Benedictus A, Mitchell R M, Linde-Widmann M, Sweeney R, Fyock T, Schukken Y H, Whitlock R H
Utrecht University, Faculty of Veterinary Medicine, Department of Farm Animal Health, Yalelaan 7, Utrecht, The Netherlands.
Prev Vet Med. 2008 Mar 17;83(3-4):215-27. doi: 10.1016/j.prevetmed.2007.07.008. Epub 2007 Sep 14.
A Johne's disease control program, including stringent management practices and a test-and-cull program (whole-herd fecal-samples taken twice a year), was implemented on a medium-sized Pennsylvania dairy farm that was suffering losses from clinical Johne's disease. The data that emerged from the control program, combined with birthdates, culling dates, lactation information and pedigrees, yielded an extensive longitudinal dataset. The dataset was processed through SAS 9.1 for statistical analysis; herd-level disease dynamics and dam-to-daughter transmission parameters were calculated. After the implementation of the program in 1984, prevalence dropped dramatically from 60% to less than 20% in 1989. After an apparent prevalence peak (25%) in 1991 due to improved test sensitivity, prevalence maintained a plateau of 10% from 1996 to 2000. After the implementation of the program, 9.5% of the offspring from test-negative dams and 26.8% of the offspring from known-infected dams became infected with Mycobacterium avium subspecies paratuberculosis (Map) (chi(2)=14.7; p=0.0001). Calves born shortly following the calving of an infected dam and calves growing up with a future high shedder were more likely to be infected compared to calves without this risk profile. It was concluded that, after the implementation of the control program, the most important causes of infections of susceptible calves were their own dams or infected animals which had calved recently.
在宾夕法尼亚州一个因临床型副结核病遭受损失的中型奶牛场实施了一项副结核病控制计划，该计划包括严格的管理措施和检测与扑杀计划（每年采集两次全群粪便样本）。从该控制计划中获取的数据，结合出生日期、扑杀日期、泌乳信息和系谱，形成了一个广泛的纵向数据集。该数据集通过SAS 9.1进行处理以进行统计分析；计算了畜群水平的疾病动态和母犊至子犊的传播参数。1984年该计划实施后，患病率从60%急剧下降至1989年的不到20%。由于检测灵敏度提高，1991年出现明显的患病率峰值（25%）后，1996年至2000年患病率维持在10%的平台期。该计划实施后，检测呈阴性的母牛所产后代中有9.5%，已知感染母牛所产后代中有26.8%感染了副结核分枝杆菌副结核亚种（Map）（卡方检验值=14.7；p=0.0001）。与没有这种风险特征的犊牛相比，在感染母牛产犊后不久出生的犊牛以及与未来高排菌量动物一起长大的犊牛更易感染。得出的结论是，控制计划实施后，易感犊牛感染的最重要原因是其自身的母牛或近期产犊的感染动物。
