By microarray analysis, TTV and related viruses were detected in 77% of the samples, from 7 different types of clinical samples. We believe this is the first report regarding the prevalence of TTV and related viruses in clinical samples from Denmark. These TTV viruses are reported to frequently infect humans, with as much as 100% in certain populations, but no direct evidence links them to any specific clinical disease [31] . They have circular genomes (cir ssDNA) and are efficiently amplified by the Phi29 polymerase through RCA.