Lassa Fever Outbreak in Nigeria: Rising Case Fatality Rate and Disproportionate Impact on Young Adults

Strategic Insights -

Nigeria is facing a severe Lassa fever outbreak, with 822 confirmed cases and 155 deaths recorded in 2025. The case fatality rate has increased to 18.9%, up from 17.1% in 2024. The disease has spread to 21 states and 105 Local Government Areas, with five states accounting for 89% of all confirmed cases. Ondo State alone contributes to 32% of the total cases. The Nigeria Centre for Disease Control and Prevention (NCDC) attributes the high mortality to late presentation of cases, poor health-seeking behaviour, and inadequate environmental sanitation.

Key Takeaways:

  • The Lassa fever outbreak in Nigeria has resulted in 822 confirmed cases and 155 deaths in 2025, with a case fatality rate of 18.9%.
  • The disease has affected 21 states and 105 Local Government Areas, with five states (Ondo, Bauchi, Edo, Taraba, and Ebonyi) accounting for 89% of all confirmed cases.
  • Ondo State has the highest number of confirmed cases, contributing to 32% of the total.
  • Lassa fever disproportionately affects young adults, particularly those aged 21-30, with a male-to-female ratio of 1:0.8.
  • The disease is transmitted primarily through contact with infected rats' urine or faeces, and symptoms include fever, sore throat, headache, vomiting, and muscle pain.
  • The NCDC has deployed 10 Rapid Response Teams to affected states and intensified community awareness campaigns.
  • The public can use the toll-free line 6232 for inquiries.

Statistics:

  • 822 confirmed cases of Lassa fever in 2025
  • 155 deaths attributed to Lassa fever in 2025
  • 18.9% case fatality rate
  • 21 states affected by the outbreak
  • 105 Local Government Areas affected by the outbreak
  • 5 states accounting for 89% of all confirmed cases (Ondo, Bauchi, Edo, Taraba, and Ebonyi)
  • Ondo State contributing to 32% of all confirmed cases
  • Male-to-female ratio of 1:0.8
  • Disease primarily transmitted through contact with infected rats' urine or faeces
  • Symptoms include fever, sore throat, headache, vomiting, and muscle pain
  • 10 Rapid Response Teams deployed by the NCDC to affected states

Sources:

  • Nigeria Centre for Disease Control and Prevention (NCDC)
  • World Health Organization (WHO) report on Lassa fever