A field laboratory is a removable diagnostic unit, set up for specific purposes and for a limited time of operation (6,7). Field laboratories can be located in buildings adapted to the purpose or in transient structures or mobile platforms. In past EVD outbreaks, field laboratories were often established and managed through bilateral agreements between the host country and international entities. In DRC, a strong national EVD response and the expertise and availability of reverse transcription quantitative PCR diagnostic tools, GeneXpert Ebola assay (Cepheid, https://www.cepheid.com), ensured that the DRC INRB could coordinate and entirely manage laboratory response activities. Preparatory stages included strategic internal INRB meetings to discuss which type of laboratory to deploy.

During the 10th EVD outbreak, INRB deployed 3 types of laboratories: basic, standard, and advanced. The basic setup was focused on Ebola virus (EBOV) diagnosis, with a maximum of 2 GeneXpert instruments; biochemistry capacity was added if required. The standard setup had >2 GeneXpert instruments, along with biochemistry and hematology capacity for patient care and survivor follow-up (viral load in the body fluids, chemistry, and hematology). In the advanced setup, either differential diagnosis (Sudan or Bundibugyo ebolavirus, in addition to Marburg, dengue, chikungunya, yellow fever, West Nile, Crimean-Congo hemorrhagic fever, or Rift Valley fever viruses) or genomic sequencing capacity was added to the standard setup. Laboratory tests related to research activities, such as administration of EBOV therapeutics (8,9), immunogenicity of Ervebo vaccine (Ebola Zaire vaccine, https://www.fda.gov/vaccines-blood-biologics/ervebo), and studies of EBOV reservoirs in bats were conducted in standard and advanced setups. After internal discussions, a proposal was presented to the response coordination team to collect feedback, if any. If agreement was reached, the laboratory was deployed according to INRB checklists for equipment, reagents, and accessories (Appendix). Materials were transported by air, land, or water with >1 INRB staff member assisted by local laboratory personnel. On site, the team set up the laboratory by adapting the workflow to the existing rooms or by rehabilitating or building additional space, if needed. In general, field laboratories were housed in structures located as close as possible to the Ebola treatment centers that they serviced. The average time between decision making and laboratory deployment was 4.7 (range 1–10) days. After deployment, the laboratory was functional within 24 hours. Thirteen field laboratories were deployed in the 3 affected provinces: 6 basic, 4 standard, and 3 advanced laboratories (Table 1). The laboratories of Beni, Mangina, and Goma were deployed from Kinshasa; the others were deployed from Beni (the main field laboratory); 1 laboratory (Tchowe, South-Kivu) was deployed from Goma field laboratory (Table 2).

Throughout the outbreak, there were multiple epicenters, which changed in intensity and locations over time. Deploying a flexible model of laboratories at the epicenters of the outbreak enabled well-structured and coordinated actions involving all pillars of the response. Results were quickly provided on site to enable timely public health interventions and mitigate the risk for security incidents as transportation of samples was reduced. Decentralized setups were maintained to support routine EVD surveillance in remote areas and detect eventual flare-ups. The presence of skillful local laboratory workers strongly decreased the number of national and foreign experts to be deployed and fostered community engagement. Field laboratories helped integrate response activities into the health system.

Seven laboratories were then decommissioned. All instruments were decontaminated according to INRB standard operating procedures, disassembled, and packed in specific boxes or suitcases, shipped to Beni, and later shipped to Goma or Kinshasa. The laboratories in Beni, Mangina, Butembo, Bunia, Bukavu, and Mambasa are still functional.

Figure 1

Figure 1. Advanced field laboratory setup used for Ebola virus disease outbreak during chronic insecurity, eastern Democratic Republic of the Congo, 2018–2020. GeneXpert, (Cepheid, https://www.cepheid.com); pocH-100i (Sysmex (https://www.sysmex.com);...

