Fig. 7From: Construction of a quadruple gene-deleted vaccine confers complete protective immunity against emerging PRV variant challenge in pigletsPathological changes in piglets after PRV GDFS challenge. Autopsy was performed on all dead and surviving piglets. The brains and tonsils were collected from the pigs and subjected to pathological observation. The red arrow represents cerebral vascular hemorrhage in the brain or ulcer of the tonsilBack to article page