A Novel In-House Enzyme-Linked Immunosorbent Assay for Genotype 3 Hepatitis E Virus Reveals High Seroprevalence in Blood Donors in Northern Argentina

Abstract

Hepatitis E virus (HEV) is an emergent virus that causes acute hepatitis in immunocompetent hosts and chronic hepatitis in immunocompromised ones. In Latin America, the main circulating genotype (GT) is 3, which is usually of zoonotic origin. Diagnosis and seroprevalence studies mainly rely on the detection of specific antibodies. In Argentina there are scarce data on the seroprevalence of HEV infection mainly due to the lack of awareness of HEV circulation and because HEV testing is not included in routine assays. The following conditions were determined: an optimal antigen concentration of 0.25 µg/ml, a serum dilution of 1:80, gelatin as blocking agent, and a secondary antibody dilution of 1:1000. Specificity (97.8%) and sensibility (100%) were determined using a panel of previously characterized sera. When we compared our in-house ELISA with a commercial test (DIA.PRO), we obtained a kappa index of 0.939. We screened 813 blood donor samples with this newly developed ELISA and found a seroprevalence of 8.31%. We further analyzed the seroprevalence of blood transmitted diseases such as Chagas disease (1.9%), syphilis (1.2%), hepatitis B (0.9%), and brucellosis (0.4%) in a group of 412 blood donors. These samples did not cross reacted with HEV positive samples according to the χ2 test for comparison of proportions. We show for the first time, the circulation of HEV in Tucuman, the most populated city in northern Argentina. We expect that this study will raise the interest of health decision makers who should intercede to include indirect testing of HEV in regular diagnostic protocols. In conclusion, the in-house ELISA developed in this work shows a very good agreement with an already licensed commercial HEV IgG ELISA (DIA.PRO, ITALY), which can be used as an epidemiologic tool for HEV surveillance.