Robinson S E, Christley R M
Epidemiology Group, Department of Veterinary Clinical Sciences, Leahurst, Neston, South Wirral, UK.
Prev Vet Med. 2007 Sep 14;81(1-3):21-37. doi: 10.1016/j.prevetmed.2007.04.011. Epub 2007 May 7.
Within Great Britain cattle are often traded at regional markets, of which there are approximately 200 located throughout England, Scotland and Wales. The movement of animals through markets was important in the spread of foot-and-mouth disease (FMD) virus during the 2001 GB outbreak. Here, we describe the movements of cattle to and from markets for 2002-2004 and, using social network analysis, we construct networks based on these movements. In 2002, 56,227 animal holdings (AH) sent cattle to 222 cattle auction markets, compared to 58,476 AH and 187 auction markets in 2004. Auction markets vary considerably in their trading with AH. The majority of markets received animals from less than 50 AH, but one received animals from as many as 6155 AH during a year. The distances travelled between origin AH and destination AH when cattle move "directly" were found to be significantly shorter compared to distances between origin and destination AH where the movement occurred via a market. However, the vast majority of distances moved, for both types of movements, were less than 50 km. Some auction markets appear as highly connected premises within the contact network and are associated with high betweenness scores. However AH also occupy positions central to the contact network. The variation in the characteristics and role of individual markets within the contact network suggests important differences in risk of disease transmission associated with each market. Inclusion of network parameters, when considering the risk associated with moving cattle through auction markets may enhance the development of effective targeted disease control strategies.
在英国，牛只通常在区域市场进行交易，全英格兰、苏格兰和威尔士约有200个这样的市场。在2001年英国口蹄疫疫情期间，动物在市场间的流动对病毒传播起到了重要作用。在此，我们描述了2002年至2004年进出市场的牛只流动情况，并利用社会网络分析，基于这些流动构建了网络。2002年，56227个动物养殖场（AH）将牛只送往222个牛只拍卖市场，而2004年有58476个AH和187个拍卖市场。拍卖市场与AH的交易量差异很大。大多数市场接收的动物来自不到50个AH，但有一个市场在一年内接收了多达6155个AH的动物。当牛只“直接”移动时，起始AH和目的地AH之间的距离明显短于通过市场移动时的起始和目的地AH之间的距离。然而，对于这两种移动类型，绝大多数移动距离都小于50公里。一些拍卖市场在接触网络中表现为高度连接的场所，并与高介数得分相关。然而，AH在接触网络中也占据中心位置。接触网络中各个市场的特征和作用的差异表明，每个市场在疾病传播风险方面存在重要差异。在考虑通过拍卖市场运输牛只的风险时纳入网络参数，可能会促进有效的针对性疾病控制策略的制定。
