Istituto Zooprofilattico Sperimentale Umbria e Marche, via Salvemini 1, 06126 Perugia, Italy.
Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493 Greifswald-Insel Riems, Germany.
Vaccine. 2014 Apr 11;32(18):2050-5. doi: 10.1016/j.vaccine.2014.02.006. Epub 2014 Feb 22.
Oral vaccination against classical swine fever (CSF) is a potent tool to control disease outbreaks in wild boar. So far, vaccination campaigns have been carried out using live attenuated vaccines that do not allow serological differentiation of infected from vaccinated animals (DIVA). Although this drawback is acceptable for wild boar, the use of marker vaccines would facilitate studies on disease and vaccination dynamics. Recently, the CSF marker vaccine candidate CP7_E2alf was assessed for oral immunization under laboratory conditions. Promising results prompted efforts to study the vaccine candidate under field conditions and in bait formulation. In this context, two oral vaccination campaigns were carried out with CP7_E2alf bait vaccines in two areas called 'faunistic-hunting farms' in the region of Umbria, Italy. One campaign was conducted using single vaccination, the second with the routinely employed double vaccination strategy. Both campaigns were carried out before concerted hunting actions were performed. Bait uptake, vaccine virus detection and antibody responses were assessed along with inspections upon gutting. As a comparator, seven wild boar were hand-fed with baits under laboratory conditions. In the field, bait uptake ranged from 63.7% to 98.7%, whereas antibody prevalence reached only 33.3-35.1%. The marker serology showed a strong influence of sample quality on the test outcome with a total of 85% of samples being classified correctly. Vaccine virus was not detectable. Under hand feeding conditions, six out of seven wild boar took up at least one bait, and five of them showed detectable antibody levels seven weeks after vaccination. These results were supplemented by stability tests. Appropriate stability of vaccine virus was shown both under field and laboratory conditions. In total, most results were in line with our expectations. However, optimization of the DIVA assay has to be attempted in the future.
口服接种猪瘟疫苗是控制野猪疫病爆发的有效工具。迄今为止，接种运动一直使用活减毒疫苗进行，该疫苗不能在血清学上区分感染动物和接种动物（DIVA）。虽然这一缺点对于野猪来说是可以接受的，但使用标记疫苗将有助于研究疾病和疫苗接种动态。最近，CSF 标记疫苗候选物 CP7_E2alf 已在实验室条件下进行了口服免疫评估。有希望的结果促使人们努力在野外条件下和诱饵配方中研究疫苗候选物。在这种情况下，在意大利翁布里亚地区的两个名为“faunistic-hunting farms”的区域，使用 CP7_E2alf 诱饵疫苗进行了两次口服接种运动。第一次接种是单次接种，第二次是常规使用的双接种策略。这两次接种运动都是在协同狩猎行动之前进行的。在屠宰时，对诱饵摄取、疫苗病毒检测和抗体反应进行了评估，并进行了检查。作为比较，在实验室条件下，有 7 头野猪接受了诱饵的人工喂食。在野外，诱饵摄取率在 63.7%至 98.7%之间，而抗体流行率仅达到 33.3-35.1%。标记血清学表明，样本质量对测试结果有很大影响，共有 85%的样本得到正确分类。未检测到疫苗病毒。在人工喂食条件下，7 头野猪中有 6 头至少摄取了一个诱饵，其中 5 头在接种后 7 周显示出可检测的抗体水平。这些结果得到了稳定性测试的补充。疫苗病毒在野外和实验室条件下都表现出了适当的稳定性。总的来说，大多数结果符合我们的预期。然而，未来还需要尝试优化 DIVA 检测。
