Emergence of mpox in Sierra Leone: investigating theindex case, January 2025

Abstract

Mpox is a reemerging zoonotic disease caused by the monkeypox virus (MPV) and continues to pose a serious global health challenge. In January 2025, Sierra Leone confirmed its first case in the Western Area Rural district, which marked a significant moment in the nation’s public health response. This report describes the clinical, epidemiological, and laboratory investigation of the index case, a 27-year-old male from Hamilton, as well as the actions taken to contain the disease. A rapid response team (RRT) was activated following World Health Organization (WHO) protocols, including the use of WHO case investigation forms, line-listing of cases and contacts, laboratory confirmation using polymerase chain reaction (PCR), genomic sequencing, contact tracing, isolation of high-risk contacts, daily monitoring for 21 days, risk communication, and community engagement. The patient was confirmed to have mpox clade IIb and recovered fully after isolation and medical care. Nine close contacts were identified, monitored for 21 days, and none developed symptoms. Although the exact source of infection was not identified and the findings suggest possible links to close human contact and recent travel during the incubation period. This case emphasizes the importance of early detection, effective surveillance, timely isolation, and clear communication in responding to emerging infectious threats. It also shows the need to protect patient confidentiality and address stigma, which are important for maintaining community trust and cooperation. The report provides valuable guidance for strengthening outbreak preparedness and response in Sierra Leone and other areas confronting mpox and similar infections.