Frontline of Lassa Fever: Clinical Predictors and Outcomes from Primary Health Care Centres in Rivers State, Nigeria
Briggs, Nduye Christie Tobin
*
Department of Community Medicine, College of Medical Sciences, Rivers State University, Port Harcourt, Nigeria.
Abo, Inye Anthony
Primary Health Care Department, Port Harcourt City Local Government, Port Harcourt, Nigeria.
Nwadiuto, Ifeoma Christiana
Department of Community Medicine, College of Medical Sciences, Rivers State University, Port Harcourt, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Introduction: Lassa fever, a viral haemorrhagic illness endemic to West Africa, remains a significant public health concern more than half a century after its discovery. Globally, annual estimates suggest a burden of approximately 300,000 to 500,000 cases, resulting in about 5,000 deaths each year.
Within West Africa, Nigeria, Sierra Leone, and Liberia bear the heaviest Lassa fever burden. A recent meta-analysis of regional epidemiological data reported a pooled attack rate of 21% and a case fatality rate (CFR) of 27%. Notably, Nigeria’s CFR was lower at 16%, although hospitalised patients and vulnerable groups (children, pregnant women) experienced much higher mortality.
Early detection at Primary Health Centres (PHCs) is essential for reducing diagnostic delays and enhancing patient outcomes.
Aims: This study aimed to identify the clinical signs that predict Lassa fever and evaluate the outcomes of patients attending PHCs in Rivers State, Nigeria.
Methods: A retrospective cross-sectional study was conducted in 15 PHCs in Rivers State from January 2023 to March 2025. A simple random sampling was used to select 5 Local Government Areas (LGAs) from the 23 LGAs of Rivers State by balloting. Also, simple random sampling using computer-generated random numbers was used to select 3 PHCs from each LGA to make the 15 PHCs.
A total of 312 suspected Lassa fever presentations were included. Data were abstracted using a structured proforma on demographics, presenting symptoms, laboratory confirmation (RT-PCR), management (referral, initial care), and outcomes (recovery, referral, death).
Bivariate analysis (Pearson chi-square) compared symptoms in confirmed and non-confirmed cases; variables with p<0.20 were entered into multivariable logistic regression to estimate adjusted odds ratios (AORs) for predictors of confirmed Lassa fever.
Results: Of 312 suspected cases, 78 (25.0%) were laboratory-confirmed by RT-PCR. Persistent fever (>7 days) was present in 52.6% confirmed cases versus 20.1% of non-confirmed cases (p<0.001). Other symptoms disproportionately represented among confirmed cases included bleeding tendencies (30.8% versus 3.4%; p<0.001), sore throat (23.1% versus 11.5%; p=0.008), and hearing loss (9.0% versus 1.3%; p=0.002). Multivariable logistic regression identified persistent fever (AOR 3.12; 95% CI 1.62-5.98), bleeding (AOR 4.85; 95% CI 2.11-11.12), sore throat (AOR 2.77; 95% CI 1.32-5.79), and hearing loss (AOR 6.41; 95% CI 1.90-21.59) as independent predictors. Outcomes among confirmed cases were recovered 49 (62.8%), referred 13 (16.7%), and died 16 (20.5%).
Conclusion: In PHC settings in Rivers State, presentation of clinical features such as persistent fever, bleeding, sore throat, and hearing loss strongly raises the probability of RT-PCR confirmed Lassa fever. Though less frequent, hearing loss had the highest AOR and should be regarded as an important clinical red flag. The observed fatality rate among confirmed cases (20.5%) is an indication of persistent fatality where timely diagnostics and referrals are limited. Strengthening PHC capacity for syndromic recognition, specimen collection and rapid referral to diagnostic centres, together with community education and strengthened surveillance, is essential to reduce morbidity and mortality from Lassa fever.
Keywords: Lassa fever, clinical predictors, primary health centres, Rivers State, Nigeria