Research on Swine High Fever without Confirmed Pathogen(II)——Isolation、Identification and Pathogenic Test about Porcine Reproductive and Respiratory Syndrome virus

A virus strain was isolated by Marc-145 cell lines from dead pigs with swine high fever disease in south China.The virus was identificated by serological neutralization,RT-PCR and electricitic microscope,the result showed that it was porcine reproductive and respiratory syndromevirus(PRRSV).13/16 healthy pigs(55~105 days) were infected by the PRRSV,and in order to reinforced the infection,7/13 pigs were injected by Escherichia coli(E.coli).Body temperature was measured and clinic symptoms were noted ereryday.6/6 pigs in the group infected by PRRSV appeared classical symptoms,and 5/6 died.7/7pigs in the group challenged by PRRSV and E.coli appeared classical symptoms,5/7 died.3/3 contagion pigs appeared classical symptoms,and 1/3 died.All the infected pigs'temperture risesd in 2~4 d,most pigs died in 34~50 d.Interstitial pneumonia,carnification,haemorrhage in all dead pigs' lung,are the features of anatomy,The result indicated that PRRSV was the major cause of swine high fever without confirmed pathogency in south China,although there were different feature in our laboratary with some disease prevalence areas in south China.