Within-host selection of drug resistance in a mouse model of repeated interrupted treatment of Plasmodium yoelii infection.

BACKGROUND: To study within-host selection of resistant parasites, an important factor in the development of resistance to anti-malarial drugs, a mouse model of repeated interrupted malaria treatment (RIT) has been developed. The characteristics of within host selection of resistance to atovaquone and pyrimethamine in Plasmodium yoelii was examined in such a model. METHODS: Treatment of P. yoelii infected mice, with atovaquone or pyrimethamine, was started at parasitaemia level of 3-5%, interrupted when reduced to less than 0.4%, and restarted following parasitaemia recovery to the initial level. Treatment cycles were repeated until stable phenotype resistance was observed. RESULTS: Plasmodium yoelii rapidly developed resistance to atovaquone (2.75 ± 1.06 cycles) and to pyrimethamine (5.4 ± 0.89 cycles) under RIT. A dose dependent phenomenon in the selection of atovaquone resistance mutations was observed. All mutations that underlie resistance to therapeutic doses of 0.3-1.44 mg kg-1 BW were found to be in the Qo2 domain of the cytochrome b gene (I258M, F267I/L/S, L271V, K272R, L271V and K272R). Those associated with lower doses of 0.01-0.03 mg kg-1 BW were in the Qo1 domain (M133I and T139S). The resistance mutations occurred at four of the 16 atovaquone putative drug binding sites suggested in P. falciparum. CONCLUSIONS: RIT of P. yoelii infected mice led to rapid development of resistance to atovaquone and pyrimethamine. The dose dependent selection of resistance mutants to atovaquone observed during RIT might reflect the outcome of two different causes of malaria treatment failure in human, repeated incomplete treatment with therapeutic dose and repeated inadequate treatment associated with sub-therapeutic dose, and need to be systematically investigated.

Within-Host Selection of Drug Resistance in a Mouse Model Reveals Dose-Dependent Selection of Atovaquone Resistance Mutations.

The evolutionary selection of malaria parasites within an individual host plays a critical role in the emergence of drug resistance. We have compared the selection of atovaquone resistance mutants in mouse models reflecting two different causes of failure of malaria treatment, an inadequate subtherapeutic dose and an incomplete therapeutic dose. The two models are based on cycles of insufficient treatment of Plasmodium berghei-infected mice: repeated inadequate treatment associated with a subtherapeutic dose (RIaT) (0.1 mg kg-1 of body weight) and repeated incomplete treatment with a therapeutic dose (RIcT) (14.4 mg kg-1 of body weight). The number of treatment cycles for the development of a stable resistance phenotype during RIaT was 2.00 ± 0.00 cycles (n = 9), which is not statistically different from that during RIcT (2.57 ± 0.85 cycles; combined n = 14; P = 0.0591). All mutations underlying atovaquone resistance selected by RIaT (M133I, T142N, and L144S) were found to be in the Qo1 (quinone binding 1) domain of the mitochondrial cytochrome b gene, in contrast to those selected by RIcT (Y268N/C, L271V, K272R, and V284F) in the Qo2 domain or its neighboring sixth transmembrane region. Exposure of mixed populations of resistant parasites from RIaT to the higher therapeutic dose of RIcT revealed further insights into the dynamics of within-host selection of resistance to antimalarial drugs. These results suggest that both inadequate subtherapeutic doses and incomplete therapeutic doses in malaria treatment pose similar threats to the emergence of drug resistance. RIcT and RIaT could be developed as useful tools to predict the potential emergence of resistance to newly introduced and less-understood antimalarials.

Parasites resistant to the antimalarial atovaquone fail to transmit by mosquitoes.

Drug resistance compromises control of malaria. Here, we show that resistance to a commonly used antimalarial medication, atovaquone, is apparently unable to spread. Atovaquone pressure selects parasites with mutations in cytochrome b, a respiratory protein with low but essential activity in the mammalian blood phase of the parasite life cycle. Resistance mutations rescue parasites from the drug but later prove lethal in the mosquito phase, where parasites require full respiration. Unable to respire efficiently, resistant parasites fail to complete mosquito development, arresting their life cycle. Because cytochrome b is encoded by the maternally inherited parasite mitochondrion, even outcrossing with wild-type strains cannot facilitate spread of resistance. Lack of transmission suggests that resistance will be unable to spread in the field, greatly enhancing the utility of atovaquone in malaria control.

Predominance of modern Mycobacterium tuberculosis strains and active transmission of Beijing sublineage in Jayapura, Indonesia Papua.

