An ecologist extracts a sample of blood from a Mastomys Natalensis rodent in the village of Jormu in southeastern Sierra Leone February 8, 2011. Lassa fever, named after the Nigerian town where it was first identified in 1969, is among a U.S. list of "category A" diseases -- deemed to have the potential for major public health impact -- alongside anthrax and botulism. The disease is carried by the Mastomys Natalensis rodent, found across sub-Saharan Africa and often eaten as a source of protein. It infects an estimated 300,000-500,000 people each year, and kills about 5,000. Picture taken February 8, 2011. To match Reuters-Feature BIOTERROR-AFRICA/ REUTERS/Simon Akam (SIERRA LEONE - Tags: HEALTH SOCIETY ANIMALS) - GM1E72F07HC01
The Nigeria Centre for Disease Control and Prevention (NCDC) has reported a notable spike in confirmed Lassa fever infections during epidemiological week 26 of 2026.
According to the agency’s latest situation report released on Friday, weekly cases jumped to 31, up from 22 infections recorded the previous week.
The newly confirmed cases were concentrated across Bauchi, Ondo, Taraba, and Benue states.
Rising Fatality and Geographic Spread
The NCDC data highlights a worsening mortality trend for the year.
Cumulatively, Nigeria has recorded 221 Lassa fever deaths in 2026. The Case Fatality Rate (CFR) has climbed to 24.0%, a significant increase from the 18.7% fatality rate reported during the same period in 2025.
The disease also continues to expand its geographic footprint. So far in 2026, at least one confirmed case has been recorded across 23 states spanning 111 Local Government Areas (LGAs).
Key Outbreak Demographics
Hotspots: Just five states account for 85% of all confirmed cases nationwide. Ondo State leads the country with 30% of the burden, followed closely by Bauchi (26%), Taraba (14%), Edo (9%), and Benue (6%). The remaining 15% are distributed across other states.
Age & Gender: Young adults aged 21 to 30 remain the most vulnerable demographic, though patient ages span from 1 to 93 years. The infection is hitting genders almost equally, with a male-to-female ratio of 1:0.9.
Healthcare Risk: The outbreak continues to pose a threat to frontline medical staff, with one healthcare worker reported infected during week 26.
National Response
Public health authorities noted that both suspected and confirmed cases have increased compared to the corresponding period in 2025.
In response to the intensifying outbreak, the National Lassa Fever multi-partner, multi-sectoral Incident Management System remains fully activated to coordinate nationwide surveillance, case management, risk communication, and emergency response activities.
