Distribution and genetic analysis of TTV and TTMV major phylogenetic groups in French blood donors.

TTV and TTMV (recently assigned to the floating genus Anellovirus) infect human populations (including healthy individuals) at high prevalence (>80%). They display notably high levels of genetic diversity, but very little is known regarding the distribution of Anellovirus genetic groups in human populations. We analyzed the distribution of the major genetic groups of TTV and TTMV in healthy voluntary blood donors using group-independent and group-specific PCR amplifications systems, combined with sequence determination and phylogenetic analysis. Analysis of Anellovirus groups revealed a non-random pattern of group distribution with a predominant prevalence of TTV phylogenetic groups 1, 3, and 5, and of TTMV group 1. Multiple co-infections were observed. In addition, TTMV sequences exhibiting a high genetic divergence with reference sequences were identified. This study provided the first picture of the genetic distribution of the major phylogenetic groups of members of the genus Anellovirus in a cohort of French voluntary blood donors. Obtaining such data from a reference population comprising healthy individuals was an essential step that will allow the subsequent comparative analysis of cohorts including patients with well-characterized diseases, in order to identify any possible relationship between Anellovirus infection and human diseases.