Mycobacterium tuberculosis genotype distribution is different between West and Central Indonesia, but there are no data on the most Eastern part, Papua. We aimed to identify the predominant genotypes of M. tuberculosis responsible for tuberculosis in coastal Papua, their transmission, and the association with patient characteristics. A total of 199 M. tuberculosis isolates were collected. Spoligotyping was applied to describe the population structure of M. tuberculosis, lineage identification was performed using a combination of lineage-specific markers, and genotypic clusters were identified using a combination of 24-locus-MIRU-VNTR and spoligotyping. A high degree of genetic diversity was observed among isolates based on their spoligopatterns. Strains from modern lineage 4 made up almost half of strains (46.9%), being more abundant than the ancient lineage 1 (33.7%), and modern lineage 2 (19.4%). Thirty-five percent of strains belonged to genotypic clusters, especially strains in the Beijing genotype. Previous TB treatment and mutations associated with drug resistance were more common in patients infected with strains of the Beijing genotype. Papua shows a different distribution of M. tuberculosis genotypes compared to other parts of Indonesia. Clustering and drug resistance of modern strains recently introduced to Papua may contribute to the high tuberculosis burden in this region.

Within-Host Selection of Drug Resistance in a Mouse Model of Repeated Incomplete Malaria Treatment: Comparison between Atovaquone and Pyrimethamine.

The evolutionary selection of malaria parasites within individual hosts is an important factor in the emergence of drug resistance but is still not well understood. We have examined the selection process for drug resistance in the mouse malaria agent Plasmodium berghei and compared the dynamics of the selection for atovaquone and pyrimethamine. Resistance to these drugs has been shown to be associated with genetic lesions in the dihydrofolate reductase gene in the case of pyrimethamine and in the mitochondrial cytochrome b gene for atovaquone. A mouse malaria model for the selection of drug resistance, based on repeated incomplete treatment (RICT) with a therapeutic dose of antimalarial drugs, was established. The number of treatment cycles for the development of stable resistance to atovaquone (2.47 ± 0.70; n = 19) was found to be significantly lower than for pyrimethamine (5.44 ± 1.46; n = 16; P < 0.0001), even when the parental P. berghei Leiden strain was cloned prior to the resistance selection. Similar results were obtained with P. berghei Edinburgh. Mutational changes underlying the resistance were identified to be S110N in dihydrofolate reductase for pyrimethamine and Y268N, Y268C, Y268S, L271V-K272R, and G280D in cytochrome b for atovaquone. These results are consistent with the rate of mitochondrial DNA mutation being higher than that in the nucleus and suggest that mutation leading to pyrimethamine resistance is not a rare event.

Genogeography and Immune Epitope Characteristics of Hepatitis B Virus Genotype C Reveals Two Distinct Types: Asian and Papua-Pacific.

Distribution of hepatitis B virus (HBV) genotypes/subgenotypes is geographically and ethnologically specific. In the Indonesian archipelago, HBV genotype C (HBV/C) is prevalent with high genome variability, reflected by the presence of 13 of currently existing 16 subgenotypes. We investigated the association between HBV/C molecular characteristics with host ethnicity and geographical distribution by examining various subgenotypes of HBV/C isolates from the Asia and Pacific region, with further analysis on the immune epitope characteristics of the core and surface proteins. Phylogenetic tree was constructed based on complete HBV/C genome sequences from Asia and Pacific region, and genetic distance between isolates was also examined. HBV/C surface and core immune epitopes were analyzed and grouped by comparing the amino acid residue characteristics and geographical origins. Based on phylogenetic tree and geographical origins of isolates, two major groups of HBV/C isolates--East-Southeast Asia and Papua-Pacific--were identified. Analysis of core and surface immune epitopes supported these findings with several amino acid substitutions distinguishing the East-Southeast Asia isolates from the Papua-Pacific isolates. A west-to-east gradient of HBsAg subtype distribution was observed with adrq+ prominent in the East and Southeast Asia and adrq- in the Pacific, with several adrq-indeterminate subtypes observed in Papua and Papua New Guinea (PNG). This study indicates that HBV/C isolates can be classified into two types, the Asian and the Papua-Pacific, based on the virus genome diversity, immune epitope characteristics, and geographical distribution, with Papua and PNG as the molecular evolutionary admixture region in the switching from adrq+ to adrq-.

Direct evidence for the atovaquone action on the Plasmodium cytochrome bc1 complex.

