Lynen Godelieve, Zeman Petr, Bakuname Christine, Di Giulio Giuseppe, Mtui Paul, Sanka Paul, Jongejan Frans
Ministry of Water and Livestock Development, Veterinary Investigation Centre, PO Box 1068, Arusha, Tanzania.
Exp Appl Acarol. 2007;43(4):303-19. doi: 10.1007/s10493-007-9123-9. Epub 2007 Nov 27.
In order to implement a robust integrated tick and tick-borne disease control programme in Tanzania, based on ecological and epidemiological knowledge of ticks and their associated diseases, a national tick and sero-surveillance study was carried out in all 21 regions of the mainland, as well as on Mafia Island, between 1998 and 2001. The current distributions of Rhipicephalus appendiculatus, R. pravus, Amblyomma variegatum, A. gemma, and A. lepidum are illustrated and discussed. Tick distribution maps were assessed using the Weights-of-Evidence method (WofE), and employing temperature, humidity, NDVI, rainfall, and land-cover predictive data. Ground-truthing was done to check correspondence both of the data employed in prediction with land-cover characteristics discerned in the field as well as of the surveyed and predicted tick distributions. Statistical methods were used to analyse associations of the tick species with their environment, cattle density, and other ticks. Except for R. appendiculatus, no appreciable changes were demonstrated in the predicted and observed tick distributions compared to the existing maps that originated in the 1950-1960s. Cattle density influenced the distribution of A. variegatum and, to a certain extent, of A. lepidum, but had no appreciable influence on the distribution of any of the other ticks discussed in this paper, neither did livestock movement. Distinct differences for environmental requirements where observed between different tick species within the same genus. The predictive maps of R. appendiculatus and R. pravus suggest their mutually exclusive distribution in Tanzania, and simultaneous statistical analysis showed R. pravus as a greater specialist. Of the three Amblyomma species, A. variegatum is the most catholic tick species in Tanzania, while both A. gemma and A. lepidum belong to the more specialized species. Despite dissimilar habitat preferences, all three Amblyomma spp. co-exist in central Tanzania, where very heterogeneous habitats may simultaneously satisfy the environmental requirements of all three species. The current study, conducted about 4 decades after the last major survey activities, has shown that changing livestock policies, unrestricted livestock movement and a continuous change in climatic/environmental conditions in Tanzania have brought about only limited changes in the distribution patterns of R. appendiculatus, R. pravus and the three Amblyomma species investigated. Whether this observation indicates a relative indifference of these ticks to environmental and/or climate changes allows room for speculation.
为了基于蜱虫及其相关疾病的生态和流行病学知识，在坦桑尼亚实施一项强有力的蜱虫及蜱传疾病综合控制计划，1998年至2001年间在大陆的所有21个地区以及马菲亚岛开展了一项全国蜱虫及血清学监测研究。本文阐述并讨论了微小扇头蜱、草原扇头蜱、变异革蜱、宝石革蜱和鳞纹革蜱的当前分布情况。使用证据权重法（WofE）并采用温度、湿度、归一化植被指数、降雨量和土地覆盖预测数据对蜱虫分布图进行了评估。进行了实地验证，以检查预测中使用的数据与实地观察到的土地覆盖特征之间的对应关系，以及调查的蜱虫分布与预测的蜱虫分布之间的对应关系。使用统计方法分析蜱虫种类与其环境、牛群密度和其他蜱虫之间的关联。与20世纪50 - 60年代的现有地图相比，除微小扇头蜱外，预测的蜱虫分布和观察到的蜱虫分布没有明显变化。牛群密度影响变异革蜱的分布，在一定程度上也影响鳞纹革蜱的分布，但对本文讨论的其他任何蜱虫的分布没有明显影响，牲畜移动也没有影响。在同一属的不同蜱虫种类之间观察到了环境要求的明显差异。微小扇头蜱和草原扇头蜱的预测图表明它们在坦桑尼亚相互排斥分布，同时进行的统计分析表明草原扇头蜱是更具专一性的物种。在三种革蜱中，变异革蜱是坦桑尼亚最具适应性的蜱虫种类，而宝石革蜱和鳞纹革蜱都属于更具专一性的物种。尽管栖息地偏好不同，但这三种革蜱在坦桑尼亚中部共存，那里非常多样化的栖息地可能同时满足这三种物种的环境要求。在最后一次主要调查活动大约40年后进行的当前研究表明，坦桑尼亚不断变化的畜牧政策、不受限制的牲畜移动以及气候/环境条件的持续变化，仅使微小扇头蜱、草原扇头蜱和所调查的三种革蜱的分布模式发生了有限的变化。这种观察结果是否表明这些蜱虫对环境和/或气候变化相对不敏感，值得进一步探讨。
