Prevalence of occult hepatitis B virus infection and Torque teno virus infection and their association with hepatocellular carcinoma in chronic hepatitis C patients.

BACKGROUND: The role of occult hepatitis B virus (HBV) infection and Torque teno virus (TTV) infection in the development of hepatocellular carcinoma (HCC) in chronic hepatitis C patients is still uncertain. AIM: The aim of the present study was to investigate the prevalence and significance of OBI and TTV infection, and to examine the genetic diversity of these viruses, in chronic hepatitis C patients with and without HCC. METHODS: Sera from 151 hepatitis C virus (HCV)-infected patients (49 patients with HCC and 102 without HCC) negative for HBV surface antigen (HBsAg) were tested for the presence of OBI and TTV infection by semi-nested and group-specific multiplex PCR assays, respectively. Nucleotide sequencing of HBV S region was further performed. RESULTS: OBI and TTV infection were detected in 5 (3.3%) and 68 (45%) patients, respectively. HBV isolates were classified into genotypes A (4/5, 80%) and D (1/5, 20%), and no HBsAg escape mutation was observed. TTV phylogenetic group 3 was the most prevalent among both HCC and non-HCC patients. OBI and TTV infection were significantly more frequent in patients with HCC than patients without HCC (p=0.003, and p=0.009, respectively). Moreover, TTV infection was associated with HCC (OR=2.23, 95%CI=1.04-4.80, p=0.040), independently of liver cirrhosis. CONCLUSIONS: A low prevalence of OBI was observed in patients with HCV-related chronic liver disease, and TTV infection was an independent factor associated with the occurrence of HCC. Whether TTV influences the progression of liver disease in chronic hepatitis C patients remains to be elucidated.

Retrospective study of the relationship of Torque teno sus virus 1a and Torque teno sus virus 1b with porcine circovirus associated disease.

Genus Iotatorquevirus consists of 2 species, Torque teno sus virus 1a and Torque teno sus virus 1b, which are ubiquitous in swine populations, and are widely reported in association with porcine circovirus associated disease (PCVAD). To evaluate the relationship with PCVAD, 100 formalin-fixed paraffin-embedded tissue samples were used to detect both Iotatorquevirus species by nested PCR and sequencing. Sixty-eight PCVAD cases were selected as well as 32 porcine circovirus type 2 (PCV2) non-affected cases. Overall, 33 of the 100 cases were positive for Torque teno sus virus 1a and 8 of 100 were positive for Torque teno sus virus 1b. Only 24 of 68 (35%) PCVAD cases were positive for Torque teno sus virus 1a; 39% (9/23) of post-weaning multisystemic wasting syndrome, and 33% (15/45) of PCV2-associated reproductive failure cases. Among PCV2 non-affected cases, 28% were positive for Torque teno sus virus 1a and 6% were positive for Torque teno sus virus 1b. Torque teno sus virus 1b was not detected in PCV2-associated reproductive failure cases. Regardless of the PCV2-status, a lower frequency of both Iotatorquevirus species was found than depicted in other reports and there was no statistical relationship with PCVAD (χ 2 < 0.01). Given the worldwide genomic variability of Iotatorquevirus species, it is feasible that species prevalent in Mexico share a lower nucleotide sequence identity, leading to different pathogenic potential.

Le genre Iotatorquevirus consiste en deux espèces, le virus Torque teno sus 1a et le virus Torque teno sus 1b, qui sont ubiquitaires dans la population porcine, et couramment rapportés en association avec la maladie associée au circovirus porcin (MACVP). Afin d'évaluer la relation avec MACVP, 100 échantillons de tissus fixés dans la formaline et enrobés de paraffine ont été utilisés pour détecter les deux espèces de Iotorquevirus par réaction d'amplification en chaîne par la polymérase nichée et séquençage. Soixante-huit cas de MACVP ont été sélectionnés ainsi que 32 cas non-affectés d'infection par le circovirus porcin de type (CVP2). Globalement, 33 des 100 cas étaient positifs pour le virus Torque teno sus 1a et 8 des 100 étaient positifs pour le virus Torque tenos sus 1b. Seulement 24 des 68 (35 %) cas de MACVP étaient positifs pour le virus Torque tenos sus 1a; 39 % (9/23) du syndrome de dépérissement post-sevrage, et 33 % (15/45) des cas de problèmes reproducteurs associés au CVP2. Parmi les cas non-affectés de CVP2, 28 % étaient positifs pour le virus Torque teno sus 1a et 6 % étaient positifs pour le virus Torque tenos sus 1b. Le virus Torque tenos sus 1b n'a pas été détecté dans les cas de problèmes reproducteurs associés au CVP2. Indépendamment du statu vis-à-vis le CVP2, une fréquence plus basse des deux espèces d'Iotatorquevirus fut trouvée comparativement à ce qui est décrit dans d'autres études et il n'y avait pas de relation statistiquement significative avec MACVP (χ2 < 0,01). Étant donné la variabilité génomique mondiale des espèces d'Iotatorquevirus il est possible que les espèces prévalentes au Mexique partagent une plus faible identité de séquences nucléotidiques, entrainant ainsi un potentiel pathogène différent.(Traduit par Docteur Serge Messier).

