Hepatitis E Virus in Domestic Pigs, Wild Boars, Pig Farm Workers, and Hunters in Estonia
While hepatitis E is a growing health concern in Europe, epidemiological data on hepatitis E virus (HEV) in Estonia are scarce. Along with imported HEV infections, autochthonous cases are reported from European countries. Both domestic and wild animals can be a source of human cases of this zoonosis. Here, we investigated the presence of anti-HEV antibodies and HEV RNA in domestic pigs and wild boars, as well as in pig farm workers and hunters in Estonia. Anti-HEV antibodies were detected in 234/380 (61.6 %) of sera from domestic pigs and in all investigated herds, and in 81/471 (17.2 %) of meat juice samples from wild boars. HEV RNA was detected by real-time PCR in 103/449 (22.9 %) of fecal samples from younger domestic pigs and 13/81 (16.0 %) of anti-HEV-positive wild boar samples. Analysis of sera from 67 pig farm workers and 144 hunters revealed the presence of HEV-specific IgG in 13.4 and 4.2 % of the samples, respectively. No HEV RNA was detected in the human serum samples. Phylogenetic analyses of HEV sequences from domestic pigs and wild boars, based on a 245 bp fragment from the open reading frame 2 showed that all of them belonged to genotype 3. The present study demonstrates the presence of HEV in Estonian domestic pig and wild boar populations, as well as in humans who have direct regular contact with these animals. Our results suggest that HEV infections are present in Estonia and require attention.
KeywordsZoonosis Hepatitis E virus RNA Seroprevalence
The authors would like to thank Sofia Sidorova, senior laboratory specialist, for technical assistance as well as Elina Shatova and Jana Muravjova for analyzing pig sera and wild boar meat juice as a part of their Bachelor theses, Nurses Anu Kuusmann, Marge Reiss for taking blood samples. The farm workers and hunters are warmly thanked for their contributions and interest in this study. The study was financially supported by the European Regional Development Fund (Estonian Research Council (http://www.etag.ee/), programme TerVe, Projects ZoonRisk 3.2.1002.11-0002, 3.2.1002.11-0002 EKZE_SS and by Ministry of Education and Research.
Compliance with Ethical Standards
Conflict of interest
The authors declare that they have no conflict of interests.
Human rights and animals and informed consent
All procedures of this work were approved by Tallinn Medical Research Committee, No. 2921. The pig sera used in this study were collected for a regular survey on porcine pathogens performed at the Estonian University of Life Sciences. The fecal samples from pigs were collected from the pen floors with no physical contact with the animals. Serosanguineous meat juice samples were primarily collected for a study of Toxoplasma gondii in Estonian wild boars (Velström et al. 2013). Approval from the Research Ethics Committee of the University of Tartu (No. 216/T-15) as well as written informed consents was obtained from volunteer pig farm workers and hunters for the use of serum samples.
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