Poljak Z, Dewey C E, Friendship R M, Martin S W, Christensen J
Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
Epidemiol Infect. 2008 Oct;136(10):1388-400. doi: 10.1017/S0950268807009855. Epub 2007 Nov 30.
The objectives of this study were to identify factors associated with Salmonella status at the farm, pen, and pig level; explore the nature of variation in the association between the pen-level Salmonella status and pen-level covariates, and pig-level Salmonella status and pig- and pen-level covariates; and to identify the relative importance of factors operating at geographical, farm, and pen level for Salmonella shedding of pigs. For these purposes, samples from 799 pigs and 374 pens on 80 farms in Ontario in 2004 were collected and bacteriologically tested in a cross-sectional study. Census division was the least variable level, and farm the most variable level for shedding. Increased frequency of disinfection and washing with cold water were positively associated with Salmonella positivity, whereas liquid and mash feed and completely closed barns were sparing factors. After farm, pen was the second most variable level for shedding. However, no measured pen-level variables were associated with Salmonella status of pigs or pens. The shedding of Salmonella at the pig level tended to be associated with pig weight, and there was no random variation around this association. Results of this study suggest that a herd test based on bacteriological culture would probably have higher sensitivity if growing animals of lower weight were sampled instead of market weight animals, and this might be beneficial for Salmonella monitoring.
本研究的目的是确定与农场、猪栏和猪个体层面沙门氏菌状态相关的因素；探究猪栏层面沙门氏菌状态与猪栏层面协变量之间以及猪个体层面沙门氏菌状态与猪和猪栏层面协变量之间关联的变化性质；并确定在地理、农场和猪栏层面起作用的因素对猪沙门氏菌排泄的相对重要性。为实现这些目的，2004年在安大略省80个农场采集了799头猪和374个猪栏的样本，并在一项横断面研究中进行了细菌学检测。普查分区是排泄变化最小的层面，而农场是排泄变化最大的层面。消毒频率增加和用冷水冲洗与沙门氏菌阳性呈正相关，而液体和糊状饲料以及完全封闭的猪舍是保护因素。在农场之后，猪栏是排泄变化第二大的层面。然而，没有测量到的猪栏层面变量与猪或猪栏的沙门氏菌状态相关。猪个体层面的沙门氏菌排泄倾向于与猪的体重相关，并且在这种关联周围没有随机变化。本研究结果表明，如果对体重较轻的生长猪而非上市体重的猪进行采样，基于细菌培养的群体检测可能具有更高的敏感性，这可能有利于沙门氏菌监测。
