Preliminary Study On Mutiplication Characteristics Of Epedemic CSFV Of Guangxi

The objective of the study was to investigate the multiplication characteristics and differences of epidemic CSFV of Guangxi in vivo and in vitro. Spleen and lymph node samples from 8 CSFV swine in Guangxi were diagnosed by RT-PCR test, 3 of which, samples from Wuzhou(GXWZ1), Bobai(GXBB4) and Beihai(GXBH1), were CSF positive. CSFV from these strains, together with Shimen and C strain, were investigated in this study.The multiplication of CSFV and Shimen, which were all acute CSF , caused the similar pathologic changes, clinical symptoms and temperature fluctuation in swine. The pathologic changes were very representative and the temperature of swine rose up to 41℃, indicating a continued fever. The multiplication characteristics of CSFV and in swine showed that they were moderate CSFV, which caused longer course of diseases and more classical pathological changes than CSFV and. And the swine temperature fluctuated under 40.5℃.Indirect Immunofluorescence test and Immunoperoxidase test were carried out to detected the distribution of CSFV in PK-15 cell. Results showed that it was mainly located around the karyotheca, endoplasmic reticulum and dictyosome. TCID50 of each CSFV was detected by Immunoperoxidase test and 200TCID50 of each CSFV was applied to infect the PK-15 cell. Secreted virus and cell-associated virus was collected at 12h, 24h, 36h, 48h, 60h, 72h and 96h, liter of which was detected and growth curves were drawn to investigate the CSFV multiplication characteristics in PK-15 cell. The results showed that the CSFV GXBB4 and C strain secreted more virus than any other CSFV at 60h and 72h, titer of which was 107.3/ml and 107/mlrespectively. And the CSFV Shimen and GXWZ1 each secreted 1065/ml and 1058/ml of virus at the time, while the GXBH1 secreted the least, only 105/ml. The liter of cell-associated virus of each CSFV rarely differed within 96h, which all roughly rose at 12h and reached around 106/ml in the end.The results of the study indicated the variations of virulence and multiplication characteristics might have occurred in some strains of CSFV in Guangxi.