Prevalence and phylogenetic analysis of hepatitis E virus in pigs in Vietnam

Abstract

Background Hepatitis E virus (HEV) is a zoonotic disease and has been reported around the world. The main objective of this study was to evaluate the sero-prevalence and phylogenetic analysis of HEV in Vietnam. Pig blood and fecal pooled samples were collected to assess the prevalence of HEV. We assessed the true prevalence (TP) of HEV from apparent prevalence (AP) by taking into account the sensitivity and specificity of diagnostic tests using a Bayesian approach. For phylogenetic analysis, the data compared with worldwide HEV reference strains including all eight genotypes (G1-G8) which were identified in previous study. Results A total of 475 sera and 250 fecal pooled samples were collected at slaughterhouses and pig farms from five provinces, in Viet Nam. Overall, the sero-AP of HEV was 58.53% (95% confidence interval: 53.95–62.70) while the sero-TP was slightly higher (65.43, 95% credible interval: 47.19–84.70). In terms of pooled samples, overall, the RNA-AP was 6.80% (95% confidence interval: 4.01–10.66). One strain in Hanoi, two strains in Dak Lak, seven strains in An Giang, four strains in Son La and two strains in Nghe An were isolated. The phylogenetic tree demonstrated that 19 Vietnamese strains were clustered into HEV 3 and 4. Conclusions This study provided evidence that HEV is circulating in domestic pigs in Vietnam. From a public health perspective, it is very important to raise public awareness for high-risk groups (e.g. slaughterhouse workers, pig traders, farmers and market sellers) who have more opportunities to come in contact with pig and contaminated meats.

Porcine Blood and Liver as Sporadic Sources of Hepatitis E Virus (HEV) in the Production Chain of Offal-Derived Foodstuffs in Poland

“…As with pig’s livers, viral RNA has also been sporadically (1.8%) found in pig’s blood, (Geng et al, 2019 ), and sera (6.7%) of slaughtered animals (Garcia et al 2020 ), despite the virus being highly prevalent (23.4–100%) in blood and blood-derived by-products such as haemoglobin, fibrinogen and plasma (Boxman et al, 2017 ; Geng et al, 2019 ). Differences in virus occurrence in edible blood between studies may stem from differences observed between countries in natural virus prevalence in pigs (Berto, Backer, et al, 2012 ; Di Bartolo et al, 2008 ; Lee et al, 2020 ) and the age of slaughtered animals, as the likelihood of viraemia increases in younger pigs (Meng et al, 1997 ; Sooryanarain et al, 2020 ; Wu et al, 2002 ).…”

Hepatitis E Virus (HEV) Spreads from Pigs and Sheep in Mongolia

“…The fecal samples were collected from 200 pigs and the liver samples were collected from 60 pigs slaughtered in Ulaanbaatar city. The ORF2 region of HEV RNA was a target sequence for viral detection [21]. In addition, the farmers were asked questions that included general knowledge about HEVs and possible contact between livestock to analyze risk factors.…”

“…RNA was precipitated with 0.5 mL isopropanol and washed with 1 mL of 75% ethanol. The RNA was solubilized in 20 µL RNase-free water [21]. A one-step RT-PCR kit (QIAGEN, Hilden, Germany) was used to amplify the ORF2 region of the HEV (primer sequences used: ORF2-F1; (5772-5794) 5 -AATTATGCYCAGTAYCGRGTTG-3 , ORF2-R1; (6416-6439) 5 -CCCTTRTCYTGCTGMGCATTCTC-3 ).…”

“…A one-step RT-PCR kit (QIAGEN, Hilden, Germany) was used to amplify the ORF2 region of the HEV (primer sequences used: ORF2-F1; (5772-5794) 5 -AATTATGCYCAGTAYCGRGTTG-3 , ORF2-R1; (6416-6439) 5 -CCCTTRTCYTGCTGMGCATTCTC-3 ). The reaction conditions were reverse transcription at 45 • C for 60 min and 95 • C for 15 min as a PCR cycle, denaturation at 94 • C for 30 s, annealing at 55 • C for 30 s, extension at 72 • C for 75 s for 35 cycles, and final extension at 72 • C for 7 min [21]. Nested PCR: the RT-PCR products were then diluted and amplified again using Takara Ex-Taq (Takara Bio.…”

Low Prevalence of HEV Infection and No Associated Risk of HEV Transmission from Mother to Child among Pregnant Women in Vietnam

“…Our previous studies of the Vietnamese population have revealed a high anti-HEV IgG seroprevalence in healthy individuals (31%), in chronic hepatitis B virus (HBV) patients (45%), and among occupational workers exposed to pigs (53%) [ 4 , 14 , 15 ]. Despite the possibility of such serious outcomes, the scale of HEV infection during pregnancy, and of potential maternal, fetal, and neonatal complications, has not been investigated in resource-poor settings where the prevalence of HEV infection is expected to be high.…”