Atovaquone, a coenzyme Q analogue has been indicated to specifically target the cytochrome bc1 complex of the mitochondrial respiratory chain in the malarial parasite and other protozoan. Various mutations in the quinone binding site of the cytochrome b gene of Plasmodium spp. such as M133I, L144S, L271V, K272R, Y268C, Y268S, Y268N, and V284F are suggesting to associate with resistance to atovaquone. There is no direct evidence of relation between the mutations and resistance to atovaquone in Plasmodium parasite that has been available. Technical difficulties in isolating active assayable mitochondria in the malarial parasite hinder us to obtain direct biochemical evidence to support the relation between the mutations and drug resistance. The establishment of a mitochondrial isolation method for the malaria parasite has allowed us to test the degree of resistance of Plasmodium berghei isolates to atovaquone directly. We have tested the activity of dihydroorotate (DHO)-cytochrome c reductase in various P. berghei atovaquone resistant clones in the presence of a wide concentration range of atovaquone. Our results show the IC(50) of P. berghei atovaquone resistant clones is much higher (1.5 up to 40 nM) in comparison to the atovaquone sensitive clones (0.132-0.465 nM). The highest IC(50) was revealed in clones carrying Y268C and Y268N mutations (which play an important role in atovaquone resistance in Plasmodium falciparum), with an approximately 100-fold increase. The findings indicate the importance of the mutation in the quinone binding site of the cytochrome b gene and that provide a direct evidence for the atovaquone inhibitory mechanism in the cytochrome bc1 complex of the parasite.

The influence of influenza virus infections on the development of tuberculosis.

Recently, it was shown that interferon-γ mediated immune responses, which play a major role in the control of infection with Mycobacterium tuberculosis (Mtb), can be inhibited by type I interferons. Since type I interferons are abundantly induced during viral infections, we hypothesized that infections with influenza viruses might play a role in the development of active TB disease either directly after exposure to Mtb or through reactivation of latent Mtb infection. To explore this hypothesis we investigated in a retrospective study whether newly diagnosed adult tuberculosis patients from Indonesia had had recent influenza infection. Plasma samples from TB patients and controls were assayed for antibodies against two subtypes of at that time relevant, seasonal influenza A viruses. Overall, no correlation was observed with the presence of antibodies and manifest tuberculosis. Still, antibody titers against circulating A/H3N2 influenza virus were slightly enhanced in tuberculosis patients as compared to controls, and highest in cases of advanced tuberculosis. This suggests that tuberculosis patients were recently infected with influenza, before clinical manifestation of the disease. Alternatively, the production of antibodies and susceptibility to tuberculosis may be influenced by a common confounding factor, for example the ability of patients to induce interferon-α. We conclude that in an endemic country like Indonesia, an influenza virus infection is not a major determinant for developing clinically manifest tuberculosis.

Genome-wide expression profiling identifies type 1 interferon response pathways in active tuberculosis.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (M.tb), remains the leading cause of mortality from a single infectious agent. Each year around 9 million individuals newly develop active TB disease, and over 2 billion individuals are latently infected with M.tb worldwide, thus being at risk of developing TB reactivation disease later in life. The underlying mechanisms and pathways of protection against TB in humans, as well as the dynamics of the host response to M.tb infection, are incompletely understood. We carried out whole-genome expression profiling on a cohort of TB patients longitudinally sampled along 3 time-points: during active infection, during treatment, and after completion of curative treatment. We identified molecular signatures involving the upregulation of type-1 interferon (α/ß) mediated signaling and chronic inflammation during active TB disease in an Indonesian population, in line with results from two recent studies in ethnically and epidemiologically different populations in Europe and South Africa. Expression profiles were captured in neutrophil-depleted blood samples, indicating a major contribution of lymphocytes and myeloid cells. Expression of type-1 interferon (α/ß) genes mediated was also upregulated in the lungs of M.tb infected mice and in infected human macrophages. In patients, the regulated gene expression-signature normalized during treatment, including the type-1 interferon mediated signaling and a concurrent opposite regulation of interferon-gamma. Further analysis revealed IL15RA, UBE2L6 and GBP4 as molecules involved in the type-I interferon response in all three experimental models. Our data is highly suggestive that the innate immune type-I interferon signaling cascade could be used as a quantitative tool for monitoring active TB disease, and provide evidence that components of the patient's blood gene expression signature bear similarities to the pulmonary and macrophage response to mycobacterial infection.

