Novel quasi-subgenotype D2 of hepatitis B virus identified in Taiwanese aborigines

The hepatitis B virus (HBV) genomes in Taiwanese aborigines, whose ancestors have lived in Taiwan for over 10,000 years, have not been characterized. In order to characterize of HBV in this special population, serum samples were obtained from serologically HBsAg-positive 27 Taiwanese aborigines. The pre-S1/S2 region and the full-length 3.2 kb of the HBV genome were amplified by PCR. Obtained amplicons were sequenced and confirmed the HBV genotypes by phylogenetic analysis. By phylogenetic analysis of the sequence of pre-S1/pre-S2 region, HBV/B2 (21/27: 78 %) was the most prevalent followed by genotype D (6/27: 22 %). Two strains of HBV/B2, each having 3,215 bp genomes, had recombination with genotype C in the pre-C/C gene which is characteristic of subgenotype B2 circulating in Southeast Asia. Interestingly, six strains of genotype D formed a distinct cluster between subgenotypes D1 and D2 suggesting a novel group of HBV. A similar finding could also be confirmed based on the entire 3,182 bp genome from four strains of HBV/D. This new cluster was supported by a branch with 99 % bootstrap value and 3.4–5.8 % nucleotide divergence over the entire genome from other known subgenotypes D1 to D9. Four strains of the new D subgenotype showed serotype ayw2, but had unique amino acid sequences consisting of N115 in the preS/S gene; P41 in the X gene; S239, K/E295, V567, and P708 in the P gene, respectively. From the above results, we provisionally proposed to designate it as novel quasi-subgenotype D2 identified in Taiwanese aborigines.     

Hepatitis B virus genotypes and serotypes in western India: lack of clinical significance

To determine hepatitis B virus genotype and subtype distribution among HBV infected individuals with different clinical manifestations in western India, serum samples from 19 asymptomatic hepatitis B surface antigen carriers, 30 chronic hepatitis B patients, 8 acute hepatitis B patients, 5 fulminant hepatitis B patients, and with circulating HBV DNA were genotyped and subtyped on the basis of the nucleotide sequence analysis of S region of the HBV genome. Genotype D was the predominant genotype circulating in western India (57/62; 91.93%). All 19 asymptomatic hepatitis B surface antigen carriers, 8 acute hepatitis B patients, 5 fulminant hepatic failure patients and 25/30 chronic hepatitis B patients were circulating genotype D and ayw3/ayw2 subtypes. HBV genotype A was prevalent in 8% (5/62) of the total number of patients and all belonged to chronic hepatitis B category. Subtyping analysis showed that all genotype A isolates were of subtype adw2. As most of the patients from different clinical categories were infected with HBV genotype D, it is concluded that this genotype did not influence the outcome of HBV infection.     

Full genome analysis of hepatitis B virus genotype E strains from South-Western Africa and Madagascar reveals low genetic variability

The eight genotypes of hepatitis B virus (HBV), A-H, have a characteristic geographical distribution. The high prevalence of genotype E within a wide expanse of Africa makes it important to characterize this genotype. Although the preS/S region of a large number of genotype E isolates has been sequenced, to date only eight complete genotype E genomes have been published. The aim of this study, therefore, was to sequence and characterize the complete genome of genotype E isolates obtained from geographically distinct regions in Africa, including Namibia, Angola, and Madagascar. The nine newly sequenced genotype E isolates were closely related with an intra-group nucleotide divergence of 1.2%, reflecting their close geographical origin. All genotype E strains have the same characteristics, an in-frame deletion of three nucleotides (one amino acid) in the 5' pre-S1, a signature pattern of amino acids in the pre-S1 region and the serological subtype ayw4. In addition, we have identified another unique attribute of genotype E strains, the introduction of another start codon Met(83) in the pre-S1 region that may result in the translation of an elongated middle hepatitis B surface protein (MHBs).     

