Identification of a novel genotype of hepatitis G virus in Southeast Asia

Interplay between HIV and Human Pegivirus (HPgV) Load in Co-Infected Patients: Insights from Prevalence and Genotype Analysis

Human pegivirus (HPgV) is transmitted through sexual or parenteral exposure and is common among patients receiving blood products. HPgV is associated with lower levels of human immunodeficiency virus (HIV) RNA and better survival among HIV-infected patients. This study aimed to investigate the prevalence of HPgV and determine its subtypes in HIV-infected individuals living in Istanbul, which has the highest rate of HIV infection in Türkiye. Total RNA extraction from plasma, cDNA synthesis, and nested PCR were performed for HPgV on plasma samples taken from 351 HIV-1-infected patients. The HPgV viral load was quantified on HPgV-positive samples. HPgV genotyping was performed by sequencing the corresponding amplicons. In the present study, the overall prevalence of HPgV RNA in HIV-infected patients was 27.3%. HPgV subtypes 1, 2a, and 2b were found, with subtype 2a being the most frequent (91.6%). Statistical analysis of HIV-1 viral load on HPgV viral load showed an opposing correlation between HIV-1 and HPgV loads. In conclusion, these data show that HPgV infection is common among HIV-positive individuals in Istanbul, Türkiye. Further comprehensive studies are needed to clarify both the cellular and molecular pathways of these two infections and to provide more information on the effect of HPgV on the course of the disease in HIV-infected individuals.

Human pegivirus type 1 infection in Asia-A review of the literature

The human pegivirus type 1 (HPgV-1)-as known as hepatitis G virus and GB virus C-is a common single-stranded RNA flavivirus. Because few studies have demonstrated an association between HPgV-1 infection and disease, screening for HPgV-1 is not performed routinely. Nonetheless, a beneficial impact of HPgV-1 infection on HIV disease progression has been reported in multiple studies. Given the burden of HIV in Asia and the complex interactions between viral co-infections and the host, we provide a comprehensive overview of the existing data from Asia on HPgV-1 infection, including the prevalence and circulating genotypes in all Asian countries with data reported. This review highlights the research conducted thus far and emphasizes the need for additional studies on HPgV-1 across the Asian continent.

Detection and phylogenetic analysis of human pegivirus (GBV-C) among blood donors and patients infected with hepatitis B virus (HBV) in Qatar

Human Pegivirus (HPgV), formerly GB virus-C/Hepatitis G virus (GBV-C/HGV), collectively known as GBV-C, is widely spread and has been reported to be associated with non-A-E hepatitis. To our knowledge, no previous study was conducted about HPgV in Qatar. Thus, the objectives of this study were as follows: (i) to determine the rates of HPgV infection in Qatar among healthy blood donors and HBV-infected patients, and (ii) to determine the most predominant HPgV genotype in Qatar. A total of 714 blood plasma samples from healthy donors (612) and HBV-infected patients (102) were collected. RNA was extracted, reversed transcribed, and then subjected for HPgV detection by two round-nested PCR using primers amplifying a 208 bp of 5'-UTR of the HPgV. For genotyping, the 5'-UTR PCR products (from 25 randomly picked samples) were cloned and sequenced. The overall infection rate of HPgV in Qatar was 13.3%. There was no significant difference (P = 0.41) in the infection rates between healthy donor (13.7%) and in HBV-infected patients (10.7%). Moreover, we did not find any significant association between HPgV infection rates and nationality, sex, or age (P > 0.05). Sequence analysis of 40 5'-UTR PCR amplicons yielded the European genotype 2 as most predominant in Qatar, although other genotypes (5 and 7) were also present. Our results indicate that there is no strong correlation between HPgV infection rate, condition, nationality, age, and sex, and genotype 2 is most predominant in Qatar.

GB virus C Viremia and Anti-E2 Antibody Response Among Hemodialysis Patients in Gorgan, Iran

Background:

GB Virus C is a blood-borne virus and a member of Flaviviridae, like hepatitis C that is distributed globally and puts hemodialysis patients at high risk of developing liver disease. The clinical significance of GBV-C in this population remains unclear.

Objectives:

The current study aimed to evaluate GBV-C infection among hemodialysis patients.

Patients and Methods:

Totally, 149 patients receiving hemodialysis were included in the study. The detection of GBV-C sequences in plasma was done by the nested Reverse transcription polymerase chain reaction (RT-PCR) using specific primers selected from highly conserved regions of 5' UTR of GBV-C and antibodies to the envelope protein of GBV-C (anti-E2 GBV-C antibody) were analyzed by also serological methods. In addition, Hepatitis B surface antigen (HBsAg), Hepatitis B core antibody (HBcAb) IgM, anti- Hepatitis C virus (HCV) and anti- hepatitis E virus (HEV) Ab was determined in patients who were GBV-C RNA and anti-E2 GBV-C antibody positive.

Results:

The total prevalence of GBV-C infection was 14.7% (95%CI: 0.09-0.21) among patients receiving hemodialysis. The rate of GBV-C viremia and anti-E2 antibody positivity were 6.04% and 10.73%, respectively. Among the subjects who were positive for GBV-C, 27.27% (95% CI: 0.02-0.09), 45.45% (95% CI: 0.03-0.11), 59.9% (95% CI: 0.06-0.16) and 0% (95% CI: 0.01-0.07) were positive for anti-HCV, anti-HBsAg, anti-HBc IgM and anti-(HEV) Ab, respectively. In addition, the rate of both anti-HBc IgM /anti-HCV/ HBsAg and anti-HBc IgM /anti-HCV positivity in GBV-C infected cases were 9.09%. The liver enzymes were normal in all of them. There was significant difference between GBV-C exposures with viral hepatitis co-infection, but there was no correlation between GBV-C exposure with gender, age, ethnicity, time on dialysis and history of blood transfusions. A relatively high frequency of positivity GBV-C-exposure among hemodialysis patients suggested that the transmission route for GBV-C may be nosocomial transmission, and via transfusions.

