In utero transmission of porcine torque teno viruses.

Sera and selected tissue homogenates collected from gnotobiotic swine never exposed to the environment or other swine tissues were tested for the presence of porcine torque teno virus (TTV) DNAs by nested and non-nested polymerase chain reactions (PCR) using primers specific for the untranslated region of porcine genogroups (g) 1 and 2. Twenty-three of 105 (21.9%) gnotobiotic piglets were g1- and/or g2-TTV DNA positive. Twenty-three of 27 (85.2%) sow sera, collected at the time of Caesarian derivation of the litters contained either or both TTV genogroup DNAs. These data demonstrate that porcine TTV may be transmitted to piglets by the in utero route and that the incidence of fetal infection is high.