不同种类呼吸道样品活体检测猪肺炎支原体抗原和抗体的比较分析

Comparative analysis of detecting antigen and antibody of Mycoplasma hyopneumoniae in different respiratory tract samples in vivo

猪支原体肺炎是由猪肺炎支原体(Mhp)引起的猪的一种慢性呼吸道疾病,Mhp基础感染率的监测对于及时实施控制措施和评估防控与净化效果至关重要。为了解在活体检测过程中的不同采集时间、样品类型和检测方法对猪肺炎支原体感染诊断结果的影响,本研究通过ELISA和实时定量PCR方法检测了来源于某大型养殖场的断奶仔猪、保育猪、屠宰猪、后备猪和种猪群活体采集的鼻拭子、喉拭子和咽拭子样品中的Mhp黏膜sIgA抗体和Mhp抗原。结果:鼻拭子、喉拭子和咽拭子样品总体的黏膜抗体阳性率分别为63.23%、62.55%和47.27%,抗原阳性率分别为74.75%、65.91%和63.64%。从不同的生产阶段看,保育猪和屠宰猪群中Mhp黏膜sIgA抗体阳性率较高,而断奶仔猪群中Mhp黏膜sIgA抗体阳性率最低。Mhp抗原的检出率随着猪群生产日龄的增加而增加,屠宰猪群和后备猪群鼻拭子和喉拭子中Mhp抗原阳性率达到峰值,种猪群中的抗原检测率出现了下降。对于鼻拭子样品中抗原与抗体的检测,从断奶仔猪至屠宰猪阶段,Mhp黏膜sIgA抗体的检出率更高,而后备猪群的抗原检出率更高。研究表明,在临床生产实际中,对于Mhp感染的活体检测,相较于喉拭子和咽拭子样本,鼻拭子样品对不同生产阶段猪群均具有更好的采集便利性与检测适用性。为了提高检测敏感性与准确度,黏膜sIgA抗体检测更适用于保育及生长育肥猪群,而定量PCR检测抗原则更适用于育肥后期以及后备猪群。

Enzootic pneumonia(EP)is a chronic respiratory disease in swine caused by Mycoplasma hyopneumoniae(Mhp).The disease has caused significant economic losses to the pig industry globally.Monitoring the basic infection rate of Mycoplasma hyopneumoniae in pigs is very important for timely implementation of control measures and evaluation of the effect of prevention,control and purification of the disease.In order to determine the influence of different collection times,sample types and detection methods on the in vivo diagnosis of Mycoplasma hyopneumoniae infection,the specific mucosal sIgA antibody and antigen against Mhp infection were detected by ELISA and real-time quantitative PCR,respectively.The nasal,laryngeal and oropharyngeal swab samples were collected from weaned piglets,nursery pigs,slaughtered pigs,replacement gilt and breeding pigs in a large-scale breeding farm.The results were as follows:The positive rates of mucosal antibodies in the nasal,laryngeal and oropharyngeal swab samples were 63.23%,62.55%and 47.27%,respectively;and the positive rates of the antigens were 74.75%、65.91%and 63.64%,respectively.In different production stages,the positive rate of the Mhp mucosal s Ig A antibody was all higher in the nursery pigs and slaughtered pigs,but the positive rate of the Mhp mucosal s Ig A antibody was the lowest in the weaned piglets.The detection rate of the Mhp antigen increased synchronously with the increase of pig production days.The positive rate of the Mhp antigen in the nasal swabs and laryngeal swabs of the slaughtered pigs and replacement gilt reached the peak,but the detection rate of the Mhp antigen in the breeding herd decreased.Comparison of the detection rates of the antigen and antibody in the nasal swab samples showed that the detection rate of the s Ig A antibody in Mhp mucosa was higher in the period from the stage of weaning to that of slaughtering,while the detection rate of the antigen in the replacement gilt was higher.The present results indicated that nasal swab samples had the advantages of easier collection and applicability in detection of Mhp infection in vivo at different production stages than did the laryngeal and oropharyngeal swab samples in clinical production.In improving the sensitivity and accuracy of detection,the detection of the mucosal s Ig A antibody would be more appropriate for nursery pigs and growth finishing pigs,but the detection of the antigen by quantitative PCR would be more suitable for pigs at a later stage of fattening and replacement gilt.