人粒细胞埃立克体病研究进展

人粒细胞埃立克体病(human granulocytic ehrli-chiosis,HGE)是近年来新发现的蜱媒自然疫源性疾病,为一种危害较大的传染性疾病,初步认为其危害程度仅次于莱姆病,而且其分布与莱姆病亦有某些方面的相似性。自1993年发现本病以来,报告病例逐渐增多,病例分布范围不断扩大,相关研究逐步增多。本文综述国外人粒细胞埃立克体病研究进展。     

查菲埃立克体和人单核细胞埃立克体病研究进展

埃立克体病是由埃立克体属微生物引起的一类人兽共患急性传染病,其特征为高热、头疼、贫血、白细胞减少、消瘦和黄疸等。查菲埃立克体是埃立克体属中代表性的蜱媒人畜共患病病原体,对人、畜均有较强致病性,在人体引起人单核细胞埃立克体病（HME）。本文较为全面地总结了查非埃立克体和HME的病原学、流行病学、临床表现、诊断和防治等方面的研究进展。     

我国南方埃立克体与犬埃立克体病研究近况

埃立克体是一类专性细胞内寄生菌 ,革兰氏染色阴性 ,主要侵害人和动物的各类白细胞、血小板 ,引起埃立克体病。目前的研究结果表明 ,埃立克体病是热带和亚热带为主的全球分布性疾病 ,也是一种人兽共患自然疫源性疾病 ,蜱是主要传播媒介。我国对埃立克体病的研究始于上世纪 90年     

我国埃立克体的研究进展

埃立克体(Ehrlichiae)是一类严格细胞内寄生的革兰氏阴性菌,主要寄生在单核细胞、粒细胞、或血小板内,引起动物和人的感染——埃立克体病(Ehrlichiosis)。埃立克体分为3个基因群,除腺热埃立克体群外,犬埃立克体群和嗜吞噬埃立克体群均是由蜱传播。长期以来人们认为蜱传埃立克体仅感染动物,而不感染人。然而1987年美国首次报     

蜱中人粒细胞埃立克体DNA的PCR检测及序列分析

目的了解吉林地区蜱种感染人粒细胞埃立克体的情况。方法采用16S rRNA基因特异引物进行半套式PCR,检测吉林省部分林区蜱中人粒细胞埃立克体DNA,并对扩增产物进行克隆和测序,与已知序列进行同源性比较。结果从采集于吉林地区的全沟硬蜱中检出人粒细胞埃立克体的特异性DNA片段,阳性率为1.98%。扩增产物经克隆、测序发现吉林地区人粒细胞埃立克体扩增片段与美国人粒细胞埃立克体分离株(GenBank注册号为U02521)16SrRNA基因序列相对应片段相差2个核苷酸,同源性为99.7%。结论吉林地区的全沟硬蜱携带人粒细胞埃立克体,提示吉林地区可能存在人粒细胞埃立克体病的自然疫源地。     

查菲埃立克体致病机制研究进展

查菲埃立克体(Ehrlichia chaffeensis)是一种侵染人单核细胞的专性细胞内寄生的革兰氏阴性菌。其所致疾病为人单核细胞埃立克体病(Human Monocytotropic Ehrlichiosis, HME),是一种经蜱传播的人兽共患病。查菲埃立克体通过受体介导的吞噬作用侵入宿主细胞,在细胞质空泡中生存和繁殖。其缺乏编码肽聚糖和脂多糖生物合成的基因,影响多种促炎细胞因子的产生,从而抑制宿主的天然或获得性免疫应答。其通过抑制吞噬体溶酶体融合、抑制宿主细胞凋亡、逃避宿主自噬清除、参与蛋白质翻译后修饰等多种方式逃避宿主杀伤而导致持续感染。本文对查菲埃立克体致病机制研究进展进行综述,为进一步了解其与宿主相互作用模式、持续感染机制提供新的研究思路。     

广东部分县市犬埃立克体抗体调查

埃立克体是一类专性细胞内寄生的革兰氏阴性球菌 ,能感染人和多种动物 ,引起埃立克体病。蜱是埃立克体的主要传播媒介。犬埃立克体病曾在世界上多个国家发生流行 ,造成大批军警犬死亡。 1998年广州市郊某养犬基地发生犬埃立克体病流行 ,2 0多条成年工作犬染病 ,死亡 6条〔1〕。 1999年广州市内另一警犬繁殖场暴发犬埃立克体病 ,36条 1～ 2月龄小犬染病 ,死亡 2 4条 ,经济损失很大。为了解犬埃立克体在我省的感染情况 ,及时控制该病的暴发流行 ,1999年 4月起 ,我们对广州周边几个县市部分犬场犬血清抗体进行调查 ,现将结果报告如下。1　材料…     

