Molecular epidemiology of hepatitis delta virus in the Western Pacific region
Section snippets
Background
Infection with hepatitis delta virus (HDV) occurs in individuals by either super-infection in someone already infected with the hepatitis B virus (HBV) or by co-infection at the time of HBV transmission. Serological surveys have shown that infection with HDV is present worldwide [1] but has an irregular distribution, being endemic in the Mediterranean basin, parts of Africa, the Middle East and South America [2], [3]. The prevalence in Western Europe [4], Scandinavia [5] and Australia [6] is
Objectives
The objective of this study was to define the molecular epidemiology of HDV isolated from individuals who reside in the Western Pacific, providing a reference point for future epidemiological comparisons and investigations.
Serum samples
HBsAg-positive samples were collected from four Pacific Islands shown in Fig. 1. A total of 184 serum samples were analysed: 54 from Kiribati, 29 from Vanuatu, 42 from Fiji, and 59 from Tonga. The demographic details of these individuals have been previously reported [11]. Written approval for all the initial and current survey procedures was obtained from the Department of Health in each country and informed consent was obtained from each adult or the mother or guardian of each participant [11]
HDV screening and quantitative testing by real-time PCR
Testing for HDV RNA was carried out on samples from four Western Pacific Islands, Fiji and Vanuatu located in Melanesia, Tonga within Polynesia and Kiribati located in Micronesia (Fig. 1). Using the qualitative screening PCR assay of Casey et al. [33], HDV RNA was detected in 18 out of 54 patients (33.3%) from Kiribati, whereas no signal was detected in any of the 59 HBsAg positive samples from Tonga, the 42 samples from Fiji nor the 29 samples from Vanuatu.
The HDV quantitative real-time PCR
Discussion
Of the 350 million chronic carriers of HBV worldwide, more than 15 million have serological evidence of exposure to HDV [39]. Traditionally, the regions where HDV is endemic are central Africa, the Horn of Africa, the Amazon Basin, eastern and Mediterranean Europe, the Middle East, and parts of Asia. In 2007 Zuberi et al. reported a sero-prevalence of 26.8% HDV infection in HBsAg positive patients in Pakistan [40], whilst Braga et al. in 2012 reported 41.9% sero-prevalence in the Brazilian
Author contributions
MH, SB, QN, SL and KJ did the conception and design of the study. MH, ML, LY, RE, UD, SB, SL and KJ did acquisition of data, and analysis and interpretation of data. MH, ML, LY, SL and KJ did drafting the article or revising it critically for important intellectual content. MH, ML, LY, RE, UD, SB, QN, SL and KJ finally approved the version to be submitted.
Funding
This study was supported by the Molecular Research and Development division of the Victorian Infectious Diseases Reference Laboratory.
Competing interests
None declared.
Ethical approval
Written approval for all the initial and current survey procedures was obtained from the Department of Health in each country and informed consent was obtained from each adult or the mother or guardian of each participant.
Acknowledgements
Funding for the initial epidemiological study was provided by UNICEF through the contributions of the Governments of Australia through the Australian Agency for International Development and New Zealand through New Zealand Overseas Development Assistance, Ministry of Foreign Affairs and Trade. The Governments of Fiji, Kiribati, Tonga and Vanuatu contributed personnel and logistic support and the authors are grateful for this support. The authors would like to acknowledge Jenny Leydon from the
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2024, The Lancet Regional Health - Western PacificTriple Threat: HDV, HBV, HIV Coinfection
2023, Clinics in Liver DiseaseHepatitis B and D in the Pacific Islands of Kiribati
2020, Journal of Clinical VirologyCitation Excerpt :HBV/HDV coinfection is associated with more severe, rapidly progressive disease and is a leading cause of fulminant hepatitis [8,9]. There are ten HBV genotypes (A –J) [10] and eight HDV genotypes [1–8] with genotype 1 having a global distribution [3,11]. Previous reports have confirmed that HBV is endemic in many Pacific Islands (PI) [12–14].
A new dual-targeting real-time RT-PCR assay for hepatitis D virus RNA detection
2018, Diagnostic Microbiology and Infectious DiseaseCitation Excerpt :In a nationwide cohort of HIV-infected patients with a positive HBsAg test in Switzerland, multivariable analyses showed that HDV-positive patients had a 2.3-fold greater risk in overall death, 8-fold greater risk in liver-related mortality, and more than 9-fold greater risk in occurrence of HCC compared to HDV-negative ones (Béguelin et al., 2017). Currently, the prevalence of HDV infection is still present worldwide, and the prevalence rate appears to vary between geographical areas, such as 43.5–65% in the Amazon region (Crispim et al., 2014; Di Filippo Villa et al., 2015), about 60% in Mongolia (Chen et al., 2017b; Baatarkhuu et al., 2017), 37% in Kiribati (Han et al., 2014), 26.1% in Democratic Republic of Congo (Makiala-Mandanda et al., 2017), 15.3% in Eastern Turkey (Dulger et al., 2016), 10% in Central Vietnam (Nguyen et al., 2017), Nigeria (9%) (Opaleye et al., 2016), and from 0.9% (Hunan) to 4.4% (Taiwan) and 6.5% (Guangdong) in China (Chen et al., 2017a; Liao et al., 2014; Lin et al., 2015). Despite the severity of liver damage caused by HDV/HBV co-infections and the estimated prevalence worldwide, high-quality and reproducible epidemiological data of affected populations in China are limited.
Hepatitis delta virus: From biological and medical aspects to current and investigational therapeutic options
2015, Antiviral ResearchCitation Excerpt :In Mongolia a prevalence of HDV antibodies as high as 82% has been reported in HBV infected patients with advanced liver disease (Oyunsuren et al., 2006). Finally, a recent report from the Pacific region also suggests high prevalence rates (37% among HBsAg positive patients) in isolated Micronesian islands (Han et al., 2014). In summary, HDV infections are far from being on the way to eradication, and remain a major health problem in developing and low-resource countries where the diagnosis is sub-optimal.