ONIRIS, Nantes, F-44307, France.
Vet Microbiol. 2012 Mar 23;155(2-4):430-3. doi: 10.1016/j.vetmic.2011.09.026. Epub 2011 Oct 1.
To describe both shedding and serological patterns following abortions detected as being associated with Coxiella burnetii (Cb), 24 cows experiencing an abortion due to Cb were followed over a one month period. Samples taken on the day of abortion (D0) were followed 3-fold by weekly samplings from day 14 (D14) to D28 after the abortion. Milk and vaginal mucus were collected at each weekly sampling and tested using real-time PCR while blood samples were collected 2-fold on D21 and D28 and tested using ELISA. We found a very short duration of C. burnetii shedding in vaginal mucus after abortion, highlighting the need to collect samples as rapidly as possible following an abortion to avoid false negative results. In contrast with previous results, concomitancy of vaginal and mucus shedding was frequent, especially for cows shedding a high bacterial load on DO leading to the hypothesis that the clinical onset of the infection influences the modalities of Cb shedding. Lastly, serological results indicating a lack of sensitivity to detect Cb shedder cows (especially for cows for which Ct values were high) suggest that ELISA is not a useful tool to diagnose abortions at the individual level.
为了描述流产后 Q 热病原体（Cb）脱落和血清学模式，我们对 24 头因 Cb 而流产的奶牛进行了为期一个月的跟踪研究。在流产当天（D0）采集样本，随后在 D14 至 D28 之间每周采集 3 次样本。在每次采样时采集牛奶和阴道黏液，使用实时 PCR 进行检测，同时在 D21 和 D28 时采集 2 次血样，使用 ELISA 进行检测。我们发现流产后阴道黏液中 C. burnetii 的脱落持续时间非常短，这突出表明需要尽快采集流产后样本，以避免假阴性结果。与之前的结果相反，阴道和黏液同时脱落的情况很常见，尤其是在 D0 时脱落大量细菌的奶牛，这导致了这样一种假设，即感染的临床发作影响了 Cb 脱落的方式。最后，血清学结果表明 ELISA 检测 Cb 脱落牛的敏感性较低（尤其是 Ct 值较高的牛），这表明 ELISA 不是一种用于个体水平诊断流产的有用工具。
