Conference Abstract | Volume 8, Abstract ELIC2025318 (Oral 024) | Published: 11 Aug 2025
Till Omansen1,&, Cyril Erameh2, Ephraim Ogbaini-Emovon3, Reuben Eifediyi4, Michael Ramharter5, Sylvanus Okogbenin4
1Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany, 2Irrua Specialist Teaching Hospital, Irrua, Nigeria, 3Institute of Viral and Emergent Pathogens Control & Research, Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria, 4Irrua Specialist Teaching Hospital, Edo State, Nigeria, 5Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
&Corresponding author: Till Omansen, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany, Email: till.omansen@bnitm.de
Received: 31 May 2025, Accepted: 09 Jul 2025, Published: 11 Aug 2025
Domain: Infectious Disease Epidemiology
Keywords: Neurological disorder, Lassa fever sequelae, Ribavirin
©Till Omansen et al. Journal of Interventional Epidemiology and Public Health (ISSN: 2664-2824). This is an Open Access article distributed under the terms of the Creative Commons Attribution International 4.0 License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Cite this article: Till Omansen et al., Divergent pathways of severe Lassa fever: Vascular leak and hyperinflammation versus neurological disease, recommendations for therapeutic countermeasure from the pathogenesis study. Journal of Interventional Epidemiology and Public Health. 2025;8(ConfProc5):00024. https://doi.org/10.37432/JIEPH-CONFPRO5-00024
Lassa fever (LF) is a viral haemorrhagic fever (VHF) prevalent in West Africa with case fatalities rates in hospitalised patients ranging from 20-30 %. Previous studies have demonstrated acute kidney injury and encephalopathy as key symptoms associated with fatal outcome. Yet to date the underlying pathophysiology is poorly understood hampering the development of adequate medical countermeasures (MCM).
From January 2022 until December 2023, we recruited a prospective observational cohort of 329 adult Lassa fever patients at Irrua Specialist Teaching Hospital in Nigeria. Bidaily study visit included assessment of clinical exams and blood sampling. Patients were classified according to common outcome definitions. To decipher the pathogenesis of AKI and encephalopathy, patients with such diagnosis were recruited into sub-cohorts with additional focused assessments such as ultrasound, urinalysis, neurological exams and electroencephalography (EEG).
The mean age of the cohort was 36.8 years and 42.7 % (137/321) were female. All patients were treated with Ribavirin and 48% also with Dexamethasone. The most common complications were acute kidney injury (AKI; 28% 96/342), hepatitis (23%, 79/342), and meningitis or focal neurological defect (8.5%, 29/342). AKI was mainly associated with hyperinflammation and a vascular leak syndrome. Fatal cases, compared with survivors, showed marked inflammation (CRP: 33 [10 – 71] vs. 98 [64 – 162], WBC: 6.7 [5.1 – 8.8] vs. 13.4 [8.9 – 25.2]) and, to a lesser extent, coagulopathy (INR: 1.07 [1.03 – 1.13] vs. 1.20 [1.05 – 1.28]). In neurologically impaired patients, distinct EEG patterns indicated viral meningitis.
Fatal cases exhibited a multi-organ failure syndrome hallmarked by hepatitis and AKI. This syndrome was associated with vascular leak and inflammation, rather than severe haemorrhage. A secondary phenotype (approx. 8.5%, 29/342) of patients had primarily neurological disease. We recommend that therapeutic approaches also target vascular leak and inflammation and address neuroinvasive infection.
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