Schwermer Heinzpeter, Forster Katharina, Brülisauer Franz, Chaubert Claude, Heim Dagmar
Swiss Federal Veterinary Office, Schwarzenburgstrasse 155, 3003 Bern-Liebefeld, Switzerland.
Vet Res. 2007 May-Jun;38(3):409-18. doi: 10.1051/vetres:2007005. Epub 2007 Mar 13.
Cross-contamination of cattle feed with meat and bone meal (MBM) allowed in feed for other species is regarded as the current hypothesis for the infection pathway of Bovine Spongiform Encephalopathy (BSE) cases occurring after the implementation of a ban on feeding MBM to cattle. This study was aimed at establishing a spatial relation between BSE cases in Switzerland and the findings of MBM in cattle feed. A cluster analysis and a cohort study were performed. Two hundred sixteen BSE cases born after December 1990 and detected until August 1st 2005, screening data of 504 feed producers between 1996 and 2001 and population data from the Swiss 2001 cattle census were included. The cluster analysis showed feed producer, positive for MBM contaminations in cattle feed, as possible cluster centres for BSE cases. In the cohort study, farms within a radius of 2 and 10 km around positive feed producers showed significantly higher odds to have a BSE case than the control group. The odds ratio and its 95% confidence interval were 2.23 (1.26-3.93) for the 2 km radius and 1.38 (1-1.9) for the 10 km radius. The results provide evidence for a spatial relation between cross-contamination and BSE occurrence. These findings support the hypothesis of cross-contamination to be an important route for BSE transmission after a feed ban.
牛饲料被允许用于其他物种的肉骨粉（MBM）交叉污染，被视为在实施禁止用MBM喂牛后出现的牛海绵状脑病（BSE）病例感染途径的当前假设。本研究旨在确定瑞士BSE病例与牛饲料中MBM检测结果之间的空间关系。进行了聚类分析和队列研究。纳入了1990年12月后出生且截至2005年8月1日被检测出的216例BSE病例、1996年至2001年间504家饲料生产商的筛查数据以及瑞士2001年牛普查的种群数据。聚类分析显示，牛饲料中MBM污染呈阳性的饲料生产商可能是BSE病例的聚类中心。在队列研究中，阳性饲料生产商周围半径2公里和10公里范围内的农场出现BSE病例的几率显著高于对照组。2公里半径的优势比及其95%置信区间为2.23（1.26 - 3.93），10公里半径的为1.38（1 - 1.9）。结果为交叉污染与BSE发生之间的空间关系提供了证据。这些发现支持交叉污染是饲料禁令后BSE传播的重要途径这一假设。
