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Background: Torque teno virus (TTV) is a widespread anellovirus that establishes persistent infections in humans and represents the most abundant component of the human virome. TTV encodes microRNAs (miRNA) which are found both in viremic and not viremic subjects being potentially ideal tools for the virus to evade the immune system response and to maintain chronic infection in the host., Objective: To investigate TTV-DNA loads and TTV-miRNAs expression in cerebrospinal fluids (CSF) from subjects under analysis for the assessment of neurological diseases., Study Design: Detection of TTV-DNA and TTV-miRNAs (e. g. miRNA t1a, t3b, and tth8) were carried out from CSF samples of 93 subjects with neurological diseases by using universal real-time PCR, real-time RT-PCR, and next-generation sequencing (NGS) analyses., Results: TTV-DNA was detected in 11 of 93 (12 %) CSFs with a mean TTV load of 155 copies/mL. Conversely, 29 CSF samples (31 %) were positive for at least one TTV-miRNA, while 15 (16 %) CSFs contained all the TTV-miRNAs examined. Overall, TTV-miRNA tth8 was detected in 62 % of samples, followed by TTV miRNA t3b (56 %), and t1a (29 %). Interestingly, TTV-miRNAs were found in CSF samples that were negative for the presence of TTV-DNA. Next-generation sequencing analysis carried out from 4 TTV-DNA negative CSF samples detected reads mapped in TTV-miRNA sequences region., Conclusions: These results shed novel light on the relationship between TTV and the central nervous system and make compelling furthered studies for investigating the potential role of TTV-miRNAs in neurological disorders., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Torque teno viruses (TTV) are small DNA viruses whose replication is closely linked to immune status. A growing number of publications underlined the potential of TTV viral load as an indicator of immunosuppression., Objectives: To demonstrate the analytical performance of the first standardized RUO (Research Use Only) assay to detect and quantify human TTV DNA in whole blood and plasma., Study Design: We established analytical performances for TTV load measurement in various populations. The TTV kinetics were followed in kidney recipients. TTV viral load was analyzed on whole blood samples from 42 kidney recipients follow-up, 53 kidney deceased donors and 31 healthy volunteers., Results: The qPCR TTV assay detects the most prevalent human TTV genotypes and does not cross react with other viruses. Limit of detection was 2.2 log 10 copies/mL in whole blood and plasma, linearity and precision were demonstrated over the range 1.61 to 10.61 log 10 copies/mL in whole blood. Prevalence of TTV DNA in blood differed significantly among groups: 45% in healthy volunteers, 74% in donors and 83% in kidney recipients. In kidney recipients, early TTV kinetics were comparable to those previously observed with in-house assays in other transplant settings: viral load increased from an average of 4.3 log 10 to 7.9 log 10 copies/mL within the first 75 days post transplantation., Conclusion: This TTV assay showed high analytical sensitivity, specificity, linearity and precision. It is a useful standardized tool to further evaluate TTV load as a biomarker of immune status that could improve individual treatment strategy., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Rolling-circle amplification-sequence-independent single primer amplifications (RCA-SISPA) and/or RCA-PCR-based approaches were applied to serial human plasma and animal (domestic cat) saliva samples. Complete SENV-H-related and PRA4 Anelloviridae genomes were characterized and analysed over time (~16 and 6.5years for human and animal samples, respectively). Genomic sequences and deduced putative coding regions were compared. Comparable values, i.e. ~2×10 -4 subs/site/year, were obtained for estimated rates of non-synonymous substitutions. A "hot-spot" of mutations located on the SENV-H-related ORF1 was identified. These results are first data concerning Anelloviridae evolution in a human and an animal host based on the analysis of complete sequences., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: Data regarding the influence of the APOBEC3B deletion on infectious diseases remain limited and shown discrepancies., Objectives: To characterize the APOBEC3B deletion polymorphism status and its association with prevalence of co-infection with blood-borne pathogens in Indonesian HIV-infected individuals., Materials and Methods: A total of 597 HIV-positive blood samples were tested for the hepatitis B virus (HBV), hepatitis C virus (HCV), Torque Teno virus (TTV), GB virus-C (GBV-C), and Toxoplasma gondii. Nucleic acid was extracted from plasma samples and used for the molecular detection of HIV RNA, HBV DNA, HCV RNA, TTV DNA, and GBV-C RNA, whereas HBsAg, anti-HCV, IgM and IgG anti-T. gondii were detected through serological testing. The APOBEC3B deletion polymorphism was genotyped by polymerase chain reaction (PCR)., Results: The deletion genotype was associated with HCV viremia (p<0.001) as well as elevated IgG anti-T. gondii (adjusted OR [aOR]=3.4). The deletion genotype was also associated with decreased levels of HBsAg (aOR=0.03), and anti-HCV (aOR=0.1). D/D was frequently found in HIV-infected individuals with CD4+T cells<14% (aOR=5.8). The intact genotype was associated with a reduced likelihood of a CD4+T cell count<200 cells/μL (aOR=0.2) but a higher prevalence of TTV co-infection (aOR=8.6)., Conclusions: The APOBEC3B deletion polymorphism was found to be associated with HBV, HCV, TTV, and T. gondii co-infection in Indonesian HIV-infected individuals., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The study describes a novel rolling circle amplification (RCA) assay to detect members of the family Anelloviridae from swine and human serum samples. The RCA was carried out using short anellovirus (AV)-specific primers based on a highly conserved region among available AV full-length genomes. Then, RCA products were used as templates to amplify full-length genomes with an AV-specific PCR. Amplification products were separated by agarose gel electrophoresis and full-length genomes were isolated based on the known size. With this novel AV-RCA/PCR approach it was possible to detect Torque teno sus virus 1 (TTSuV1) and Torque teno sus virus 2 (TTSuV2) in swine and many species of Torque teno virus (TTV) in human sera, which were previously tested negative by conventional PCRs., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Porcine Torque teno virus (TTV) has a single-stranded circular DNA genome and is currently classified into a new genus Iotatorquevirus with two species in a newly established family Anelloviridae. Viral DNA of both porcine TTV species (TTSuV1 and TTSuV2) has a high prevalence in both healthy and diseased pigs worldwide and multiple infections of TTSuV with distinct genotypes or subtypes of the same species has been documented in the United States and in Europe. However, the prevalence of specific TTSuV antibodies in pigs remains unknown. In this study, the putative ORF1 capsid protein from TTSuV2 isolate PTTV2c-VA was expressed in Escherichia coli. The purified recombinant ORF1 protein was used as the antigen for the development of Western blot and indirect ELISA to detect TTSuV2-specific IgG antibodies in pig sera. The results revealed a relatively high rate of seropositivity to TTSuV2 in conventional pigs from different sources but not in gnotobiotic pigs. Overall, pigs with undetectable TTSuV2 viral load were more likely to have a lower anti-TTSuV2 antibody level. An analysis of 10 conventional pigs during a 2-month period showed that decreased viral loads or presumed virus clearance were associated with elevated anti-ORF1 IgG antibody levels. Interestingly, porcine circovirus associated disease (PCVAD)-affected pigs had a significantly lower level of TTSuV2 antibody than PCVAD-unaffected pigs (p<0.01). This is the first study to establish essential serodiagnostic tools for investigation of TTSuV seroprevalence and infection dynamics, which will help elucidate the potential pathogenicity of TTSuV infection in pigs., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Background: To commence proper antiviral treatment, timely knowledge of whether the infection is caused by DNA or RNA virus would be beneficial for the clinician., Objectives: Our objective was to develop a method for distinguishing between DNA and RNA virus infections., Study Design: In this prospective study, total and differential count of leukocytes, serum C-reactive protein level, erythrocyte sedimentation rate, and quantitative flow cytometric analysis of FcgammaRI (CD64) on neutrophils and monocytes were obtained from 289 hospitalized febrile patients. After microbiological confirmation, 89 patients (31%) were found to have either bacterial (n=46) or viral (n=43) infection. The patient data was compared to 60 healthy controls., Results: For the first time ever, it was noticed that in dsDNA virus infections (n=21) the average amount of CD64 on neutrophils was over five-fold compared to ssRNA virus infections (n=22)., Conclusions: DNA virus score (DNAVS) point, which incorporates quantitative analysis of CD64 on neutrophils and total and differential count of leukocytes, varied between 0 and 8, and displayed 95% sensitivity and 100% specificity in distinguishing between dsDNA and ssRNA virus infections [average (S.D.); DNAVS points: 5.4 (2.5) vs. 0.3 (0.4); p<0.001].

Background: Little is known about the pathogenic role and the endemic situation of transfusion transmitted virus (TTV)., Objectives: In this study, a molecular assay for detection of TTV based on automated nucleic acid extraction and real-time PCR was developed and evaluated. The new assay includes an internal control., Study Design: After optimization of the molecular assay, 103 clinical samples were studied retrospectively. All sera had been tested for anti-HCV and anti-HIV-1 antibodies earlier., Results: The amplification efficiency was found to be 102%. When clinical specimens were tested, 79 of 103 serum samples were found to be positive for TTV. There was no significant difference between various groups of patients. The internal control was detected in all negative and weak positive samples., Conclusions: This molecular assay proved to be suitable for routine detection of TTV in clinical samples. Moreover, a relative statement on the TTV serum load can be done.