The Nigeria Centre for Disease Control and Prevention (NCDC) has confirmed 717 cases of Lassa fever from a total of 4,881 suspected cases between January and May 4, 2025.
According to the agency’s latest situation report released on its website Wednesday, the infections were recorded across 93 local government areas in 15 states.
So far, 138 deaths have been reported, resulting in a Case Fatality Rate (CFR) of 19.3%, an increase from the 18.0% recorded during the same period in 2024.
In epidemiological week 18 alone, the number of new confirmed cases dropped slightly to 10 from 11 in the previous week.
The new cases were reported from Ondo, Edo, Bauchi, and Benue states. Despite the slight weekly decline, the virus continues to spread, with 15 states having reported at least one confirmed case in 2025.
The death toll has been distributed across 15 states, with Taraba reporting the highest number of fatalities at 34, followed by Ondo (27), Edo (19), and Bauchi (15).
Other states with deaths include Ebonyi (11), Gombe (7), Plateau (5), Benue (5), Kogi (4), Nasarawa (4), Delta (2), Kaduna (2), and one death each in Enugu, Cross River, and Ogun.
Transmission and epidemiology
Lassa fever is a serious viral illness endemic to West Africa. In Nigeria, it is primarily transmitted through contact with food or household items contaminated by the urine or feces of infected Mastomys rats.
According to the NCDC, 71% of all confirmed cases this year were reported from just three states: Ondo, Bauchi, and Taraba.
“Of these, Ondo alone accounted for 30%, Bauchi 25%, and Taraba 16%, while the remaining 28% were spread across the other 15 states.
“The most affected age group is between 21 and 30 years, with patient ages ranging from one to 96 years and a median age of 30. There is also a slight male predominance, with a male-to-female ratio of 1 to 0.8.
“No new infections were reported among healthcare workers in week 18, “the agency noted.
The NCDC noted that both suspected and confirmed cases have declined when compared to the same period last year.
Challenges and ongoing response efforts
Despite this, the agency has activated a multi-partner, multi-sectoral Lassa fever Incident Management System (IMS) to coordinate response efforts at the national level.
The agency, however, highlighted several ongoing challenges hampering effective containment.
These include the late presentation of patients at health facilities, which contributes to the high case fatality rate; poor health-seeking behaviour driven by the high cost of treatment; and inadequate environmental sanitation in high-burden communities.
Furthermore, limited public awareness in affected areas continues to delay timely diagnosis and intervention.
Public health advisory
Health authorities are urging Nigerians to practice proper hygiene, avoid contact with rodents, and seek medical attention promptly when symptoms of Lassa fever appear.
