Hepatitis E in southern Vietnam: Seroepidemiology in humans and molecular epidemiology in pigs

Berto, Alessandra; Pham, Ha; Thao, Tran Thi Nhu; Vy, Nht; Caddy, Sarah; Hiraide, Rintaro; Tue, N; Goodfellow, Ian; Carrique-Mas, Juan; Thwaites, Guy; Baker, Stephen; Boni, M.

doi:10.1111/zph.12364

Cited by 25 publications

(21 citation statements)

References 34 publications

(47 reference statements)

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“…Our samples are from individuals who have attended hospital for some reason, so are not fully representative of the population. However, for the younger individuals, we would assume this would bias the study towards finding positive individuals as in Berto et al [ 35 ], which we did not. For older individuals, this may be more representative of the population as a whole and as the exposure is assumed to be over 30 years ago, it is reasonable to assume this hospital visit is unrelated to the CHIKV infection exposure.…”

Section: Discussionmentioning

confidence: 86%

Evidence of previous but not current transmission of chikungunya virus in southern and central Vietnam: Results from a systematic review and a seroprevalence study in four locations

Tran

Phuong

et al. 2018

PLoS Negl Trop Dis

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BackgroundArbovirus infections are a serious concern in tropical countries due to their high levels of transmission and morbidity. With the outbreaks of chikungunya (CHIKV) in surrounding regions in recent years and the fact that the environment in Vietnam is suitable for the vectors of CHIKV, the possibility of transmission of CHIKV in Vietnam is of great interest. However, information about CHIKV activity in Vietnam remains limited.MethodologyIn order to address this question, we performed a systematic review of CHIKV in Vietnam and a CHIKV seroprevalence survey. The seroprevalence survey tested for CHIKV IgG in population serum samples from individuals of all ages in 2015 from four locations in Vietnam.Principal findingsThe four locations were An Giang province (n = 137), Ho Chi Minh City (n = 136), Dak Lak province (n = 137), and Hue City (n = 136). The findings give us evidence of some CHIKV activity: 73/546 of overall samples were seropositive (13.4%). The age-adjusted seroprevalences were 12.30% (6.58–18.02), 13.42% (7.16–19.68), 7.97% (3.56–12.38), and 3.72% (1.75–5.69) in An Giang province, Ho Chi Minh City, Dak Lak province, and Hue City respectively. However, the age-stratified seroprevalence suggests that the last transmission ended around 30 years ago, consistent with results from the systematic review. We see no evidence for on-going transmission in three of the locations, though with some evidence of recent exposure in Dak Lak, most likely due to transmission in neighbouring countries. Before the 1980s, when transmission was occurring, we estimate on average 2–4% of the population were infected each year in HCMC and An Giang and Hue (though transmision ended earlier in Hue). We estimate lower transmission in Dak Lak, with around 1% of the population infected each year.ConclusionIn conclusion, we find evidence of past CHIKV transmission in central and southern Vietnam, but no evidence of recent sustained transmission. When transmission of CHIKV did occur, it appeared to be widespread and affect a geographically diverse population. The estimated susceptibility of the population to chikungunya is continually increasing, therefore the possibility of future CHIKV transmission in Vietnam remains.

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Section: Discussionmentioning

confidence: 86%

Evidence of previous but not current transmission of chikungunya virus in southern and central Vietnam: Results from a systematic review and a seroprevalence study in four locations

Tran

Phuong

et al. 2018

PLoS Negl Trop Dis

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“…We have previously shown that HEV circulates among healthy Vietnamese individuals and in hepatitis B virus-infected patients with anti-HEV immunoglobulin (Ig)G seroprevalences of 31% and 45%, respectively [23]. A previous study found 19.1% and 8.2% positivity of HEV-3 viral ribonucleic acid (RNA) in fecal samples and in rectal swabs from pigs, respectively, as well as a HEV seroprevalence of 16% in pig farmers in southern Vietnam [24]. However, the molecular epidemiology of HEV infection both in animals and humans is not yet completely understood.…”

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confidence: 99%

High Hepatitis E virus (HEV) Positivity Among Domestic Pigs and Risk of HEV Infection of Individuals Occupationally Exposed to Pigs and Pork Meat in Hanoi, Vietnam

Hoàn

Huy

et al. 2019

Open Forum Infectious Diseases

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Background Hepatitis E virus (HEV) infection can occur through consumption of undercooked pork meat or exposure to animal feces. Because there are scarce data only in developing countries, we assessed whether pigs might be a potential source of human HEV infections in Vietnam. In addition, we determined anti-HEV seroprevalences in the general population and in individuals professionally exposed to pigs and pork meat. Methods The study took place in Hanoi, Vietnam. Liver tissues from domestic pigs (n = 210) and serum samples obtained from individuals occupationally exposed to pigs and pork meat (n = 283) and from unexposed healthy controls (n = 168) were screened for HEV-ribonucleic acid (RNA) by reverse-transcription polymerase chain reaction. The exposed group was divided into pork meat vendors (n = 81), pig farmers (n = 96), and slaughterers (n = 106). Serum samples were subjected to HEV immunoglobulin (Ig)G and IgM enzyme-linked immunosorbent assays. The HEV genotypes were assessed by direct sequencing, followed by phylogenetic analyses. Results Hepatitis E virus seroprevalence was higher among persons occupationally exposed to pigs/pork meat compared with unexposed individuals (anti-HEV IgM 11% vs 6%, P = .07; anti-HEV IgG 53% vs 31%, P < .0001). Positivity of anti-HEV IgG among slaughterhouse staff was 66%, followed by 51% in pig-farmers and 38% in pork meat vendors (P = .00073). A similar trend was observed for IgM positivity. Of the pig liver tissues, 26 of 210 (12.4%) were positive for HEV-RNA and assessed to be HEV genotype 3. Conclusions Hepatitis E virus circulates in domestic pigs in Hanoi and constitutes a permanent zoonotic disease risk. The high HEV seroprevalence among occupationally exposed individuals indicates an associated risk of HEV infection.

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“…In Vietnam, the first HEV outbreak in humans was reported in 1994 along the river bordering Cambodia in the southwestern part [ 19 ]. One study showed that HEV is circulating in pigs (prevalence: 19.1% in fecal samples and 8.2% in rectal samples) while humans showed 31.7% seroprevalence [ 20 ]. In addition, a recent study in Vietnam found that pig farmers, slaughterhouse workers and pork meat retailers had high seroprevalence compared to unexposed groups [ 21 ].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2020

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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.

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Hepatitis E in southern Vietnam: Seroepidemiology in humans and molecular epidemiology in pigs

Cited by 25 publications

References 34 publications

Evidence of previous but not current transmission of chikungunya virus in southern and central Vietnam: Results from a systematic review and a seroprevalence study in four locations

Evidence of previous but not current transmission of chikungunya virus in southern and central Vietnam: Results from a systematic review and a seroprevalence study in four locations

High Hepatitis E virus (HEV) Positivity Among Domestic Pigs and Risk of HEV Infection of Individuals Occupationally Exposed to Pigs and Pork Meat in Hanoi, Vietnam

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

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