Hepatitis E virus in Norway rats (Rattus norvegicus) captured around a pig farm

Abstract

BackgroundHepatitis E virus (HEV) transmitted via the oral route through the consumption of contaminated water or uncooked or undercooked contaminated meat has been implicated in major outbreaks. Rats may play a critical role in HEV outbreaks, considering their negative effects on environmental hygiene and food sanitation. Although the serological evidence of HEV infection in wild rodents has been reported worldwide, the infectivity and propagation of HEV in wild rats remain unknown. To investigate if rats are a possible carrier of HEV, we studied wild Norway rats (Rattus norvegicus) that were caught near a pig farm, where HEV was prevalent among the pigs.MethodsWe examined 56 Norway rats for HEV. RNA from internal organs was examined for RT-PCR and positive samples were sequenced. Positive tissue samples were incubated with A549 cell line to isolate HEV. Anti-HEV antibodies were detected by ELISA.ResultsSixteen rats were seropositive, and the HEV RNA was detected in 10 of the 56 rats. Sequencing of the partial ORF1 gene from 7 samples resulted in partially sequenced HEV, belonging to genotype 3, which was genetically identical to the HEV prevalent in the swine from the source farm. The infectious HEVs were isolated from the Norway rats by using the human A549 cell line.ConclusionsThere was a relatively high prevalence (17.9%) of the HEV genome in wild Norway rats. The virus was mainly detected in the liver and spleen. The results indicate that these animals might be possible carrier of swine HEV in endemic regions. The HEV contamination risk due to rats needs to be examined in human habitats.

Host Immune Status and Response to Hepatitis E Virus Infection

“…The known animal reservoirs of HEV continue to multiply; novel members of the Hepeviridae have been detected in wild and farmed rabbits, wild rats, birds, bats, and trout (13,15,(88)(89)(90)(91)(92)(93)(94)(95)(96)(97)(98)(99)(100)(101)(102)(103)(104)(105)(106). Of these, only rabbit HEV strains have been shown to share a close phylogenetic relationship and possess antigenic similarity to human-and swine-associated HEV strains.…”

“…2). HEV-3 is prevalent among swine worldwide (71)(72)(73)(74)(75)(76)(77)(78)(79)(80)(81)(82)(83)(84)(85)(86) as well as in other mammals, including deer and mongooses (83,(87)(88)(89), though little is known about the sylvatic circulation of HEV.…”

Characterization of Hepatitis E Virus Recombinant ORF2 Proteins Expressed by Vaccinia Viruses

“…However, antibody titers were lower and less lasting than those previously observed after vaccination with baculovirus-expressed proteins (18). Although HEV has recently been detected in rats with shedding of virus (21,23,37), and HEV experimental infection has been reported with nude mice (15), HEV does not seem to infect immunocompetent mice (26); therefore, the protective capacity of the immunological status acquired by these animals after vaccination with the recombinant vaccinia viruses was not evaluated.…”

“…HEV is classified into four genotypes (gt) that infect humans, although only gt3 and gt4 have been isolated in other animal species, mainly pigs (2,6,29,36) and, recently, rats (21,23,37). HEV is enterically transmitted and causes epidemic outbreaks in areas with inadequate hygienic conditions and/or water supplies, and thus, it has become an important public health concern.…”

Hepatitis-E-Virus

“…Des Weiteren konnte in Japan gezeigt werden, dass Ratten in der Nachbarschaft einer Schweinefarm mit HEV-3 infiziert und diese Viren phylogenetisch eng verwandt waren mit HEV-3 der Schweine [138]. Es ist unklar, inwieweit es HEV-3-Varianten gibt, die Menschen und Schweine, aber auch Ratten infizieren können, da in Übertragungsver-suchen gezeigt wurde, dass HEV-1, HEV-3 und HEV-4 nicht auf Ratten übertragen werden konnten [16].…”