Phylogenetic analysis of new hepatitis B virus isolates from Nigeria supports endemicity of genotype E in West Africa

Isolates of hepatitis B viruses were collected from 20 acute and chronic hepatitis patients in a highly endemic region of Nigeria. Sequencing classified the isolates to the ayw4, as they all contained the amino acid variations characteristic for that serotype. In the pre-S2 region of five isolates, three to seven amino acids were deleted, suggesting that immune escape mutations previously associated only with chronic HBV infection may be observed also in acute disease. Phylogenetic analysis of the complete pre-S2/S (large S) genes (831 nt) demonstrated that all the viruses belonged to the same genotype E. So far, no isolates of genotype E have been found in any other region of the world, including the Americas. This may suggest a relatively recent introduction of this genotype into humans and would explain the relatively low genetic diversity of viruses belonging to this genotype. One genotype E virus had been found previously in a chimpanzee, and viruses belonging to the CHIMP genotype are related to other genotype E viruses. These findings are compatible with a transmission of genotype E viruses from chimpanzees to humans.     

Characterization of hepatitis B virus genome variability in Iranian patients with chronic infection, a nationwide study

Hepatitis B virus (HBV) isolates from Iranian patients around the country were characterized. Eighty-one complete genomes from HBV isolates were sequenced and analyzed. The studied population was grouped into three categories including inactive carriers, patients with chronic hepatitis, and patients with liver cirrhosis. Molecular and phylogenetic analyses revealed that Iranian patients were infected with HBV genotype D and subgenotype D1. The most common subtype was ayw2, followed by ayw3 and ayw4. Several deletions and insertions that had no correlation with disease outcome were observed in the HBV genomes. The most frequent mutation in the major hydrophilic region (MHR) of HBV surface antigen (HBsAg) was sP120S. Almost half of the patients studied carried precore (PC) mutant variants and one-third of the studied population was infected with variants carrying basal core promoter (BCP) mutations. PC and BCP mutations were observed in older patients, especially in those with chronic liver disease. Sixty-seven patients (82.7%) were HBeAg negative, and the prevalence of precore mutant isolates (G1896A) was higher in this group than in HBeAg-positive patients. Lamivudine drug resistance mutations were detected after 1 year of treatment in about 30% of lamivudine-treated patients. In conclusion, these results demonstrate that HBV subgenotype D1 is the only subgenotype circulating in Iran, and there is no evidence of any exotic genotype in the region. The HBV PC (G1896A) mutation may play an important role in the clinical outcome of the disease by increasing the risk of progressive liver disease among Iranian patients infected with HBV.     

Molecular epidemiology of hepatitis B virus in Spain: identification of viral genotypes and prediction of antigenic subtypes by limited sequencing

The hepatitis B virus (HBV) genotypes were studied by a line probe assay (LiPA) and by direct sequencing of a 339 nucleotide fragment from the S region of the viral genome in samples from 269 carriers living in Spain, either native to Spain (231) or immigrants from Africa, Asia, and Eastern Europe (38). The sequences were also used to predict the HBV surface antigen (HBsAg) subtype on the basis of the amino acids specified at selected positions of the HBsAg molecule. Agreement between the two genotyping methods was found in most cases (98.1%) and a HBV genotype could be assigned to all samples. The viral groups D/ayw2 (30.1%), D/ayw3 (28.6%), and A/adw2 (21.2%) were prevalent, with an additional participation of the groups D/ayw4 (4.8%), F/adw4q- (1.9%), A/ayw1 (1.9%), and D/adw3 (0.7%), all of them present among the autochthonous carriers. Strains from genotypes B and C were found exclusively among Chinese immigrants. Genotype E strains were found in immigrants from Central Africa and in one patient native of Spain. Point mutations leading to amino acid changes of residues involved in the expression of the HBsAg subtype determinants were found in 12 samples (4.5%). Some mutations would predict the putative novel genotype-subtype associations A/adw4q+, A/ayr, D/ayr, and E/ayw1, while others would suggest the loss of subtype-specific determinants. The finding of HBV strains characteristic for Africa among the autochthonous carriers confirms the emergence of African HBV strains in Spain.     

