HUMAN BABESIA

巴贝斯虫病正在成为一种具有公共卫生意义的疾病， U.S.A.随着越来越多的临床甚至致命病例报告， 以前没有认识到感染巴伯菌的风险。 这些血原虫寄生虫的潜在重要性也是 在莱姆，蜱虫传播的巴贝虫的风险增加 疾病流行区和患者的易感性增强， 人类免疫缺陷病毒感染到严重的巴贝虫病。 直到 最近，这个国家的人类巴贝斯虫感染被归因于 到B。田鼠，来自啮齿动物。 拟议项目的设计 来研究两个假设 初步的假设是， 在美国，巴贝虫病可能是由巴贝虫寄生虫引起的， 在抗原性和基因型上与B不同。显微镜 探讨 这种可能性，巴氏杆菌将从无症状的携带者中分离出来， 主要是在莱姆病流行区，并从患者的临床 巴贝斯虫病 将对分离株进行分子表征和比较 从人类和动物中分离出的形态相似的巴伯氏杆菌， 其他地理位置。 我们的研究重点将集中在 代表基因型不同分离株的寄生虫， 在人类中特别致命和/或在感染后从患者中分离 从临床疾病或无症状携带者中恢复。 分离株 根据这些标准选择的将用于测试主要的 假设，这是小型巴贝斯虫寄生虫，如B。田鼠 和其他人类巴贝斯虫分离株，可以具有 红细胞外发育阶段，如果像淋巴细胞内 泰勒虫幼虫期，能够诱导宿主细胞 转化和增殖。 为了评估这种可能性，组织 从巴贝斯虫病患者和仓鼠感染蜱传播 将检查人巴贝斯虫分离株是否存在 红细胞外寄生虫阶段。 选择的组织， 淋巴增生病灶和/或潜在的细胞内寄生虫将 通过荧光标记的， 巴贝虫特异性ss-rDNA探针。 离体培养技术 开发用于维持泰勒虫感染的 将使用淋巴母细胞样细胞来分离类似的阶段， 人和仓鼠的血液和/或淋巴组织中的蜱源性 巴氏杆菌感染。 此外，蜱源性的传染性 巴贝斯虫子孢子的人单核细胞在体外将是 测定 拟议的研究将提供以下方面的宝贵信息： 这些巴氏疟原虫的基本生物学和方法学， 应用于提高人类巴贝斯虫病的诊断和控制。

Babesiosis is emerging as a disease of public health significance in the U.S.A. with increased reports of clinical, even fatal, cases in areas where the risk of infection with Babesia was not recognized previously. The potential importance of these hemoprotozoal parasites is also evidenced by the increased risk of tick-transmitted Babesia in Lyme disease endemic areas and the enhanced susceptibility of patients with human immunodeficiency virus infections to severe babesiosis. Until recently, human babesial infections in this country have been attributed to B. microti, derived from rodents. The proposed project is designed to investigate two hypotheses. The preliminary hypothesis is that human babesiosis in the U.S.A. may be caused by babesial parasites that are antigenically and genotypically distinct from B. microti. To investigate this possibility, Babesia will be isolated from asymptomatic carriers, primarily in Lyme disease endemic areas, and from patients with clinical babesiosis. The isolates will be characterized and compared molecularly to morphologically similar Babesia isolates from humans and animals in other geographic locations. The emphasis of our studies will focus on parasites that represent genotypically distinct isolates, are particularly virulent in humans and/or were isolated from a patient after recovery from clinical disease or from an asymptomatic carrier. Isolates selected by these criteria will be utilized to test the primary hypothesis, which is that small babesial parasites, such as B. microti and other human babesial isolates in the U.S.A., may have an exoerythrocytic developmental stage, which if like the intralymphocytic schizont stage of Theileria, would be capable of inducing host cell transformation and proliferation. To evaluate this possibility, tissues from babesiosis patients and hamsters infected by tick-transmission of human babesial isolates will be examined for the presence of exoerythrocytic parasite stages. Selected tissues with lymphoproliferative foci and/or potential intracellular parasites will be evaluated further by in situ hybridization of fluorescent-labelled, Babesia-specific ss-rDNA probes. In vitro cultivation techniques developed for the maintenance of Theileria schizont-infected lymphoblastoid cell will be employed to isolate similar stages in the blood and/or lymphoid tissues of humans and hamsters with tick-derived Babesia infections. In addition, the infectivity of tick-derived babesial sporozoites for human mononuclear cells in vitro will be determined. The proposed study will provide valuable information about the basic biology of these Babesia parasites and methodology which can be applied to improve the diagnosis and control of human babesiosis.