Conclusions:

The current study found a relatively high frequency of positivity GBV-C-exposure among the patients receiving hemodialysis in the area understudy. Nosocomial transmission seems to be the main route of GBV-C infection in the area.

GB virus C infection in Indonesian HIV-positive patients

GB virus C (GBV-C), a human virus of the Flaviviridae family that is structurally and epidemiologically closest to hepatitis C virus (HCV), has been reported to confer beneficial outcomes in HIV-positive patients. However, the prevalence of GBV-C in HIV-positive individuals in Indonesia is unknown. Since GBV-C is more prevalent in anti-HCV positive patients than in anti-HCV negative subjects, transmission of GBV-C and HCV could be by the same method. This study examined the prevalence and molecular characteristics of GBV-C infection in HIV patients in Yogyakarta, Indonesia. The prevalence of GBV-C among HIV patients (n = 125, median age 31 years) based on the 5'UTR region was 111/125 (88.8%), including 39/48 (81.3%) and 72/77 (93.5%) HIV-infected patients with and without HCV infection, respectively. GBV-C isolates were of genotype 2a, 3 and 6 in 58.3%, 12.6% and 28.4% of patients, respectively. Patients with genotype 3 were significantly younger than those with genotypes 2a or 6 (P = 0.001 and P = 0.012, respectively). Genotypes 3 and 6 were significantly associated with injection drug use (P = 0.004 and P = 0.002, respectively) and HCV co-infection (P < 0.001 for both genotypes), indicating a shared transmission route with HCV. In conclusion, the prevalence of GBV-C among HIV-positive patients in Indonesia is high, and three genotypes were detected, namely genotype 2a, 3 and 6.

Deep sequencing identifies two genotypes and high viral genetic diversity of human pegivirus (GB virus C) in rural Ugandan patients

Human pegivirus (HPgV), formerly 'GB virus C' or 'hepatitis G virus', is a member of the genus Flavivirus (Flaviviridae) that has garnered significant attention due to its inhibition of HIV, including slowing disease progression and prolonging survival in HIV-infected patients. Currently, there are six proposed HPgV genotypes that have roughly distinct geographical distributions. Genotypes 2 and 3 are the most comprehensively characterized, whereas those genotypes occurring on the African continent, where HPgV prevalence is highest, are less well studied. Using deep sequencing methods, we identified complete coding HPgV sequences in four of 28 patients (14.3%) in rural Uganda, east Africa. One of these sequences corresponds to genotype 1 and is the first complete genome of this genotype from east Africa. The remaining three sequences correspond to genotype 5, a genotype that was previously considered exclusively South African. All four positive samples were collected within a geographical area of less than 25 km(2), showing that multiple HPgV genotypes co-circulate in this area. Analysis of intra-host viral genetic diversity revealed that total single-nucleotide polymorphism frequency was approximately tenfold lower in HPgV than in hepatitis C virus. Finally, one patient was co-infected with HPgV and HIV, which, in combination with the high prevalence of HIV, suggests that this region would be a useful locale to study the interactions and co-evolution of these viruses.

Intra-host diversity and emergence of unique GBV-C viral lineages in HIV infected subjects in central China

GB virus C (GBV-C), which is highly prevalent among HIV/AIDS, seemed to slow the HIV disease progression. The HIV/GBV-C co-infected individuals may represent an interesting model for the investigation of the role played by HIV infection and/or the immune system in driving the evolution of the GBV-C viral populations. The present study investigated the prevalence and population dynamics of GB virus C in HIV infected individuals representing 13 geographic regions of Hubei Province of China. Approximately 37% of HIV-1 infected individuals were infected with GBV-C and genotype 3 is appeared to be predominant. Utilizing the 196 complete E2 nucleotide sequence data from 10 HIV/GBV-C infected individuals and employing coalescence based phylogenetic approaches; the present study has investigated the intra-host dynamics of GBV-C. The results revealed patient-specific unique GBV-C viral lineages and each viral lineage showed the evidence of rapid population expansion in respective HIV-1 infected patients, thus suggesting HIV-1 was unlikely to have been inhibiting effect on the GBV-C viral replication. GBV-C in all patients has experienced intense purifying selection, suggesting the GBV-C viral invasion and subsequent expansion within the HIV-1 infected hosts without any modification of the functional epitopes at their membrane protein. The finding of within host GBV-C recombinant sequences indicated recombination was one of the significant forces in the evolution and divergence of GBV-C.

Frequency and genotypic distribution of GB virus C (GBV-C) among Colombian population with Hepatitis B (HBV) or Hepatitis C (HCV) infection

BACKGROUND

GB virus C (GBV-C) is an enveloped positive-sense ssRNA virus belonging to the Flaviviridae family. Studies on the genetic variability of the GBV-C reveals the existence of six genotypes: genotype 1 predominates in West Africa, genotype 2 in Europe and America, genotype 3 in Asia, genotype 4 in Southwest Asia, genotype 5 in South Africa and genotype 6 in Indonesia. The aim of this study was to determine the frequency and genotypic distribution of GBV-C in the Colombian population.

