Existence of hepatitis B virus surface protein mutations and other variants: demand for hepatitis B infection control in Cambodia

Abstract

Background: This study aimed to detect Hepatitis B virus (HBV) genome sequences and their variants as of nationwide scale using dried blood spot (DBS) samples and to provide up-to-date reference data for infection control and surveillance in Cambodia. Method: Among 2518 children age 5-7 years and their 2023 mothers participated in 2017 Cambodia nationwide sero-survey on hepatitis B surface antigen (HBsAg) prevalence using multistage random sampling strategy, 95 mothers and 13 children positive to HBsAg were included in this study. HBV DNA was extracted from DBS, then performed polymerase chain reaction. HBV genotypes and potential variants were examined by partial and full length genomic analysis. Results: HBsAg positive rate was 4.7% (95/2023) in mothers and 0.52% (13/2518) in their children. Genotype C (80.49%) was abundantly found throughout the whole Cambodia whilst genotype B (19.51%) was exclusively found in regions bordering Vietnam. S gene mutants of HBV were found in 24.29% of mothers and 16.67% of children with HBV DNA positive sera. Full-length genome analysis revealed the homology of 99.62-100% in each motherchild pair. Genotype B was clarified to recombinant genotype B4/C2 and B2/C2. Double (48.39%) and combination mutation (32.26%) were observed in core promoter region of HBV C1 strains. Conclusions: This study showed the capable of DBS for large-scale molecular epidemiological study of HBV in resource limited countries. Full-genome sequences yield the better understanding of sub-genotypes, their variants and the degree of homology between strains isolated from mother-child pairs calls for effective strategies on prevention, control and surveillance of mother-to-child HBV transmission in Cambodia.

Global Prevalence of Domestic Cat Hepadnavirus: An Emerging Threat to Cats’ Health?

“…Moreover, X proteins are multifunctional regulatory proteins that modulate protein degradation pathways, apoptosis, transcription, signal transduction, cell cycle progress, and genetic stability (van Hemert et al, 2011;Zhang et al, 2019). Although DCH and HBV are grouped together in genus Orthohepadnavirus, the function of each viral protein of DCH remains to be elucidated since there is a large difference between DCH and HBV (Aghazadeh et al, 2018;Ko et al, 2020;Piewbang et al, 2020). Since its first identification, surveys on DCH prevalence in domestic cats have been conducted in several countries.…”

Prevalence of total hepatitis A antibody among 5 to 7 years old children and their mothers in Cambodia

“…Another noteworthy finding of this study was that we used the DBS as the new sampling strategy instead of collecting whole blood samples from all participants. The validity and efficacy of DBS for detection of HBV sero-markers 14 and also the usefulness of DBS for molecular analysis of HBV 15 had been reported previously. This study examined the sensitivity and specificity of total anti-HAV detection using DBS-driven samples against gold standard serum samples and set the cutoff value for the DBS-driven samples.…”

Residual risk of mother-to-child transmission of HBV despite timely Hepatitis B vaccination: a major challenge to eliminate hepatitis B infection in Cambodia

“…Inc, Shiga, Japan) and primer set targeting the overlapping region of surface and polymerase gene (nt475 to nt933). Those samples positive amplified to above region were then performed the amplification of full-length genome using the same protocol as described in previous study [ 10 , 12 ]. Those samples negative amplified to above region, were then attempted for s-region fragment (partial genome sequence) using the primer set targeting surface gene (nt455-nt687) [ 10 ].…”