Sequence analysis of pre-S/S gene of hepatitis B virus strains of genotypes A,D, and F isolated in Brazil

Summary The nucleotide sequences of pre-S/S gene of nine hepatitis B virus strains (3adw2, 3ayw2, and 3ayw3) and of pre-S region of twoadw4 isolates from Rio de Janeiro, Brazil, were determined. Phylogenetic analysis allowed to classify these strains into three genotypes, A, D and F, reflecting the diverse origin of the population. However, strains belonging to a same genotype were separated by a short evolutionary distance. The presence of aminoacid mutations into pre-S region not found in hepatitis B viruses isolated in other parts of the world is described.The sequences reported in this paper have been submitted to Genbank and assigned accession numbers U55220-U55230.     

Phylogenetic relatedness and genetic diversity of hepatitis B virus isolates in Eastern India

Hepatitis B virus (HBV) has been classified into eight genotypes, and several subgenotypes, distinctly distributed geographically. The genotypes A and D were previously reported to be predominant in India. Recent studies indicated evidence of circulation of genotype C in Eastern part of India. With the aim to confirm the phylogenetic relation and molecular genetic characteristics of the HBV circulating in Kolkata, the most populous city in Eastern India, 11 strains were isolated and the complete genome sequences were analyzed. Phylogenetic analysis determined; three genotype C (adr-serotype) isolates closely related with C1 (Cs) subgenotype references from South East Asia, and three genotype A (adw2-serotype) isolates, related to Asia-variant references of subgenotype A1 (Aa). Whereas, five genotype D (ayw2, ayw3 serotype) isolates were highly divergent; one was related to subgenotype D1, two to subgenotype D3, and the remaining two clustered with a single genotype D isolate from Japan belonging to an unclassified subgenotype. Together, these two isolates differed from HBV D1-D4 subgenotypes by nucleotide differences ranging from 5.0 to 5.49%, probably indicating a new subgenotype, which we designate as D5. All serotype ayw3 of genotype D isolates had specific amino acid substitution Threonine at codon 118 and Methionine at codon 125 in antigenic determinant of surface gene that has not been reported previously in isolates from other parts of India. In conclusion; using the complete genome analyses this study has confirmed circulation of the genotype C in Eastern part of India and demonstrated considerable genotypic heterogeneity of the Indian genotype D.     

Characteristics of hepatitis B virus in Ghana: full length genome sequences indicate the endemicity of genotype E in West Africa

Hepatitis B virus (HBV) genotypes from A to H have distinct geographical distributions and have been shown to affect the clinical features as well as the course of the HBV infection. HBV genotype E has been found only in Africa. However, the complete genomes of this genotype, which were isolated mainly from West Africa, were available only for a few samples. In this study, five full-length genomes and seven other small S genes of HBV strains from Ghanaian blood donors were sequenced and investigated. Following phylogenetic analysis, all of the Ghanaian HBV strains were clustered closely in genotype E. All of the 12 small S genes showed the same characteristic of subtype ayw4. The complete genomes of the five Ghanaian strains showed marked similarity with each other and with the reported genotype E strains (96.7%-99.1%). Genotype E strains showed low intra-genotypic diversity (1.8%) and carried the conserved signature pattern in pre-S1 as well as in the full genome sequence. Of note, the finding of the G145R escape mutant in an unvaccinated Ghanaian blood donor might raise concern as to the ongoing nation-wide hepatitis B vaccination program in Ghana.     

