Polymerase chain reaction analysis demonstrated the presence of PTV RNA in the CNS , tonsils and large intestines of 21 of the 22 pigs inoculated .
Direct CNS invasion via the blood vessels appears to be a major route of infection for PTV .
Polymerase chain reaction analysis demonstrated the presence of PTV RNA in the CNS , tonsils and large intestines of 21 of the 22 pigs inoculated .
Direct CNS invasion via the blood vessels appears to be a major route of infection for PTV .