Figure 2

Figure 2. Basic field laboratory setup used for Ebola virus disease outbreak during chronic insecurity, eastern Democratic Republic of the Congo, 2018–2020. GeneXpert, Cepheid, https://www.cepheid.com; pocH-100i, Sysmex, https://www.sysmex.com;...

To mitigate the risk for exposure, protect the safety of the laboratory workers, and prevent environmental contamination, EBOV-suspected samples must be handled in a Biosafety Level 3 (BSL-3) laboratory or BSL-3–like conditions (standard personal protective equipment [PPE], negative pressurized glove box, restricted access to the laboratory, laboratory staff trained and vaccinated) (10,11). Hence, deployment of BSL-3–like structures is needed at outbreak locations. An INRB field laboratory contained 3 mandatory areas: hot zone, cold zone, and extra space. Inside the hot zone, we considered the red zone as the space for sample reception, unpacking and testing (Piccolo [Abaxis, https://www.abaxis.com], pocH-100i [Sysmex, https://www.sysmex.com], and iStat [Abbott, https://www.abbott.com]), and PPE doffing; the orange areas were set up for GeneXpert bench (Cepheid, https://www.cepheid.com) and cold chain. The cold zone included multiple-step donning areas. The extra space was used for supply storage and the administrative office (Figure 1). The basic setup had a hot zone and an extra space in which donning PPE, supplies storage, and administrative offices were located (Figure 2). Samples for diagnosis were inactivated and aliquoted within the glove box. Piccolo discs and iStat cartridges were prepared in the glove box and tested with respective instruments at the bench. Because the red and orange zones were contiguous in most settings, the staff working in these areas dressed in full PPE (Tyvek coverall, goggles or face shield, mask [N100 or FFP3], long-cuff nitrile gloves, and laboratory shoes with shoe covers). In cold zones, staff were dressed with light PPE (surgical gown, head covering, and mask [N95 or FFP2]; short-cuff nitrile gloves; and laboratory shoes). Access to the laboratory was restricted to INRB-trained and Ervebo-vaccinated persons (vaccinated >10 days before working).

At the beginning of the day, trained hygienists cleaned the floors with 0.5% bleach and emptied the dustbins while dressed in full PPE (hot zone) or light PPE (cold zone). At the end of the day, laboratory operators disinfected the inner part of the glove boxes and the benches with bleach 0.5% or other solutions (e.g., Rely+On [Virkon, https://relyondisinfection.com], CDiffend [2XL Corporation, https://www.2xlpro.com]), according to INRB standard procedures. In addition to daily cleaning/decontamination, every 2 weeks in each laboratory, workers decontaminated the glove boxes (inside/outside), benches, and all other surfaces and, maintained instruments. Cleaning/decontamination activities were recorded in laboratory registers, maintenance sheets, and decontamination sheets.

During the 10th EVD outbreak, field laboratories faced tremendous challenges. The 7 main challenges were: 1) activities interruption after attacks on response teams; 2) movement of contacts and suspected and confirmed case-patients resulting in further spread of the disease; 3) slow resumption of activities after security incidents; 4) evacuation of response staff out of outbreak areas during insecurity events; 5) delayed implementation of activities; 6) disruption to refilling laboratory supplies and fuel; and 7) delayed sample transportation to the laboratory (especially for sequencing unit) (13).

The most prominent activities conducted in the field laboratories were EVD diagnosis and training. Laboratories contributed to providing investigational therapeutics to treat patients with confirmed cases, and they were equipped with clinical laboratory capacities (8,9). Five laboratories supported survivor activities, 1 conducted genomic sequencing, and 2 performed differential diagnoses (13,14). Throughout the outbreak, 9.3 tons of equipment were deployed across sites (3), 230,936 Ebola Xpert cartridges were used and subsequently shipped to the Goma laboratory for proper disposal by incineration, as per World Health Organization recommendations. Laboratory performance was evaluated by 2 indicators: proportion of new suspect samples tested within 48 hours and proportion of results delivered within 24 hours. Despite challenging conditions, field laboratories tested 100% of samples with turnaround times of <48 hours.

