NEIKER - Instituto Vasco de Investigación y Desarrollo Agrario, Department of Animal Health, Berreaga 1, 48160 Derio, Bizkaia, Spain.
Res Vet Sci. 2011 Dec;91(3):e58-63. doi: 10.1016/j.rvsc.2010.11.014. Epub 2010 Dec 17.
Abortion due to Coxiella burnetii was confirmed in the 2007/08 season in two naturally-infected dairy sheep flocks. Proportion of C. burnetii shedders and bacterial loads in vaginal mucus were high among aborted or lambed ewes, as was within-flock seroprevalence. Before the next reproductive season (2008/09) 75% of ewes and 50% of replacement lambs were vaccinated (Coxevac, CEVA Santé Animale) keeping the remaining as untreated controls. Compared with the previous year results when abortion outbreak started, a great reduction in the percentage of abortions, in the number of shedders and in the bacterial burden excreted by the ewes was found in both flocks. However, seroconversion in non-vaccinated yearlings from both flocks and the presence of C. burnetii DNA in bioaerosols taken at sheep premises at lambing indicated that infection was still active. No differences were observed between vaccinated and control groups in terms of proportion of C. burnetii shedders. These results suggest that optimal results of vaccination in heavily infected flocks may not be obtained in a short-term period.
2007/08 季，在两个自然感染的奶牛羊群中确认了因柯克斯体引起的流产。在流产或分娩的母羊中，柯克斯体脱落者和阴道黏液中的细菌负荷比例很高，群内血清阳性率也很高。在下一个繁殖季节（2008/09 年），75%的母羊和 50%的后备羔羊接种了疫苗（Coxevac，CEVA Santé Animale），其余的作为未处理的对照组。与前一年流产爆发开始时的结果相比，两个羊群的流产百分比、脱落者数量以及母羊排出的细菌负荷都有了很大的减少。然而，来自两个羊群的未接种疫苗的一岁青年羊的血清转换以及在分娩时从绵羊场采集的生物气溶胶中存在柯克斯体 DNA 表明感染仍然活跃。在脱落者比例方面，接种组和对照组之间没有观察到差异。这些结果表明，在高度感染的羊群中，疫苗接种的最佳效果可能无法在短期内获得。
