Publications scientifiques
Arnaud Fondjo Kouam
Philipe Herman Nfombouot Njitoyap
Brice Fredy Nemg Simo
Cromwel Tepap Zemnou
Kerinyuy Juliene Kongnyuy
Armel Jackson Seukep
Elisabeth Menkem Zeuko’o
Paul Fewou Moundipa
Microbes & Immunity
Hepatitis E virus (HEV) is a major zoonotic pathogen, and pigs are an important reservoir. Serology for anti-HEV antibodies poorly reflects active infection, while reverse transcription polymerase chain reaction (RT-PCR) is sensitive but not always feasible for large-scale surveillance. This study aimed to develop an immunoglobulin Y (IgY)-based sandwich enzyme-linked immunosorbent assay (ELISA) for direct detection of HEV antigen (HEV-Ag). An antigenic epitope from the HEV open reading frame 2 capsid protein was identified in silico, synthesized, and used to immunize laying hens; IgY was purified from egg yolk and characterized by sodium dodecyl sulfate&ndash;polyacrylamide gel electrophoresis. An in-house sandwich ELISA was subsequently developed using the anti-HEV IgY antibodies. Its diagnostic performance was evaluated against RT-PCR using 350 field-collected pig serum samples and compared with commercial anti-HEV IgG and IgM ELISA kits. Immunization yielded high-purity IgY antibodies, with antigen-specific antibody kinetics showing a significant increase in specific immunoreactivity from week 4 onward and peak sensitivity at weeks 6&ndash;8 post-immunization. The anti-HEV IgY showed high specificity, with no cross-reactivity observed against a heterologous antigen (HBsAg). The optimized sandwich ELISA detected HEV-Ag with a sensitivity of 95.4% and a specificity of 100% relative to RT-PCR. The prevalence of HEV-Ag was 17.7% (62/350), which was not significantly different from RT-PCR (18.6%, 65/350; p=0.250). In contrast, commercial IgG and IgM ELISAs showed high seroprevalence rates (34.9% and 28.3%, respectively) but exhibited significant discrepancies with RT-PCR (p<0.0001), indicating limited utility for identifying active infection. Overall, the developed IgY-based sandwich ELISA demonstrated high diagnostic performance for detecting active HEV infection. This assay represents a viable alternative to RT-PCR for large-scale surveillance, particularly in resource-constrained settings, and may contribute to improved control of zoonotic HEV transmission.
