Vitale N, Radaelli M C, Chiavacci L, Paoletti M, Teodori L, Savini G
Osservatorio Epidemiologico, Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Torino, Italy.
OIE Reference Laboratory for Bluetongue, Istituto Zooprofilattico Sperimentale dell'Abruzzo e Molise G. Caporale, Teramo, Italy.
Transbound Emerg Dis. 2016 Apr;63(2):175-83. doi: 10.1111/tbed.12241. Epub 2014 Jun 6.
The immunogenicity of two inactivated bluetongue virus serotype 8 (BTV-8) vaccines was evaluated in 880 cattle under field conditions. The effect of selected factors on vaccine performance was also analysed at the herd and animal levels (vaccine, herd size and production, age, sex, time interval between vaccination and blood sampling and veterinary training). The immunogenicity elicited by vaccination with the two vaccines was monitored with the aid of a competitive enzyme-linked immunosorbent assay (c-ELISA) and serum neutralization test (SNT). To investigate whether the selected factors influenced seroconversion at the herd and animal levels, a multilevel logistic regression model developed in a mixed model was applied. Of the 880 cattle vaccinated, 76.0% yielded BTV c-ELISA antibodies, whereas only 25.0% seroconverted based on SNT. Type of vaccine (odds ratio [OR] 4.5; 95% confidence interval [CI], 2.2-9.0 for SNT and OR 3.5; 95% CI, 2.1-5.9 for c-ELISA), veterinary training in vaccine administration (OR 8.1; 95% CI, 4.7-14.1 for SNT and OR 2.4; 95% CI, 1.3-4.2 for c-ELISA), animal age (OR 1.4; 95% CI, 1.1-1.8 for SNT and OR 1.7; 95% CI, 1.4-2.1 for c-ELISA) and days between first vaccine administration and blood collection (OR 1.9; 95% CI, 1.1-3.1 for SNT and OR 2.6; 95% CI, 1.7-3.8 for c-ELISA) were the major factors affecting vaccine performance under field conditions. This is the first study to use multilevel logistic regression in the evaluation of selected risk factors affecting BTV-8 vaccine performance in cattle.
在田间条件下，对880头牛评估了两种灭活蓝舌病病毒8型（BTV - 8）疫苗的免疫原性。还在畜群和动物水平分析了选定因素对疫苗性能的影响（疫苗、畜群规模和生产情况、年龄、性别、疫苗接种与采血之间的时间间隔以及兽医培训）。借助竞争酶联免疫吸附测定（c - ELISA）和血清中和试验（SNT）监测两种疫苗接种所引发的免疫原性。为了调查选定因素是否在畜群和动物水平影响血清转化，应用了在混合模型中建立的多水平逻辑回归模型。在880头接种疫苗的牛中，76.0%产生了BTV c - ELISA抗体，而基于SNT的血清转化率仅为25.0%。疫苗类型（SNT的优势比[OR]为4.5；95%置信区间[CI]为2.2 - 9.0，c - ELISA的OR为3.5；95% CI为2.1 - 5.9）、疫苗接种的兽医培训（SNT的OR为8.1；95% CI为4.7 - 14.1，c - ELISA的OR为2.4；95% CI为1.3 - 4.2）、动物年龄（SNT的OR为1.4；95% CI为1.1 - 1.8，c - ELISA的OR为1.7；95% CI为1.4 - 2.1）以及首次疫苗接种与采血之间的天数（SNT的OR为1.9；95% CI为1.1 - 3.1，c - ELISA的OR为2.6；95% CI为1.7 - 3.8）是田间条件下影响疫苗性能的主要因素。这是第一项在评估影响牛BTV - 8疫苗性能的选定风险因素时使用多水平逻辑回归的研究。
