Development of ELISA test kits for semi-quantitative detection of anti-HEV antibodies in pigs in the Republic of Belarus

Viral hepatitis E infection affects up to 80-100 % of domestic pigs worldwide and is characterized by high seroprevalence among domestic pigs in temperate climate countries. Epizootic monitoring of HEV infection is insufficient in the Republic of Belarus due to lack of the required number of available and inexpensive diagnostic ELISA kits with good sensitivity and specificity. In this regard, research on development of domestic ELISA kit for semi-quantitative detection of antibodies to hepatitis E virus in pigs with subsequent assessment of seroprevalence to HEV in pig population in the Republic of Belarus is relevant. The results of studies on development of enzyme-linked immunosorbent assay kit for semi-quantitative determination of class G immunoglobulins to HEV in pig blood serum using recombinant proteins, including immunodominant amino acid sequences corresponding to the ORF2 and ORF3 proteins of HEV genotype 3 are presented in the paper. The optimal concentration for sorption of ORF2 and ORF3 proteins has been determined, which is 2 μg/ml and 1 μg/ml, respectively. The diagnostic sensitivity of this test kit makes 94.8 %, and the diagnostic specificity makes 100 %. Coefficients of variation being the criterion for assessing the intra-serial and inter-serial reproducibility of this test kit, make 3.5 % and 12.4 %, respectively, which allows to obtain reproducible results and identify specific anti-HEV antibodies in all positive samples of pig blood serum. When studying 1235 pig sera samples from various pig farms of Brest, Vitebsk, Gomel, Grodno, Minsk and Mogilev regions, seroprevalence of anti-HEV antibodies has been determined in 168 or 13.6 % of animals. The described diagnostic method can be widely used in science and practice for the further study of seroprevalence of anti-HEV. Acknowledgments. The research was carried out as part of the Interstate program of innovation cooperation of States - participants of the CIS up to 2020, with the financial support of the Ministry of education and science of the Russian Federation, the project ID RFMEFI61316X0 061, and the State Committee for Science and Technology of the Republic of Belarus.