First laboratory confirmation and sequencing of Zaire ebolavirus in Uganda following two independent introductions of cases from the 10(th) Ebola Outbreak in the Democratic Republic of the Congo, June 2019

Uganda established a domestic Viral Hemorrhagic Fever (VHF) testing capacity in 2010 in response to the increasing occurrence of filovirus outbreaks. In July 2018, the neighboring Democratic Republic of Congo (DRC) experienced its 10(th) Ebola Virus Disease (EVD) outbreak and for the duration of the outbreak, the Ugandan Ministry of Health (MOH) initiated a national EVD preparedness stance. Almost one year later, on 10(th) June 2019, three family members who had contracted EVD in the DRC crossed into Uganda to seek medical treatment. Samples were collected from all the suspected cases using internationally established biosafety protocols and submitted for VHF diagnostic testing at Uganda Virus Research Institute. All samples were initially tested by RT-PCR for ebolaviruses, marburgviruses, Rift Valley fever (RVF) virus and Crimean-Congo hemorrhagic fever (CCHF) virus. Four people were identified as being positive for Zaire ebolavirus, marking the first report of Zaire ebolavirus in Uganda. In-country Next Generation Sequencing (NGS) and phylogenetic analysis was performed for the first time in Uganda, confirming the outbreak as imported from DRC at two different time point from different clades. This rapid response by the MoH, UVRI and partners led to the control of the outbreak and prevention of secondary virus transmission. Author summary n the effort to control the on-going COVID-19 pandemic, countries instituted lock downs and closed international borders. But is this the best approach to controlling transboundary infectious diseases? In this publication we demonstrate how we managed to control Ebola Virus Disease (EVD) introduced into Uganda from Democratic Republic of Congo (DRC) in 2019. Once the EVD outbreak was announced in DRC, we intensified cross-border surveillance and instituted acceptable public health control measures following international health regulations to limit onward community and nosocomial transmission in Uganda. Consequently, on July 10th, 2019, three (3) cases crossed into Uganda and were detected at the point of first contact with health facility in Uganda in Kasese district and the fourth case was detected in August 2019 at a point of entry at the Uganda-DRC border by temperature screening. Sequencing of these cases showed that they were independent introductions related to two different clades of the ongoing outbreak in DRC. All the patients died without onward secondary transmissions in Uganda. We invite you to read this publication and learn how this was achieved as it can be used as a model for cross border surveillance to control similar infectious disease outbreaks.