ENTERIC LESIONS INDUCED BY DIFFERENT PSEUDORABIES (AUJESZKYS-DISEASE)VIRUS-STRAINS INOCULATED INTO CLOSED INTESTINAL LOOPS OF PIGS

Three different strains of pseudorabies (Aujeszky's disease) virus wer e inoculated into ligated closed loops in the jejunum and ileum of fiv e specific-pathogen-free pigs. Infected areas were compared with respe ct to distribution of histologic lesions and pseudorabies virus antige n. Two wild-type strains of pseudorabies virus produced enteric lesion s consisting of necrosis of the subepithelial macrophages in the basil ar crypt epithelium, necrosis of the lymphoid follicles in the Peyer's patches, degeneration of the epithelial cells in the crypt and villi, degeneration of the neuronal cells in the myenteric plexuses, and for mation of intranuclear inclusion bodies on postinoculation days 2-4. P seudorabies virus antigen was initially detected in subepithelial macr ophages of the dome of Peyer's patches on postinoculation day 2 and su bsequently extended to superficial epithelium and deeper into the lymp hoid follicles and myenteric plexuses on postinoculation days 3-4. Man y pseudorabies virus particles were also detected in the center of the ir necrotic foci. However, 1 mutant strain (ara-T-resistant) of pseudo rabies virus did not produce enteric lesions. The results suggest that the primary target of infection by wild-type strains of pseudorabies virus might be the macrophages distributed in the subepithelial area o f the dome Peyer's patches.