Department of Animal Medicine, Production and Health (MAPS), University of Padua, Legnaro PD, Italy.
Transbound Emerg Dis. 2022 Sep;69(5):e2175-e2184. doi: 10.1111/tbed.14556. Epub 2022 Apr 22.
Porcine reproductive and respiratory syndrome (PRRS) is among the most devastating diseases affecting the pig industry. Despite vaccines having been available for decades, the remarkable genetic variability of this virus, leading to poor cross-protection, has limited their efficacy, and other measures must be adopted to effectively control the viral circulation. Some recent studies have investigated the factors involved in viral spreading and persistence, at least at the local level. However, despite the topic's relevance, no statistically grounded evidence is currently available evaluating the variables more involved in porcine reproductive and respiratory syndrome virus (PRRSV) epidemiological success at a broader scale, such as the European scale. In the present study, an extensive phylodynamic and phylogeographic analysis was performed on more than 1000 ORF5 sequences to investigate the history, dynamics and spreading patterns of PRRSV within European borders. Moreover, several potential predictors, representative of swine population features and trade, human population, economy and geographic characteristics, were evaluated through a specifically designed generalized linear model (GLM) to assess their weight on viral migration rate between countries over time. Although pig stock density, mean PRRSV strain genetic diversity, investments in agriculture (including a likely role of vaccination) and farmer education were involved to a certain extent, the major determinant was proven to be by far the live pig trade. Providing a robust depiction of PRRSV European molecular epidemiology patterns and determinants, the present study could contribute to a more rational allocation of limited resources based on an effective prioritization of control measures.
猪繁殖与呼吸综合征（PRRS）是影响养猪业的最具破坏性疾病之一。尽管几十年来一直有疫苗可用，但该病毒的显著遗传变异性导致交叉保护效果不佳，限制了其效力，因此必须采取其他措施来有效控制病毒的传播。最近的一些研究已经调查了至少在当地层面上涉及病毒传播和持续存在的因素。然而，尽管这个主题很重要，但目前没有基于统计学的证据来评估在更广泛的范围内（如欧洲范围内）与猪繁殖与呼吸综合征病毒（PRRSV）流行病学成功更相关的变量。在本研究中，对超过 1000 个 ORF5 序列进行了广泛的系统发育和系统地理学分析，以调查 PRRSV 在欧洲境内的历史、动态和传播模式。此外，通过专门设计的广义线性模型（GLM）评估了几个潜在的预测因子，这些因子代表了猪群特征和贸易、人口、经济和地理特征，以评估它们对各国之间病毒迁移率的影响随时间的变化。尽管猪存栏密度、平均 PRRSV 株遗传多样性、农业投资（包括疫苗接种的可能作用）和农民教育在一定程度上有所涉及，但主要决定因素显然是活猪贸易。本研究对 PRRSV 欧洲分子流行病学模式和决定因素进行了强有力的描述，这有助于根据控制措施的有效优先级，更合理地分配有限的资源。
