
Read more on the Lassa fever trend in Nigeria .