Department of Population Health Sciences, Faculty of Veterinary Medicine, Farm Animal Health Unit, Utrecht University, Yalelaan 7, 3584CL, Utrecht, the Netherlands.
Vion Food Group, Boseind 10, 5281 RM, Boxtel, the Netherlands.
Vet Res. 2022 Jul 7;53(1):50. doi: 10.1186/s13567-022-01068-3.
Humans can become infected with hepatitis E virus (HEV) by consumption of undercooked pork. To reduce the burden of HEV in humans, mitigation on pig farms is needed. HEV is found on most pig farms globally, yet within-farm seroprevalence estimates vary considerably. Understanding of the underlying variation in infection dynamics within and between farms currently lacks. Therefore, we investigated HEV infection dynamics by sampling 1711 batches of slaughter pigs from 208 Dutch farms over an 8-month period. Four farm types, conventional, organic, and two types with strict focus on biosecurity, were included. Sera were tested individually with an anti-HEV antibody ELISA and pooled per batch with PCR. All farms delivered seropositive pigs to slaughter, yet batches (resembling farm compartments) had varying results. By combining PCR and ELISA results, infection moment and extent per batch could be classified as low transmission, early, intermediate or late. Cluster analysis of batch infection moments per farm resulted in four clusters with distinct infection patterns. Cluster 1 farms delivered almost exclusively PCR negative, ELISA positive batches to slaughter (PCRELISA), indicating relatively early age of HEV infection. Cluster 2 and 3 farms delivered 0.3 and 0.7 of batches with intermediate infection moment (PCRELISA) respectively and only few batches with early infection. Cluster 4 farms delivered low transmission (PCRELISA) and late infection (PCRELISA) batches, demonstrating that those farms can prevent or delay HEV transmission to farm compartments. Farm type partly coincided with cluster assignment, indicating that biosecurity and management are related to age of HEV infection.
人类可能会因食用未煮熟的猪肉而感染戊型肝炎病毒 (HEV)。为了降低人类的 HEV 负担，需要在养猪场采取缓解措施。HEV 在全球大多数养猪场都有发现，但农场内的血清阳性率估计差异很大。目前缺乏对农场内和农场之间感染动态的潜在变异的了解。因此，我们通过在 8 个月的时间里从 208 个荷兰农场中抽取 1711 批屠宰猪进行采样，来研究 HEV 的感染动态。包括四种农场类型：常规农场、有机农场和两种严格关注生物安全的农场。单独用抗 HEV 抗体 ELISA 检测血清，用 PCR 对每批血清进行混合检测。所有农场都向屠宰场输送了血清阳性的猪，但每批猪（类似于农场隔间）的结果各不相同。通过结合 PCR 和 ELISA 的结果，可以将每批猪的感染时刻和程度分为低传播、早期、中期或晚期。对每批农场的感染时刻进行聚类分析，结果形成了四个具有不同感染模式的聚类。聚类 1 农场向屠宰场输送的几乎都是 PCR 阴性、ELISA 阳性的批次（PCRELISA），表明 HEV 感染相对较早。聚类 2 和 3 农场分别输送了 0.3 和 0.7 批处于中间感染时刻（PCRELISA）的批次，只有少数批次处于早期感染。聚类 4 农场输送的是低传播（PCRELISA）和晚期感染（PCRELISA）的批次，表明这些农场能够防止或延迟 HEV 向农场隔间的传播。农场类型部分与聚类分配相吻合，表明生物安全和管理与 HEV 感染的年龄有关。