Detection and molecular characterization of Torque Teno Virus (TTV) in Uruguay.

Torque Teno Virus (TTV), member of Anelloviridae family, is considered a worldwide distributed emergent virus and is currently classified into seven genogroups. Interestingly, the pathogenicity of TTV remains unclear. However, it has been constantly associated to hepatitis cases of unknown etiology (HUE) as well as extensively studied in concurrent infections with Hepatitis B Virus (HBV), Hepatitis C Virus (HCV) and Human Immunodeficiency Virus type 1 (HIV-1). In South America, TTV epidemiological data is scant, involving some studies from Brazil, Venezuela, Colombia and Bolivia. The aim of this work was to investigate for the first time in Uruguay the presence of TTV by a nested-PCR system in 85 human serum samples infected with HBV and/or HCV and/or HIV-1 and in HUE cases. Overall, our results reported a TTV infection rate of 79% (67/85). Furthermore, the molecular characterization of Uruguayan strains revealed that one of them clustered in genogroup 1, while the remaining ones formed separate clusters closely related to genogroup 3, which should be confirmed by complete genome sequencing. Further investigation about TTV circulation in Uruguayan population is needed in order to provide additional information about the genetic variability and TTV epidemiology in South America.

Torque teno virus among dialysis and renal-transplant patients.

Patients who undergo dialysis treatment or a renal transplant have a high risk of blood-borne viral infections, including the Torque teno virus (TTV). This study identified the presence of TTV and its genome groups in blood samples from 118 patients in dialysis and 50 renal-transplant recipients. The research was conducted in a hospital in the city of Maringá, state of Paraná. The viral DNA, obtained from whole blood, was identified by using two nested Polymerase Chain Reactions (PCR). The frequencies of TTV were 17% and 36% in dialysis patients using the methodology proposed by Nishizawa et al . (1997) and Devalle and Niel (2004) , respectively, and 10% and 54% among renal-transplant patients. There was no statistically significant association between the frequency of the pathogen and the variables: gender, time in dialysis, time since transplant, blood transfusions, and the concomitant presence of hepatitis B, for either the dialysis patients or the renal-transplant recipients. Among dialysis patients and renal-transplant recipients, genogroup 5 was predominant (48% and 66% respectively), followed by genogroup 4 (37% and 48%) and genogroup 1 (23% and 25%). Genogroup 2 was present in both groups of patients. Some patients had several genogroups, but 46% of the dialysis patients and 51% of the renal-transplant recipients had only a single genogroup. This study showed a high prevalence of TTV in dialysis patients and renal-transplant recipients.

Torque teno virus among dialysis and renal-transplant patients

Patients who undergo dialysis treatment or a renal transplant have a high risk of blood-borne viral infections, including the Torque teno virus (TTV). This study identified the presence of TTV and its genome groups in blood samples from 118 patients in dialysis and 50 renal-transplant recipients. The research was conducted in a hospital in the city of Maringá, state of Paraná. The viral DNA, obtained from whole blood, was identified by using two nested Polymerase Chain Reactions (PCR). The frequencies of TTV were 17% and 36% in dialysis patients using the methodology proposed by Nishizawa et al. (1997) and Devalle and Niel (2004), respectively, and 10% and 54% among renal-transplant patients. There was no statistically significant association between the frequency of the pathogen and the variables: gender, time in dialysis, time since transplant, blood transfusions, and the concomitant presence of hepatitis B, for either the dialysis patients or the renal-transplant recipients. Among dialysis patients and renal-transplant recipients, genogroup 5 was predominant (48% and 66% respectively), followed by genogroup 4 (37% and 48%) and genogroup 1 (23% and 25%). Genogroup 2 was present in both groups of patients. Some patients had several genogroups, but 46% of the dialysis patients and 51% of the renal-transplant recipients had only a single genogroup. This study showed a high prevalence of TTV in dialysis patients and renal-transplant recipients.

