The present invention relates to nucleic oligomer primers or probes useful for detection of TTV in test samples. Also provided are assays which utilize these primers and probes, as well as test kits which contain these oligomer primers and/or probes. In addition, the present invention encompasses the use of TTV nucleotide sequences as nucleic acid vectors and as markers for determining transmission between individuals as well as the route thereof. Additionally, the present invention encompasses a method of detecting TTV infection prior to xenotransplatation of a tissue or organ.