Daniels T J, Fish D
Department of Community and Preventive Medicine, New York Medical College, Valhalla 10595.
J Med Entomol. 1995 Jan;32(1):5-11. doi: 10.1093/jmedent/32.1.5.
Effects of deer exclusion on abundance of immature Ixodes scapularis Say parasitizing small and medium-sized mammals, and the role mammals have in introducing ticks to exclosure areas, were examined at two sites in Westchester County, New York. In total, 686 mammal captures representing nine species were obtained, with white-footed mice, Peromyscus leucopus Rafinesque, composing > 80% of all captures, followed by raccoons, Procyon lotor (L.); opossums, Didelphis virginiana (Kerr); and striped skunks, Mephitis mephitis Schreber. At the Near Archives site, 14% of 81 individual mice, 46% of raccoons, and 33% of opossums captured were found to cross the exclosure fence, as did 12% of 50 mice and 38% of raccoons at the Hudson Pines site. Skunks apparently did not cross the fence at either site. Mice captured exclusively outside the Near Archives exclosure hosted significantly more larvae than mice captured inside only, with fence crossers hosting an intermediate number of larvae. At Hudson Pines, numbers of larvae on fence-crossing mice and those captured solely inside the exclosure were equivalent, with tick loads on mice captured outside the exclosure significantly greater. The number of larvae per raccoon did not differ significantly with capture location (inside, outside, or both sides of exclosure fence) at either site. Densities of host-seeking larvae and nymphs were significantly higher outside the exclosure than inside at Near Archives, though not at Hudson Pines. Differences in tick density inside and outside exclosures declined with each successive developmental stage so that adult density inside exclosures tended to converge with that outside at both sites. Although deer exclosures can have a significant impact on nymphal I. scapularis abundance, they may not reduce the risk of encountering infected adults. Mice, raccoons, and opossums have a role in introducing potentially infective ticks to areas where deer have been excluded, though the level of immigration of ticks into the area will likely depend on the density of ticks outside the exclosure.
在纽约韦斯特切斯特县的两个地点，研究了排除鹿对寄生在中小型哺乳动物身上的未成熟肩突硬蜱（Ixodes scapularis Say）数量的影响，以及哺乳动物在将蜱引入禁牧区中所起的作用。总共捕获了代表9个物种的686只哺乳动物，其中白足鼠（Peromyscus leucopus Rafinesque）占所有捕获量的80%以上，其次是浣熊（Procyon lotor (L.)）、负鼠（Didelphis virginiana (Kerr)）和条纹臭鼬（Mephitis mephitis Schreber）。在近档案馆地点，捕获的81只个体小鼠中有14%、浣熊中有46%、负鼠中有33%被发现越过了围栏，在哈德逊松树林地点，50只小鼠中有12%、浣熊中有38%越过了围栏。臭鼬显然在两个地点都没有越过围栏。仅在近档案馆围栏外捕获的小鼠身上的幼虫明显比仅在围栏内捕获的小鼠多，越过围栏的小鼠身上的幼虫数量处于中间水平。在哈德逊松树林，越过围栏的小鼠和仅在围栏内捕获的小鼠身上的幼虫数量相当，围栏外捕获的小鼠身上的蜱负荷明显更大。在两个地点，每只浣熊身上的幼虫数量在捕获地点（围栏内、围栏外或围栏两侧）之间没有显著差异。在近档案馆，寻找宿主的幼虫和若虫的密度在围栏外明显高于围栏内，而在哈德逊松树林则不然。随着发育阶段的依次推进，围栏内外蜱密度的差异逐渐减小，因此在两个地点，围栏内成虫的密度趋于与围栏外的密度趋同。虽然排除鹿对肩突硬蜱若虫的数量有显著影响，但它们可能不会降低遇到受感染成虫的风险。小鼠、浣熊和负鼠在将潜在感染性蜱引入鹿被排除的区域中起作用，不过蜱进入该区域的迁移水平可能取决于围栏外蜱的密度。
