The Nigeria Centre for Disease Control and Prevention (NCDC) has reported a rise in Lassa fever infections during epidemiological week 22 (May 26–June 1, 2025), with eight new confirmed cases recorded in Ondo, Bauchi, Edo, and Nasarawa states, up from six cases reported the previous week.
According to the NCDC’s latest situation report, a total of 142 deaths have been recorded so far in 2025, translating to a case fatality rate (CFR) of 19.0%, slightly higher than the 18.1% reported during the same period in 2024. The trend underscores a continued severity in disease outcomes.
As of week 22, Lassa fever has been confirmed in 96 Local Government Areas across 18 states. However, the majority—91%—of confirmed cases are concentrated in just five states: Ondo (31%), Bauchi (25%), Edo (16%), Taraba (16%), and Ebonyi (3%). The remaining 9% of cases were spread across 13 other states.
Demographic data shows that the most affected age group is 21–30 years, with a broader age range spanning from 1 to 96 years. The median age of infected individuals is 30, and the male-to-female ratio among confirmed cases is 1:0.8.
Despite the recent weekly uptick, the NCDC noted a general year-on-year decline in both suspected and confirmed cases when compared to the same period in 2024.
Meanwhile, the report showed no new infections among healthcare workers were recorded in week 22, though the cumulative number of affected health workers remains at 28.
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State-by-State breakdown indicated that Ondo State remains the epicentre of the outbreak, with the highest number of both suspected and confirmed cases.
In week 22 alone, it recorded 83 suspected cases and 3 confirmed, while cumulatively, Ondo reported 1,770 suspected and 229 confirmed cases since the beginning of the year.
The report also showed that Bauchi followed as the second most affected state, with 12 suspected and one confirmed cases reported in the current week.
Overall, the agency stated that Bauchi logged 844 suspected cases and 14 confirmed cases. Edo State comes next, with 55 suspected and one confirmed cases in week 22, and cumulative figures of 1,607 suspected and 122 confirmed.
NCDC, also noted that there was a discrepancy in the data for Taraba State, which was reported to have 31 suspected cases in the week, though other sources suggest it may have had 116 confirmed cases, pointing to a possible reporting error.
Ebonyi State, meanwhile, reported 238 suspected and 21 confirmed cases in week 22 alone.
Altogether, the NCDC highlighted that Ondo, Bauchi, and Taraba States accounted for 72% of all confirmed cases so far in 2025.
The cumulative CFR for the year, according to NCDC stands at 19.2%, reinforcing the deadly nature of the outbreak, adding that among the confirmed deaths, 28 occurred in week 22 alone.
In response to the continued spread of the disease, the NCDC announced that it had already activated its multi-partner, multi-sectoral National Lassa Fever Incident Management System (IMS).
The emergency coordination framework, Tue agency assured, is working to streamline the country’s response across federal, state, and local levels.
The agency cautioned the public on the need for sustained vigilance, improved disease surveillance, and strengthened response capacity, particularly in high-burden states like Ondo, Bauchi, and Edo, in addition to enhanced resource mobilization and public health interventions to contain the outbreak and reduce fatalities.






