Hughes V L, Randolph S E
Department of Zoology, University of Oxford, UK.
J Parasitol. 2001 Feb;87(1):49-54. doi: 10.1645/0022-3395(2001)087[0049:TDIAAR]2.0.CO;2.
The effects of testosterone on acquired resistance to ticks, Ixodes ricinus, in their natural rodent hosts (voles, Clethrionomys glareolus, and wood-mice, Apodemus sylvaticus) were investigated by manipulating testosterone levels and exposing the hosts to repeated tick infestations. Testosterone reduced both innate and acquired resistance to tick feeding. During primary infestations, attachment rates were higher on rodents with high testosterone levels than on oil-implanted controls. Successive infestations on voles were accompanied by a decrease in tick feeding success and survival, but this decrease was significantly greater in ticks fed on control voles than in those fed on voles implanted with testosterone. When reduced feeding success had been induced, either by vaccination with tick salivary gland extract or by 4 successive infestations, implantation with testosterone partially reversed the acquired resistance. These effects of testosterone will generate heterogeneities within the rodent population with respect to tick distribution and microparasite transmission. The lowest innate and acquired resistance to tick feeding occurs in that fraction of the host population, i.e., sexually active males, most actively involved in the transmission of both Babesia microti and Borrelia burgdorferi s.l.
通过调节睾酮水平并使宿主反复遭受蜱虫侵袭，研究了睾酮对其天然啮齿动物宿主（田鼠，棕背䶄，以及林姬鼠，森林姬鼠）获得性抗蓖麻硬蜱能力的影响。睾酮降低了对蜱虫取食的先天和获得性抗性。在初次侵染期间，睾酮水平高的啮齿动物上的附着率高于植入油剂的对照动物。对田鼠的连续侵染伴随着蜱虫取食成功率和存活率的下降，但对照田鼠上取食的蜱虫的这种下降幅度明显大于睾酮植入田鼠上取食的蜱虫。当通过用蜱唾液腺提取物接种疫苗或通过4次连续侵染诱导取食成功率降低时，植入睾酮可部分逆转获得性抗性。睾酮的这些作用将在啮齿动物种群中产生关于蜱虫分布和微寄生虫传播的异质性。对蜱虫取食的最低先天和获得性抗性出现在宿主种群中那部分，即性活跃的雄性，它们最积极地参与微小巴贝斯虫和伯氏疏螺旋体狭义亚种的传播。