Torque teno virus among dialysis and renal-transplant patients

Patients who undergo dialysis treatment or a renal transplant have a high risk of blood-borne viral infections, including the Torque teno virus (TTV). This study identified the presence of TTV and its genome groups in blood samples from 118 patients in dialysis and 50 renal-transplant recipients. The research was conducted in a hospital in the city of Maringá, state of Paraná. The viral DNA, obtained from whole blood, was identified by using two nested Polymerase Chain Reactions (PCR). The frequencies of TTV were 17% and 36% in dialysis patients using the methodology proposed by Nishizawa et al. (1997) and Devalle and Niel (2004), respectively, and 10% and 54% among renal-transplant patients. There was no statistically significant association between the frequency of the pathogen and the variables: gender, time in dialysis, time since transplant, blood transfusions, and the concomitant presence of hepatitis B, for either the dialysis patients or the renal-transplant recipients. Among dialysis patients and renal-transplant recipients, genogroup 5 was predominant (48% and 66% respectively), followed by genogroup 4 (37% and 48%) and genogroup 1 (23% and 25%). Genogroup 2 was present in both groups of patients. Some patients had several genogroups, but 46% of the dialysis patients and 51% of the renal-transplant recipients had only a single genogroup. This study showed a high prevalence of TTV in dialysis patients and renal-transplant recipients.(AU)

Torque teno sus virus infection in suckling piglets from Brazilian pig herds.

Torque teno sus virus (TTSuV) is responsible for the infection of pig herds around the world. The aim of this study was to analyse the presence of natural infection by both species of TTSuV in suckling piglets from major pig-producing regions of Brazil. Faecal samples (n = 135) from 1 to 3-week-old suckling piglets from the Southern, Southeast and Midwest regions of Brazil were analysed by PCR assay to detect TTSuV1 and 2. TTSuV1 and 2 DNA was identified in 65 (48.1 %) and 23 (17 %) of piglet faecal samples, respectively. Co-infection by both species of TTSuV was detected in 17 (12.6 %) samples. Detection of TTSuV1 was significantly higher than that of TTSuV2 in the three Brazilian regions together (p < 0.05). Based on age of animals, TTSuV1 infection was statistically higher than TTSuV2 in each age group (p < 0.05). For all of the age groups together, no statistical difference was detected in the number of TTSuV1 and 2 positive results (p > 0.05). These findings revealed that TTSuV infection has disseminated in pig herds from different geographic Brazilian regions, and the presence of TTSuV in suckling piglet faecal samples suggested the early infection by the virus and the potential of these animals in spreading the virus.

Molecular detection of Torque teno sus virus in lymphoid tissues in concomitant infections with other porcine viral pathogens.

In this study, 40 pigs with respiratory and wasting disorders from Cuban swine herds were screened by PCR for the presence of TTSuV1, TTSuV2, PCV-2, PPV and CSFV in spleen samples. The variability of the porcine TTSuV sequences obtained was investigated by phylogenetic analysis. This study showed for the first time that TTSuV1 and TTSuV2 were present in Cuban swine herds. The investigation revealed the following infection rates: TTSuV1 40%, TTSuV2 37.5%, PCV-2 70%, PPV 37.5% and CSFV in 52.5%. The presence of two or more of these viruses at different rates in the same spleen samples was revealed. Also, a higher genetic diversity of TTSuV2 sequences was observed regarding TTSuV1 sequences.

Torque teno virus in fecal samples of patients with gastroenteritis: prevalence, genogroups distribution, and viral load.

