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PLoS Negl Trop Dis. 2018 Mar 29;12(3):e0006361. doi: 10.1371/journal.pntd.0006361. eCollection 2018 Mar.

Development and evaluation of antibody-capture immunoassays for detection of Lassa virus nucleoprotein-specific immunoglobulin M and G.

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Department of Virology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
Institute of Lassa Fever Research and Control, Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria.
Department of Virology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.
Department of Tropical Medicine and Infectious Diseases, Center of Internal Medicine II, University of Rostock, Rostock, Germany.
Institute of Molecular Virology, Westfälische Wilhelms University of Münster, Münster, Germany.
Department of Medicine, Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria.
Department of Obstetrics and Gynecology, Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria.
Department of Pediatrics, Irrua Specialist Teaching Hospital, Irrua, Edo State, Nigeria.
German Center for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Germany.



The classical method for detection of Lassa virus-specific antibodies is the immunofluorescence assay (IFA) using virus-infected cells as antigen. However, IFA requires laboratories of biosafety level 4 for assay production and an experienced investigator to interpret the fluorescence signals. Therefore, we aimed to establish and evaluate enzyme-linked immunosorbent assays (ELISA) using recombinant Lassa virus nucleoprotein (NP) as antigen.


The IgM ELISA is based on capturing IgM antibodies using anti-IgM, and the IgG ELISA is based on capturing IgG antibody-antigen complexes using rheumatoid factor or Fc gamma receptor CD32a. Analytical and clinical evaluation was performed with 880 sera from Lassa fever endemic (Nigeria) and non-endemic (Ghana and Germany) areas. Using the IFA as reference method, we observed 91.5-94.3% analytical accuracy of the ELISAs in detecting Lassa virus-specific antibodies. Evaluation of the ELISAs for diagnosis of Lassa fever on admission to hospital in an endemic area revealed a clinical sensitivity for the stand-alone IgM ELISA of 31% (95% CI 25-37) and for combined IgM/IgG detection of 26% (95% CI 21-32) compared to RT-PCR. The specificity of IgM and IgG ELISA was estimated at 96% (95% CI 93-98) and 100% (95% CI 99-100), respectively, in non-Lassa fever patients from non-endemic areas. In patients who seroconverted during follow-up, Lassa virus-specific IgM and IgG developed simultaneously rather than sequentially. Consistent with this finding, isolated IgM reactivity, i.e. IgM in the absence of IgG, had no diagnostic value.


The ELISAs are not equivalent to RT-PCR for early diagnosis of Lassa fever; however, they are of value in diagnosing patients at later stage. The IgG ELISA may be useful for epidemiological studies and clinical trials due its high specificity, and the higher throughput rate and easier operation compared to IFA.

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