Torque teno virus review

It has recently been proposed that the level of TTV DNA in the blood of patients undergoing organ transplantation should be used as an endogenous marker of the body's immune status. The available data show the polytropism of the virus and deny the fact that TTV can be assigned exclusively to hepatitis viruses.

Fortunately, the rare detection of the damaging effect of TTV on hepatic and bile duct epithelial cells may be indirect evidence of its conditionally pathogenic properties. The ubiquity of the virus and the variability of its existence in humans cannot put an end to its study.

Keywords: Prevalence of torque teno virus; Torque teno virus; Torque teno virus and human immune status; Torque teno virus in liver disease; Virome and torque teno virus. Published by Baishideng Publishing Group Inc. Heterogeneity of TT virus related sequences isolated from human tumour biopsy specimens. Journal of Molecular Medicine Berlin, Germany , 80 1 , De Villiers, E. TTV infection in colorectal cancer tissues and normal mucosa [1].

International Journal of Cancer, 9 , Desai, M. Journal of Clinical Gastroenterology. Replication of TT virus in hepatocyte and leucocyte cell lines. Journal of Medical Virology, 77 1 , Garibyan, L. The Journal of Investigative Dermatology, 3 , e6. Hassuna, N. Intervirology, 60 3 , Heller, F.

Hettmann, A. Detection and phylogenetic analysis of torque teno virus in salivary and tumor biopsy samples from head and neck carcinoma patients. Hino, S. Torque teno virus TTV : Current status. Reviews in Medical Virology. Hsiao, K. New phylogenetic groups of torque teno virus identified in eastern Taiwan indigenes.

Hu, Y. Hussain, T. Virology Journal, 9 1 , Virology Journal, 9 1 , 1. Ikeda, H. Journal of Hepatology. Irshad, M. Torque teno virus: Its prevalence and isotypes in North India. World Journal of Gastroenterology, 14 39 , Iso, K. Mother-to-infant transmission of TT virus in Japan.

International Journal of Gynecology and Obstetrics, 75 1 , Izadi, S. Jentashapir Journal of Health Research, 7 3 , Jafari, M. Indian Journal of Pathology and Microbiology. Jalali, H. Kakkola, L. Virology, 2 , Kalkan, A. Japanese Journal of Infectious Diseases, 58 4 , Koohi, A. Phylogenetic analysis of Torque teno virus in hepatitis C virus infected patients in Shiraz. Hepatitis Monthly, 12 7 , Leppik, L. Journal of Virology, 81 17 , Lozano, R.

Global and regional mortality from causes of death for 20 age groups in and a systematic analysis for the Global Burden of Disease Study Lancet, Maggi, F. Journal of Virology, 77 4 , Magu, S. Incidence and clinical implication of TT virus in patients with hepatitis and its frequency in blood donors in India.

Medical Journal Armed Forces India, 71 4 , The high prevalence of Torque teno virus DNA in blood donors and haemodialysis patients in southern Brazil. Mi, Z. High-throughput sequencing exclusively identified a novel Torque teno virus genotype in serum of a patient with fatal fever. TT virus genomic size varies among isolates. Approximately the genome is about 3. The genome has a coding region of approximately 2. It contains a GC-rich region of about nucleotides which is present in all isolates.

Despite TT virus sequence variability among isolates, the ORF1 is found in all isolates and encodes a capsid. The mechanism by which TT virus replicates is still unknown. It is assumed that replication in TT virus is similar to that of other circular single stranded DNA viruses.

It was suggested that only a minor fraction of the TT viruses have all the components required for a successful infection or that a co infection of isolates brings the necessary component together. It is globally dispersed and can be detected in blood and blood products, in semen, water, cord blood, faeces, breast milk, throat swabs, nose swabs, saliva etc.

TTV infections are extremely prevalent both in healthy individuals and diseased patients but no definitive causal association with TTV infection has been found for any of the diseases investigated. The ubiquitous nature of this virus raises the speculation whether the virus is pathogenic, opportunistic, a cofactor of other infections or a modulator of immunity that can promote other virus to be infectious. Ever since the discovery of this virus, several studies have being done to understand the biology of this virus, its mechanism of infection and replication, association with any disease, the immunology of infection and the prevalence in different human tissues and study groups.

The true identity of TT virus will still remain a puzzle until a suitable cell culture system is developed to study its biological characteristics. TTMV was found to be about 2. The patients presented with post transfusion hepatitis of unknown etiology. Further investigation also revealed that the patients had elevated alanine aminotransferase levels ALT after transfusion.