Abstract：
Swine disease elimination programs for Mycoplasma hyopneumoniae are commonly applied in the North American swine industry and may include the aerosolization of medium containing lung tissue to achieve population exposure prior to start. Field data has indicated M. hyopneumoniae PCR detection in pigs beyond 240 days post-herd closure (dphc; planned end of an elimination program) and is thought to contribute to disease elimination programs\' failure. Here, the duration of M. hyopneumoniae detection in sows and replacement gilts following aerosolized lung homogenate exposure, as part of a dual disease elimination program, was determined. A subset of sows and gilts from a commercial sow herd and off-site gilt development unit were longitudinally sampled to collect deep tracheal catheter secretions at various times post-exposure. Samples were tested for M. hyopneumoniae using a species-specific real-time PCR. A proportion of 58, 51, 52, 19, and 2% females were detected positive at 30, 60, 120, 180 and 240 dphc, respectively. Noteworthy, a greater proportion of gilts exposed at the off-site GDU were detected PCR positive for M. hyopneumoniae at each sampling event, compared to sows. In this study, assaying for genetic material in live female pigs showed extended detection of M. hyopneumoniae until at least 240 dphc. This data suggests persistence of M. hyopneumoniae longer than previously reported and highlights the importance of performing diagnostic testing to confirm negativity to the bacterium, prior to opening sow herds, especially late in the herd closure timeline.
摘要：
猪肺炎支原体的猪疾病消除程序通常应用于北美养猪业，可能包括对含有肺组织的培养基进行雾化，以在开始之前实现人群暴露。现场数据表明猪肺炎支原体PCR检测在猪群关闭后超过240天（dphc；计划结束的消除计划），并被认为是导致疾病消除计划失败的原因。这里,雾化肺匀浆暴露后母猪和替代母猪猪肺炎支原体检测的持续时间，作为双重疾病消除计划的一部分，已确定。对来自商业母猪群的母猪和后备母猪的子集进行了纵向采样，以在暴露后的不同时间收集深层气管导管分泌物。使用物种特异性实时PCR测试样品的猪肺炎支原体。在30、60、120、180和240dphc时，有58、51、52、19和2％的女性检测到阳性，分别。值得注意的是,在每个采样事件中，在场外GDU暴露的小母猪被检测到猪肺炎支原体PCR阳性的比例更高，与母猪相比。在这项研究中,在活的雌性猪中检测遗传物质显示，猪肺炎支原体的检测延长到至少240dphc。该数据表明猪肺炎支原体的持久性比以前报道的更长，并强调了进行诊断测试以确认细菌阴性的重要性。在开放母猪群之前，尤其是在群体关闭时间表的后期。
