猪繁殖与呼吸综合征疑似病例实验室诊断

Laboratory Diagnosis of Porcine Reproductive and Respiratory Syndrome Cases

为确诊铜仁市郊区部分养猪场发生的猪繁殖与呼吸综合征(PRRS)疑似病例,开展了临床症状与剖检病变观察和PRRS病原核酸与血清抗体检测,结果显示,患猪体温升高达41.5℃、咳嗽、打喷嚏、呼吸困难、耳和四肢皮肤发绀,妊娠母猪流产、产死胎或弱仔等;剖检可见肺淤血出血呈肉样变、脾边缘丘状出血或梗死、肾点状或块状出血呈雀斑肾、淋巴结出血呈大理石样变等;免疫猪群PRRSV抗体阳性率为44.1%,而未免疫猪群PRRSV抗体检出率为33.9%;采用PRRSV N基因特异性引物和PRRSV变异毒株检测试剂盒进行RT-PCR扩增,均可得到与预期大小相一致的特异性片段。以上结果表明,该次疫情是由高致病性PRRSV感染所致,且未免疫猪群普遍存在PRRSV隐性感染。

To diagnose cases of suspected PRRS happened in some pig farms of Tongren city suburb on August 2012, some of serum samples and tissue materials were collected and used for detection of the serum antibody and the pathogen nucleic acid after observation of the clinical symptoms and pathological lesions. The results showed as following： The sick pigs were observed with characteristics of PRRS, such as the temperature rise, cough, sneeze and dyspnea, the cyanosis of skin in limbs and ears, the reproductive dis- orders as miscarriage, stillbirth and weak piglets in the pregnant sows; And the visible anatomy changes with congestion and hemorrhage of lung like meat, hemorrhage or infarction in the marginal of spleen, punctate or massive hemorrhage of kidney as freckle, hemorrhage of lymph node like marble, etc. The positive rates of anti- PRRSV antibody was 44. 1% in the immune herd, but the detected rates of anti- PRRSV antibody reached 33.9 % in the un-immune herd. The specific fragments of PRRSV gene were obtained by RT-PCR amplification using the specific primers of PRRSV N gene and the detection kit for the varied PRRSV strain. These results indicated that the outbreak diseases in some pig farms in Tongren city suburb was caused by the highly pathogenic PRRSV, and the latent infection of PRRSV was popularly existed in the um-immune herd.