Performance of Hepatitis E Virus (HEV)-antibody tests: a comparative analysis based on samples from individuals with direct contact to domestic pigs or wild boar in Germany

Abstract

In Europe, Hepatitis E virus (HEV) genotype 3 causes most human infections, and domestic pigs and wild boar represent the main reservoirs. Contact to these animals represents one source of human infection. However, interpretation of studies is challenged in the absence of a serological gold standard. Hence, this study compared results of different HEV immunoassays. Plasma samples from 139 individuals who had professional contact to pigs (veterinarians, meat inspectors, slaughterhouse workers; n = 114) or hunted regularly (n = 25) were tested with assays specific for HEV IgG, HEV IgM, HEV IgA, and total HEV immunoglobulin as well as for viral RNA. Furthermore, overall HEV IgG was defined (i.e., two of three IgG assays reveal the same result) to compare serological findings. Borderline results were always quoted as positive. For IgG, apparent prevalence was higher in Wantai (48.2%) compared to Euroimmun (11.5%) and Mikrogen assays (17.3%) (p = 0.0001). The overall IgG prevalence was estimated to be 18.7%. For total Ig, Wantai (40.3%) also yielded higher prevalence than Euroimmun (15.8%) (p = 0.0001). The HEV IgM prevalence ranged from 0% (Euroimmun) to 4.3% (Mikrogen). Four percent of individuals tested IgA positive, whilst none harboured HEV RNA. Our results support previous studies that the higher IgG prevalence estimated with the Wantai assay result from a higher sensitivity of this test. However, further studies are needed to verify specificity given the challenge of defining true negative samples. The high percentage of individuals with HEV IgG observed in this study underlines that direct contact to pigs represents a risk factor for HEV infection.

Comprehensive Evaluation of Hepatitis E Serology and Molecular Testing in a Large Cohort

“…This is not necessarily true for immunocompetent hosts though. Although older serological assays for HEV diagnosis had come in disrepute due to their unacceptable performance, newer assays perform as shown in our and previous studies reasonably well [2,11,12,22]. According to our data, performing HEV PCR in immunocompetent hosts would be advisable only if the HEV serology (IgM or/and IgG) is positive.…”

“…Previous studies have evaluated the diagnostic performance of different serological assays for HEV IgG, IgM and to a lesser degree HEV IgA [11,12]. Variability in the performance of such assays is common [13][14][15][16], but false positive cases in healthy blood donors and false negative cases in patients with acute hepatitis seem to be rare [17,18].…”

Hepatitis E virus strains infecting Swedish domestic pigs are unique for each pig farm and remain in the farm for at least 2 years

“…Swedish strains from most human cases with acute HEV and HEV from pigs and wild boar belong to subtype 3f in clade 3II (Norder et al, 2009;Roth et al, 2016). Zoonotic transmission of HEV by direct or indirect contact with infected animals, as pigs, may therefore be a further factor (Huang, Huang, Wagner, Chen, & Lu, 2018;Krumbholz et al, 2012Krumbholz et al, , 2014Sommerkorn, Schauer, Schreiner, Fickenscher, & Krumbholz, 2017) contributing to the surprisingly high seroprevalence in Sweden.…”

HEV seroprevalence in blood donors in Turkey by two commercial total anti‐HEV Ab ELISA kits

“…Since, the study groups are blood donors in both studies, these conflicting results in anti‐HEV seropositivity might be explained by the low performance of the commercial ELISA assay (Euroimmun, Germany) used in the study. In this regard, two recent studies comparing assay performances of Euroimmun and Wantai ELISA assays reported a low assay performance of the Euroimmun assay compared with the Wantai ELISA . In Kayseri anti‐HEV seropositivity was determined as 8.2% and 7.4% with Wantai and Dia.Pro assays in the present study, respectively, although it was previously reported to be 1.6% in blood donors…”

“…6 Subsequent studies from Germany, France, Korea, and Australia comparing different enzyme-linked immunosorbent assay (ELISA) kits confirmed the higher sensitivity of the Wantai assay. [7][8][9][10][11][12] In this study, new generation serological assays (Wantai, Beijing, China and Dia.Pro, Milan, Italy) utilizing total anti-HEV antibodies (Ab) based on HEVlike particles, including anti-HEV IgG, immunoglobulin M (IgM) and…”