Kocan K M
Department of Veterinary Pathology, College of Veterinary Medicine, Oklahoma State University, Stillwater 74078, USA.
Vet Parasitol. 1995 Mar;57(1-3):121-51. doi: 10.1016/0304-4017(94)03116-e.
Development in and transmission of hemoparasites by tick vectors are phenomena closely synchronized with the tick feeding cycle. In all known life cycles, initial infection of tick tissues occurs in midgut epithelial cells and transmission is effected as ticks feed after parasites have developed and multiplied in salivary glands. Many factors reviewed affect development and transmission of hemoparasites by ticks including age of ticks, artificial temperature, climate and/or season, tick stage or sex, hemoparasite variation, concurrent infection of ticks with other pathogens, host cell susceptibility, transovarial transmission, effect of hemoparasites on tick biology, and the effect of infecting parasitemia level in cattle on infection rates in ticks. Four hemoparasites of cattle, Anaplasma marginale, Cowdria ruminantium, Theileria parva, and Babesia spp., are all dependent on ticks for biological transmission. Babesia is transmitted transovarially whereas the other three are transmitted transstadially. Mechanical transfer of infective blood via fomites and mouthparts of biting arthropods is also a major means of transmission for Anaplasma marginale but not of the others. Potential control methods for hemoparasites that target parasites as they are developing in their respective tick hosts include tick control, vaccines (against ticks and parasites), and drugs (against ticks and parasites). Successful application of control strategies will be dependent upon thorough understanding of parasite developmental cycles, biology of the tick vectors and the immune response of cattle to ticks and to hemoparasites. The most effective control measures will be those that are targeted against both ticks and the hemoparasites they vector.
蜱传播血寄生虫的发育和传播现象与蜱的取食周期密切同步。在所有已知的生命周期中，蜱组织的初始感染发生在中肠上皮细胞中，当寄生虫在唾液腺中发育和繁殖后，随着蜱的取食而实现传播。所综述的许多因素影响蜱传播血寄生虫，包括蜱的年龄、人工温度、气候和/或季节、蜱的阶段或性别、血寄生虫变异、蜱与其他病原体的同时感染、宿主细胞易感性、经卵传播、血寄生虫对蜱生物学的影响以及牛感染的寄生虫血症水平对蜱感染率的影响。牛的四种血寄生虫，即边缘无浆体、反刍兽考德里氏体、小泰勒虫和巴贝斯虫属，都依赖蜱进行生物传播。巴贝斯虫通过经卵传播，而其他三种通过经变态期传播。通过污染物和叮咬节肢动物的口器机械传播感染性血液也是边缘无浆体的主要传播方式，但其他寄生虫不是。针对在各自蜱宿主中发育的寄生虫的血寄生虫潜在控制方法包括蜱控制、疫苗（针对蜱和寄生虫）和药物（针对蜱和寄生虫）。控制策略的成功应用将取决于对寄生虫发育周期、蜱传播媒介生物学以及牛对蜱和血寄生虫的免疫反应的透彻理解。最有效的控制措施将是针对蜱及其传播的血寄生虫的措施。
