| Pseudorabies virus (PRV), or suid herpes virus I, is a member of Alphaherpesvirinae, herpesviridae, which can cause Aujeszky's disease in swine, bovine, sheep and wild animals. PRV infection could cause its natural and main storing host-swine (also its main infectious origination) a huge loses, the most huge economical lose in all swine infectious diseases except Classic Swine Fever and Food and Mouth Disease.About 3550 sera samples from east china during the four years from 2002 to 2004 were detected with the IDEXX indirect ELISA Kit which can distinguish the vaccination from wild-type virus infection. The serological data were analysed systematically. The results showed that the PRV infection is very popular in east china region .In order to effectively differentiate between gene-deleted vaccine and wild-type isolates of Pseudorabies virus(PRV), the PCR method, based on sequences of gE and gI of the PRV genome, had been established after selection of the optimal reaction conditions. We applied the PCR to detect 285 tissue samples from 47 pig farms in Jiangsu, An'hui, Zhejiang, Jiangxi, Fujian and Shanghai during 2002-2004, wild-type isolates of PRV were found in 76 tissue samples (26.67%) and 24 pig farms(51.06%). PRV distributed widely in naturally infected pig's tissues including brain, liver, spleen, kidney, lung and lymph nodes. The PRV positive detection rate in lymph nodes was the highest in all tissues examined and reached 83.33%. The established PCR method provided a more sensitive, specific and reliable method to detect rapidly wild-type PRV and epizootic study of PRV.According to the relevant sequences of PRRSC ORF7, PCV-2 ORF2, CSFV E2, JEV E and PPV ORF2 on the GeneBank, four pairs of specific primers were designed for the co-infection detection of other reproductive failure diseases in 87 samples from seven provinces of east china, which were PRV positive. The result shows that PRV, PCV-2, PRRSV and CSFV coinfection is very popular in the pig farm in east china.Three partial gI and gE gene sequences obtained from PRV infected pig tissue samples in jiangsu province were compared with other PRV isolates in the Genbank,by use of the software of Dnastar. The results indicated that three PRV isolates sequenced in the present study are closely related to other PRV isolates in the Genbank, displaying 97.2%~100% nucleotide sequence identities and 70.8-100% amino acid sequence identities. Phylogenetic analysis revealed that all of three PRV isolates in jiangsu province in the present study are closely related and belong to the same groups. Kunshan isolate were 100% homologous with SH strain (AY683136). Jurong isolate were closely related to LA strain (AY173125S2). Nanjing isolate have the highest homologous with Ea strain (AF171937).
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