Madec F, Gourreau J M, Kaiser C, Le Dantec J, Vannier P, Aymard M
Comp Immunol Microbiol Infect Dis. 1985;8(3-4):247-58. doi: 10.1016/0147-9571(85)90003-7.
A study is carried on in a group of 16 commercial breeding-finishing units in Brittany (France). The aim of this study is to try to reveal the persistence of activity of the Influenza Virus within these intensive units after an acute epizootic. In each farm two batches of pigs are selected, individually identified and followed from suckling period to slaughter. Serological controls are conducted every month on the same pigs. Both Influenza and Aujeszky's disease antibodies are apprehended. Furthermore nasal swabs and lungs are submitted to analysis for virus isolation purposes and data are collected from each herd for epidemiological studies. Influenza passive H.I. Antibodies rapidly decrease in the piglets. Later a seroconversion is observed in 10% of the investigated piglets. These pigs belong to 4 herds. The conversion happens usually after 3 months of age. All attempts to isolate the virus failed. Special herd conditions may be associated with a persistence of the viral activity inside the units between epizootics: bad demography (unbalance in the breeding stock), inadequate hygiene policy in the fattening house (with permanent arrivals of pigs coming from subsequent batches of sows), a high prevalence of respiratory and specially pulmonary enzootic diseases. A seroconversion against Aujeszky's disease is pointed out in 3 out of the 4 herds concerned with Influenza virus activity suggesting that closely the same conditions may be related both to influenza and Aujeszky's disease virus activity.
在法国布列塔尼地区的16个商业育肥场开展了一项研究。本研究旨在揭示急性 epizootic 后，流感病毒在这些集约化养殖场内的活动持续性。在每个农场中，选取两批猪，进行个体识别，并从哺乳期跟踪至屠宰。每月对同一批猪进行血清学检测。同时检测流感抗体和伪狂犬病抗体。此外，采集鼻拭子和肺组织用于病毒分离分析，并从每个猪群收集数据用于流行病学研究。仔猪体内的流感被动血凝抑制抗体迅速下降。随后，在10% 的受调查仔猪中观察到血清转化。这些猪来自4个猪群。血清转化通常发生在3月龄之后。所有病毒分离尝试均失败。特殊的猪群状况可能与 epizootics 之间养殖场内病毒活动的持续性有关：种群结构不佳（繁殖种群失衡）、育肥舍卫生措施不当（后续批次母猪的猪只不断进入）、呼吸道疾病尤其是肺部地方病的高流行率。在与流感病毒活动相关的4个猪群中，有3个猪群出现了针对伪狂犬病的血清转化，这表明相似的状况可能与流感病毒和伪狂犬病病毒的活动均有关。
