ANSES, French Agency for Food, Environmental and Occupational Health & Safety, Ploufragan-Plouzané Laboratory, Ploufragan, France.
Bretagne-Loire University, Rennes, France.
Transbound Emerg Dis. 2019 Sep;66(5):1930-1945. doi: 10.1111/tbed.13224. Epub 2019 May 22.
Hepatitis E virus (HEV) is a zoonotic pathogen, in particular genotype 3 HEV is mainly transmitted to humans through the consumption of contaminated pork products. This study aimed at describing HEV infection patterns in pig farms and at assessing the impact of immunomodulating co-infections namely Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) and Porcine Circovirus Type 2 (PCV2), as well as other individual factors such as piglets' immunity and litters' characteristics on HEV dynamics. A longitudinal follow-up was conducted in three farrow-to-finish farms known to be HEV infected. Overall, 360 piglets were individually monitored from birth to slaughter with regular blood and faecal sampling as well as blood and liver samples collected at slaughterhouse. Virological and serological analyses were performed to detect HEV, PCV2 and PRRSV genome and antibodies. The links between 12 explanatory variables and four outcomes describing HEV dynamics were assessed using cox-proportional hazard models and logistic regression. HEV infection dynamics was found highly variable between farms and in a lower magnitude between batches. HEV positive livers were more likely related to short time-intervals between HEV infection and slaughter time (<40 days, OR = 4.1 [3.7-4.5]). In addition to an influence of piglets' sex and sows' parity, the sequence of co-infections was strongly associated with different HEV dynamics: a PRRSV or PCV2/PRRSV pre- or co-infection was associated with a higher age at HEV shedding (Hazard Ratio = 0.3 [0.2-0.5]), as well as a higher age at HEV seroconversion (HR = 0.5 [0.3-0.9] and HR = 0.4 [0.2-0.7] respectively). A PCV2/PRRSV pre- or co-infection was associated with a longer duration of shedding (HR = 0.5 [0.3-0.8]). Consequently, a PRRSV or PCV2/PRRSV pre- or co-infection was strongly associated with a higher risk of having positive livers at slaughter (OR = 4.1 [1.9-8.9] and OR = 6.5 [3.2-13.2] respectively). In conclusion, co-infections with immunomodulating viruses were found to affect HEV dynamics in the farrow-to-finish pig farms that were followed in this study.
戊型肝炎病毒（HEV）是一种人畜共患病原体，特别是基因型 3 的 HEV 主要通过食用受污染的猪肉产品传播给人类。本研究旨在描述猪场中 HEV 的感染模式，并评估免疫调节性共感染（即猪繁殖与呼吸综合征病毒（PRRSV）和猪圆环病毒 2 型（PCV2））以及其他个体因素（如仔猪的免疫力和产仔数特征）对 HEV 动态的影响。在已知感染 HEV 的三个肥育-育肥农场中进行了纵向随访。总体而言，360 头仔猪从出生到屠宰进行了个体监测，定期进行血液和粪便采样，并在屠宰场采集血液和肝脏样本。进行了病毒学和血清学分析以检测 HEV、PCV2 和 PRRSV 基因组和抗体。使用 Cox 比例风险模型和逻辑回归评估了 12 个解释变量与描述 HEV 动态的四个结果之间的关系。结果发现，HEV 感染动态在农场之间差异很大，批次之间差异较小。HEV 阳性肝脏更可能与 HEV 感染和屠宰时间之间的时间间隔较短（<40 天，OR=4.1[3.7-4.5]）有关。除了仔猪性别和母猪产仔数的影响外，共感染的顺序与不同的 HEV 动态密切相关：PRRSV 或 PCV2/PRRSV 先感染或共感染与 HEV 排毒年龄较高相关（风险比=0.3[0.2-0.5]），以及 HEV 血清转换年龄较高（HR=0.5[0.3-0.9]和 HR=0.4[0.2-0.7]）。PCV2/PRRSV 先感染或共感染与排毒时间延长相关（HR=0.5[0.3-0.8]）。因此，PRRSV 或 PCV2/PRRSV 先感染或共感染与屠宰时肝脏阳性的风险增加密切相关（OR=4.1[1.9-8.9]和 OR=6.5[3.2-13.2]）。总之，在本研究中监测的肥育-育肥猪场中，免疫调节性病毒的共感染被发现会影响 HEV 的动态。