METHODS

Two groups were analyzed: i) 408 Colombian blood donors infected with HCV (n = 250) and HBV (n = 158) from Bogotá and ii) 99 indigenous people with HBV infection from Leticia, Amazonas. A fragment of 344 bp from the 5' untranslated region (5' UTR) was amplified by nested RT PCR. Viral sequences were genotyped by phylogenetic analysis using reference sequences from each genotype obtained from GenBank (n = 160). Bayesian phylogenetic analyses were conducted using Markov chain Monte Carlo (MCMC) approach to obtain the MCC tree using BEAST v.1.5.3.

RESULTS

Among blood donors, from 158 HBsAg positive samples, eight 5.06% (n = 8) were positive for GBV-C and from 250 anti-HCV positive samples, 3.2%(n = 8) were positive for GBV-C. Also, 7.7% (n = 7) GBV-C positive samples were found among indigenous people from Leticia. A phylogenetic analysis revealed the presence of the following GBV-C genotypes among blood donors: 2a (41.6%), 1 (33.3%), 3 (16.6%) and 2b (8.3%). All genotype 1 sequences were found in co-infection with HBV and 4/5 sequences genotype 2a were found in co-infection with HCV. All sequences from indigenous people from Leticia were classified as genotype 3. The presence of GBV-C infection was not correlated with the sex (p = 0.43), age (p = 0.38) or origin (p = 0.17).

CONCLUSIONS

It was found a high frequency of GBV-C genotype 1 and 2 in blood donors. The presence of genotype 3 in indigenous population was previously reported from Santa Marta region in Colombia and in native people from Venezuela and Bolivia. This fact may be correlated to the ancient movements of Asian people to South America a long time ago.

Evidence for extensive genotypic diversity and recombination of GB virus C (GBV-C) in Germany

Multiple genotypes of GB virus C (GBV-C)-a non-pathogenic flavivirus-have been identified to date, although they are not uniformly distributed worldwide. It has also been suggested that GBV-C genotype may play a role in modulating HIV disease; however, the prevalence and genotype distribution of GBV-C has not been adequately studied in most countries. Among 408 HIV positive subjects in Germany, 97 (23.8%) had detectable GBV-C RNA. Based on sequencing of the 5' untranslated region (5'-UTR), the GBV-C genotypes were 1 (n=8; 8.2%), 2 (n=81; 83.5%), and 3 (n=2; 2.1%), as well as a unique genotype not previously reported (n=6; 6.2%). Among 17 samples also sequenced in the envelope 2 (E2) region, 14 had concordant genotype results when comparing the 5'-UTR and E2, while evidence of intergenotypic recombination was observed among E2 sequences from 3 individuals. These results suggest that genotypic diversity and viral recombination contribute to the overall genetic variability of GBV-C.

Prevalence, incidence density, and genotype distribution of GB virus C infection in a cohort of recently HIV-1-infected subjects in Sao Paulo, Brazil

BACKGROUND

The results of previous studies elsewhere have indicated that GB virus C (GBV-C) infection is frequent in patients infected with the human immunodeficiency virus type 1 (HIV-1) due to similar transmission routes of both viruses. The aim of this study was to determine the prevalence, incidence density and genotypic characteristics of GBV-C in this population.

METHODOLOGY/PRINCIPAL FINDINGS

The study population included 233 patients from a cohort primarily comprised of homosexual men recently infected with HIV-1 in São Paulo, Brazil. The presence of GBV-C RNA was determined in plasma samples by reverse transcriptase-nested polymerase chain reaction and quantified by real-time PCR. GBV-C genotypes were determined by direct sequencing. HIV viral load, CD4+ T lymphocyte and CD8+ T lymphocyte count were also tested in all patients. The overall prevalence of GBV-C infection was 0.23 (95% CI: 0.18 to 0.29) in the study group. There was no significant difference between patients with and without GBV-C infection and Glycoprotein E2 antibody presence regarding age, sex, HIV-1 viral load, CD4+ and CD8+T cell counts and treatment with antiretroviral drugs. An inverse correlation was observed between GBV-C and HIV-1 loads at enrollment and after one year. Also, a positive but not significant correlation was observed between GBV-C load and CD4+ T lymphocyte. Phylogenetic analysis of the GBV-C isolates revealed the presence of genotype 1 and genotype 2, these sub classified into subtype 2a and 2b.

CONCLUSION/SIGNIFICANCE

GBV-C infection is common in recently HIV -1 infected patients in Sao Paulo, Brazil and the predominant genotype is 2b. This study provides the first report of the GBV-C prevalence at the time of diagnosis of HIV-1 and the incidence density of GBV-C infection in one year.

Prevalence and distribution of the GBV-C/HGV among HIV-1-infected patients under anti-retroviral therapy

Infection with GB virus C (GBV-C) or hepatitis G virus (HGV) is highly prevalent among HIV/AIDS patients. GBV-C/HGV viremia has not been associated with liver disease and seems to slow HIV disease progression. To study the GBV-C/HGV genotypes prevalence among HIV/AIDS patients and its association with HIV viral load (VL) and CD4+ lymphocyte counts. From February 2003 to February 2004, we analyzed 210 HIV-1-infected subjects who were on anti-retroviral therapy (ART). For 63 of them a PCR-nested to the non-coding 5' (5'NCR) region of the GBV-C/HGV was done, and for 49 a DNA direct sequencing was done. A phylogenetic analysis was performed by PHYLIP program. 63 (30%) of the HIV-1-infected patients were co-infected with GBV-C/HGV. The phylogenetic analysis revealed the following genotypes (and respective relative frequencies): 1 (10%), 2a (41%), 2b (43%), and 3 (6%). Co-infected patients presented lower HIV-1 VL and higher T CD4+ lymphocyte cells counts as compared with patients negative for GBV-C/HGV sequences (log=4.52 vs. 4.71, p=0.036), and T CD4+ lymphocyte counts (cells/mm(3)=322.6 vs. 273.5, p=0.081, respectively). T CD4+ cells counts equal to, or higher than, 200/mm(3) were significantly more common among co-infected patients than among HIV-infected-only patients (p=0.042). The lowest T CD4+ cells counts were associated with genotype 1 and the highest with genotype 2b (p=0.05). The GBV-C/HGV infection prevalence was 30% among HIV-1-infected subjects, and was associated with lower VL and higher CD4+ lymphocyte counts. GBV-C/HGV genotype 2b may be associated with better immunological response.

