Le Gall-Ladevèze Chloé, Nouvel Laurent-Xavier, Souvestre Marie, Croville Guillaume, Hygonenq Marie-Claude, Guérin Jean-Luc, Le Loc'h Guillaume
IHAP, ENVT, INRAE, Université de Toulouse, Toulouse, France.
Transbound Emerg Dis. 2022 Jul;69(4):e883-e894. doi: 10.1111/tbed.14382. Epub 2021 Nov 17.
Recent outbreaks of highly pathogenic avian influenza in southwest France have raised questions regarding the role of commensal wild birds in the introduction and dissemination of pathogens between poultry farms. To assess possible infectious contacts at the wild-domestic bird interface, the presence of Mycoplasma gallisepticum (MG) was studied in the two sympatric compartments in southwest France. Among various peridomestic wild birds (n = 385), standard PCR primers targeting the 16S rRNA of MG showed a high apparent prevalence (up to 45%) in cloacal swabs of European starlings (Sturnus vulgaris, n = 108), while the MG-specific mgc2 gene was not detected. No tracheal swab of these birds tested positive, and no clinical sign was observed in positive birds, suggesting commensalism in the digestive tract of starlings. A mycoplasma strain was then isolated from a starling swab and its whole genome was sequenced using both Illumina and Nanopore technologies. Phylogenetic analysis showed that it was closely related to MG and M. tullyi, although it was a distinct species. A pair of specific PCR primers targeting the mgc2-like gene of this MG-like strain was designed and used to screen again the same avian populations and a wintering urban population of starlings (n = 50). Previous PCR results obtained in starlings were confirmed to be mostly due to this strain (20/22 positive pools). In contrast, the strain was not detected in fresh faeces of urban starlings. Furthermore, it was detected in one cloacal pool of white wagtails, suggesting infectious transmissions between synanthropic birds with similar feeding behaviour. As the new Starling mycoplasma was not detected in free-range ducks (n = 80) in close contact with positive starlings, nor in backyard (n = 320) and free-range commercial (n = 720) chickens of the area, it might not infect poultry. However, it could be involved in mycoplasma gene transfer in such multi-species contexts.
近期法国西南部高致病性禽流感的爆发引发了关于共生野生鸟类在病原体引入和传播到家禽养殖场过程中所起作用的问题。为了评估野生鸟类与家禽之间可能存在的感染性接触，研究人员对法国西南部两个同域分布区域中鸡败血支原体（MG）的存在情况进行了研究。在各种家禽周围的野生鸟类（n = 385）中，针对MG的16S rRNA的标准PCR引物显示，在欧洲椋鸟（Sturnus vulgaris，n = 108）的泄殖腔拭子中具有较高的表观患病率（高达45%），而未检测到MG特异性mgc2基因。这些鸟类的气管拭子检测均为阴性，且阳性鸟类未观察到临床症状，这表明椋鸟消化道内存在共生现象。随后从一只椋鸟的拭子中分离出一株支原体，并使用Illumina和Nanopore技术对其全基因组进行了测序。系统发育分析表明，尽管它是一个独特的物种，但与MG和图利支原体密切相关。设计了一对针对这种MG样菌株mgc2样基因的特异性PCR引物，并再次用于筛查相同的鸟类种群以及一个城市越冬椋鸟种群（n = 50）。之前在椋鸟中获得的PCR结果证实大多归因于该菌株（20/22个阳性样本池）。相比之下，在城市椋鸟的新鲜粪便中未检测到该菌株。此外，在白鹡鸰的一个泄殖腔样本池中检测到了该菌株，这表明具有相似觅食行为的伴人鸟类之间存在感染传播。由于在与阳性椋鸟密切接触的散养鸭（n = 80）以及该地区的后院鸡（n = 320）和散养商业鸡（n = 720）中均未检测到新的椋鸟支原体，它可能不会感染家禽。然而，在这种多物种环境中，它可能参与支原体基因转移。
