Nigeria has recorded 166 deaths from Lassa fever between January 1 and September 14, 2025, according to the Nigeria Centre for Disease Control and Prevention (NCDC).

The Case Fatality Rate (CFR) now stands at 18.5 per cent, up from 16.9 per cent during the same period in 2024, signalling a modest but notable increase in the lethality of the disease.

As of epidemiological Week 37, the NCDC reported a total of 7,673 suspected cases and 895 confirmed cases of Lassa fever across 21 states and 106 Local Government Areas.

“In week 37, the number of new confirmed cases decreased from 13 in week 36 to 11,” the agency stated, noting that these cases were reported in Ondo, Bauchi, Kogi, and Anambra States.

The agency added, “Cumulatively, as at week 37, 2025, 166 deaths have been reported with a Case Fatality Rate (CFR) of 18.5 per cent, which is higher than the CFR for the same period in 2024 (16.9 per cent). In total for 2025, 21 States have recorded at least one confirmed case across 106 Local Government Areas.”

A disproportionate share of cases has been reported from five states, which account for 90 per cent of confirmed infections. Ondo State leads with 33 per cent, followed by Bauchi (23 per cent), Edo (18 per cent), Taraba (13 per cent), and Ebonyi (3 per cent). The remaining 10 per cent were recorded in 16 other states.

The NCDC highlighted the demographic profile of affected individuals, noting, “The predominant age group affected is 21–30 years, with a range of 1 to 96 years and a median age of 30 years. The male-to-female ratio for confirmed cases is 1:0.8.”

The agency reassured the public that no new healthcare workers were affected during the reporting week, and that both suspected and confirmed cases showed a decline compared to the same period in 2024.

Lassa fever, an acute viral illness caused by the Lassa virus, is endemic in Benin, Ghana, Guinea, Liberia, Mali, Nigeria, and Sierra Leone, and may exist in other parts of West Africa.

The World Health Organisation (WHO) explains that the virus is primarily transmitted through contact with food or household items contaminated with rodent urine or faeces. Person-to-person transmission can also occur, particularly in healthcare settings lacking adequate infection prevention and control measures.

The NCDC confirmed that its multi-partner, multi-sectoral Technical Working Group continues to coordinate response activities nationwide.

“The National Lassa Fever Technical Working Group continues to coordinate response activities at all levels,” the agency stated, emphasising ongoing efforts to curb the spread of the disease and support affected communities.