[Prevalence of hepatitis G, B and C virus infections among positive HIV population in a Tunisian Hospital, La Rabta, Tunis]

OBJECTIVE

The viral hepatitis G and HIV coinfection has been largely treated in the litterature. The aim of this study was to evaluate the coinfection rate in our hospital and to compare the HGV frequency to other hepatitis viruses (B and C) in positive HIV subjects at the Rabta hospital in Tunis, Tunisia.

PATIENTS AND METHODS

The studied population included 125 HIV positives patients from the infectious diseases unit. The detection of the hepatitis B and C was carried out using serologic test (Elisa-Biorad). The molecular detection of the HGV was realized by reverse transcriptase polymerase chain reaction (RT-PCR).

RESULTS

The prevalence of serological markers of hepatitis B (antibodies and/or antigens) and C (antibodies) was respectively 32.25% and 26.4%. HGV RNA was detected in 36.8% of the studied population. The unprotected intercourse was the predominant risk factor of the HGV contamination. Among the HGV (+) patients, 28.2% were carriers of the hepatitis C antibodies (anti-HCV).

CONCLUSION

This work was the first study enabling to assess the coinfection rate of viral hepatitis B, C and G with HIV patients (+) in Rabta Hospital. The regular screening of HGV is recommended regarding its high frequency and the possibility of its pathogenic role.

Beneficial effect of GB virus C co-infection in Human Immunodeficiency Virus type 1-infected individuals

Several reports have documented a better prognosis for HIV-1-infected patients co-infected with GBV-C, while other reports have contradicted such findings with the result that this issue remains controversial. We attempted to clarify the complicated status of the effect of GBV-C co-infection on HIV-1-infected patients. GBV-C RNA was detected in 37 samples in 182 HIV-1-infected patients (20.3%) using RT/nested PCR. Of these, 3 were determined to be GBV-C genotype 1, 12 were genotype 2, and the remaining 22 were genotype 3. The GBV-C viral load quantified by real-time PCR ranged from 7.8x10(3) to 3.3x10(6) copies/ml. Weakly negative correlation was observed between GBV-C viral load and HIV-1 viral load in 19 HAART-naïve patients, indicating that a higher GBV-C viral load is associated with a greater suppression of HIV-1 replication. A previously published in vitro study suggested that GBV-C infection would induce up-regulation of RANTES, leading to suppression of HIV-1 replication. However, in our present study, the blood RANTES level was significantly lower in the GBV-C co-infected group than in the uninfected group (190-9,959 vs. 264-31,038 pg/ml, P=0.004). Our results suggested that a suppression of HIV-1 replication by GBV-C co-infection is not mediated by up-regulated RANTES, and thus call for another as yet unknown factor.

A previously unrecognized sixth genotype of GB virus C revealed by analysis of 5'-untranslated region sequences

GB virus C (GBV-C) is a positive-strand RNA virus that infects a large proportion of the world's human population. It has been classified tentatively as a member of the Flaviviridae family and has been shown to exist as a group of five closely related genotypes. Recently, we reported the first full-length genome sequence of a genotype 5 isolate from South Africa. As part of the analysis of that sequence, a phylogenetic tree was elucidated from the 5'-untranslated region (UTR) that showed excellent congruence to the tree produced by analysis of complete open reading frame sequences. When 5'-UTR analysis was broadened subsequently to include additional isolates from around the globe, a heretofore unrecognized GBV-C genotype was discovered in Indonesia. When first reported in 2000, these isolates were described as constituting a novel fifth genotype. However, comparison to isolates from the then-known fourth and fifth genotypes (from Myanmar/Vietnam and South Africa, respectively) was not performed. A dataset of 121 GBV-C 5'-UTR sequences was complied and included representatives of the fourth and fifth genotypes as well as the "novel" Indonesian sequences and demonstrated, with strong support via bootstrap analysis, the existence of a sixth GBV-C genotype among infected individuals in Indonesia. The discovery of this sixth genotype emphasizes the diverse nature of GBV-C isolates and may have important implications for the interpretation of studies involving GBV-C/HIV co-infected individuals.

African origin of GB virus C determined by phylogenetic analysis of a complete genotype 5 genome from South Africa

GB virus C (GBV-C), a positive-strand RNA virus, currently infects approximately one-sixth of the world's population. This virus exists as a collection of genotypes whose global distribution correlates with geographical origin. Genotyping of GBV-C isolates by phylogenetic analysis has relied upon the use of 5'-untranslated region (5'-UTR) sequences, however, complete genome sequences are used to demonstrate definitively their existence and geographical correlation. Initial identification of the fifth genotype from South Africa was based upon phylogenetic analysis of the 5'-UTR. It was sought to confirm this classification by analysis of full-length E2 genes from South African isolates and by analysis of a complete genotype 5 genome. Analysis of full-length E2 genes from 28 GBV-C-infected South African individuals revealed the existence of a unique group of 18 isolates, distinct from the other four genotypes. Bootstrap analysis provided strong support (95 %) for this fifth group. The remaining isolates were either genotype 1 (n=8) or 2 (n=2). Analysis of human E2 gene sequences, with the E2 gene from the chimpanzee variant GBV-Ctro included as the outgroup, produced a tree rooted on the genotype 1 branch. The complete genome nucleotide sequence of South African genotype 5 isolate D50 was determined. Phylogenetic analysis of the 5'-UTR and open reading frame produced congruent trees that grouped the sequences into five major genotypes. Inclusion of the corresponding region of the chimpanzee isolate GBV-Ctro in the analysis produced trees rooted on the branch leading to the genotype 5 isolate D50, suggesting an ancient African origin of GBV-C.