Genotypes and phylogenetic characterization of hepatitis B and delta viruses in Egypt

Hepatitis B virus (HBV) and hepatitis D virus (HDV) sequences among HBV carriers from Egypt have not been evaluated sufficiently. The genotypes of HBV isolated from 105 serum samples from Egyptian carriers were determined. Four complete genomes and 11 entire preS1/S2/S genes were sequenced and evaluated. All serum samples were classified into HBV genotype D using serologic and genetic methods. The length of four complete nucleotide sequences was 3,182 bp. In all 15 samples, the common 33 nucleotides (11 amino acids) deletions in the preS1 region specific for HBV genotype D were observed. In the phylogenetic analysis based on the complete nucleotide sequences, all samples were clustered with the HBV isolates reported from previously Western and Mediterranean countries with nucleotide homology ranging from 96.0-98.0%. Of 75 HBsAg positive samples, anti-HDV was found in 15 (20%), and HDV RNA was detected in 9 of 15 (60%). The proportion of the patients with liver disease was higher in HBV carriers of anti-HDV positive with HDV RNA than in HBV carriers of anti-HDV positive without HDV RNA (P < 0.05). In the phylogenetic analysis based on the sequences in nucleotide position 853-1267 of HDV, nine samples were classified into HDV genotype I with the nucleotide homology ranging from 88.3-92.1% (mean; 90.5%) and clustered with HDV strains reported previously from Ethiopia, Somalia, Egypt, and Lebanon. These results indicate that HBV genotype D and HDV genotype I are most prevalent in Egypt, and HDV co-infection in HBV carriers is related to severity of liver disease.     

Naturally occurring MHR variants in Turkish patients infected with hepatitis B virus

Major B-cell epitopes are located at the major hydrophilic region (MHR) of hepatitis B virus (HBV) surface antigen (HBsAg). The genotypes, subtypes, and naturally occurring amino acid (aa) substitutions of MHR were analyzed in 81 Turkish adult patients (41 inactive HBsAg carriers and 40 patients with chronic hepatitis B) by direct sequencing of the S gene fragment. All the isolates were genotype D according to the phylogenetic analysis. The most common HBsAg subtype was ayw2, followed by ayw3 while one isolate specified ayw4 by encoding Leu127. MHR variants were detected in 22 of the 81 (27.2%) isolates. The prevalence was significantly higher in the chronic hepatitis B group (42.5%) compared to inactive HBsAg carriers (12.2%). Twenty-two samples had a total of 26 amino acid substitutions involving 14 positions. The majority of the patients had a single variation. Most of the amino acid substitutions were located at the HBs1 region of the MHR, while 9 of the 26 were in the classic "a" determinant (aa 124-147). When samples with "a" variants were evaluated by two different commercial HBsAg tests, only the isolate with Ser143Leu variation had a decreased reactivity in the assay using monoclonal antibodies for capture and detection. In conclusion, the findings of the study was in accordance with previous studies showing HBV genotype and subtype homogeneity (genotype D/ayw) in Turkey. Naturally occurring MHR and "a" determinant variants were common, especially among chronic hepatitis B patients. The influence of detected "a" variants on diagnostic assays was limited.     

青海同德藏族人群感染HBV基因型、血清型调查

目的 了解青海同德藏族人群乙型肝炎病毒(HBV)基因型、血清型的分布状况.方法 用巢式PCR扩增青海同德藏族人群表面抗原(HBsAg)阳性者的HBV S、C基因,测定其序列,判定其基因型和血清型.结果 源于自然人群的311份血清标本中,同时获得S和C基因序列者271份,其中C型基因10例,占3.7%,C/D重组型261例,占96.3%;血清ayw2亚型259例,占95.6%,adr亚型10例,占3.7%,adw2亚型2例,占0.7%.结论 青海同德藏族人群感染HBV以C/D重组型为主,血清型以ayw2为主.     

