Mooring M S, Mazhowu W, Scott C A
Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California, Davis 95616, USA.
Exp Appl Acarol. 1994 Sep;18(9):507-20. doi: 10.1007/BF00058934.
The effect of rainfall pattern on tick challenge was investigated at Kyle Recreational Park, Zimbabwe, from 1991 to 1992 using drag and removal plot methods to sample environmental tick density. The abundance of adults and nymphs of the brown ear-tick Rhipicephalus appendiculatus and larvae of the bont tick Amblyomma hebraeum was positively correlated with monthly rainfall, whereas no relationship with rainfall was revealed for larval R. appendiculatus, adults of the red-legged tick R. evertsi, or larvae of the blue tick Boophilus decoloratus. A comparison between 1991 (490 mm rainfall) and the drought year of 1992 (161 mm) revealed significant differences in the abundance of R. appendiculatus, A. hebraeum, and B. decoloratus. During the wet season, R. appendiculatus adults were 2-3 times more numerous in the environment during the higher rainfall year of 1991. A. hebraeum larval abundance exhibited a similar pattern to that of R. appendiculatus adults, but B. decoloratus larvae were more abundant in the drought year of 1992 during both the wet and dry seasons. Comparable tick abundance data collected at Kyle during the above-average rainfall years of 1975-1977 (mean = 1029 mm) were compared with tick challenge during the below-average rainfall years of 1991-1992 (mean = 326 mm). In grassland sand habitat and all habitats combined R. appendiculatus adults, nymphs, and larvae were much more abundant during the high rainfall years. In contrast, larvae of B. decoloratus were more numerous during the drier years. A hebraeum larvae were also more abundant during the drier years. The strong positive correlation of adult R. appendiculatus abundance with rainfall and the coincidence of increased adult tick challenge with increased rainfall indicate that adult R. appendiculatus tick burden on hosts would be heaviest during the wet season and high rainfall years.
1991年至1992年期间，在津巴布韦的凯尔休闲公园，采用拖拽和清除样地法对环境蜱密度进行采样，研究降雨模式对蜱虫侵袭的影响。褐耳蜱（Rhipicephalus appendiculatus）的成虫和若虫以及南非山蜱（Amblyomma hebraeum）的幼虫数量与月降雨量呈正相关，而附肢硬蜱（R. appendiculatus）的幼虫、红腿蜱（R. evertsi）的成虫或消色牛蜱（Boophilus decoloratus）的幼虫数量与降雨量无相关性。1991年（降雨量490毫米）与干旱的1992年（降雨量161毫米）的比较显示，附肢硬蜱、南非山蜱和消色牛蜱的数量存在显著差异。在雨季，1991年降雨量较高的年份里，环境中附肢硬蜱成虫的数量是其他年份的2至3倍。南非山蜱幼虫数量的变化模式与附肢硬蜱成虫相似，但消色牛蜱幼虫在1992年干旱年份的雨季和旱季数量更多。将1975 - 1977年降雨量高于平均水平（平均 = 1029毫米）期间在凯尔收集的可比蜱虫数量数据与1991 - 1992年降雨量低于平均水平（平均 = 326毫米）期间的蜱虫侵袭情况进行比较。在草地沙地栖息地以及所有栖息地中，降雨量高的年份里附肢硬蜱的成虫、若虫和幼虫数量更多。相比之下，消色牛蜱的幼虫在较干旱年份数量更多。南非山蜱幼虫在较干旱年份数量也更多。附肢硬蜱成虫数量与降雨量的强正相关以及成年蜱虫侵袭增加与降雨量增加的巧合表明，宿主身上附肢硬蜱的成年蜱虫负担在雨季和降雨量高的年份最重。