Detection and genotyping of GBV-C virus in the United Arab Emirates

GB virus-C/Hepatitis G virus (GBV-C/HGV), collectively known as GBV-C, is spread widely and has been reported to be associated with non A-E hepatitis. The aim of the current project was to determine the rate of infection and genotypic characteristics of GBV-C in the United Arab Emirates (UAE). A total of 379 plasma/serum samples representing different populations in the UAE and comprising healthy as well as patients positive for HBV and HCV were screened using RT-PCR/nested PCR of the 5'-untranslated region (UTR). National subjects (n=168) and non-nationals residing in the UAE (n=211) were tested. The results obtained showed that the rate of GBV-C infection in healthy nationals, and those positive for HCV or HBV were 11.1%, 14.3%, and 5.7%, respectively, compared to 8.3%, 33.3%, and 8.6%, respectively, in non-nationals. No statistically significant correlation between infection with GBV-C and HCV or HBV (P>0.05) was found. Sequence analysis of the 5'-UTR using 37 and 46 clones from 8 and 6 healthy nationals and non-nationals, respectively, revealed the prevalence of the European/North American genotype 2 when compared to the five reference genotypes in GenBank.

Prevalence of infection and genotypes of GBV-C/HGV among homosexual men

Since the discovery of GB virus-C (GBV-C) and hepatitis G virus (HGV), many studies have been performed. These viruses are now known to be parenterally, as well as sexually transmitted. A phylogenetic analysis also revealed that GBV-C has five major genotypes: type 1 predominates in West Africa, type 2 in Europe and the United States, type 3 in parts of Asia, type 4 in Southeast Asia, and type 5 in South Africa. Despite the number of reports so far, there have been few large-scale surveys of homosexual men to determine the prevalence of the GBV-C/HGV infections. We examined the levels of GBV-C/HGV viremia in 297 homosexual men who attended the Nagoya Lesbian and Gay Revolution held in Nagoya, Japan. Reverse transcription-polymerase chain reaction (RT-PCR)/nested PCR of the GBV-C/HGV 5 ' -non-coding region (NCR), and base sequence analyses showed that the infection rate was 12.5%, and genotypes in this population were classified into type 2 (32%) and type 3 (68%). None were classified as types 1, 4, or 5 in this study. Our results indicate that the GBV-C/HGV type 2 seen mainly in Europe and the US is spreading widely in Japan, especially in the Nagoya district.

A novel subtype of GB virus C/hepatitis G virus genotype 1 detected uniquely in patients with hemophilia in Japan

GB virus C (GBV-C) or hepatitis G virus (HGV) has been transmitted to Japanese patients with hemophilia through the frequent use of unheated blood products. Sequence analysis showed that most of the viruses isolated from these patients belonged to GBV-C/HGV genotype 1, which is usually found in persons from Africa. This may point to the origin of this virus in Japanese patients with hemophilia. The phylogeny of 11 GBV-C/HGV isolates from Japanese patients with hemophilia was investigated by a detailed analysis with a fragment spanning from the 5' non-coding region to part of the E1 gene. Except for one that belonged to the genotype 3 cluster, all isolates were GBV-C/HGV type 1. Five main clades exist within the GBV-C/HGV genotype 1 sequences. These isolates are grouped in 2 defined clades. Three of the isolates are clustered in subtype 1c clade whereas the other 7 strains formed a new statistically well-supported monophyletic group (named subtype 1e). Our results suggest that GBV-C/HGV type 1 can at present be classified into at least 5 clades and in this group a majority of Japanese patients with hemophilia was infected with a GBV-C/HGV of a unique and newly described subtype within genotype 1.

Genotyping of GB virus C by restriction pattern analysis of the 5' untranslated region

GB virus C (GBV-C) is a virus that has been proposed as a member of the Flaviviridae family, distantly related to hepatitis C virus (HCV). The virus is able to infect humans parenterally and perinatally, although its true pathogenicity remains unknown. The 5' terminal region of GBV-C is the most highly conserved region of the virus genome. Comparison of 5' untranslated region (5' UTR) sequences from GBV-C infected individuals shows that variation is limited to particular sites that are often covariant and associated with different virus genotypes. Extensive sequence analysis of the GBV-C genome provides evidence for the existence of at least five major genotypes, some of which can be further divided into subtypes. For genotyping by restriction fragment length polymorphism (RFLP), it is essential to identify genomic positions that not only reflect genotype differences, but that also harbor restriction sites that allow recognition of these differences. Restriction site analysis of type-specific sequence motifs predicted that endonucleases BsmFI, HaeII, HinfI, and ScrFI could be used for the identification all known genotypes (types 1-5) with 99.6% accuracy. The method was applied to serum samples from 46 chronic GBV-C carriers of heterogeneous geographical and ethnic origin, comparing observed cleavage patterns of GBV-C variants amplified by reverse transcriptase-polymerase chain reaction (RT-PCR) of the 5' UTR with the RFLP predicted from sequences deposited in GenBank database. cDNA sequencing and subsequent alignment of the 46 GBV-C isolates confirmed RFLP profiles predicted theoretically. The observed geographical distribution of genotypes is also in agreement with previous reports. This method may be useful for rapid and reliable characterization of GBV-C isolates when either epidemiological or transmission studies are carried out.