Torque teno virus (TTV, genus Alphatorquevirus, family Anelloviridae) is a DNA virus, highly prevalent in populations from around the world. TTV isolates have been classified into five main phylogenetic groups (1-5) showing a large genetic distance between them. The presence of TTV has been detected in feces. However, whether all five TTV genogroups are excreted in feces and the frequency of these events are presently unknown. The presence of TTV DNA was assessed in feces from 135 Brazilian (0-90 years old) patients with gastroenteritis by using three PCR methods, including real-time PCR. One hundred twenty one (91.1%) samples were positive with at least one method. Using a genogroup-specific assay, it was shown that all genogroups were present. Thirty-seven (27.4%), 27 (20.0%), 57 (42.2%), 29 (21.5%), and 33 (24.4%) fecal samples contained TTV isolates belonging to genogroups 1-5, respectively. Coinfections with two, three, four, and five TTV genogroups were found in 23 (17.0%), 15 (11.1%), 7 (5.2%), and 7 (5.2%) fecal samples, respectively. Thus, 52 (38.5%) samples contained more than one TTV genogroup. Viral loads ranged from 2.6 to 6.5 log genome equivalents per gram of feces. However, only moderate variations of viral load were noted depending on genogroup and number of coinfecting TTV genogroups. These results show a high prevalence and a diversity of TTV isolates in feces.

Variations in the frequencies of torque teno virus subpopulations during HAART treatment in HIV-1-coinfected patients.

Sera from 15 patients coinfected with TTV and HIV-1, collected before and at two times after introduction of highly active anti-retroviral therapy (HAART), were tested for TTV load and the presence of the five highly divergent TTV phylogenetic groups. Seven patients showed a 1-5 log TTV load decrease during HAART, while the others did not show significant variations. A decrease in the number of coinfecting TTV genogroups was detected in 12 of 15 patients, with the mean number of TTV genogroups/patient decreasing from 2.33 before HAART to 1.47 at the last collect. All five genogroups were less frequently found after introduction of HAART. Three hundred sixty-seven TTV clones from four different genogroups, derived from two patients, were sequenced. Noticeable fluctuations in TTV subpopulation frequencies were observed in both patients analyzed. In conclusion, HAART tends to reduce the number of TTV genotypes/genogroups and may affect the balance between different TTV isolates coinfecting single individuals.

TT virus (TTV) genotyping in blood donors and multiple transfused patients in Brazil.

TT virus (TTV) is widely distributed in the general population. The objective of the present study was to investigate the prevalence and distribution of TTV genotypes among blood donor candidates and multiple transfused patients in the Southeast region of the state of São Paulo, Brazil. TTV-DNA detection by amplification of a segment of the ORF-1 region, presented a prevalence of 11.9% in 270 serum samples from blood donors, of 46.2% in 18 samples from patients with coagulopathies, and of 31.8% in 15 samples from patients with hemoglobinopathies. When specific primers for the non-coding (UTR) region of the TTV genome were used the prevalences were 50.5%, 95.0%, and 82.0% for blood donors, patients with coagulopathies and patients with hemoglobinopathies, respectively. Positive samples from 49 individuals were sequenced and partial segments of 230 base pairs referring to the ORF-1 region of the TTV genome were used for the determination of their genotypes with the aid of phylogenetic analysis. The most frequent genotype was 1 (74.0%), followed by genotype 2 (26.0%). These data indicate a high prevalence of this virus in the populations of blood donors and transfused patients, providing further evidence for the role of transfusions as an efficient pathway in the transmission chain.

Rolling-circle amplification of Torque teno virus (TTV) complete genomes from human and swine sera and identification of a novel swine TTV genogroup.

Multiply primed rolling-circle amplification is a novel technology that uses bacteriophage phi29 DNA polymerase to amplify circular DNA molecules, without the need for prior knowledge of their sequences. In an attempt to detect Torque teno virus (TTV), rolling-circle amplification was used to amplify DNA extracted from eight human and four pig serum samples. All samples gave high molecular weight (>30 kb) amplification products. By restriction endonuclease digestion, these products generated DNA fragments whose sizes were consistent with those of human TTV (3.8 kb) and swine TTV (Sd-TTV; 2.9 kb) genomes. Two TTV isolates derived from a single AIDS patient, as well as two Sd-TTV isolates derived from a single pig, were characterized by complete nucleotide sequencing. One of the Sd-TTV isolates showed very low (43-45 %) nucleotide sequence similarity to the other Sd-TTV isolate and to the prototype isolate Sd-TTV31, and could be considered the prototype of a novel genogroup.