Analysis of the complete hepatitis B virus genome in patients with genotype C chronic hepatitis in relation to HBeAg and anti-HBe

To investigate the relationship between viral factors and the development of chronic hepatitis B, the entire hepatitis B virus (HBV) genome of chronic carriers at different disease stages were analyzed. Eighty genotype C HBV carriers including 12 hepatitis B e antigen (HBeAg) positive asymptomatic carriers (Group A), 49 HBeAg positive patients with chronic liver diseases (Group B) and 19 anti-HBe positive patients with chronic liver diseases (Group C) were studied. HBV nucleic acid from serum samples was sequenced directly and compared with GenBank reference sequences HBV X01587 and M12906. On phylogenetic analysis, 76 cases were genotype C2. Of the 76 genotype C2 cases, the nucleotide and amino acid substitution rates in the precore/core region were significantly higher in Groups B and C than in Group A, also in Group C than in Group B. The nucleotide substitution rates in the full genome and the core promoter region were significantly higher in Group C than in Group A, also in group C than in Group B. The nucleotide and amino acid substitution rates in the X region were significantly higher in Group C than in Group A. The amino acid substitution rate in the pre-S2 region was significantly higher in Group C than in Group B. Deletion mutations were found mainly in Groups B and C. This whole genome analysis of HBV chronic carriers suggested that the nucleotide substitutions and deletions in HBV were closely associated with the pathogenesis of chronic HBV infection.     

Novel subgenotypes of hepatitis B virus genotypes C and D in Papua, Indonesia

Eight genotypes (A to H) and nine subtypes (adw2, adw4, ayw1, ayw2, ayw3, ayw4, adrq+, adrq-, and ayr) of hepatitis B virus (HBV) have been identified worldwide. They appear to be associated with geographical distribution, virological characteristics, and possibly clinical outcomes. We performed sequence analysis of part of the S gene and the entire precore/core gene of HBV isolates obtained from HBsAg-positive blood donors in Papua Province, Indonesia. Phylogenetic analysis of the S gene sequences revealed that 23 (85.2%) of the 27 HBV isolates tested belonged to genotype C (HBV/C) and 2 (7.4%) each to HBV/B and HBV/D. Interestingly, 19 (82.6%) of the 23 isolates of HBV/C clustered in a branch that was distinct from the previously reported subgenotypes C1 to C5 (HBV/C1 to HBV/C5). Similarly, two isolates of HBV/D clustered in a branch distinct from the reported subgenotypes HBV/D1 to HBV/D5. Phylogenetic analysis of the entire precore/core gene confirmed the consistent presence of the distinct branches in HBV/C and HBV/D. We therefore propose novel subgenotypes designated HBV/C6 and HBV/D6. The majority of HBV/C6 isolates in Papua had alanine at positions 159 and 177 (A159/A177) in the HBsAg. A159/A177 is different from the determinants for adrq+ (A159/V177), found throughout Asia, and adrq- (V159/A177), found in New Caledonia and Polynesia, possibly representing a unique antigenic group (provisionally referred to as adrq indeterminate). In conclusion, we have identified two novel HBV subgenotypes, HBV/C6 and HBV/D6, the first of which is the most prevalent subgenotype of HBV in Papua, Indonesia.     

Identification of hepatitis B virus subgenotype A3 in rural Gabon

An hepatitis B virus (HBV) molecular survey was conducted in five remote villages in the equatorial forest in Gabon, Central Africa. Two hundred seventy out of 311 inhabitants (86.8%) were HBV-infected or had evidence of past HBV infection. Chronic hepatitis corresponding to hepatitis B surface antigen (HBsAg) positivity was suspected in 27 (8.6%) of the HBV-infected subjects. High HBV viral loads were detected mainly in children aged 4-7 years. The pre-S/S domains were sequenced in 13 cases and 12 strains belonged to HBV-A genotype. In one case we found evidence for recombination between genotypes A and E. Phylogenetic analysis revealed that Gabonese HBV strains were distinct from HBV-A subgenotypes (A1 and A2). These new HBV strains from Gabon clustered with previously reported HBV-A3 subgenotype strains from Cameroon and Democratic Republic of Congo. The analysis of the pre-S2 domain allowed us to determine two amino acid substitutions (N/152/S and N/174/T) specific to the Central African HBV-A3 subgenotype strains and one amino acid substitution (P/155/Q) unique to these new Gabonese HBV-A3 subgenotype isolates. Two full genome sequences of two new Gabonese HBV isolates are also presented and confirm the distinctive HBV-Gab-A3 cluster.     

