Viral and antibody HEV prevalence in swine at slaughterhouse in Italy

Abstract

1Hepatitis E is an acute disease of humans caused by a small RNA virus, Hepatitis E virus (HEV). In 2 recent years, an increasing number of autochthonous human infections have been reported in 3 industrialized countries. Genotype 3 is the main HEV type circulating in swine, and is also reported 4 in sporadic cases of hepatitis E in humans worldwide. To date one serotype has been described. We 5 have conducted a survey to detect antibodies against HEV in 48 swine at a slaughterhouse in 6Northern Italy, using ELISA test. Mean seroprevalence in the studied animal group was 87.%. Bile, 7 liver and feces from the 48 animals were also collected, and HEV RNA was detected by nested 8 reverse transcription-polymerase chain reaction, amplifying a fragment of the ORF2. HEV genome 9 was most frequently detected in bile samples (51.1%), followed by feces (33.3%) and liver (20.8%). 10Thirty-one out of 48 studied pigs (64.6%) were positive for HEV RNA in at least one sample. 11Overall, HEV RNA was found at a statistically higher rate in the 3-4 month-old than in 9-10 month-12 old animals (95.0% vs. 42.9%). Genetic characterization of swine strains identified was performed 13 by sequencing and database alignment. Phylogenetic analysis on the nucleotide sequences from 16 14 positive PCR products indicated that all strains belonged to genotype 3, clustering in two branches 15 subtypes g3c and g3f. 16 17

HEV infection in swine from Eastern Brazilian Amazon: Evidence of co-infection by different subtypes

“…HEV replication without serological evidence of HEV infection in pigs has been related to recent infection when HEV RNA was detected in liver or bile. On the other hand, when it was detected only in stools, it was suggested a possible transient intestinal presence of the virus without replication after ingestion [35]. This pattern was found in eight pigs in this study.…”

“…Moreover, several studies had reported that detection of HEV RNA in the liver samples was less frequent than in feces or bile [5]. The latter is the sample where HEV RNA has been found more frequently [35,40]. It is possible that in the present study seronegative animals with positive PCR only in feces had also HEV RNA detectable in their bile, but we cannot confirm this because it was not collected.…”

“…HEV subtypes 3c and 3f have also been identified conjointly in slaughtered pigs from Italy, however, the sequences obtained from multiple samples taken from the same animal were identical, i.e., they did not group into different subtypes [35], as was found in pig #035 case. Although they did not detect cases of co-infection with multiple viral subtypes, the aforementioned authors did not rule out this possibility.…”

“…Anti-HEV IgM antibody levels appear to be age-dependent, with the highest proportion found in young pigs (up to three months old) in response to their first contact with the virus, which usually occurs soon after weaning [20,[35][36][37][38]. The samples analyzed in the present study were obtained from pigs at slaughter age (approximately six months), what may have led to the failure in detecting IgM antibodies.…”

Detection of hepatitis E virus genome in pig livers in Antioquia, Colombia

“…The high levels of HEV detected in pigs from different countries (Clayson et al, 1995;de Deus et al, 2006;Baechlein et al, 2010) suggests that they could be carriers of HEV, and that this virus is a zoonosis transmitted to humans through water contaminated with pig feces or through contaminated viscera intended for consumption (La Rosa et al, 2010). However, swine HEV infection is asymptomatic; thus, it is difficult to determine when the infection peaks in order to optimize the sensitivity of tests for the virus (Di Bartolo et al, 2011).…”