Seroprevalence of hepatitis E virus (HEV) in humans living in high pig density areas of Germany

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.

Systematic Serological Testing for Hepatitis E Virus in Kidney Transplant Recipients

“…It confirmed that these products represent a source of HEV transmission, particularly in these geographical areas (15). Direct contact with pigs through farming and slaughtering or with wild boars through hunting are other potential risks for the zoonotic transmission of HEV (1,(16)(17)(18)(19)(20). In addition, several studies demonstrated that pigs and wild boars in southern France can be infected with HEV (21,22), and Carpentier et al (23) reported that wild boars from southern France are at higher risk of HEV infection than wild boars from northern France.…”

An Epidemiologic Investigation of a Case of Acute Hepatitis E

“…By the time the animals are transferred to the research campus, most no longer are viremic or shedding the virus, and with good workplace practices, transmission to persons with pig contact will be low. Individuals with close contact to the pigs, such as veterinarians and farm workers, or to pig blood, such as slaughter-house workers and hunters, have been found to have higher rates of anti-HEV than the general population and suggest that close contact with pigs or wild boar is a risk factor for acquiring HEV (31)(32)(33)(34).…”

Hepatitis E virus in humans, farm animals and animals from the sylvatic environment

“…Wyniki badań serologicznych prowadzonych wśród hodowców świń, lekarzy weterynarii oraz pracowników leśnych dowodzą częstszej obecności anty-HEV IgG u osób z tych grup zawodowych. Niemniej jednak nie obserwuje się gwałtownego wzrostu zachorowań osób zawodowo narażonych na kontakt ze zwierzętami (7,27,39,42,64).…”

“…w stadach trzody chlewnej w Norwegii (29), USA (88,8%) (69), a także Belgii i Holandii (73%) (2). Niższą częstość infekcji stwierdzano u świń w Niemczech (46,9%), Wielkiej Brytanii (21,5%) i Czechach (5%) (2,27). Zakażenie zwierząt przebiega bezobjawowo z okresowym wydalaniem wirusa w kale.…”