Sanson R L
AsureQuality Limited, Batchelar Centre, PO Box 585, Palmerston North, New Zealand.
N Z Vet J. 2007 Dec;55(6):273-9. doi: 10.1080/00480169.2007.36781.
To use a simulation model of the spread of the Asian honeybee mite (Varroa destructor) amongst apiaries, to evaluate a series of detection surveillance programmes for the South Island of New Zealand.
Five potential incursion sites into the South Island were selected. A stochastic spatial simulation model, Varroa_ sim, was adapted to simulate spread of the mite from these sites as a series of silent-phase propagating epidemics. The study population comprised all apiaries in the South Island registered in the Ministry of Agriculture and Forestry's (MAF's) apiary database in 2003. Six different surveillance programmes were simulated to try and detect the mite. Three of these were the actual multi-stage sampling plans conducted during the autumn (March-May) of 2001, 2002 and 2003, and the other three involved simple random sampling with sampling fractions equivalent to the actual numbers of apiaries tested in each of those years. The relative performances of the different surveillance plans were evaluated in terms of their ability to detect the mite early before it had spread too far and whilst there might still be a chance of eradication.
There were 13,798 registered apiaries in the South Island with valid map coordinates in the apiary database at the time of the study. The model generated 50 epidemics against which the various surveillance programmes were evaluated. The actual surveillance programmes conducted during the autumn of 2001 and 2002 generally performed fairly well in detecting the mite. The programme conducted in autumn 2003 detected the mite reasonably well in high-risk areas, but was very poor in low-risk areas. The simple random sampling strategies performed surprisingly well, and their relative rankings were proportional to the sampling fractions employed.
This study showed the value in using a spatial simulation model to generate plausible silent-phase epidemics, against which detection surveillance programmes could be evaluated, in ways that would otherwise not be possible.
利用亚洲蜜蜂螨（狄斯瓦螨）在养蜂场之间传播的模拟模型，评估针对新西兰南岛的一系列检测监测计划。
选择了五个可能传入南岛的地点。采用一个随机空间模拟模型Varroa_sim，将螨从这些地点的传播模拟为一系列无症状期传播的流行病。研究群体包括2003年在农业和林业部（MAF）养蜂场数据库中登记的南岛所有养蜂场。模拟了六种不同的监测计划以试图检测到螨。其中三种是在2001年、2002年和2003年秋季（3月至5月）实际实施的多阶段抽样计划，另外三种涉及简单随机抽样，抽样比例等同于那些年份中实际检测的养蜂场数量。根据不同监测计划在螨扩散太远之前且仍有可能根除时早期检测到螨的能力，评估它们的相对性能。
在研究时，南岛有13798个登记养蜂场在养蜂场数据库中有有效的地图坐标。该模型生成了50次流行病，据此评估各种监测计划。2001年和2002年秋季实施的实际监测计划在检测螨方面总体表现相当不错。2003年秋季实施的计划在高风险地区检测螨的情况还算合理，但在低风险地区表现很差。简单随机抽样策略的表现出人意料地好，其相对排名与所采用的抽样比例成正比。
本研究表明了使用空间模拟模型生成似是而非的无症状期流行病的价值，据此可以评估检测监测计划，而这在其他情况下是不可能做到的。
