猪瘟病毒FJFQ-39株的毒力鉴定

Virulence evaluation of classical swine fever virus FJFQ-39 strain

为探索一种相对客观、稳定的方法鉴定猪瘟病毒(CSFV)FJFQ-39株的毒力。本研究采用2×103TCID50的FJFQ-39株分别肌肉接种6头敏感猪,通过RT-nPCR检测扁桃体和血液监测动物感染情况,对动物临床症状和病理变化进行系统评分,结合体温分析,判定病毒毒力。同时用相同剂量的石门株接种4头敏感猪作对照。FJFQ-39和石门接种猪的扁桃体和血液均检测到CSFV核酸;FJFQ-39接种猪的最大临床症状评分(CS)平均值为3.53.5±1.0、病理评分(PS)平均值为3.3±0.9(低于5),平均最高体温为39.3±0.2℃(低于40℃);石门接种猪的最大CS平均值为25.5±2.1、PS平均值为29.5±2.4(大于15),平均最高体温为41.8±0.2℃(高于41.0℃)。实验结果表明:猪瘟病毒FJFQ-39株和石门株均成功感染了动物;评分系统结合体温测定评价CSFV毒力是可行的;FJFQ-39属于低毒力株,而石门属于强毒株。

To determine the virulence of classical swine fever virus （CSFV） FJFQ-39 strain, healthy piglets were inoculated with 2 × 10^3 TCID50 of FJFQ-39 and compared with those infected by Shimen strain. Blood and tonsil samples were collected every 3 days and CSFV nucleic acids were detected by RT-nPCR to monitor the occurrence of animals＇ infection. Clinical scores （CS）, pathological scores （PS） and body temperatures of animals were recorded to determine the virulence of viruses. The results showed that CSFV nucleic acids could be detected out in samples from all animals. In piglets inoculated with FJFQ-39, the peak value of CS and PS were 3.5 ± 1.0 and 3.3 ± 0.9 respectively, with the highest body temperature of 39.3 ± 0.2 ℃ ; while piglets infected by Shimen strain virus showed a peak CS 25.5 ± 2.1 and PS 29.5 ± 2, with the highest body temperature of 41.8 ± 0.2 ℃. This method was successfully used to evaluate the virulence of FJFQ-39 as low virulent strain and Shimen strain as a highly virulent sWain, which could be useful in differenciating the virulent of CSFV starins.