Concurrent Lassa fever outbreaks in Kaduna and Kano States, Nigeria: Lessons in Health Worker Safety and Emergency Response

Abstract

Introduction: Lassa fever remains a major public health threat in Nigeria, with recurrent seasonal outbreaks causing significant morbidity and mortality. In 2025, concurrent outbreaks occurred in Kaduna and Kano States, prompting coordinated surveillance and emergency response efforts. This study documents the epidemiology of these outbreaks and highlights lessons in outbreak detection, healthcare worker safety, and response coordination. Methods: A retrospective descriptive study was conducted using surveillance, laboratory, and case management data from the NCDC-supported surveillance system in Kaduna State and the Kano State Centre for Disease Control (KNCDC), with technical support from the World Health Organization (WHO) in Kano State. Laboratory confirmation was performed using real-time reverse transcriptase polymerase chain reaction (RT-qPCR). Kaduna’s outbreak occurred from epidemiological weeks 1–28 (January–July 2025), while Kano’s outbreak occurred in epidemiological week 15 (April 2025). All suspected cases meeting the national case definition were included. Data sources included SORMAS, situation reports, laboratory records, and health facility data. Descriptive and comparative analyses were performed using Microsoft Excel 365. Results: Kaduna reported 54 suspected cases, 8 confirmed cases, and 5 deaths among confirmed cases (CFR 62.5%), including 2 healthcare worker infections. Kano reported 7 suspected cases, 2 confirmed cases, and 2 deaths. One death occurred among confirmed cases (CFR: 50.0%, 1/2), while the second occurred among a suspected case (CFR: 28.6%, 2/7). Using confirmed cases as the denominator, Kaduna had a higher CFR than Kano (62.5%, 5/8 vs. 50.0%, 1/2). Kaduna’s outbreak was prolonged, while Kano’s outbreak was rapidly contained. Both states achieved complete contact tracing. Conclusion: Differences in outbreak outcomes highlight the importance of timely detection, strong infection prevention and control (IPC), healthcare worker protection, coordinated response and effective surveillance systems for preventing wider transmission.