Diagnostics for filovirus detection: impact of recent outbreaks on the diagnostic landscape

Ebolaviruses and Marburg virus (MARV) both belong to the family Filoviridae and cause severe haemorrhagic fever in humans. Due to high mortality rates and potential for spread from rural to urban regions, they are listed on the WHO R&D blueprint of high-priority pathogens. Recent ebolavirus outbreaks in Western and Central Africa have highlighted the importance of diagnostic testing in epidemic preparedness for these pathogens and led to the rapid development of a number of commercially available benchtop and point-of-care nucleic acid amplification tests as well as serological assays and rapid diagnostic tests. Despite these advancements, challenges still remain. While products approved under emergency use licenses during outbreak periods may continue to be used post-outbreak, a lack of clarity and incentive surrounding the regulatory approval pathway during non-outbreak periods has deterred many manufacturers from seeking full approvals. Waning of funding and poor access to samples after the 2014-2016 outbreak also contributed to cessation of development once the outbreak was declared over. There is a need for tests with improved sensitivity and specificity, and assays that can use alternative sample types could reduce the need for invasive procedures and expensive equipment, making testing in field conditions more feasible. For MARV, availability of diagnostic tests is still limited, restricted to a single ELISA test and assay panels designed to differentiate between multiple pathogens. It may be helpful to extend the target product profile for ebolavirus diagnostics to include MARV, as the viruses have many overlapping characteristics.