Beyond Symptoms in the Clinical Epidemiology of Lassa Fever and Determinants of Health-Seeking Delay

Background: Lassa fever (LF) is an acute viral hemorrhagic diseases endemic to some Sub-Saharan Africa countries. Ondo state is located in the South-Western region of Nigeria with high burden of Lassa fever reported. This study used secondary patient-level clinical surveillance records to identify key predictors of LF confirmation and characterize factors associated with late clinical presentation and severe disease proxy. Methods: Descriptive and retrospective analysis was used to analyze and report the demographic characteristics. Binary Logistic Regression was used to assess predictors for three binary outcomes; LF Confirmation (PCR Positive), Severe Clinical Presentation, and Health-Seeking Delay. Chi-squared test wasused to determine associations between symptom profiles. Results: Late presentation of cases reported after 6 days symptom onset, was a statistically significant independent predictor of LF confirmation (aOR: 3.70; 95% CI: 1.08–13.9; \((p=0.042)\)). The prevalence of severe clinical presentation increased from \((11.1%)\) in early presenters (0-2 days) to \((53.5%)\) in late presenters (\((\geq 6)\) days). No demographic factors were significantly associated with health-seeking delay. Symptom profile analysis confirmed no clinical symptom reliably distinguished confirmed LF cases from other febrile illnesses. Conclusion: The findings indicate that LF diagnosis in this endemic epicentre is largely dependent on the timing of presentation. Triage protocol should prioritises PCR testing for patients with fever persisting for six days or longer could enhance early identification.Effective public health responses require a shift from awareness based communication to practical measures that reduce systemic and economic barriers to timely care, as delayed presentation remains the leading cause of severe LF cases.