Healthcare-associated Transmission of Lassa Fever, Sierra Leone, November 2019–January 2020

On 20 Nov 2019 the Tonkolili District Health Office was notified that a physician working in the district hospital was diagnosed with Lassa Fever (LF). The Tonkolili District had its last LF case in 2012. An investigation was performed to determine mode of transmission, magnitude and scope of this outbreak. Clinical information, exposure history, and blood samples were collected. Active case search and Infection Prevention and Control (IPC) assessment were conducted in the hospital and community. Three of five people with symptoms compatible with LF were polymerase chain reaction positive. The primary case, a pregnant woman from the community, was admitted with severe bleeding and operated by two surgeons and anesthetist. The same medical staff operated on another woman later that day. Three of the five cases died. The hospital assessment revealed non-adherence to IPC procedures. The primary case’s residence had unhygienic conditions and inappropriate food storage. Low index of suspicion for LF and non-compliance to IPC procedures contributed to the associated healthcare workers’ infection spread. Health workers were sensitized to LF and trained on IPC. Education of the community in high-risk areas is recommended about LF recognition, transmission and ways to decrease rodent populations in and around their homes.