Conference Abstract | Volume 8, Abstract ELIC2025214 (Poster 075) | Published: 18 Aug 2025
Sa’adatu Aliyu Abubakar1,&,, Adama Abubakar Ahmed1, Zacchaeus Adeniran Adejuyigbe1, Item Inya Item1, Adesola Semiu Adeleye1, Mustapha Lawal1, Eugene Samuel Bwede1, Osarenmwinda Omobude1, Munzali Shamsu Zubairu1, Agwu Enoch Ojenya1, Ikulughan Iibinmo Love1, James Avong1, Olajumoke Babatunde1, Jide Idris1
1Nigeria Centre for Disease Control and Prevention, Abuja, Nigeria
&Corresponding author: Sa’adatu Aliyu Abubakar, Nigeria Centre for Disease Control and Prevention, 801 Ebitu Ukiwe Street, Jabi, Abuja, Nigeria. Email: Saadatu.abubakar@ncdc.gov.ng
Received: 25 May 2025, Accepted: 09 Jul 2025, Published: 18 Aug 2025
Domain: Infectious Disease Epidemiology
Keywords: Real-time polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), immunoglobulin G (IgG), Lassa fever virus (LASV), nucleoprotein (NP)
©Sa’adatu Aliyu Abubakar 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: Sa’adatu Aliyu Abubakar et al., Serological evidence of prior exposure in suspected Lassa fever cases with negative real-time polymerase chain reaction (PCR) results. Journal of Interventional Epidemiology and Public Health. 2025;8(ConfProc5):00075. https://doi.org/10.37432/JIEPH-CONFPRO5-00219
Lassa virus, an RNA virus causing haemorrhagic fever and belonging to the Arenaviridae family, is prevalent in West Africa. Nigeria is highly endemic due to the primary host, Mastomys natalensis, residing within the human population. Though 80% of cases are asymptomatic or possess mild symptoms, in 20% of cases, the symptoms manifest gradually as the infection progresses. Presently, RT-PCR is the diagnostic gold standard in Nigeria, effectively detecting acute infection (first 3 weeks) before antibody emergence; however, viral clearance in survivors coincides with antibody emergence. This study investigated the prevalence of serological Immunoglobulin-G (IgG) biomarkers in suspected Lassa fever cases relative to PCR results, aiming to understand prior exposure.
A retrospective study was conducted on 93 archived suspected Lassa fever cases using the Real Star Altona Lassa fever RT-PCR 2.0 Assay. Subsequently, all samples underwent IgG serological testing with the Panadea LASV (NP) IgG ELISA kit, following the manufacturer’s instructions. Data was analysed using non-parametric statistics, the Mann-Whitney U test at p<0.005.
Of the 93 cases, RT-PCR confirmed 21 (22.6%) as positive and 72 (77.4%) as negative for Lassa virus RNA. IgG antibody testing revealed that 5 (7%) of the PCR-negative samples were seropositive, indicating prior Lassa virus exposure. Conversely, only 4 (19.0%) of the PCR-positive samples were IgG-positive.
The detection of IgG antibodies in PCR-negative cases suggests prior Lassa virus exposure, highlighting potential missed past infections when relying solely on PCR. The low IgG positivity in PCR-positive cases may indicate early infection before significant antibody development or limitations in acute-phase IgG detection. Given that approximately 80% of Lassa fever infections are mild or asymptomatic, many individuals with immunity (IgG) may remain undetected by surveillance focusing on symptomatic cases and PCR testing. These findings underscore the value of integrating serological assays with molecular methods for a more comprehensive understanding of Lassa fever exposure and to inform public health strategies in endemic regions like Nigeria.
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