Luehrs Adrian, Siegenthaler Salome, Grützner Niels, Grosse Beilage Elisabeth, Kuhnert Peter, Nathues Heiko
Clinic for Swine, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bremgartenstr. 109a, 3001 Bern, Switzerland; Field Station for Epidemiology, University of Veterinary Medicine Hannover, Foundation, Bueschelerstr. 9, 49456 Bakum, Germany.
Clinic for Swine, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bremgartenstr. 109a, 3001 Bern, Switzerland.
Vet Microbiol. 2017 May;203:1-5. doi: 10.1016/j.vetmic.2017.02.001. Epub 2017 Feb 3.
Respiratory disorders in fattening pigs are of major concern worldwide. Particularly Enzootic Pneumonia remains a problem for the pig industry. This chronic respiratory disease is primarily caused by Mycoplasma hyopneumoniae (M. hyopneumoniae). However, more recently it was hypothesised that M. hyorhinis can also cause similar lung lesions. To investigate the relevance of M. hyorhinis as a cause of pneumonia in fattening pigs 10 farms in Switzerland (considered free of Enzootic Pneumonia) and 20 farms in Germany (regarded as endemic for Enzootic Pneumonia) with a history of chronic and/or recurrent respiratory diseases were included in the study. During a one-time farm visit the coughing index was determined in the batch of oldest fattening pigs in each farm before submission to slaughter. In total, 1375 lungs from these pigs were collected at the abattoir and individually scored for lesions. Furthermore, 600 lungs with, if present, indicative lesions for Enzootic Pneumonia (purple to grey areas of tissue consolidation in the cranio-ventral lung lobes) were tested for mycoplasma species by culture and by real-time PCR for the presence of M. hyorhinis and M. hyopneumoniae. In total, 15.7% of the selected lungs were tested positive for M. hyorhinis by real-time PCR. The prevalence of M. hyorhinis was 10% in Switzerland and 18.5% in Germany and differed significantly between these two countries (p=0.007). M. hyorhinis was detected significantly more often in pneumonic lungs (p=0.004) but no significant association was found between M. hyorhinis and the coughing index or the M. hyopneumoniae status of the pig. M. hyopneumoniae was detected in 0% and 78.5% of the selected lungs in Switzerland and Germany, respectively. We found no evidence that M. hyorhinis alone can lead to similar lung lesions as seen by an infection with M. hyopneumoniae in fattening pigs. In addition, a simultaneous infection with both M. hyorhinis and M. hyopneumoniae did not aggravate the observed lung lesions. Moreover, the presence of M. hyorhinis showed no clinical effect in terms of coughing at least at the end of the fattening phase. However, different levels of virulence of M. hyorhinis isolates as well as interactions with viral pathogens like porcine reproductive and respiratory syndrome virus (PRRSV) or porcine circovirus type 2 (PCV2) were reported in the literature and need to be further investigated.
育肥猪的呼吸道疾病是全球主要关注的问题。特别是地方性肺炎仍然是养猪业面临的一个问题。这种慢性呼吸道疾病主要由猪肺炎支原体（M. hyopneumoniae）引起。然而，最近有人提出猪鼻支原体也可导致类似的肺部病变。为了调查猪鼻支原体作为育肥猪肺炎病因的相关性，瑞士10个农场（被认为无地方性肺炎）和德国20个农场（被视为地方性肺炎流行区）有慢性和/或复发性呼吸道疾病病史的猪场被纳入研究。在一次农场访问期间，在每个农场即将屠宰的最老一批育肥猪中测定咳嗽指数。总共从这些猪身上在屠宰场收集了1375个肺，并对病变进行个体评分。此外，对600个有（如果存在）地方性肺炎指示性病变（颅腹侧肺叶紫色至灰色组织实变区域）的肺进行支原体菌种培养检测，并通过实时PCR检测猪鼻支原体和猪肺炎支原体的存在。通过实时PCR，总共15.7%的选定肺被检测出猪鼻支原体呈阳性。猪鼻支原体的流行率在瑞士为10%，在德国为18.5%，两国之间差异显著（p = 0.007）。在肺炎性肺中猪鼻支原体的检出率明显更高（p = 0.004），但未发现猪鼻支原体与咳嗽指数或猪的猪肺炎支原体感染状况之间存在显著关联。在瑞士和德国选定的肺中，猪肺炎支原体的检出率分别为0%和78.5%。我们没有发现证据表明猪鼻支原体单独感染能导致育肥猪出现与猪肺炎支原体感染相似的肺部病变。此外，猪鼻支原体和猪肺炎支原体同时感染并没有加重观察到的肺部病变。此外，至少在育肥期结束时，猪鼻支原体的存在在咳嗽方面没有显示出临床影响。然而，文献报道了猪鼻支原体分离株的不同毒力水平以及与猪繁殖与呼吸综合征病毒（PRRSV）或猪圆环病毒2型（PCV2）等病毒病原体的相互作用，需要进一步研究。