Genotype distribution of the GB virus C in citizens of São Paulo City, Brazil

There has been several studies worldwide on phylogenetics and genotype distribution of the GB-virus C / Hepatitis G virus (GBV-C/HGV). However, in their great majority, those investigations were based on some epidemiologically linked group, rather than on a representative sampling of the general population. The present is a continuation of the first study in Brazil with such a population; it addresses the GBV-C/HGV phylogenetics and genotype distribution based on samples identified among more than 1,000 individuals of the city of S o Paulo. For this purpose, a 728 bp fragment of the 5 non-coding region (5 NCR) of the viral genome, from 24 isolates, was sequenced and subjected to phylogenetic analysis. Genotypes 1, 2a and 2b were found at 8.3% (2/24), 50% (12/24) and 41.7% (10/24), respectively. In conclusion S o Paulo displays a genotype distribution similar to the published data for other States and Regions of Brazil, endorsing the notion that types 1 and 2 would have entered the country with African and European people, respectively, since its earliest formation.

High prevalence of GB virus C/hepatitis G virus RNA among Brazilian blood donors

The aim of this study was to investigate the presence of the Hepatitis G Virus on a population of blood donors from S o Paulo, Brazil and to evaluate its association to sociodemographic variables. Two RT-PCR systems targeting the putative 5'NCR and NS3 regions were employed and the former has shown a higher sensitivity. The observed prevalence of HGV-RNA on 545 blood donors was 9.7% (CI 95% 7.4;12.5). Statistical analysis depicted an association with race/ethnicity, black and mulatto donors being more frequently infected; and also with years of education, less educated donors presenting higher prevalences. No association was observed with other sociodemographic parameters as age, gender, place of birth and of residence. DNA sequencing of nine randomly chosen isolates demonstrated the presence of genotypes 1, 2 and 3 among our population but clustering of these Brazilian isolates was not detected upon phylogenetic analysis.

Hepatitis G virus genotypes in a tertiary care centre in southern India

BACKGROUND

The association of GBV-C/HGV in patients at high risk of parenteral infection and those with chronic liver disease in southern India is unknown.

OBJECTIVES

To study the occurrence of GBV-C/HGV in three patient groups attending a tertiary care centre in Vellore and identify the prevailing genotype(s).

STUDY DESIGN

Two hundred and twenty-seven individuals were studied using an RT-PCR assay with primers specific for the 5'NCR and the NS5a-coding regions. Ten randomly selected samples were sequenced in the 5'NCR region of the GBV-C/HGV genome.

RESULTS

GBV-C/HGV RNA was detected in 37/70 (52.9%) of renal transplant recipients, 18/70 (25.7%) of patients with haematological disorders and in 9/87 (10.3%) patients with chronic liver disease. Nine of the ten sequences could be assigned to genotype 2a while the remaining sequence could not be assigned.

CONCLUSIONS

In this centre, GBV-C/HGV is widely prevalent in patients with high parenteral risk and in those with chronic liver disease. The predominantly circulating genotype among study patients is genotype 2a.

Molecular characteristic-based epidemiology of hepatitis B, C, and E viruses and GB virus C/hepatitis G virus in Myanmar

We carried out a molecular characteristic-based epidemiological survey of various hepatitis viruses, including hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis E virus (HEV), and GB virus C (GBV-C)/hepatitis G virus (HGV), in Myanmar. The study population of 403 subjects consisted of 213 healthy individuals residing in the city of Yangon, Myanmar, and the surrounding suburbs and 190 liver disease patients (155 virus-related liver disease patients and 35 nonviral disease patients). The infection rates of the viruses among the 213 healthy subjects were as follows: 8% for HBV (16 patients), 2% for HCV (4 patients), and 8% for GBV-C/HGV (17 patients). In contrast, for 155 patients with acute hepatitis, chronic hepatitis, liver cirrhosis, or hepatocellular carcinoma, the infection rates were 30% for HBV (46 patients), 27% for HCV (41 patients), and 11% for GBV-C/HGV (17 patients). In the nonviral liver disease group of 35 patients with alcoholic liver disease, fatty liver, liver abscess, and biliary disease, the infection rates were 6% for HBV (2 patients), 20% for HCV (7 patients), and 26% for GBV-C/HGV (9 patients). The most common viral genotypes were type C of HBV (77%), type 3b of HCV (67%), and type 2 of GBV-C/HGV (67%). Moreover, testing for HEV among 371 subjects resulted in the detection of anti-HEV immunoglobulin G (IgG) in 117 patients (32%). The age prevalence of anti-HEV IgG was 3% for patients younger than 20 years and 30% or more for patients 20 years of age or older. Furthermore, a high prevalence of anti-HEV IgG (24%) was also found in swine living together with humans in Yangon. These results suggest that these hepatitis virus infections are widespread in Myanmar and have led to a high incidence of acute and chronic liver disease patients in the region.

Homologous recombination in GB virus C/hepatitis G virus

Analysis of 33 GB virus C/hepatitis G virus (GBV-C/HGV) full or nearly full genome sequences revealed several putative inter- and intrasubtype recombinants. The breakpoints of the recombinant regions were mapped using a maximum-likelihood method, and the statistical significance for each region was tested using Monte Carlo simulation. The results were highly significant and provided evidence for the existence of complex mosaic genomes showing as many as nine recombination events, with breakpoints in the 5' UTR and in all of the coding regions except the short NS4b gene. Recombination was confirmed by separate phylogenetic analysis of the various recombinant regions and by Sawyer's runs test. Taken together, these findings demonstrate for the first time that recombination is common in natural populations of GBV-C and that it takes place both within and between subtypes. The wide-ranging implications of such nonclonal history for reconstructing the spread and timescale of GBV-C evolution are discussed.

