Raquib Ahsan, Hammell K Larry, Sanchez Javier, O'Brien Nicole, Thakur Krishna Kumar
Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada.
Centre for Veterinary Epidemiological Research (CVER), Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada.
Front Vet Sci. 2025 Jun 18;12:1568484. doi: 10.3389/fvets.2025.1568484. eCollection 2025.
An inherent issue to the Atlantic salmon aquaculture production is the possible transmission of infectious pathogens due to the transportation of live fish. This study employed network analysis to model the contribution of Atlantic salmon transfers to the spread of pathogens. We used a publicly available salmon transfer dataset covering the period 2015-2022. Official records showed that 812 transfers of Atlantic salmon occurred between various British Columbian (BC) salmon production units in that timeframe. For the purpose of evaluating changes in the network structure of farmed Atlantic salmon movements, the daily networks were aggregated into two-year periods to generate a time-ordered series of biennial movements. The freshwater hatchery and marine netpen sites comprised the two types of facilities that made up the Atlantic salmon transfer network, which consisted of 99 nodes (facilities) and 350 edges (links) overall. All the networks showed both scale-free and small-world topology, which would encourage the persistence and spread of pathogens in the Atlantic salmon facilities while simultaneously making it easier to develop risk-based surveillance techniques by focusing on high centrality nodes. Additionally, the rare occurrence of high betweenness and reach, presence of disassortative mixing, negative correlation between the in- and out-degree and between ingoing and outgoing infection chain of facilities, and the identification of freshwater hatcheries as potential superspreaders all suggest that Atlantic salmon transfers might not play a significant role in the spread of pathogens between facilities in the British Columbian Atlantic salmon farming industry. Community detection revealed two or three communities persistently in the aquaculture management unit (AMU) level network, and it would be more effective to make zoning based on AMU. In conclusion, targeted surveillance efforts on high-centrality facilities can be employed to combat any infectious outbreak in the BC Atlantic salmon industry caused by live Atlantic salmon movement.
大西洋鲑鱼养殖生产中一个固有的问题是，活鱼运输可能会传播传染性病原体。本研究采用网络分析方法，对大西洋鲑鱼转移对病原体传播的影响进行建模。我们使用了一个公开的鲑鱼转移数据集，该数据集涵盖了2015年至2022年期间。官方记录显示，在该时间段内，不列颠哥伦比亚省（BC）各鲑鱼生产单位之间共发生了812次大西洋鲑鱼转移。为了评估养殖大西洋鲑鱼移动网络结构的变化，将每日网络汇总为两年期，以生成按时间顺序排列的两年期移动序列。淡水孵化场和海洋网箱养殖场构成了组成大西洋鲑鱼转移网络的两种设施类型，该网络总共由99个节点（设施）和350条边（链接）组成。所有网络均呈现出无标度和小世界拓扑结构，这既会促使病原体在大西洋鲑鱼设施中持续存在和传播，同时通过关注高中心性节点，也更容易开发基于风险的监测技术。此外，高介数和高可达性的情况罕见、存在异配混合、设施的入度和出度之间以及传入和传出感染链之间呈负相关，以及将淡水孵化场确定为潜在的超级传播者，所有这些都表明，在不列颠哥伦比亚省大西洋鲑鱼养殖行业中，大西洋鲑鱼转移可能在设施间病原体传播中不发挥重要作用。社区检测在水产养殖管理单位（AMU）层面的网络中持续发现了两到三个社区，基于AMU进行分区会更有效。总之，针对高中心性设施进行有针对性的监测工作，可用于应对不列颠哥伦比亚省大西洋鲑鱼行业中由活大西洋鲑鱼移动引起的任何传染病爆发。