Polymorphisms in SP110 are not associated with pulmonary tuberculosis in Indonesians.

Despite being high transmissible, Mycobacterium tuberculosis (M. tuberculosis) infection causes active disease in only 5-10% of disease-susceptible individuals. This has instigated interest in studying potentially underlying genetic host factors and mechanisms in tuberculosis (TB). The recent identification of the Intracellular pathogen resistance 1 (Ipr1) gene, which plays a major role in controlling M. tuberculosis susceptibility and infection severity in mice (Pan et al., 2005), has prompted studies on its human homolog; SP110 in humans. Association of SP110 SNPs with pulmonary TB were first reported in a study on West African families (Tosh et al., 2006). Subsequent attempts to replicate these findings in other populations, including another West African (Ghanaian) cohort (Thye et al., 2006), however, were unsuccessful. Here we have genotyped 20 SNPs located in the SP110 gene, including the previously TB associated variants; rs2114592 and rs3948464, for the first time in a South East Asian cohort from Indonesia. Our study did not reveal any statistically significant associations between SP110 SNPs and pulmonary TB. In addition, a meta-analysis of the two previously TB associated SNPs revealed that these are not associated with TB, further confirming the lack of convincing evidence for SP110 to be implicated in TB susceptibility, as yet in humans.

A genome wide association study of pulmonary tuberculosis susceptibility in Indonesians.

BACKGROUND: There is reason to expect strong genetic influences on the risk of developing active pulmonary tuberculosis (TB) among latently infected individuals. Many of the genome wide linkage and association studies (GWAS) to date have been conducted on African populations. In order to identify additional targets in genetically dissimilar populations, and to enhance our understanding of this disease, we performed a multi-stage GWAS in a Southeast Asian cohort from Indonesia. METHODS: In stage 1, we used the Affymetrix 100 K SNP GeneChip marker set to genotype 259 Indonesian samples. After quality control filtering, 108 cases and 115 controls were analyzed for association of 95,207 SNPs. In stage 2, we attempted validation of 2,453 SNPs with promising associations from the first stage, in 1,189 individuals from the same Indonesian cohort, and finally in stage 3 we selected 251 SNPs from this stage to test TB association in an independent Caucasian cohort (n = 3,760) from Russia. RESULTS: Our study suggests evidence of association (P = 0.0004-0.0067) for 8 independent loci (nominal significance P < 0.05), which are located within or near the following genes involved in immune signaling: JAG1, DYNLRB2, EBF1, TMEFF2, CCL17, HAUS6, PENK and TXNDC4. CONCLUSIONS: Mechanisms of immune defense suggested by some of the identified genes exhibit biological plausibility and may suggest novel pathways involved in the host containment of infection with TB.

Ethnogeographical structure of hepatitis B virus genotype distribution in Indonesia and discovery of a new subgenotype, B9.

The distribution of hepatitis B virus (HBV) in the populations of island Southeast Asia is of medical and anthropological interest and is associated with an unusually high genetic diversity. This study examined the association of this HBV genetic diversity with the ethnogeography of the populations of the Indonesian archipelago. Whole genome analysis of 21 HBV isolates from East Nusa Tenggara and Papua revealed two recently reported HBV/B subgenotypes unique to the former, B7 (7 isolates) and B8 (5 isolates), and uncovered a further novel subgenotype designated B9 (4 isolates). Further isolates were collected from 419 individuals with defined ethnic backgrounds representing 40 populations. HBV/B was predominant in Austronesian-language-speaking populations, whereas HBV/C was the major genotype in Papua and Papua-influenced populations of Moluccas; HBV/B3 was the predominant subgenotype in the western half of the archipelago (speakers of the Western Malayo-Polynesian [WMP] branch of Austronesian languages), whereas B7, B8 and B9 were specific to Nusa Tenggara (Central Malayo-Polynesian (CMP)). The result provides the first direct evidence that the distribution of HBV genotypes/subgenotypes in the Indonesian archipelago is related to the ethnic origin of its populations and suggests that the HBV distribution is associated with the ancient migratory events in the peopling of the archipelago.

Genetic structure of a unique admixed population: implications for medical research.