Molecular epidemiology of hepatitis B virus in Iran

Hepatitis B virus (HBV) infection is a major cause of liver disease worldwide. Eight genotypes and 24 subgenotypes of HBV have been identified. The aim of this study was to determine the distribution of HBV genotypes, subgenotypes and subtypes, and to understand HBV genetic variability in the HBV genome circulating in Iranian provinces. Two hundred and forty-nine sera from HBV-infected patients living in 25 provinces of Iran were collected (2004–2007). A part of the HBV S / pol and whole BCP / C genes were amplified, sequenced and then subjected to phylogenetic, recombination and genetic variability analysis. Results revealed genotype D of HBV in all samples and subgenotypes  D1 (98.52%), D2 (0.74%) and D3 (0.74%) among Iranian patients living in different provinces of Iran. Subtypes  ayw2 (94.4%), ayw1 (2.8%), ayw3 (2%) and ayw4 (0.4%) were deduced, on the basis of HBV small surface antigen (HBsAg) amino acid sequences. The mean percentage intra-genotypic distance of S plus core regions was 2.8%; the mean percentage inter-genotypic distance of this region between Iranian strains and genotype D isolates was 3.1%; and this rate for other genotypes was 5.2–11.4%. Various rates of point mutations have been found within different HBV genes, e.g. HBsAg (17.2%), precore-G1896A (59.5%) and Basal core promoter (BCP) double mutations (49.2%), whereas no recombination was found. In conclusion, these results indicate that the only genotype circulating in the provinces of Iran is genotype D. There exist high genetic variabilities in the S / pol and BCP / C regions among the Iranian HBV isolates.     

Hepatitis B virus DNA splicing in lebanese blood donors and genotype a to e strains: implications for hepatitis B virus DNA quantification and infectivity

Hepatitis B virus (HBV) is one of the major viruses transmissible by blood that causes chronic infection in immunocompromised individuals. The study of 61 HBV carrier blood donors from Lebanon revealed multiple patterns of spliced HBV DNA. HBV DNA splicing was examined and quantified in samples of five genotypes and in seroconversion panels. The Lebanese sample median viral load was 1.5 ×10(2) IU/ml. All strains were genotype D, serotype ayw; 35 clustered as subgenotype D1 and 7 clustered as subgenotype D2. Three splice variants (SP1, SP1A, and Pol/S) were observed in 12 high-viral-load samples. Twenty samples of each genotype, A to E, were tested for the presence of HBV spliced DNA and SP1-specific splice variant. An unspliced HBV genome was dominant, but 100% of strains with a viral load of ≥10(5) copies/ml contained various proportions of spliced DNA. SP1 was detected in 56/100 (56%) samples in levels that correlated with the overall viral load. HBV DNA quantification with S (unspliced) and X (total DNA) regions provided different levels of viral load, with the difference corresponding to spliced DNA. During the highly infectious window period, the SP1 variant became detectable shortly after the hepatitis B surface antigen (HBsAg), suggesting a correlation between the initiation of splicing and the production of detectable levels of HBsAg. The quantification of HBV DNA with primers located outside and inside the spliced region might provide different estimations of viral load and differentiate between infectious and defective viral genomes. The role of splicing neoproteins in HBV replication and interaction with the host remains to be determined.     

