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Last update
20 Jul 2026 · 12:49 UTC
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Lassa fever outbreaks — tracked episodes and clusters

Each tracked episode as a citable page — with its own epidemic curve, timeline, and map.

  • 2026 Nigeria Lassa fever season

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    Jan 5, 2026 – OngoingNigeriaLineage II

    Nigeria's 2026 dry-season Lassa fever outbreak, the country's annual epidemic amplified by the Natal multimammate mouse (Mastomys natalensis). Confirmed cases climbed through a January–early-April peak (epi weeks 3–13) concentrated in Ondo, Edo, Bauchi, Taraba and Benue states, with the Irrua Specialist Teaching Hospital (Edo) and the Federal Medical Centre / FUTA treatment centres in Owo and Akure (Ondo) as the epicentres, before tapering into the mid-year low-transmission tail. Dominated by Lassa virus Lineage II, with Lineage III in the north-central states. NCDC coordinated the response with WHO and partners; the case fatality rate held around 25% among confirmed cases.

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