Investigating the Sudan virus outbreak in Uganda through the deployment of a mobile laboratory

BACKGROUND: Uganda faced its sixth reported Ebola outbreak between September 2022 and January 2023, the fifth to be recorded as Sudan Virus Disease (SVD) in the country. In response to this, the Ugandan Ministry of Health (MoH), rapidly deployed a mobile laboratory from the National Health Laboratory and Diagnostics Services (NHLDS) within one week of the declared outbreak. Here we describe the deployment of the mobile laboratory to Mubende, the outbreak epicentre, as part of the national response. This provided (1) efficient diagnostics and characterization of Sudan virus cases to support national data reporting (2), greater insight into Sudan virus kinetics, including viral clearance and risk factor analysis and (3) evaluation of the integration of the mobile laboratory into the national outbreak response. METHODS: The mobile laboratory was deployed to the Mubende Regional Referral Hospital and positioned next to the established Ebola Treatment Unit (ETU). The laboratory was deployed for 177 days, in continuous operation by a team of 18 trained personnel. Molecular testing, using reverse-transcriptase polymerase chain reaction (RT-PCR) was carried out on all samples received in the laboratory for both Sudan virus diagnosis and differential diagnosis for other viral haemorrhagic fever (VHFs). All results from the mobile laboratory were fed directly into the national database, to enable a coordinated response to the outbreak and analysis of the outbreak data on a national level. RESULTS: Nationwide, there were 142 confirmed cases, 55 deaths and 22 probable cases reported in the outbreak. During the mobile laboratory deployment, 3282 samples were tested and 72 SVD cases confirmed by RT-PCR, with an average turn-around-time (TAT) of 6 h. In addition to molecular diagnostic confirmation of suspect cases, the mobile laboratory functioned to support follow-up surveillance of Sudan virus survivors (4 breast feeding mothers and 22 males). Sudan virus RNA was found in the breast milk a median of 135 days after initial test positivity and in the semen of male survivors median 176 days later. We observed the highest risk for contracting the disease in health care workers and a significant correlation between patient viral load at initial diagnosis and patient outcome. Differential diagnosis of other VHFs in the mobile laboratory and at the Uganda Virus Research Institute (UVRI) identified 6 Rift Valley fever (RVF) and 7 Crimean-Congo haemorrhagic fever (CCHF) cases co-circulating in the current SVD outbreak. CONCLUSION: Having the mobile laboratory stationed next to the ETU at the epicentre of the outbreak, markedly reduced diagnostic turn-around-time (TAT) and improved interoperability between the laboratory and the ETU, supporting containment and treatment. Furthermore, integration of the mobile laboratory into existing national outbreak systems, ensured rapid data provision for daily decision making by the national task force. The data from this study contributes to a greater understanding of Sudan virus. CLINICAL TRIAL NUMBER: Not applicable.