Hepatitis B virus genotype D strains from Estonia share sequence similarity with strains from Siberia and may specify ayw4

The genotypes and subtypes of 205 HBV isolates collected during 1989-2002 in Estonia and 14 other regions of the former USSR were determined by sequencing and phylogenetic analysis of the S gene. The in Europe prevailing genotypes, A and D, were also circulating in the whole territory of the former USSR including Estonia and accounted for 18.5 and 81% of the strains, respectively. All genotype A strains specified adw2, and a single genotype C strain specified adrq+. Most genotype D strains specified ayw3 and ayw2, although, three strains from Estonia and Siberia specified ayw4. Due to unique substitutions, Ser122 and Ala127, four strains could not be classified according to the subtype. One strain specifying ayw3 encoded Leu143 and Ala145 and was possibly an immune "escape" mutant. At phylogenetic analysis 93% of the Estonian genotype D strains belonged to a cluster specifying mainly ayw3 and were more similar to isolates from Siberia and the Far-East of Russia than to isolates originating from Central Russia which belonged to another cluster of strains specifying mainly ayw2. This pattern might be explained by part of the Estonian population, has roots east of European Russia, based on linguistic evidence. Eight dominant HBV strains represented by identical S gene sequences were identified, one within genotype A and seven within genotype D, three of which included isolates from Estonia and Siberia. Some of these strains were collected over a period of at least 13 years indicating there are genetically stable variants of HBV that remain conserved over decades.     

Distribution of HBV genotypes,subgenotypes and HBsAg subtypes among chronically infected patients in Serbia

Hepatitis B virus (HBV) has been classified into eight genotypes (some of them further divided into two or more subgenotypes) and nine HBsAg subtypes, distinctly distributed geographically. The aim of this study was to gain insight into the distribution of HBV genotypes, subgenotypes and HBsAg subtypes among HBV chronically infected patients in Serbia, since there were no previously published data on this subject. Eighty-nine plasma samples that gave a positive result in a nested PCR were included for genotype identification. Genotyping was performed by direct sequencing of the part of the S/pol gene, and the HBsAg subtype was deduced from the HBsAg sequence. Two HBV genotypes, A and D, were encountered in Serbia, with genotype D (D - 82%, A - 18%) and subgenotype D3 (47.9%) being prevalent. Genotype D isolates had three assigned subtypes (ayw2, ayw3, ayw4), with ayw2 found to be the most prevalent (ayw2 - 53.4%, ayw3 - 43.8%, ayw4 - 1.4%). Genotype A isolates belonged to the A2 subgenotype and the HBsAg subtype adw2, as expected for samples from European population. The results correspond to country's geographical position, being in close proximity to the Mediterranean basin and on the main route between the Middle East and Central Europe.     

Complete genomic sequence and phylogenetic relatedness of hepatitis B virus isolates from Iran

Hepatitis B virus (HBV) is one of the main etiological agents of acute and chronic liver disease that is still a major public health problem in the world. Numerous HBV isolates have grouped into eight genotypes, A to H, based on the complete genome sequence. To date, no study has been carried out on the complete HBV genome sequence in Iran. The objective of this study was to investigate the complete genome sequence organization and phylogenetic analysis of the five HBV strains, which obtained from Iranian chronic infected patients. Results showed that Iranian strains were closely related to each other, with 97-100% nucleotide similarity. Phylogenetic analysis based on the complete genome sequences and the precore/core gene sequences revealed that all strains were of genotype D, sub-genotype D1 with bootstrap value 100 and 99%, respectively. The S gene encoded Arg122, Pro127, and Lys160 corresponding to subtype ayw2. Iranian HBV isolates had closely related with Turkish HBV strains. All strains had a nucleotide length of 3,182 base pair (bp) except IR-P4 strain, with a 3,185 bp in length and with a unique Phe89 insertion in the X gene. The intragenotypic divergence of the complete genome sequence of Iranian strains was 1.8% and the intergenotypic in genotype D was 3.8% and with the other genotypes was 7.9-15.4%. In conclusion, this study revealed that the HBV genotype D, sub-genotype D1, subtype ayw2 dominates in the Iranian infected patients. A single Phe89 insertion in the X gene of the one Iranian strain with an unforeseen length of 3185 bp was identified.