The mobile laboratory units
The deployable laboratory units provide molecular diagnostics and serology for infectious diseases caused by the high and highest risk group 3 and 4 pathogens as well as pathogens of differential diagnostic consideration. The choice of methods depends on clinical factors, epidemiology, pathogenesis and the availability of diagnostic assays. The laboratory units are provided with all the necessary equipment and protocols to enable safe, efficient and comfortable work by responders to an infectious disease outbreak. The units are able to work in a self-contained manner in the field and are supplied by their home bases.
- Diagnostic assays: Diagnostic assays mainly aim to detect infectious pathogens of the two highest risk groups 3 and 4, which are often viruses, namely the flavi-, bunya-, filo-, arena- and alphavirus as well as respiratory viruses. Analysis of sample material (in most cases the patient’s serum) is performed by direct molecular detection using polymerase chain reaction (PCR) or by using indirect serology to detect antibodies. The spectrum may also be extended to the hepatitis viruses and paramyxoviruses. Bacterial pathogens are taken into account as well, since infections caused by salmonellae, shigellae, leptospirae and meningococcae may clinically mimic viral fevers and viral hemorrhagic fevers.
- Reagents: Diagnostic reagents and assays for the PCR analysis are adapted to avoid the need for sophisticated cold chains and to the technology used in the mobile lab units.
- Microscopy: Conventional light microscopy and immunofluorescence microscopy are available. Conventional microscopy combined with suitable staining of slide preparations may be used for the detection of parasites and bacteria in patient samples. Malaria infections for example are the most important differential diagnosis in Sub-Saharan Africa and can be diagnosed using this method. Immunofluorescence microscopy may be used for the detection of antibodies against viruses in patient’s sera.
- Test kits and rapid tests: For some infections, commercially available test kits or rapid tests are available and these may also be used by the mobile laboratory units if suitable. One example being the dengue virus, for which high-quality rapid tests are available.
- Clinical chemistry, blood gas analysis and blood count: At the sites of outbreaks of infectious diseases in Sub-Saharan Africa, there is often a lack of conventional blood analysis facilities and often hospital laboratories are reluctant to accept highly infectious samples for biosafety reasons. These investigations are however necessary to guide therapy for patients. Therefore if required, the mobile laboratory units may also provide conventional blood analysis in the form of clinical chemistry, blood gas analysis with electrolytes and whole blood counts. If necessary, suitable diagnostic appliances will be procured and service can be set up in the medium term.
- Equipment storage and transport: The mobile laboratory equipment is stored in rugged, dust and waterproof boxes that can be carried by individual responders. These boxes are packed according to the diagnostic methods used meaning that depending on the situation, only the required equipment can be taken to the field. Teams of four responders are however able to deploy each full laboratory unit and common means of transportation – such as airplane, public transport, small vehicle and on foot – can be used.
- Power supply: Uninterrupted electric power supply needs to be assured for the conducting of sophisticated molecular diagnostic assay. Electricity to the laboratory units can be supplied by small generator or small vehicle through a power converter.
- Facility: A suitable room or a tent may be used to set up the laboratory units. The room is divided into compartments because separation is necessary to allow for infection control and the specific workflow of the polymerase chain reaction (PCR) diagnostic processes.
- Appliances, reagents and consumables: The mobile laboratory units provide all necessary appliances for independent, safe and self-contained operation. These include real-time PCR cyclers, conventional PCR cyclers, enzyme-linked immunosorbent assay (ELISA) plate reader, microscope, centrifuges, coolers, biosafety equipment and other small equipment. Batches of consumables and reagents for the diagnostic processes are taken along and a steady chain of supplies to the site of operation is achieved through the logistical infrastructure which is provided by the home bases of each respective laboratory unit.
- Biosafety: The safety of the responding staff is of the highest priority. Therefore, the laboratory units operate according to SOPs that are drafted by the consortium as well as preexisting rules and regulations that describe the safe handling and disposal of infectious substances and decontamination of materials. Through the provision of filter ventilated biosafety cabinets (gloveboxes), the handling of infectious samples is performed under hermetically sealed conditions to shield responding staff from hazards.
- Workflow: Diagnostic procedures using PCR and serology require organized workflows. These are defined through protocols and SOPs provided by the project consortium.
- Further provisions: The units include a medical kit for minor health problems of staff and procedures are established to cater for medical problems that might arise. Every responder goes through health checks. Prophylaxis for malaria is provided if necessary and vaccinations are encouraged. Mosquito nets are provided as well as water filters for safe drinking water if necessary. Under certain circumstances, food may also be provided by the home bases. The laboratory units are equipped with flashlights and portable floodlight equipment to enable work in dark conditions.