( Laboratory of Animal Virology, College of Animal Medical Science, Huazhong Agricultural University, Wuhan 430070;
¹ Laboratory of Molecular Cell Biology, College of Life and Technology Science, Huazhong Agricultural University, Wuhan 430070, China )

Abstract To study induction or inhibition of apoptosis by pseudorabies virus (PrV) Ea strain in suckling piglets, Aujeszky's disease was replicated by artificially inoculating 15 day-old piglets with PrV-Ea strain. Various tissue sections, such as lymphoid tissues and nervous tissues were collected. Transmission electron microscopy, DNA fragmentation assay and in situ terminal-deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining were carried to analyze apoptotic cells. It was shown that piglets infected with PrV-Ea strain took on typical clinical symptoms and apoptotic cells were found in lymphoid tissues but not in nerve tissues. The results indicated that the PrV infection caused apoptosis in a big number of lymphatic cells, thus leading to death of suckling pigs due to lowered immune function. It might play an important role in PrV's attack on immune system. A latent infection of pseudorabies virus was established in the neuronal tissue cells by inhibition of nervous cell apoptosis; this might be the way for PrV to establish latent infection, leading to sporadic recurrence of the disease.