Persistence of Mycoplasma hyopneumoniae sequence types in spite of a control program for enzootic pneumonia in pigs
Persistence of Mycoplasma hyopneumoniae sequence types in spite of a control program for enzootic pneumonia in pigs
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DOI：
10.1016/j.prevetmed.2017.06.007
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发表时间：
2017-09-15
影响因子：
2.6
通讯作者：
Kuhnert, Peter
中科院分区：
文献类型：
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作者：
Overesch, Gudrun;Kuhnert, Peter
由支原体（M.）在瑞士成功地消灭了猪流感。2004年全面实施了一项控制计划，该计划是基于受影响的育肥场的全部灭绝策略以及育种场的部分灭绝策略。因此，案件数量从2003年的200多起大幅下降到2013年的两起。目前的监测是根据临床观察和咳嗽猪的后续诊断进行的。此外，如果每个屠宰批次的大体病理学病变超过10%，则必须对EP进行实验室确认。尽管采取了这些严格的措施，但还是不可能消灭M。瑞士猪生产的猪瘦肉精。事实上，在过去几年中，EP病例的数量略有增加。因此，对涉及的M.为了阐明可能的感染来源和途径，进行了猪肺炎链球菌菌株的鉴定。采用扩展多位点序列分型（MLST）对2014-2016年共22例病例的所有可用和可分型样本进行了调查。因此，共有16例病例，包括2014年的8例，2015年的5例和2016年的3例，可纳入研究。MLST显示，2014/2015年的大多数病例是由于两种主要的传播情况，即两种M。在不同的情况下，每个情景分别涉及五到六个不同州（州）的六个单独的生产农场。此外，通过比较档案序列，在十年内观察到一些序列类型，表明它们在很长一段时间内持续存在，瑞士的消除措施可能部分失败。受影响农场的卫生设施不足以及随后动物运输无病毒感染的猪可能导致病例复发。野猪具有与EP相同的菌株，但缺少可靠的数据来指定这种野生动物作为水库的角色。实施了M.野猪的猪流感与家猪的所有可用样本的基因分型相结合，可以指导负责当局采取控制措施，以打击地方性肺炎的可能差距和缺陷。随着新安装的PubMLST数据库序列类型为M。现在已经有了流感疫苗，可以在国际一级追溯菌株。(C)2017爱思唯尔B. V.保留所有权利。
Enzootic pneumonia (EP) in pigs caused by Mycoplasma (M.) hyopneumoniae has successfully been combatted in Switzerland. A control program was fully implemented in 2004 which is based on total depopulation strategies of affected fattening farms as well as partial depopulation on breeding farms. Thereby, the number of cases has dropped drastically from more than 200 in 2003 to two cases in 2013. Currently monitoring is done based on clinical observation and subsequent diagnostic of coughing pigs. Moreover, in case of more than 10% gross pathological lesions per slaughter batch laboratory confirmation for EP is compulsory. Despite these strict measures it was not possible to eliminate M. hyopneumoniae from Swiss pig production. In fact, during the last few years the number of EP cases has slightly increased. Therefore, genotyping of the involved M. hyopneumoniae strains was conducted in order to elucidate possible sources and routes of infection. All available and typeable samples from totally 22 cases during the period 2014-2016 were investigated by extended multilocus sequence typing (MLST). A total of 16 cases, including eight from 2014, five from 2015 and three from 2016 could thereby be included in the study. MLST revealed that the majority of cases in 2014/2015 were due to two major spread scenarios, i.e. two M. hyopneumoniae sequence types, each scenario involving six individual production farms in five to six different Cantons (states), respectively. Moreover, by comparison of archived sequences some sequence types were observed over ten years demonstrating their persistence over a long time and the possible partial failure of elimination measures in Switzerland. Insufficient sanitation on affected farms and subsequent animal transport of symptomless infected pigs could lead to recurrent cases. Wild boar harbor identical strains found with EP but solid data are missing to assign a role as reservoir to this wild animal. Implementing a monitoring scheme for M. hyopneumoniae in wild boar in combination with genotyping of all available samples from domestic pigs could direct responsible authorities to possible gaps and deficiencies of control measures taken for combating enzootic pneumonia. With the newly installed PubMLST database sequence types for M. hyopneumoniae are now available and allow tracing back strains on the international level. (C) 2017 Elsevier B.V. All rights reserved.