STATEMENT: In naming population groups, we think a chief aim is to use terms that the group members use themselves, or find familiar and comfortable. The terms used in this manuscript to describe populations are as historically correct as possible and are chosen so as not to offend any population group. Two of the authors (DCP and REvdR) belong to the Coloured population, with one of the authors (REvdR) having contributed extensively to current literature on the history of the Coloured people of South Africa and served as Vice-President of the South African Institute of Race Relations. According to the 2001 South African census (http://www.statssa.gov.za/census01/HTML/CInBrief/CIB2001.pdf), "Statistics South Africa continues to classify people by population group, in order to monitor progress in moving away from the apartheid-based discrimination of the past. However, membership of a population group is now based on self-perception and self-classification, not on a legal definition. Five options were provided on the questionnaire, Black African, Coloured, Indian or Asian, White and Other. Responses in the category 'Other' were very few and were therefore imputed". We have elected to use the term Bushmen rather than San to refer to the hunter-gatherer people of Southern Africa. Although they have no collective name for themselves, this decision was based on the term Bushmen (or Bossiesman) being the more familiar to the communities themselves, while the term San is the more accepted academic classification. Understanding human genetic structure has fundamental implications for understanding the evolution and impact of human diseases. In this study, we describe the complex genetic substructure of a unique and recently admixed population arising approximately 350 years ago as a direct result of European settlement in South Africa. Analysis was performed using over 900 000 genome-wide single nucleotide polymorphisms in 20 unrelated ancestry-informative marker selected Coloured individuals and made comparisons with historically predicted founder populations. We show that there is substantial genetic contribution from at least four distinct population groups: Europeans, South Asians, Indonesians and a population genetically close to the isiXhosa sub-Saharan Bantu. This is in good accord with the historical record. We briefly examine the implications of determining the genetic diversity of this population, not only for furthering understanding of human evolution out of Africa, but also for genome-wide association studies using admixture mapping. In conclusion, we define the genetic structure of a uniquely admixed population that holds great potential to advance genetic-based medical research.

Mapping human genetic diversity in Asia.

Asia harbors substantial cultural and linguistic diversity, but the geographic structure of genetic variation across the continent remains enigmatic. Here we report a large-scale survey of autosomal variation from a broad geographic sample of Asian human populations. Our results show that genetic ancestry is strongly correlated with linguistic affiliations as well as geography. Most populations show relatedness within ethnic/linguistic groups, despite prevalent gene flow among populations. More than 90% of East Asian (EA) haplotypes could be found in either Southeast Asian (SEA) or Central-South Asian (CSA) populations and show clinal structure with haplotype diversity decreasing from south to north. Furthermore, 50% of EA haplotypes were found in SEA only and 5% were found in CSA only, indicating that SEA was a major geographic source of EA populations.

Infection with Mycobacterium tuberculosis Beijing genotype strains is associated with polymorphisms in SLC11A1/NRAMP1 in Indonesian patients with tuberculosis.

Differences in host immune genes may predispose to tuberculosis caused by particular Mycobacterium tuberculosis genotypes. We examined this hypothesis in Indonesia by spoligotyping M. tuberculosis isolates recovered from 336 patients with pulmonary tuberculosis and typing the patients' SLC11A1 gene (formerly known as "NRAMP1"), which is involved in susceptibility to tuberculosis. The M. tuberculosis Beijing genotype, which comprised 29.8% of all isolates, was strongly associated with 2 polymorphisms in SLC11A1: the D543N G allele (odds ratio [OR], 2.15; P=.005) and the 3' untranslated region (3'UTR) insertion/insertion genotype (OR, 2.5; P=.001). This finding supports the hypothesis of coevolution of M. tuberculosis and the human immune system.

Genetic admixture history of Eastern Indonesia as revealed by Y-chromosome and mitochondrial DNA analysis.

Eastern Indonesia possesses more linguistic diversity than any other region in Southeast Asia, with both Austronesian (AN) languages that are of East Asian origin, as well as non-Austronesian (NAN) languages of likely Melanesian origin. Here, we investigated the genetic history of human populations from seven eastern Indonesian islands, including AN and NAN speakers, as well as the relationship between languages and genes, by means of nonrecombining Y-chromosomal (NRY) and mitochondrial DNA (mtDNA) analysis. We found that the eastern Indonesian gene pool consists of East Asian as well as Melanesian components, as might be expected based on linguistic evidence, but also harbors putative indigenous eastern Indonesian signatures that perhaps reflect the initial occupation of the Wallacea by aboriginal hunter-gatherers already in Palaeolithic times. Furthermore, both NRY and mtDNA data showed a complete lack of correlation between linguistic and genetic relationships, most likely reflecting genetic admixture and/or language shift. In addition, we noted a small fraction of the NRY and mtDNA data shared between eastern Indonesians and Australian Aborigines likely reflecting an ancient link between Asia and Australia. Our data thus provide insights into the complex genetic ancestry history of eastern Indonesian islanders characterized by several admixture episodes and demonstrate a clear example of the lack of the often-assumed correlation between the genes and languages of human populations.

