New Phylogenetic Groups of Torque Teno Virus Identified in Eastern Taiwan Indigenes

Abstract

Torque teno virus (TTV) is a single-stranded DNA virus highly prevalent in the world. It has been detected in eastern Taiwan indigenes with a low prevalence of 11% by using N22 region of which known to underestimate TTV prevalence excessively. In order to clarify their realistic epidemiology, we re-analyzed TTV prevalence with UTR region. One hundred and forty serum samples from eastern Taiwanese indigenous population were collected and TTV DNA was detected in 133 (95%) samples. Direct sequencing revealed an extensive mix-infection of different TTV strains within the infected individual. Entire TTV open reading frame 1 was amplified and cloned from a TTV positive individual to distinguish mix-infected strains. Phylogenetic analysis showed eleven isolates were clustered into a monophyletic group that is distinct from all known groups. In addition, another our isolate was clustered with recently described Hebei-1 strain and formed an independent clade. Based on the distribution pattern of pairwise distances, both new clusters were placed at phylogenetic group level, designed as the 6th and 7th phylogenetic group. In present study, we showed a very high prevalence of TTV infection in eastern Taiwan indigenes and indentified new phylogenetic groups from the infected individual. Both intra- and inter-phylogenetic group mix-infections can be found from one healthy person. Our study has further broadened the field of human TTVs and proposed a robust criterion for classification of the major TTV phylogenetic groups.

Characterization of the human DNA gut virome across populations with different subsistence strategies and geographical origin

“…Indeed, the diffusion of Torque teno viruses in healthy human populations had already been observed as proven by their prevalence in serum samples of people of wide geographical origin (Takahashi et al, 1998;Huang et al, 2001;Muljono et al, 2001;Peng et al, 2002;Vasilyev et al, 2009). The ubiquitous presence of Torque teno viruses has also been recently confirmed in a study on a traditional Taiwan indigenous population (Hsiao et al, 2016). However, no abundance data were reported in these publications.…”

The Molecular Epidemiology and Phylogeny of Torque Teno Virus (TTV) in Jordan

“…TTV is a naked single stranded DNA virus, which belongs to the family Anelloviridae. Among the ten Anelloviridae genera [15,16], the genus Alphatorquevirus is especially widespread among human populations worldwide and has been classified into seven phylogenetic or genogroups which include at least 39 genotypes [8,17,18]. The TTV genogroups were defined using open reading frame 1 (ORF1) sequences [16]; however, it has been repeatedly demonstrated that primers specific for the 5 untranslated region (5 -UTR) are much more efficient in TTV detection than those specific to the ORFs of the TTV genome [19][20][21][22].…”

Development of an Immunoassay for Detection of Torque Teno Virus (TTV) Antibodies Using the N22 Expression Product from TTV Genotype 2

“…In fact, some PCR-negative samples produced positive signals in the dot blot assay. Possibly, these false-positive samples could represent: (1) cases of past infection where the active virus was already eliminated from the body at the time of collection of the blood sample but antibodies were still prevalent in the circulatory system, (2) samples containing very low viral titers that were beyond the limit of PCR detection, or (3) cases where the primer set was unable to pick one particular strain or genotype of TTV [14,39,40].…”

“…All of these viruses exhibit a high prevalence, a global distribution, and a high genetic variability [10,11]. The genetic variation represents the basis for the current classification of TTV isolates into more than 40 genotypes (> 30% nucleotide divergence) and 5 genogroups (> 50% nucleotide divergence) by use of phylogenetic analysis [12][13][14]. These numbers are continuing to increase with the introduction of new molecular techniques of higher sensitivity.…”