School of Veterinary Medicine, Ross University, Basseterre, St, Kitts and Nevis, West Indies.
Parasit Vectors. 2014 Apr 14;7:182. doi: 10.1186/1756-3305-7-182.
Amblyomma variegatum is an important cause of morbidity, mortality and economic losses in Africa and the West Indies. Attempts to control and/or eradicate the tick from the Caribbean have largely been unsuccessful because of difficulties relating to the biology of the three-host tick and problems with applying acaricides on a regular basis to free-ranging domestic ruminants. While plastic collars impregnated with insecticides are widely and effectively used in companion animals to control external parasites there is little information on this technology in ruminants.
Over 21 months we tested the efficacy of slow-release plastic tags impregnated with deltamethrin (7%) and aggregation-attachment pheromones (DPITs) in controlling A. variegatum on free-ranging cattle on two farms on St. Kitts. The tags were replaced every three months or when found to be lost.
On sentinel animals fitted with tags containing only aggregation-attachment pheromones there were an average of 23.1 ticks per semi-monthly visit although this number varied considerably, peaking in the dry season around May and being lowest in August to October during the wet season. Significantly fewer ticks (3.5 on average) were found on cattle with DPITs at each visit (P < 0.001). Although the DIPTs provided good control (92% on average), they did not significantly reduce A. variegatum in the environment with tick numbers on sentinels being higher in the second year of the study, despite up to 44% of animals being fitted with DPITs. The tags were economical, costing 0.2% of the 1% flumethrin pour-on treatment widely recommended for A. variegatum control in the Caribbean. The major problem encountered was that 38% of tail tags were lost before they were due for replacement every three months.
Our study has shown that DPITs are cheap to produce, easy to place, only require handling of animals every three months, and are very effective in protecting cattle from A. variegatum. Before DPITs can be considered for eradication programs the problems needing to be addressed include loss of tail tags, particularly in thick vegetation, and the optimum number of animals that must be treated to reduce numbers of ticks in the environment.
扁虱是导致非洲和西印度群岛发病率、死亡率和经济损失的一个重要原因。由于三宿主扁虱的生物学特性以及定期在自由放养的家养反刍动物身上使用杀螨剂存在困难，因此试图从加勒比地区控制或根除该扁虱的尝试大多没有成功。虽然驱虫塑料项圈在伴侣动物中被广泛有效地用于控制外部寄生虫，但关于这种技术在反刍动物中的应用却知之甚少。
在 21 个月的时间里，我们在圣基茨的两个农场的自由放养牛身上测试了缓慢释放的、含有氯菊酯（7%）和聚集-附着信息素（DPITs）的塑料标签对控制扁虱的效果。标签每三个月或发现丢失时更换一次。
在装有仅含有聚集-附着信息素的标签的哨兵动物身上，每半个月进行一次访问，平均有 23.1 只扁虱，尽管数量变化很大，在 5 月左右的旱季达到峰值，在 8 月至 10 月的雨季达到最低。在每次访问时，DPIT 牛身上发现的扁虱数量明显较少（平均 3.5 只）（P<0.001）。尽管 DPIT 提供了良好的控制效果（平均 92%），但它们并没有显著减少环境中的扁虱数量，第二年的研究中，尽管有多达 44%的动物佩戴了 DPIT，但哨兵身上的扁虱数量更高。标签经济实惠，成本仅为 1%氟虫腈滴剂处理费的 0.2%，这种处理方法广泛推荐用于加勒比地区的扁虱控制。遇到的主要问题是，38%的尾巴标签在每三个月更换一次之前就丢失了。
我们的研究表明，DPIT 生产成本低，易于放置，只需每三个月处理一次动物，并且对保护牛免受扁虱侵害非常有效。在考虑使用 DPIT 进行根除计划之前，需要解决的问题包括尾巴标签丢失，特别是在茂密的植被中，以及必须治疗的动物数量，以减少环境中的扁虱数量。
