Diagnosis of Mixed Infections with Pseudorabies Virus and Classical Swine Fever Virus in A Pig Farm

The swine were initially diagnosed as mixed infection with Porcine pseudorabies virus(PRV)and Classical swine fever virus(CSFV)in a farm of Shandong through the clinical examination and combining with the local epidemiology and the vaccine inoculation status.Therefore,the lesion tissues of sick swine were collected and treated by routine method in laboratory.Sequentially,the total DNA and RNA were extracted and analyzed by PCR.The 217bp fragment and 510bp fragment were obtained through PCR and RT-PCR,that demenstrated that the swine co-infected with PRV and CSFV in the farm.The PRV and CSFV were isolated and cultured in BHK-21 cells and PK-15 cells independently.The results showed that BHK-21 cells displayed the typical PRV CPE and the cell cultures were further identified as PRV positive by PCR technology.Furthermore,the TCID50 of PRV cell cultures was determined as 106.68 TCID50/0.1mL.On the other hand,the cell cultures were identified as CSFV positive after three passages since the lisions were inoculated in PK-15 cells.Based on the above results,the swine in the farm were diagnosed as CSFV and PRV mixed infection finally.The swine were inoculated with PRV and CSFV emergently and some swine were emilinated.The curative effect was satisfactory,and the economic loss was reduced.