Ovine enzootic abortion (OEA), caused by Chlamydia abortus, is an economically important disease in many countries. Inactivated vaccines have been used for many years as they induce immunity in sheep, although outbreaks of abortions have been described in vaccinated flocks. In addition, there is a commercially available live attenuated vaccine that provides good protective results. Recently however, reports question the attenuation of this vaccine and associate it with the appearance of outbreaks of OEA in vaccinated flocks. In the present study, a recently commercialized inactivated vaccine (INMEVA®; Laboratorios Hipra S.A., Amer, Spain) has been evaluated using mouse and sheep experimental models. In the mouse models (non-pregnant and pregnant models), the efficacy of INMEVA vaccine has been compared to an unvaccinated control group and to an experimental inactivated vaccine considered as a positive protection control (UMU vaccine). In the non- pregnant model, the UMU vaccine was more effective than the INMEVA vaccine regarding the impact on body weight or the presence of C. abortus in the liver, but both vaccinated groups (UMU and INMEVA) had significantly lower C. abortus in the liver compared to the control group. In the pregnant model in terms of reproductive failures, pups per mouse or the presence of C. abortus in the liver or uterus, no significant differences were found between both vaccines, inducing protection compared to the control group. In the ovine pregnant model, where INMEVA vaccine was compared only to an unvaccinated group, the results indicate that this new commercial vaccine is safe and provides a suitable level of protection against an experimental challenge with C. abortus. A 75% reduction in reproductive disorders, 55% reduction in animals with C. abortus shedding on day of parturition/abortion, and a significant reduction of the average amount of chlamydial shedding from parturition/abortion over the next 21 days was observed, in relation to the infected control group. The results suggest that this vaccine is adequate for the control and prevention of OEA; however, future studies are necessary to elucidate the type of protective immune response that it induces.

引起的绵羊阴道流产（OEA） 流产衣原体在许多国家/地区是一种重要的经济疾病。灭活疫苗已经使用了很多年，因为它们可以在绵羊中诱导免疫力，尽管已经在疫苗接种的鸡群中描述了流产的爆发。另外，存在可提供良好保护效果的可商购的减毒活疫苗。但是，最近有报道质疑这种疫苗的减毒作用，并将其与接种疫苗的鸡群中爆发的OEA有关。在本研究中，已使用小鼠和绵羊实验模型评估了一种最近商业化的灭活疫苗（INMEVA®； Laboratorios Hipra SA，西班牙阿梅尔）。在鼠标模型（非怀孕和怀孕模型）中，已将INMEVA疫苗的功效与未接种疫苗的对照组和被视为阳性保护对照的实验灭活疫苗（UMU疫苗）进行了比较。在非怀孕模型中，就对体重的影响或是否存在UMU而言，UMU疫苗比INMEVA疫苗更有效。C.流产 在肝脏中，但两个疫苗接种组（UMU和INMEVA）的血药浓度均显着降低 C.流产与对照组相比 在怀孕模型中，就生殖衰竭，每只小鼠幼崽或是否存在C.流产在肝或子宫中，两种疫苗之间均未发现显着差异，与对照组相比可诱导保护作用。在绵羊怀孕模型中，仅将INMEVA疫苗与未接种疫苗的组进行比较，结果表明，这种新的商业疫苗是安全的，并提供了适当水平的保护，可抵御实验性挑战。C.流产。生殖疾病减少75％，动物有以下疾病减少55％C.流产与受感染的对照组相比，在分娩/堕胎的当天脱落，并且在接下来的21天中观察到了从分娩/堕胎的衣原体平均脱落量显着降低。结果表明，该疫苗足以控制和预防OEA。但是，有必要进行进一步的研究来阐明其诱导的保护性免疫应答的类型。