ANSES, French Agency for food, environmental and occupational health and safety, Ploufragan-Plouzané-Niort Laboratory, Swine Virology Immunology Unit, National Reference Laboratory for Swine Influenza, Ploufragan, France; Bretagne Loire University, France.
Coop de France, Animal Health Service, Paris, France; Epidemiological Surveillance Platform for Animal Health (ESA Platform), Operational Team, Paris, France.
Vet Microbiol. 2019 Dec;239:108477. doi: 10.1016/j.vetmic.2019.108477. Epub 2019 Nov 3.
Swine influenza A viruses (swIAVs) cause acute respiratory syndromes in pigs and may also infect humans. Following the 2009 pandemic, a network was established in France to reinforce swIAV monitoring. This study reports virological and epidemiological data accumulated through passive surveillance conducted during 1,825 herd visits from 2011 to 2018. Among them, 887 (48.6 %) tested swIAV-positive. The proportion of positive cases remained stable year-on-year and year-round. The European avian-like swine H1N1 (H1N1) virus was the most frequently identified (69.6 %), and was widespread across the country. The European human-like reassortant swine H1N2 (H1N2) virus accounted for 22.1 % and was only identified in the north-western quarter and recently in the far north. The 2009 pandemic H1N1 (H1N1pdm) virus (3.6 %) was detected throughout the country, without settling in areas of higher pig densities. Its proportion increased in winter, during the seasonal epidemics in humans. The European human-like reassortant swine H3N2 as well as H1N2 viruses were identified sporadically. In up to 30 % of swIAV-positive cases, pigs exhibited clinical signs of high intensity, regardless of the viral subtype and vaccination program. The recurrent pattern of the disease, i.e., an endemic infection at the herd level, was reported in 41% of cases and mainly affected post-weaning piglets (OR = 5.11 [3.36-7.76]). Interestingly, the study also revealed a significant association between the recurrent pattern and sow vaccination (OR = 1.96 [1.37-2.80]). Although restricted to the studied pig population, these results bring new knowledge about swIAV dynamics and infection patterns in pig herds in France.
猪流感 A 病毒（swIAVs）可引起猪的急性呼吸道综合征，也可能感染人类。2009 年大流行后，法国建立了一个网络，以加强对 swIAV 的监测。本研究报告了 2011 年至 2018 年期间通过被动监测在 1825 次畜群访问中积累的病毒学和流行病学数据。其中，887 份（48.6%）检测为 swIAV 阳性。阳性病例的比例逐年和全年保持稳定。最常鉴定到的是欧洲类禽流感 H1N1（H1N1）病毒（69.6%），并在全国范围内广泛传播。欧洲类人流感重组猪 H1N2（H1N2）病毒占 22.1%，仅在西北部和最近的北部地区发现。2009 年大流行 H1N1（H1N1pdm）病毒（3.6%）在全国范围内均有检出，但并未在猪密度较高的地区定居。其比例在冬季人类季节性流行时增加。也零星发现了欧洲类人流感重组猪 H3N2 以及 H1N2 病毒。在高达 30%的 swIAV 阳性病例中，无论病毒亚型和疫苗接种计划如何，猪均表现出高强度的临床症状。在 41%的病例中报告了疾病的复发性模式，即在畜群层面上发生地方性感染，主要影响断奶后的仔猪（OR=5.11[3.36-7.76]）。有趣的是，该研究还揭示了复发性模式与母猪接种疫苗之间存在显著关联（OR=1.96[1.37-2.80]）。尽管这些结果仅限于所研究的猪群，但它们提供了有关法国猪群中 swIAV 动态和感染模式的新知识。