Figure 3

Figure 3. Organizational chart for field laboratories used for Ebola virus disease outbreak during chronic insecurity, eastern Democratic Republic of the Congo, 2018–2020. INRB, Institut National de Recherche Biomédicale.

Activities were conducted by medical-biologist doctors, biologists, and laboratory technicians assisted by supporting staff (administrative, logistics, hygienists, security guards, drivers) (Table 5; Figure 3). Local staff members were recruited mostly in the main health facilities of affected provinces or cities; national staff came from INRB (Kinshasa). All laboratory personnel were trained with regard to biosafety and biosecurity; PPE donning and doffing; good clinical and laboratory practices; sample collection, packaging, and transportation; sample manipulations within a glove box; instrument manipulation and troubleshooting; and safety and emergency management. Refresher trainings were scheduled each trimester, whenever a new staff member started at the laboratory or when an error occurred throughout the testing process. The laboratory was headed by a medical-biologist doctor or biologist assisted by a bench supervisor. The laboratory head was responsible for sample processing, results validation and delivery, quality control and final laboratory records, participation in daily coordination meeting, engaging with other working groups, and drafting the reports and communication. The laboratory head reported daily to the coordinator of all field laboratories who, in turn, presented the global situation at the general coordination meeting. Staff were granted a break after 3 months of work or in any emergency situation. The bench supervisor was responsible for organizing the bench workload and schedules, sample processing and storage, functioning and maintenance of laboratory instruments, cleaning and decontamination procedures, records tracking, and training of new staff. The administrative staff were in charge of preparing paperwork, data entry, data management, results typing, printing, and distribution. Over the course of the outbreak, INRB created a unique database template used by all laboratories, which were shared monthly with the coordinator of field laboratories. We employed 134 personnel, including 9 medical-biologist doctors, 21 biologists, and 62 laboratory technicians (Table 5). INRB fostered capacity building to quickly hand over Ebola response tools and competences to local staff to empower the health system and decentralize the diagnostics. The local capacity setup at the peripheral level allowed sustained and successful management of 3 successive EVD flare-ups (Butembo in 2021, Beni in 2021 and 2022).

The overall societal context of the eastern DRC led to express reluctance toward most EVD countermeasures. Of the 13 laboratories, 10 were deployed within unsafe areas. Thus, on several occasions, teams were attacked by rebels, militia, and other hostile groups. Those threats delayed or impeded deployment and supervision of activities, sample handling, and staff movement (Tables 6, 7). To manage security in the field, transportation of all personnel movement, equipment, and supplies had to be approved by a security commission. Depending on the context, some convoys had to be escorted by security forces, using military devices such as armored vehicles and pickup trucks with machine guns and bulletproof vests for passengers. In unsafe areas, a curfew was set from 6:00 pm to 6:00 am, except for a few teams, which were circulating under security escort until late to maximize timely results. In unsafe areas, laboratories were protected by armed guards to prevent eventual attacks, sabotage, or disruption. Despite the security incidents encountered, field laboratories operated for an average of 21 months, supporting all pillars of the response.

In countries at high risk for EVD outbreaks, decentralized laboratories should be strategically positioned to timely detect EBOV. Health authorities should supply them with dedicated equipment and well-prepared teams, built on local know-how to organize efficient responses. A tiered and decentralized policy of laboratories during outbreaks provides flexibility for managing materials and supplies, logistics, and human resources in the health system. The quick handover of competences and capacities to local staff led during the 10th EVD outbreak in the DRC led to sustained and successful management of further outbreaks. Nonetheless, efforts should be made to use new diagnostic and research tools in the laboratory to considerably reduce turnaround time to <24 hours, to strongly improve patient management and research activities, to foster real-time genomic sequencing, and to support follow-up of EVD survivors.