Abstract：
Coxiella burnetii is the causative agent of zoonotic Q fever. Animals are the natural reservoirs of C. burnetii, and domestic livestock represent the major sources of human infection. C. burnetii infection in pregnant females may causes abortion during late pregnancy, whereby massive shedding of C. burnetii with abortion products becomes aerosolized and persists in the environment. Therefore, monitoring and surveillance of this infection in livestock is important for the prevention of the C. burnetii transmission. Previous serological surveys have shown that C. burnetii infection is endemic in livestock in China. However, few data are available on the diagnosis of C. burnetii as a cause of abortion by molecular methods in livestock. To get a better understanding of the impact of C. burnetii infection on domestic livestock in China, a real-time PCR investigation was carried out on collected samples from different domestic livestock suffering abortion during 2021-2023. A total of 338 samples collected from eight herds of five livestock species were elected. The results showed that 223 (66 %) of the collected samples were positive for C. burnetii DNA using real-time PCR. For the aborted samples, 82 % (128/15) of sheep, 81 % (34/42) of goats, 44 % (15/34) of cattle, 69 % (18/26) of camels, and 50 % (17/34) of donkeys were positive for C. burnetii. Besides, 44 % (8/18) and 4 % (1/25) of asymptomatic individuals of sheep and donkey were also positive for C. burnetii. In addition, the positive samples were further confirmed by amplification and sequencing of the C. burnetii-specific isocitrate dehydrogenase (icd) gene. Phylogenetic analysis based on specific gene fragments of icd genes revealed that the obtained sequences in this study were clustered into two different groups associated with different origin of hosts and geographic regions. This is the first report confirming that C. burnetii exists in aborted samples of sheep, goats, cattle, donkeys and camels in China. Further studies are needed to fully elucidate the epidemiology of this pathogen in livestock as well as the potential risks to public health.
摘要：
伯氏柯氏菌是人畜共患Q热的病原体。动物是C.burnetii的天然宿主，家畜是人类感染的主要来源。孕妇中的C.Burnetii感染可能会导致妊娠晚期流产，由此,具有流产产物的大量伯氏梭菌脱落被雾化并持续存在于环境中。因此,监测和监测牲畜中的这种感染对于预防C.burnetii传播很重要。先前的血清学调查表明，伯氏梭菌感染在中国家畜中是地方性的。然而,关于通过分子方法在牲畜中诊断为流产的C.burnetii的数据很少。为了更好地了解伯氏梭菌感染对中国家畜的影响，在2021-2023年期间，对从遭受流产的不同家畜收集的样本进行了实时PCR调查。共从5种家畜的8群中收集338个样本。结果表明，使用实时PCR，所收集的样品中有223（66％）的伯氏芽孢杆菌DNA呈阳性。对于中止的样本，82%(128/15)的绵羊，81%(34/42)的山羊，44％（15/34）的牛，69%(18/26)的骆驼，50％（17/34）的驴为C.burnetii阳性。此外,44％（8/18）和4％（1/25）的无症状个体的绵羊和驴也为C.burnetii阳性。此外,通过伯氏芽孢杆菌特异性异柠檬酸脱氢酶（icd）基因的扩增和测序进一步证实了阳性样品。基于icd基因的特定基因片段的系统发育分析表明，本研究中获得的序列被分为两个不同的组，这些组与宿主和地理区域的不同起源相关。这是第一份报告，证实羊的流产样本中存在肉芽胞杆菌，山羊,牛,中国的驴和骆驼。需要进一步的研究来充分阐明这种病原体在牲畜中的流行病学以及对公共卫生的潜在风险。
