Establishment of an Ebola Treatment Unit and Laboratory - Bombali District, Sierra Leone, July 2014-January 2015.

The first confirmed case of Ebola virus disease (Ebola) in Sierra Leone related to the ongoing epidemic in West Africa occurred in May 2014, and the outbreak quickly spread. To date, 8,704 Ebola cases and 3,955 Ebola deaths have been confirmed in Sierra Leone. The first Ebola treatment units (ETUs) in Sierra Leone were established in the eastern districts of Kenema and Kailahun, where the first Ebola cases were detected, and these districts were also the first to control the epidemic. By September and October 2014, districts in the western and northern provinces, including Bombali, had the highest case counts, but additional ETUs outside of the eastern province were not operational for weeks to months. Bombali became one of the most heavily affected districts in Sierra Leone, with 873 confirmed patients with Ebola during July-November 2014. The first ETU and laboratory in Bombali District were established in late November and early December 2014, respectively. T- evaluate the impact of the first ETU and laboratory becoming operational in Bombali on outbreak control, the Bombali Ebola surveillance team assessed epidemiologic indicators before and after the establishment of the first ETU and laboratory in Bombali. After the establishment of the ETU and laboratory, the interval from symptom onset to laboratory result and from specimen collection to laboratory result decreased. By providing treatment to Ebola patients and isolating contagious persons to halt ongoing community transmission, ETUs play a critical role in breaking chains of transmission and preventing uncontrolled spread of Ebola (4). Prioritizing and expediting the establishment of an ETU and laboratory by pre-positioning resources needed to provide capacity for isolation, testing, and treatment of Ebola are essential aspects of pre-outbreak planning.

Rapid outbreak sequencing of Ebola virus in Sierra Leone identifies transmission chains linked to sporadic cases.

To end the largest known outbreak of Ebola virus disease (EVD) in West Africa and to prevent new transmissions, rapid epidemiological tracing of cases and contacts was required. The ability to quickly identify unknown sources and chains of transmission is key to ending the EVD epidemic and of even greater importance in the context of recent reports of Ebola virus (EBOV) persistence in survivors. Phylogenetic analysis of complete EBOV genomes can provide important information on the source of any new infection. A local deep sequencing facility was established at the Mateneh Ebola Treatment Centre in central Sierra Leone. The facility included all wetlab and computational resources to rapidly process EBOV diagnostic samples into full genome sequences. We produced 554 EBOV genomes from EVD cases across Sierra Leone. These genomes provided a detailed description of EBOV evolution and facilitated phylogenetic tracking of new EVD cases. Importantly, we show that linked genomic and epidemiological data can not only support contact tracing but also identify unconventional transmission chains involving body fluids, including semen. Rapid EBOV genome sequencing, when linked to epidemiological information and a comprehensive database of virus sequences across the outbreak, provided a powerful tool for public health epidemic control efforts.