Spedicato Massimo, Lorusso Alessio, Salini Romolo, Gennaro Annapia Di, Leone Alessandra, Teodori Liana, Casaccia Claudia, Portanti Ottavio, Calistri Paolo, Giovannini Armando, Savini Giovanni
OIE Reference Laboratory for Bluetongue, Istituto Zooprofilattico Sperimentale dell'Abruzzo e Molise (IZSAM), Campo Boario, 64100, Teramo, Italy.
OIE Reference Laboratory for Bluetongue, Istituto Zooprofilattico Sperimentale dell'Abruzzo e Molise (IZSAM), Campo Boario, 64100, Teramo, Italy.
Prev Vet Med. 2017 Jan 1;136:49-55. doi: 10.1016/j.prevetmed.2016.11.016. Epub 2016 Nov 27.
Vaccination is the most effective strategy for controlling Bluetongue virus (BTV) spread and economic consequences thereof. In this study we verified in sheep, using one commercially available inactivated vaccine for BTV-8 (BTVPUR AlSap 8), when, during the recommended vaccination schedule, animals start to be effectively protected against challenge with wild-type strain. To this aim, sheep were challenged at different time points shortly after the first vaccine injection. Twenty-four Sarda sheep were divided into four groups vaccinated two weeks before challenge (Group A), one week before challenge (Group B) and concurrently with challenge (Group C). A second vaccine was performed twenty-eight days later with respect the first vaccine administration in each experimental group. The last group consisted of six non vaccinated-infected animals (NVIA). Virological and serological examinations were performed before and after challenge up to 42 and 77days post challenge, respectively. The results of the study show that vaccination commenced as little as two weeks before challenge (Group A) prevented viremia and RNAemia in challenged sheep altogether. Conversely, Group B was partially protected from challenge and Group C showed viraemia and RNAemia similar to NVIA. This study indicates that the first administration of inactivated vaccine performed two weeks before challenge was able to prevent viraemia. Overall, our findings may have direct consequences for the management of an unexpected BTV-8 outbreak in sheep and for the legislation on sheep trade from BTV restriction areas.
疫苗接种是控制蓝舌病病毒（BTV）传播及其经济后果的最有效策略。在本研究中，我们使用一种市售的BTV-8灭活疫苗（BTVPUR AlSap 8），在绵羊身上验证了在推荐的疫苗接种计划中，动物何时开始有效抵御野生型毒株的攻击。为此，在首次疫苗注射后不久的不同时间点对绵羊进行攻毒。24只撒丁岛绵羊被分为四组，在攻毒前两周接种疫苗（A组）、攻毒前一周接种疫苗（B组）以及与攻毒同时接种疫苗（C组）。在每个实验组中，相对于首次疫苗接种，28天后进行第二次疫苗接种。最后一组由6只未接种疫苗的感染动物（NVIA）组成。在攻毒前后分别进行病毒学和血清学检查，直至攻毒后42天和77天。研究结果表明，早在攻毒前两周开始接种疫苗（A组）可完全预防攻毒绵羊出现病毒血症和RNA血症。相反，B组受到部分保护，C组出现的病毒血症和RNA血症与NVIA相似。本研究表明，在攻毒前两周进行首次灭活疫苗接种能够预防病毒血症。总体而言，我们的研究结果可能对绵羊中意外爆发的BTV-8疫情管理以及来自BTV限制区的绵羊贸易立法产生直接影响。