Genotyping system of GBV-C/HGV type 1 to type 4 by the polymerase chain reaction using type-specific primers and geographical distribution of viral genotypes

Based on variation in nucleotide sequence of 5'-untranslated region, GB virus type C (GBV-C) and hepatitis G virus (HGV) can be classified into three major genotypes. In addition to this classification, a novel genotype of GBV-C/HGV was identified and designated type 4. However, genotyping of GBV-C/HGV has been hampered by the lack of suitable assays. In this study, a simple and precise genotyping system based on PCR using the type-specific primers was developed for the determination of genotypes 1, 2, 3, and 4 of GBV-C/HGV. A total of 235 serum samples obtained from 11 different countries were tested by our PCR genotyping system of GBV-C/HGV. The results revealed that type 1 was prevalent mainly in Ghana, type 2 was prevalent in the USA, Spain, Egypt, Nepal and Myanmar, type 3 was prevalent in Japan and Bolivia, and type 4 was prevalent in Vietnam and Myanmar among the countries investigated in the present study. To confirm the specificity of the results of genotyping by PCR, phylogenetic analysis in the 5'-untranslated region of GBV-C/HGV was undertaken in 99 serum samples. By this analysis, the specificity of the genotyping system by PCR was confirmed. This assay system may be useful for rapid typing of GBV-C/HGV RNA when either epidemiological or transmission studies of this agent are carried out.

The serological and molecular epidemiology of GB virus C/hepatitis G virus infection in a hepatitis C and B endemic area

OBJECTIVES

To investigate the serological and molecular characteristics of GB virus C/hepatitis G virus (GBV-C/HGV) infection in the hepatitis C virus (HCV)/hepatitis B virus (HBV)-endemic areas in Taiwan.

METHODS

Sera from 200 residents from Masago, an HCV/HBV-endemic community in Taiwan, and 400 blood donors were tested for GBV-C/HGV RNA by using nested reverse transcription-polymerase chain reaction and for antibodies to GBV-C/HGV E2-protein (anti-E2) by an enzyme-linked immunosorbent assay. Phylogenetic analysis of GBV-C/HGV was performed.

RESULTS

The prevalence of GBV-C/HGV viraemia, anti-E2 and GBV-C/HGV exposure among residents of Masago was significantly higher than that among donors (17.0%, 25.5% and 39.5% vs. 3.3%, 7.5% and 10.3%, respectively; all P < 0.0001). In Masago, the prevalence of GBV-C/HGV exposure was significantly higher in residents exposed to HCV than in those without HCV exposure (45.8% vs. 24.1%;P< 0.005). Based on multivariate analyses, HCV viraemia was the only significant factor associated with elevated levels of alanine aminotransferase in Masago. Phylogenetic analysis showed all 34 GBV-C/HGV isolates from Masago clustered within genotype 3.

CONCLUSIONS

GBV-C/HGV was highly prevalent in Masago, an HCV/HBV-endemic community in Taiwan. HCV viraemia played the most important clinical hepatopathic role in the area. Infections with other hepatitis viruses did not influence the anti-E2 seroconversion from GBV-C/HGV infections.

GBV-C/HGV genotypes: proposed nomenclature for genotypes 1-5

The GB virus-C and hepatitis G virus (GBV-C/HGV) are variants of the same flavivirus. This proposal attempts to clarify the conflicting nomenclature for GBV-C/HGV genotypes. The first three genotypes described were genotype 1 (West Africa); genotype 2 (US/Europe) and genotype 3 (Asia). Subsequently, two groups published data from South Africa and Southeast Asia both stating the presence of a novel "4th genotype." These isolates are distinct phylogenetically. It is proposed that the nomenclature for genotypes 1-3 remains as per previous publications, and that the Southeast Asian isolates be known as genotype 4, and the South African isolates as genotype 5.

Phylogenetic analysis of GBV-C/hepatitis G virus

Comparison of 33 epidemiologically distinct GBV-C/hepatitis G virus complete genome sequences suggests the existence of four major phylogenetic groupings that are equally divergent from the chimpanzee isolate GBV-C(tro) and have distinct geographical distributions. These four groupings are not consistently reproduced by analysis of the virus 5'-noncoding region (5'-NCR), or of individual genes or subgenomic fragments with the exception of the E2 gene as a whole or of 200-600 nucleotide fragments from its 3' half. This region is upstream of a proposed anti-sense reading frame and contains conserved potential RNA secondary structures that may be capable of directing the internal initiation of translation. Phylogenetic analysis of this region from certain South African isolates is consistent with previous analysis of the 5'-NCR suggesting that these belong to a fifth group. The geographical distribution of virus variants is consistent with a long evolutionary history that may parallel that of pre-historic human migrations, implying that the long-term evolution of this RNA virus is extremely slow.

