by the oral route , ppv took 23-32 days to cross the placenta following infection of the dam , as compared to 15 days by the i.m . route , successful transplacental infection occurred following oral infection of dams only in the second third of gestation , whilst i.m . infection resulted in infection of foetuses in both first and second thirds of gestation .
C1527415
oral route
C0013153
route