Distribution of TT virus genomic groups 1-5 in Brazilian blood donors, HBV carriers, and HIV-1-infected patients.

Human isolates of the highly prevalent TT virus (TTV) have been classified into five major genomic groups (1-5). The geographical distribution of the groups throughout the world is not well known. Five different PCR assays were developed in an attempt to amplify specifically TTV DNAs of each genomic group. Serum samples collected from 72 Brazilian adults (24 voluntary blood donors, 24 hepatitis B virus (HBV) carriers, and 24 human immunodeficiency virus type 1 (HIV-1)-infected patients) were tested. TTV DNA from at least one genomic group was detected in 11 (46%) blood donors, 13 (54%) HBV carriers, and 24 (100%) HIV-1 patients. All five genomic groups were detected in the three populations, with the exception of group 2 in blood donors. Some samples, negative with all five specific assays, were positive with the commonly used untranslated region (UTR) PCR system. On the other hand, TTV DNA was detected in some samples by using specific assays but not with the UTR PCR. Mixed infections with 2-5 TTV isolates from different groups were detected in 21% blood donors, 29% HBV carriers, and 71% HIV-1 patients. Fifteen PCR products (three obtained with each assay) were sequenced. Most sequences showed high (>86%) homology with those of TTV isolates belonging to their presumed groups. However, three sequences had low homology with all TTV sequences available from the DNA databanks. In conclusion, TTV isolates belonging to all five known genomic groups circulate in Brazil, and the results suggest the existence of new and as yet uncharacterised major genomic groups.

Prevalence and genetic diversity of TT virus genotype 21 (YONBAN virus) in Brazil.

Isolates of the newly characterized, single-stranded DNA virus TTV, have been tentatively classified into four major phylogenetic groups and at least 28 genotypes. Four Japanese isolates, designated as YONBAN viruses, belong to the fourth group and to genotype 21. In this study, a genotype 21-specific PCR assay was standardized. With this assay, 48/184 (26%) serum samples and 76/167 (46%) saliva samples, collected from unselected ambulatory patients (aged 2 to 82) of a Brazilian public hospital, were positive. A total of 110 (66%) patients had TTV genotype 21 DNA in serum, saliva, or both fluids. Furthermore, 18/37 (49%) serum samples, collected from Indians belonging to three ethnic groups of the Western Brazilian Amazon, were also positive. Nucleotide sequences (253 bases at the 3' end of the non-coding region of the genome) were determined, that derived from 25 individuals, i.e. 17 patients and eight Indians. Phylogenetic analysis showed that three isolates from Indians of a particular ethnic group formed a separate subgroup within genotype 21. Among non-Indians, a clustering of strains was observed according to their country of origin (Japan or Brazil), with all 17 sequences derived from Brazilian patients located in a unique subgroup.

Mixed infections of adults and children with multiple TTV-like mini virus isolates.

Testing of the DNA of TTV-like mini virus (TLMV) was done with serum samples obtained from 184 patients (children and adults) who visited different outpatient clinics at a university hospital in Florianopolis, south of Brazil. TLMV DNA was detected by PCR primers from the non-coding region of the genome. A global TLMV prevalence of 78% was found (94% among children below 11 years). PCR products from three serum samples (patients A-C) were cloned, and the sequences with a length of 201-227 nucleotides were determined for 16-19 clones derived from each of the sera. Among the 16 clones derived from patient C, 15 were identical, and the remaining one had a sequence homology of 99%. In contrast, eight different sequences were obtained among the 19 clones derived from patient A, and 10 distinct sequences were depicted among the 17 clones derived from the serum of patient B. Additionally, 13 clones derived from a saliva sample of patient B were sequenced, and seven different nucleotide sequences obtained. One particular sequence was predominant in both serum (8/17 clones) and saliva (7/13 clones) of patient B. On a phylogenetic tree, sequences derived from patient A (a 6-year-old boy), as well as those derived from patient B (a 24-year-old man), were located in five distinct evolutionary branches, taking a minimum divergence of 5% between branches. This suggested that adults and children are coinfected frequently with several TLMV isolates of different origins.