Evaluation of Lassa fever surveillance system in Kogi State, north-central Nigeria

Introduction Lassa fever, a viral hemorrhagic disease endemic in West Africa, remains a major public health concern in Nigeria, with 10,098 suspected cases, 1,309 confirmed, and 214 deaths reported across 28 states and 139 Local Government Areas (LGAs) in 2024. Kogi State, an important route linking the north to the south of Nigeria, ranked fourth in confirmed cases in 2021. Surveillance system evaluations are critical for informing disease control and assessing performance. This study evaluated the Lassa fever surveillance system in Kogi State to assess its key attributes. Methods In March 2024, a mixed-methods evaluation was conducted, guided by the Centers for Disease Control’s updated public health surveillance evaluation guidelines. Surveillance data from 2022–2023 were analysed using the state line list. Key informant interviews were held with 18 Local Government Area Disease Surveillance and Notification Officers (LGA DSNOs) and four state-level stakeholders. System attributes such as simplicity, flexibility, data quality, and acceptability were assessed using descriptive statistics. Ethical approval was obtained from the Kogi State Ministry of Health. Results The response rate among DSNOs was 85.7%, with participants averaging 47.9±7.2 years of age and 23.8±5.9 years of service. Data revealed 112 suspected Lassa fever cases, 38 confirmed (33.9% positivity), and 12 deaths, indicating a case fatality rate of 31.6%. Most respondents (94%) had dedicated personnel for data verification. The system was largely viewed as simple and flexible, with 88.9% reporting the forms could accommodate changes. Despite challenges with logistics and funding, participants expressed continued commitment to the system. Conclusion Kogi State’s Lassa fever surveillance system is effective, demonstrating simplicity, acceptability, and flexibility. However, challenges in stability and resource availability may limit long-term performance. Strengthening the system through improved funding, continuous training, and staff incentives is recommended to enhance sustainability and effectiveness in Lassa fever detection and response.