Due to the increasing number of non-travel-associated hepatitis E virus (HEV) infections observed in several industrialised countries including Germany, there is a substantial interest in the characterisation of risk factors and transmission routes relevant to autochthonous HEV infections. Autochthonous cases are believed to be the result of a zoonotic HEV transmission from pigs, wild boars and deer. Recently, a high prevalence of HEV-specific antibodies in the German domestic pig population has been demonstrated. Thus, one may assume a higher prevalence of HEV-specific antibodies in humans with occupational exposure to pigs. In this study, sera obtained from 24 slaughterers, 14 meat inspectors, 46 pig farmers and 22 veterinarians were tested for the presence of HEV-specific antibodies using a line immunoassay. For comparison, sera obtained from 116 age- and gender-matched blood donors were also included. Twenty eight per cent (28.3%; 30/106) of the swine-exposed humans and 15.5% (18/116) of the blood donors without contact to pigs exhibited IgG-antibodies determined as reactive (i.e. borderline or positive) against HEV. Thus, an increased risk of HEV infection in humans occupationally exposed to pigs and particularly for slaughterers (41.7%; 10/24) was demonstrated.

No abstract

An increase in acute autochthonous hepatitis E virus (HEV) infections has been recorded in Germany. These are suspected to be zoonotically transmitted from wild boar, deer and domestic pig. The latter may represent a major reservoir for HEV. In this study, 537 sera from humans living in Westphalia and Lower Saxony, representing areas of high pig density in Germany, were tested for the presence of HEV-specific antibodies. Among them were 302 individuals with occupational, direct contact to pigs and 235 individuals without direct contact to pigs. Two commercial tests and one in-house assay were applied for the detection of HEV-specific immunoglobulin G (IgG) antibodies. Sera were also tested in an assay that detects all classes of HEV-specific antibodies. Depending on the test used, the seroprevalence ranged from 4.1 to 27.9 %. Exposition to pigs was found to be associated with a significantly higher seroprevalence in subjects with contact to pigs (13.2-32.8 %) compared with that in non-exposed humans (7.7-21.7 %). In particular, individuals younger than 40 years with occupational exposure exhibited a markedly higher HEV seroprevalence compared with non-exposed individuals of that age group. In general, HEV seroprevalence increased with age resulting in a similar prevalence level in the age group of ≥ 50 years for exposed and non-exposed individuals. Analysis of all sera by a commercial anti-HEV IgM ELISA revealed 35 positive and 25 borderline samples. However, only one positive serum could be confirmed by an IgM line assay. Selected samples from IgM and/or IgG as well as total HEV antibody-positive individuals were also tested for the presence of HEV RNA. In one of the 78 samples, the only IgM ELISA positive and IgM line assay confirmed sample, RNA of HEV genotype 3 was detected. This sequence has high similarity to HEV sequences obtained from wild boars and domestic pigs from Germany and The Netherlands. This study demonstrates that in addition to the consumption of raw or undercooked meat, direct contact to pigs has to be considered as an additional risk factor for HEV infection.