Prevalence of GB virus C/Hepatitis G virus infection among various populations in Surabaya, Indonesia, and identification of novel groups of sequence variants

A molecular epidemiological study was performed to investigate the prevalence of GB virus C/hepatitis G virus (GBV-C/HGV) infection among various populations in Surabaya, Indonesia. The prevalence of GBV-C/HGV RNA, determined by reverse transcription-PCR for a portion of the NS3 region of the viral genome, was 2.7% (4 of 150) among randomly collected blood donor sera, which were all negative for both hepatitis B virus surface antigen and antibodies against hepatitis C virus (HCV). On the other hand, the prevalence among anti-HCV-positive blood donors was 17.8% (13 of 73), with the ratio being significantly higher than that observed with the anti-HCV-negative blood donors (P < 0.001). A high prevalence of GBV-C/HGV infection was also observed among patients with chronic liver disease, such as chronic hepatitis (5.7%), liver cirrhosis (11. 5%), and hepatocellular carcinoma (7.0%), and patients on maintenance hemodialysis (29.0%). No correlation was observed between GBV-C/HGV viremia and serum alanine aminotransferase levels in the populations tested, suggesting the possibility that GBV-C/HGV does not cause apparent liver injury. Phylogenetic analysis of sequences of a portion of the 5' untranslated region and the E1 region of the viral genome identified, in addition to a previously reported then novel group of GBV-C/HGV variants (group 4), another novel group of variants (group 5). This result suggests that GBV-C/HGV can be classified into at least five genetic groups. GBV-C/HGV isolates of group 4 and group 5 were each shown to comprise approximately 40% of the total Indonesian isolates.

The entire nucleotide sequence of two hepatitis G virus isolates belonging to a novel genotype: isolation in Myanmar and Vietnam

A novel genotype of hepatitis G virus (HGV) was recently identified in sera of subjects from countries in South-East Asia. These isolates were recovered from serum of Myanmarese (designated HGV-MY14) and Vietnamese (designated HGV-VT48) subjects, respectively. To characterize the viral genome in more detail, the full-length nucleotide sequence of the two different HGV isolates belonging to the novel genotype was cloned. Both HGV isolates were composed of 9228 nt and had a single open reading frame spanning 8529 nt and encoding 2843 aa residues. The isolates differed from previously reported HGV/GBV-C isolates types 1 to 3 by 13-15% (nucleotide sequence) and 4-6% (amino acid sequence). The putative core region of both isolates was not clearly identifiable as it consisted of only 16 aa residues. Based on phylogenetic analysis of full-length genome sequences and 5'-UTR sequences, HGV-MY14 and HGV-VT48 isolates can be classified as a novel genotype, designated type 4.

Genetic diversity of GBV-C/HGV strains among HIV infected-IVDU and blood donors from Buenos Aires, Argentina

GBV-C/HGV RNA was investigated in serum samples from 70 HIV(+) intravenous drug users (IVDU), as well as from 200 blood donors from Buenos Aires, Argentina. Viral RNA was demonstrated in 21 IVDU by reverse transcription-nested PCR of the 5' UTR. c-DNA amplified products were analyzed and their sequences compared with those downloaded from GenBank. A phylogenetic tree based on 171 sequences demonstrated the presence of three major genogroups, including two subgroups, within local samples, i.e. group 1 (n=1), 2a (n=11), 2b (n=4) and 3 (n=5). These results agreed entirely with those obtained by a novel RFLP (J. Clin. Microbiol. 37, 1340-1347, 1999) of the same 5' UTR amplicons. As expected, GBV-C/HGV RNA prevalence was significantly higher among IVDU than among blood donors (P<0.0001), although within the latter group an unexpectedly high rate was also detected, since 11 of 200 sera (5.5%) proved positive. These viral isolates were ascribed either to subgroup 2a (n=5), subgroup 2b (n=5) or genogroup 3 (n=1). Briefly, this partial view of GBV-C/HGV molecular epidemiology in Argentina shows: (i) different rates of GBV-C/HGV infection within both IVDU and blood donors; (ii) a high prevalence of viral RNA among blood donors; and (iii) a predominant circulation of genogroup 2, with minor contribution of groups 3 and 1.

Epidemiology of hepatitis B, C, E, and G virus infections and molecular analysis of hepatitis G virus isolates in Bolivia

Prevalence of hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis G virus (HGV), and hepatitis E virus (HEV) was investigated among 574 healthy blood donors in Bolivia. HCV RNA and HGV RNA in the serum were identified by a nested reverse transcription-PCR using primers derived from the 5' untranslated region (5' UTR). We also tested for hepatitis B surface antigen (HBsAg) and for the antibody to HEV. The results revealed that HGV RNA was present in 84 of 574 (14.6%) tested blood donors, whereas HBsAg was detected in only 2 (0.3%) donors, and no individuals positive for HCV RNA were found. Anti-HEV immunoglobulin G (IgG) was detected in 93 (16.2%) individuals and anti-HEV IgM was found in 10 (1.7%) individuals among the same population. Phylogenetic analysis of 44 HGV isolates in the 5' UTR showed that 27 (61%) isolates were genotype 3 (Asian type) and the remaining 17 (39%) isolates were genotype 2 (United States and European type). Moreover, we obtained a full-length nucleotide sequence of the HGV genome (designated HGV-BL230) recovered from a Bolivian blood donor. The BL230 was composed of 9,227 nucleotides and had a single open reading frame, encoding 2,842 amino acid residues. Interestingly, the BL230 belonged to genotype 2 of HGV at the level of a full-length sequence, although this was classified as genotype 3 by a phylogenetic analysis based on the 5' UTR sequence. The BL230 differed from previously reported HGV/hepatitis GB virus type C isolates by 12 to 13% of the nucleotide sequence and 4% of the amino acid sequence. Our data indicate a high prevalence of HGV in native Bolivians, and the major genotype of HGV was type 3.

TT virus infection is widespread in the general populations from different geographic regions

By PCR screening, we found an extremely high prevalence of TT virus (TTV) in the general populations from different geographic regions. This suggests that TTV may be a common DNA virus with no clear disease association in humans. TTV genotyping by phylogenetic analysis was also performed.