DNA analysis in perpetrator identification of terrorism-related disaster: suicide bombing of the Australian Embassy in Jakarta 2004.

We report the strategy that we employed to identify the perpetrator of a suicide car bombing in front of the Australian Embassy in Jakarta, Indonesia, on 9 September 2004. The bomb was so massive that only small tissue pieces of the perpetrator could be recovered, preventing conventional approach to the identification of the bomber, necessitating the introduction of DNA analysis as the primary means for perpetrator identification. Crime scene investigation revealed the trajectory of the bomb blast, which was used to guide the collection of charred tissue fragments of the perpetrator. Mitochondrial DNA analysis was first conducted on 17 tissue fragments, recovered over large areas of the trajectory to, (a) confirm that they are of a common source, i.e. the perpetrator, and thus (b) establish the mtDNA HV1 sequence profile of the perpetrator. The mtDNA of the perpetrator matches that of a maternally related family member of one of four suspects. Standard autosomal STR analysis confirmed the identification. This case is of interest as an illustration of a successful application of DNA analysis as the primary means of disaster perpetrator identification.

Paternal genetic affinity between Western Austronesians and Daic populations.

BACKGROUND: Austronesian is a linguistic family spread in most areas of the Southeast Asia, the Pacific Ocean, and the Indian Ocean. Based on their linguistic similarity, this linguistic family included Malayo-Polynesians and Taiwan aborigines. The linguistic similarity also led to the controversial hypothesis that Taiwan is the homeland of all the Malayo-Polynesians, a hypothesis that has been debated by ethnologists, linguists, archaeologists, and geneticists. It is well accepted that the Eastern Austronesians (Micronesians and Polynesians) derived from the Western Austronesians (Island Southeast Asians and Taiwanese), and that the Daic populations on the mainland are supposed to be the headstream of all the Austronesian populations. RESULTS: In this report, we studied 20 SNPs and 7 STRs in the non-recombining region of the 1,509 Y chromosomes from 30 China Daic populations, 23 Indonesian and Vietnam Malayo-Polynesian populations, and 11 Taiwan aboriginal populations. These three groups show many resemblances in paternal lineages. Admixture analyses demonstrated that the Daic populations are hardly influenced by Han Chinese genetically, and that they make up the largest proportion of Indonesians. Most of the population samples contain a high frequency of haplogroup O1a-M119, which is nearly absent in other ethnic families. The STR network of haplogroup O1a* illustrated that Indonesian lineages did not derive from Taiwan aborigines as linguistic studies suggest, but from Daic populations. CONCLUSION: We show that, in contrast to the Taiwan homeland hypothesis, the Island Southeast Asians do not have a Taiwan origin based on their paternal lineages. Furthermore, we show that both Taiwan aborigines and Indonesians likely derived from the Daic populations based on their paternal lineages. These two populations seem to have evolved independently of each other. Our results indicate that a super-phylum, which includes Taiwan aborigines, Daic, and Malayo-Polynesians, is genetically educible.

Genetic study of hepatitis B virus in Indonesia reveals a new subgenotype of genotype B in east Nusa Tenggara.

The hepatitis B virus (HBV) genotype is associated with viral anthropological history, clinical outcome of disease and response to treatment. This study examines the HBV genotypes in Indonesia. HBV genotypes were determined by whole-genome sequencing and from the sequence of the Pre-S2 and S regions in a larger series. Two HBV genotypes, B (HBV/B) and C (HBV/C), were predominant. Three previously reported HBV/B subgenotypes were identified, with certain population association: HBV/B2 (HBV/Ba) was found mostly in Indonesians of Chinese ethnic origin, HBV/B3 was dominant among the Javanese, and HBV/B5, reported earlier from the Philippines, was also discovered, albeit at low frequency. Two other subgenotypes, HBV/B4 from Vietnam and HBV/B6, recently reported from the Arctic region, were not found. A novel subgenotype, HBV/B7, was recognized, associated with populations of the Nusa Tenggara islands in eastern Indonesia. Characteristic differences in HBsAg serotype and single nucleotide polymorphisms (SNPs) in the Pre-S2 region distinguish HBV/B7 from other HBV/B subgenotypes and further establish the new HBV subgenotype.