Moronato M L, Cecchinato M, Facchetti G, Mainenti M, Gobbo F, Catania S
Department of Animal Medicine Production and Health - MAPS, Università degli Studi di Padova, Viale dell'Università 16, 35020. Legnaro, Padova, Italy.
Avian Medicine Laboratory Mycoplasma Unit - SCT1, Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università 10, 35020. Legnaro, Padova, Italy.
BMC Vet Res. 2018 Nov 20;14(1):357. doi: 10.1186/s12917-018-1669-8.
Mycoplasma synoviae (MS) is a major poultry pathogen which causes severe economic losses in all the productive sectors. The prevalence of MS in European countries has increased in the last few years, leading to greater attention to the available methods to prevent its spread. The main strategy currently applied for its containment is the development and maintenance of MS-free breeder flocks. A live MS vaccine (MS-H) obtained by mutagenizing an Australian field strain has recently been introduced in Italy. The aim of the present study was to evaluate the vaccine behaviour in broiler breeder groups at different production stages and the effectiveness of the available laboratory tests in discriminating the MS-H from a field strain.
The vaccine diffused extensively through the population, shown by the wide serological response (over 80% of positive samples in RSA and 85% in ELISA), the high serological titres, the positivity of all the tracheal samples collected during the production phase by MS PCR and the positivity by cultivation from tracheal swabs at the end-point (55 weeks after vaccination). In contrast, only one swab from a sternal bursa was positive in MS PCR, while all the joint and oviduct samples were negative. There was no evidence of vertical transmission. Different genotyping techniques were used to achieve a clear classification of the MS positive samples. The vlhA and the obg gene analysis showed that most of the strains were homologous with the vaccine, but some ambiguous samples were further investigated with the multi locus sequence typing (MLST) scheme which confirmed the homology.
The development of a multi-technique approach to monitor vaccinated avian flocks, based both on serological and biomolecular methods, is advised as well as the use of effective genotyping techniques to analyse the MS strains circulating in high densely populated poultry areas.
滑膜支原体（MS）是一种主要的家禽病原体，在所有生产部门都会造成严重的经济损失。在过去几年中，MS在欧洲国家的流行率有所上升，这使得人们更加关注现有的预防其传播的方法。目前用于控制MS的主要策略是培育和维持无MS的种鸡群。一种通过诱变澳大利亚野毒株获得的MS活疫苗（MS-H）最近已在意大利引入。本研究的目的是评估该疫苗在不同生产阶段的肉鸡种鸡群中的表现，以及现有实验室检测方法区分MS-H和野毒株的有效性。
疫苗在群体中广泛传播，血清学反应广泛（RSA检测中阳性样本超过80%，ELISA检测中为85%）、血清学滴度高、生产阶段采集的所有气管样本通过MS PCR检测呈阳性以及接种后55周从气管拭子培养物中检测呈阳性均表明了这一点。相比之下，MS PCR检测中只有一个胸骨囊拭子呈阳性，而所有关节和输卵管样本均为阴性。没有垂直传播的证据。使用了不同的基因分型技术对MS阳性样本进行明确分类。vlhA和obg基因分析表明，大多数菌株与疫苗同源，但一些不明确的样本通过多位点序列分型（MLST）方案进一步研究，该方案证实了同源性。
建议开发一种基于血清学和生物分子方法的多技术方法来监测接种疫苗的禽群，并使用有效的基因分型技术来分析在高密度家禽养殖区传播的MS菌株。
