Prevalence and genotype distribution of hepatitis delta virus among chronic hepatitis B carriers in Central Vietnam

Abstract

Hepatitis D virus (HDV) infection plays an important role in liver diseases. However, the molecular epidemiology and impact of HDV infection in chronic hepatitis B (CHB) remain uncertain in Vietnam. This cross-sectional study aimed to investigate the prevalence and genotype distribution of HDV among HBsAg-positive patients in Central Vietnam. 250 CHB patients were tested for HDV using newly established HDV-specific RT-PCR techniques. HDV genotypes were determined by direct sequencing. Of the 250 patients 25 (10%) had detectable copies of HDV viral RNA. HDV-2 was predominant (20/25; 80%) followed by HDV-1 (5/25; 20%). Proven HDV genotypes share the Asian nomenclature. Chronic hepatitis B patients with concomitant HDV-1 showed higher HBV loads as compared to HDV-2 infected patients [median log10 (HBV-DNA copies/ml): 8.5 vs. 4.4, P = 0.036]. Our findings indicate that HDV infection is highly prevalent and HDV-2 is predominant in Central Vietnam. The data will add new information to the management of HBsAg-positive patients in a highly HBV endemic region to in- or exclude HDV infection in terms of diagnostic and treatment options.

HDV infection rates in northern Vietnam

“…Although the difference was not significant, our data show that HBV-DNA loads were lower in HDV/HBV coinfection compared to HBV monoinfection, in part supporting the previous finding that HDV-infection suppresses HBV replication 31 , 32 . While other studies have demonstrated an impact of HDV genotypes on the clinical presentation of HBV-infected patients 3 , 10 , 22 , our study did not show any significant association of HDV genotypes with liver function test, HBV-DNA loads, and AFP levels. This lack of association may result from the small number of patients infected with HDV2.…”

“…A high predominance of 90% of the HDV1 genotype in northern Vietnam was shown in HBV-infected patients recruited between 2000 and 2003 23 . In contrast, a recent study has reported that HDV2 was the predominant genotype (80%) in southern Vietnam 22 . However, both studies were conducted with small sample sizes of HBV patients only (n < 300).…”

“…Varying distributions of HDV genotypes in North and South Vietnam have recently been reported 21 – 23 , with the HDV1 genotype being predominant in all parts of Vietnam 21 . In contrast, HDV1 has been shown to prevail in northern Vietnam with 90% 23 , but accounted for only 20% in central Vietnam 22 . We here confirm the predominance of HDV1 (HDV1, 91% vs .…”

“…A previous study conducted in a cohort of HBV-infected patients collected over a decade ago had already shown a high HDV-RNA prevalence in northern Vietnam (15.4%) 23 . The prevalence of HDV-RNA was 10% in chronic hepatitis B carriers collected in 2015 in Central Vietnam 22 . The difference in HDV-RNA prevalences between these two studies reflects distinct geographic distributions of the infection.…”

Epidemiology and phylogenetic analysis of hepatitis D virus infection in Australia

“…Six isolates (3.5%) were genotype 2, reported in Japan and other Asian countries, including Vietnam. 28,29 The genotype 2 strains documented in this study may well reflect the significant numbers of Australians born in Vietnam. 30 Genotype 2 and 5 tended to be detected in younger patients, likely reflecting the younger age of patients immigrating into Australia from Asia and Africa.…”