Bayesian estimation of hepatitis E virus seroprevalence for populations with different exposure levels to swine in The Netherlands

Abstract

SUMMARYHepatitis E virus (HEV) is ubiquitous in pigs worldwide and may be zoonotic. Previous HEV seroprevalence estimates for groups of people working with swine were higher than for control groups. However, discordance among results of anti-HEV assays means that true seroprevalence estimates, i.e. seroprevalence due to previous exposure to HEV, depends on choice of seroassay. We tested blood samples from three subpopulations (49 swine veterinarians, 153 non-swine veterinarians and 644 randomly selected individuals from the general population) with one IgM and two IgG ELISAs, and subsets with IgG and/or IgM Western blots. A Bayesian stochastical model was used to combine results of all assays. The model accounted for imperfection of each assay by estimating sensitivity and specificity, and accounted for dependence between serological assays. As expected, discordance among assay results occurred. Applying the model yielded seroprevalence estimates of y11 % for swine veterinarians, y6% for non-swine veterinarians and y2% for the general population. By combining the results of five serological assays in a Bayesian stochastical model we confirmed that exposure to swine or their environment was associated with elevated HEV seroprevalence.

Preliminary study on the detection of hepatitis E virus (HEV) antibodies in pigs and wild boars in Poland

“…Pigs can be infected through direct contact with infected animals, or via feed and water contaminated with faeces. The basic reproduction ratio (R0) is 8.8, which means that one infected animal can be the source of infection for eight other animals (2). HEV infection in swine is subclinical and is observed for approximately 10 weeks.…”

Transmission routes and risk factors for autochthonous hepatitis E virus infection in Europe: a systematic review

“…Moreover, a comparison of five serological tests showed that the agreement between the tests was moderate at best (kappa y0 . 5) [22]. A couple of IgG enzyme-linked immunosorbent assay (ELISA) commercial kits were withdrawn from the market or replaced by new tests by the manufacturer due to recognition of a high proportions of false-negative results [22,23].…”

Chronic hepatitis E: A brief review

“…A positive RT-PCR after a minimum of 3-6 mo from the time of diagnosis of HEV, establishes the presence of chronic HEV [24][25][26] . This is because spontaneous clearance may occur within the first 6 mo as noted in initial followup studies in immunosuppressed patients with positive HEV RNA [22,23] . However, recently [24] , Kamar et al [24] reported that in transplant recipients who acquired HEV infection, none of the patients cleared the virus between 3 and 6 mo.…”

“…The reasons for this high seroprevalence could be due to subclinical infection, exposure to animals, serological cross reactivity with other agents or false positive results. In particular, individuals coming in contact with swine, like veterinarians, pig breeders and slaughter house personnel have been found to have statistically significant higher rates of hepatitis E seropositivity in developed countries [18][19][20][21][22] .…”