title: Hepatitis E virus seroprevalence among the general population in a livestock-dense area in the Netherlands: a cross-sectional population-based serological survey.
abstract: Recent serological studies indicate that hepatitis E virus (HEV) is endemic in industrialised countries. The increasing trend in the number of autochthonous cases of HEV genotype 3 in Western European countries, stresses the importance to get insight in the exact routes of exposure. Pigs are the main animal reservoir, and zoonotic food-borne transmission of HEV is proven. However, infected pigs can excrete large amounts of virus via their faeces enabling environmental transmission of HEV to humans. This might pose a risk for of neighbouring residents of livestock farming.
  
  
  
  Within a large study on the health of people living in the vicinity of livestock farming we performed a cross-sectional population-based serological survey among 2,494 non-farming adults from the general population in a livestock-dense area in the south of the Netherlands. Participants completed risk factor questionnaires and blood samples of 2,422 subjects (median age 58 years, range 20-72) were tested for anti-HEV IgG using an enzyme immune assay (Wantai). The aim of this study was to determine the HEV seroprevalence and to assess whether seropositivity in adults was associated with living in the vicinity of pig farms.
  
  
  
  The average seroprevalence of HEV was 28.7% (95% CI: 26.9-30.5). Determinants associated with an increased risk for HEV seropositivity were male gender and low level of education. There was a clear trend of increasing prevalence with increasing age (Chi-square test for linear trend, X2= 83.1; p < 0.001). A high number of pigs within 1,000 m of the residential address was not a risk factor for seropositivity.
  
  
  
  This study confirmed the high HEV seroprevalence (29%) in the general population of the Netherlands, but presence of antibodies was not associated with residential proximity to pig farms. The prevalence increased with age from 10% in adolescents to 33% among those aged 50 and above, supporting the assumption of a cumulative lifetime exposure to HEV in the Netherlands as well as a higher infection pressure in the past. Our findings cannot refute the assumption that transmission is primarily food-borne.
authors.affiliation: National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands. rianne.van.gageldonk@rivm.nl.
authors.forename: Arianne B
authors.initials: AB
authors.lastname: van Gageldonk-Lafeber
authors.affiliation: National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Wim
authors.initials: W
authors.lastname: van der Hoek
authors.affiliation: Institute for Risk Assessment Sciences, IRAS, Utrecht University, Utrecht, The Netherlands.|Netherlands Institute for Health Services Research (NIVEL), Utrecht, The Netherlands.
authors.forename: Floor
authors.initials: F
authors.lastname: Borlée
authors.affiliation: Institute for Risk Assessment Sciences, IRAS, Utrecht University, Utrecht, The Netherlands.
authors.forename: Dick J J
authors.initials: DJ
authors.lastname: Heederik
authors.affiliation: National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Sofie H
authors.initials: SH
authors.lastname: Mooi
authors.affiliation: National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Catharina B M
authors.initials: CB
authors.lastname: Maassen
authors.affiliation: Netherlands Institute for Health Services Research (NIVEL), Utrecht, The Netherlands.
authors.forename: C Joris
authors.initials: CJ
authors.lastname: Yzermans
authors.affiliation: National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Barry
authors.initials: B
authors.lastname: Rockx
authors.affiliation: Institute for Risk Assessment Sciences, IRAS, Utrecht University, Utrecht, The Netherlands.
authors.forename: Lidwien A M
authors.initials: LA
authors.lastname: Smit
authors.affiliation: National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Johan H J
authors.initials: JH
authors.lastname: Reimerink
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D005260:Female; D016751:Hepatitis E / Q000453:epidemiology*; D006801:Humans; D058751:Livestock; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D012307:Risk Factors; D012424:Rural Population; D016036:Seroepidemiologic Studies; D011795:Surveys and Questionnaires; D013552:Swine / Q000821:virology; D055815:Young Adult
keywords: Environmental exposure; Hepatitis E virus; Livestock; Seroprevalence; Zoonoses