Lassa Cases Triple in a Week—NCDC’s New Containment Plan

In the third week of May 2025, Nigeria experienced a significant surge in Lassa fever cases, with confirmed infections tripling compared to the previous week. This sudden increase has raised concerns among health authorities and the public alike. The Nigeria Centre for Disease Control and Prevention (NCDC) promptly responded by implementing a comprehensive containment strategy to address the escalating situation.

Lassa fever, an acute viral hemorrhagic illness endemic in West Africa, poses a persistent public health challenge in Nigeria. Understanding the dynamics of this recent spike is crucial for both awareness and prevention. This article delves into the nature of Lassa fever, analyzes the data from Epidemiological Week 20, and outlines the NCDC’s strategic response to curb the outbreak.

By examining the current landscape, we aim to provide a clear and factual overview of the situation, emphasizing the importance of vigilance and proactive measures in combating Lassa fever.

Understanding Lassa Fever

Lassa fever is an acute viral hemorrhagic illness endemic to West Africa, with Nigeria reporting cases annually. The disease is caused by the Lassa virus, a member of the Arenaviridae family. Transmission to humans primarily occurs through exposure to food or household items contaminated with the urine or feces of infected Mastomys rats. Human-to-human transmission can also occur, particularly in healthcare settings lacking adequate infection control measures.

Transmission and Symptoms

Individuals can contract Lassa fever through direct contact with the bodily fluids of infected persons, ingestion of contaminated food, or inhalation of airborne particles. The incubation period ranges from 6 to 21 days. Early symptoms are often nonspecific and may include fever, general weakness, and malaise. As the disease progresses, more severe symptoms such as hemorrhaging, respiratory distress, facial swelling, and shock may develop. Approximately 80% of infections are mild or asymptomatic, but the remaining 20% can be severe and potentially fatal.

Endemic Regions and Impact

Lassa fever is endemic in several West African countries, including Nigeria, Sierra Leone, Liberia, and Guinea. In Nigeria, the disease poses a significant public health challenge, with outbreaks occurring annually. The Nigeria Centre for Disease Control and Prevention (NCDC) monitors and reports on Lassa fever cases, implementing strategies to control and prevent outbreaks.

Prevention and Control

Preventing Lassa fever involves promoting good community hygiene to discourage rodents from entering homes. This includes storing food in rodent-proof containers, disposing of garbage far from the home, and maintaining clean households. In healthcare settings, strict adherence to infection prevention and control measures is crucial to prevent nosocomial transmission. Early diagnosis and prompt treatment are vital to improving patient outcomes and reducing the risk of transmission.

Epidemiological Week 20: Data Analysis

Between May 12 and May 18, 2025—Epidemiological Week 20—Nigeria experienced a significant surge in Lassa fever cases, with confirmed infections tripling compared to the previous week. This sudden increase has raised concerns among health authorities and the public alike.

Confirmed Cases and Trends

In Week 20, the Nigeria Centre for Disease Control and Prevention (NCDC) reported 13 new confirmed cases of Lassa fever. This represents a substantial increase from the previous week’s figures, indicating a worrying trend in the disease’s transmission. The cumulative number of confirmed cases for 2025 reached 596 by the end of this week.

Geographical Distribution

The majority of the new cases were reported in Ondo, Bauchi, and Edo states, which have consistently been among the most affected regions. These states accounted for 72% of all confirmed cases, highlighting the need for targeted interventions in these areas.

Demographics and Healthcare Workers

The predominant age group affected during this period was 21–30 years, with a male-to-female ratio of 1:0.8. Notably, no new infections among healthcare workers were reported in Week 20, a positive sign that infection prevention measures in healthcare settings may be effective.

Comparative Analysis

When compared to the same period in the previous year, the data indicates a higher incidence of Lassa fever cases in 2025. This underscores the importance of sustained public health efforts and community engagement to control the spread of the disease.

NCDC’s New Containment Plan

In response to the alarming surge in Lassa fever cases during Epidemiological Week 20 of 2025, the Nigeria Centre for Disease Control and Prevention (NCDC) has implemented a comprehensive containment strategy. This multi-faceted approach aims to curb the spread of the disease, enhance surveillance, and strengthen the country’s capacity to manage and respond to outbreaks effectively.

Activation of the Incident Management System (IMS)

The NCDC has activated the multi-partner, multi-sectoral Incident Management System (IMS) to coordinate response activities at all levels. This system facilitates collaboration among various stakeholders, ensuring a unified and efficient response to the outbreak. The IMS operates through the National Public Health Emergency Operations Centre, which serves as the central hub for coordinating surveillance, laboratory services, case management, and risk communication efforts.

Enhanced Surveillance and Laboratory Capacity

To improve early detection and reporting of Lassa fever cases, the NCDC has intensified surveillance activities across the country. This includes deploying National Rapid Response Teams to support on-site control and management efforts using a One Health approach. Additionally, the NCDC has expanded laboratory testing capabilities to ensure timely diagnosis, with all samples being processed in the eight designated Lassa fever testing laboratories nationwide.

Risk Communication and Community Engagement

Recognizing the importance of public awareness in controlling the spread of Lassa fever, the NCDC has intensified risk communication efforts. This involves disseminating public health advisories and educational materials to inform communities about preventive measures, symptoms, and the importance of seeking prompt medical attention. The NCDC has also launched an Infection Prevention and Control (IPC) e-learning platform, powered by DRASA and funded by the Global Fund, to educate healthcare workers and the public on best practices for preventing disease transmission.

Strengthening Infection Prevention and Control (IPC) Measures

To safeguard healthcare workers and patients, the NCDC has prioritized the distribution of personal protective equipment (PPE) and other essential commodities to treatment centers. Training sessions on IPC measures have been conducted for healthcare workers in various states, including Bauchi, Ebonyi, and Benue. These efforts aim to reinforce adherence to IPC protocols and reduce the risk of nosocomial infections.

Capacity Building and Training

The NCDC, in collaboration with partners such as Georgetown Global Health Nigeria (GGHN), has organized a series of webinars and training sessions to enhance the capacity of healthcare workers in managing Lassa fever cases. These initiatives focus on case management, laboratory preparedness, and IPC practices, ensuring that healthcare providers are equipped with the necessary knowledge and skills to respond effectively to the outbreak.

Through these comprehensive measures, the NCDC aims to contain the current outbreak, prevent further transmission, and strengthen Nigeria’s overall preparedness and response capabilities for Lassa fever and other infectious diseases.

Public Health Advisory

In light of the recent surge in Lassa fever cases during Epidemiological Week 20 of 2025, the Nigeria Centre for Disease Control and Prevention (NCDC) has issued a comprehensive public health advisory. This advisory aims to inform and guide the public on preventive measures, early detection, and appropriate responses to curb the spread of the disease.

Preventive Measures