Human anelloviruses: diverse, omnipresent and commensal members of the virome

Abstract

Anelloviruses are small, single stranded circular DNA viruses. They are extremely diverse and have not been associated with any disease so far. Strikingly, these small entities infect most probably the complete human population, and there are no convincing examples demonstrating viral clearance from infected individuals. The main transmission could be via fecal-oral or airway route, as infections occur at an early age. However, due to the lack of an appropriate culture system, the virus–host interactions remain enigmatic. Anelloviruses are obviously mysterious viruses, and their impact on human life is not yet known, but, with no evidence of a disease association, a potential beneficial effect on human health should also be investigated.

High-Depth Viral Blood Metagenomics Reveals Extensive Anellovirus Diversity in Healthy Humans

“…Together with previous studies, our result show that the diversity of anelloviruses is particularly remarkable in comparison with other viral families 9 . The fact that human and non-human primate isolates cluster phlylogenetically 38 suggests that anelloviruses are an ancient family, and that the genetic diversity of this family is the consequence of millions of years of evolution.…”

“…Human anelloviruses, and probably most members of this family, seem to be essentially innocuous 17 . Indeed, potentially beneficial effects on human health have been suggested 9 . For instance, infection of newborns 61 could promote the development and maturation of the immune system 17 .…”

“…Viral metagenomics has been used to identify viral agents causing disease outbreaks or associated with specific symptoms 2,3 , to study the virosphere diversity [4][5][6] , and to address specific aspects of viral evolution 7,8 . Many of the newly discovered viruses are not associated with any disease and are consequently called "orphans" 9 . The family Anelloviridae provides the clearest example, since only one member of the genus Gyrovirus has been confirmed to cause disease in chickens 10 , despite an increasing number of anelloviruses being discovered in wild and domestic animals [11][12][13][14][15] .…”

Deep viral blood metagenomics reveals extensive anellovirus diversity in healthy humans

“…Viral metagenomics has been used to identify viral agents causing disease outbreaks or associated with specific symptoms 2 , 3 , to study the virosphere diversity 4 – 6 , and to address specific aspects of viral evolution 7 , 8 . Many of the newly discovered viruses are not associated with any disease and are consequently called “orphans” 9 . The family Anelloviridae provides the clearest example, since only one member of the genus Gyrovirus has been confirmed to cause disease in chickens 10 , despite an increasing number of anelloviruses being discovered in wild and domestic animals 11 – 15 .…”

Current Views of Torque Teno Virus (TTV) in Liver Diseases

“…Некоторые авторы называют вирус непатогенным и, более того, выделяют его как часть человеческого вирома [12,[161][162][163][164]. Это суждение обосновывают главным образом невозможностью связать заражение вирусом с развитием конкретного заболевания.…”