Rodent-borne Viral Haemorrhagic Fevers in Sub-Saharan Africa: A Critical Narrative Review of the Epidemiology, Surveillance, Genomic Insights and Diagnostic Advances in Lassa Fever
Christopher Ononiwu Elemuwa
*
Department of Medical Microbiology, Immunology and Parasitology, Faculty of Medical Laboratory Science, Federal University, Otuoke, Bayelsa State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Lassa fever, caused by Lassa mammarenavirus, remains the most consequential rodent-borne viral haemorrhagic fever in sub-Saharan Africa, with recurrent seasonal epidemics concentrated in Nigeria, Sierra Leone, Liberia and Guinea and sporadic detections across a widening geographical range. Over the past decade, the field has been transformed by portable genomic sequencing, large-scale ecological modelling of the rodent reservoir, and the first randomised trials of candidate vaccines, yet no licensed vaccine or unequivocally effective antiviral therapy exists, and routine diagnosis still depends on centralised molecular assays that are inaccessible to most peripheral health facilities. This critical narrative review synthesises the contemporary evidence base on the epidemiology, reservoir ecology, molecular evolution, surveillance architecture and diagnostic landscape of Lassa fever, situating it within the broader category of African rodent-borne arenaviral haemorrhagic fevers that includes the rarer but more lethal Lujo virus. Evidence was drawn from peer-reviewed literature, systematic reviews and meta-analyses, and programmatic reports from national and international public health bodies. The review finds that the burden of disease remains poorly quantified because of substantial underascertainment, that genomic surveillance has repeatedly resolved uncertainty over whether case surges reflect novel strain emergence or intensified zoonotic spillover, and that promising point-of-care diagnostics have so far failed field validation despite encouraging laboratory performance. Ecological and climate-modelling studies converge on the conclusion that the geographical range suitable for virus circulation is likely to expand substantially by mid-century, while the evidence supporting ribavirin, the current standard of care, remains methodologically fragile. Pregnant women, healthcare workers and survivors experiencing long-term sequelae such as sensorineural hearing loss constitute under-served populations requiring dedicated research attention. The review concludes that an integrated One Health approach combining reservoir surveillance, decentralised diagnostics, and equitable vaccine deployment offers the most defensible pathway toward reducing the regional burden of this neglected but expanding threat.
Keywords: Lassa fever, Lassa mammarenavirus, Mastomys natalensis, viral haemorrhagic fever, genomic surveillance, point-of-care diagnostics, zoonotic spillover, West Africa