Lassa Fever: Rats used to illustrate the story.

Nigeria has reported a decline in new Lassa fever cases, but deaths linked to the disease remain alarmingly high, according to the Nigeria Centre for Disease Control and Prevention (NCDC).

In its latest update for epidemiological week 34, the NCDC confirmed three new cases of the viral haemorrhagic illness, down from five cases the previous week. The new infections were identified in Ondo and Edo States.

Situation so far in 2025

Cumulatively, Nigeria has recorded 857 confirmed cases of Lassa fever and 160 deaths this year, representing a case fatality rate of 18.7%. This is higher than the 17.1% fatality rate reported during the same period in 2024.

The outbreak has spread across 21 states and 106 local government areas, with the majority of cases concentrated in five states:

• Ondo State – 33% of all confirmed cases
• Bauchi State – 23%
• Edo State – 17%
• Taraba State – 14%
• Ebonyi State – 3%

These five states alone account for 90% of all confirmed infections nationwide.

Who is most affected?

The NCDC noted that young adults are the most affected demographic.

• The predominant age group: 21–30 years
• Median age: 30 years
• Male-to-female ratio: 1 to 0.8, showing a slightly higher infection rate among men

Encouragingly, no new infections among healthcare workers were recorded during the reporting week.

Understanding Lassa fever

Lassa fever is an acute viral haemorrhagic illness transmitted mainly through contact with food or household items contaminated by rodents.

Early symptoms include: fever, weakness, and headaches.
Severe symptoms may progress to bleeding, chest pain, difficulty breathing, and organ failure.

National response efforts

The NCDC-led multi-sectoral Technical Working Group continues to coordinate outbreak response across states.

Key activities during the week included:

• Ongoing clinical management training for Lassa fever fellows at ISTH Edo and FMC Owo, supported by Georgetown University and the US CDC.
• Distribution of thermometers in Lagos for monitoring identified contacts.
• After-action reviews of recent outbreaks in Ondo and Edo States.
• Launch of an Infection Prevention and Control (IPC) e-learning platform with support from DRASA Health Trust and the Global Fund.
• Deployment of 10 rapid response teams across affected states.
• Distribution of Ribavirin, PPEs, disinfectants, and other essential commodities to treatment centres.
• Community sensitisation campaigns and risk communication through media.

Challenges slowing progress

Despite these efforts, several obstacles continue to hinder effective control of the disease:

• Late presentation of patients for treatment, leading to higher fatalities.
• High cost of treatment, discouraging timely health-seeking behaviour.
• Poor environmental sanitation in high-burden communities.
• Low awareness of preventive measures.

NCDC’s recommendations

The NCDC urged states and communities to:

• Intensify community engagement and prevention campaigns year-round.
• Encourage early reporting and referral of suspected cases.
• Improve environmental sanitation and rodent control in high-risk areas.