江西省赣州市蜱携带立克次体和埃立克体的调研

目的 了解江西省赣州市蜱的种类及其携带的病原体,为蜱传疾病的防控提供科学依据方法 在野外用布旗法和在动物体表采集蜱,进行种类鉴定。用PCR法扩增立克次体(Rickettsia sp.)gltA基因和埃立克体(Ehrlichia sp.)16S rRNA基因片段并测序,进行系统进化分析结果 江西省赣州市4县采集的395只蜱的种类包括2属4种,分别为血蜱属的长角血蜱(Haemaphysalislongicornis)、嗜群血蜱(H. concinna)、具角血蜱(H. cornigera)和扇头蜱属的微小扇头蜱(Rhipicephalus microplus)。395只蜱分为43批检测立克次体和埃立克体,共有18批阳性。系统进化分析显示,龙南县22批蜱中检测到16批阳性,来源于具角血蜱的LN1615株与扇头蜱立克次体(R. rhipicephali)处于同一分支,来源于微小扇头蜱的LN1620株与马赛立克次体(R. massiliae)处于同一分支,其余的12株来源于具角血蜱和2株来源于微小扇头蜱,与日本立克次体(R. japonica)处于同一分支。崇义县CY1602株来源于嗜群血蜱与R. raoultii处于同一分支。于都县YD1606株为来源于长角血蜱的埃立克体,与2010年Yonaguni206(HQ697589)、Yonaguni138(HQ697588)和2009年HLAE178(GU075695)处于同一分支。安远县微小扇头蜱检测均为阴性结论 本文对江西省赣州市采集的蜱进行了鉴定,首次在江西省赣州市的蜱中检测到日本立克次体、扇头蜱立克次体、马赛立克次体、R. raoultii和埃立克体,为江西省蜱种类的调查及其传播疾病的预防控制提供根据。     

Ehrlichiosis associated vasculitis

OBJECTIVE: To test the hypothesis that some cases of primary vasculitis are caused by ehrlichiosis. DESIGN: A retrospective case study and serological analysis of stored sera. SETTING: University hospital. SUBJECTS: Fifty-five patients discharged with any type of vasculitis over a 6-year period. MAIN OUTCOME MEASURES: Serology for human monocytic ehrlichiosis, and the human granulocytic ehrlichiosis agent, and polymerase chain reaction (PCR) analysis of biopsy specimens. RESULTS: Three patients (5.5%) had titres of 1 : 128 or higher against E. chaffeensis; none was positive for the human granulocytic ehrlichiosis agent. Skin biopsies of these patients showed lesions compatible with polyarteritis nodosa, allergic purpura and unspecified vasculitis. PCR analysis of the biopsies was unrevealing. CONCLUSIONS: Infection with human monocytic ehrlichiosis may underlie some forms of vasculitis. If confirmed, these findings may help identify patients with vasculitis who would benefit from antibiotic treatment.     

Ehrlichiosis and human anaplasmosis

Human ehrlichiosis and anaplasmosis are acute febrile tick-borne diseases caused by various species of the genera Ehrlichia and Anaplasma (Anaplasmataceae). To date, only cases of human granulocytic anaplasmosis (HGA) caused by Anaplasma phagocytophilum (formerly human granulocytic Ehrlichia, Ehrlichia phagocytophila, and E. equi) have been diagnosed in Europe. HGA and Lyme borreliosis are closely related diseases that share vector and reservoirs. In addition to HGA, human monocytic ehrlichiosis caused by E. chaffeensis has been reported in North America, as well as cases of infection due to E. ewingii in immunocompromised hosts. Ehrlichia spp. and A. phagocytophilum have tropism for blood cells, especially leukocytes and platelets, causing a considerable decrease of both components in these patients. HGA should be suspected in tick-bitten patients or those who have visited an endemic area and show symptoms of flu-like fever, leukopenia and thrombocytopenia.     

Ehrlichiosis: a cause of bone marrow hypoplasia in humans

Infection with Ehrlichia canis should be suspected in patients with fever, headache, malaise, leukopenia, thrombocytopenia, and a history of recent exposure to ticks. The cytopenia is caused by bone marrow hypoplasia which may be severe. The disease may be confused with spotless Rocky Mountain spotted fever but can be differentiated from this infection serologically with acute and convalescent sea. In humans, recovery has occurred with and without antibiotic therapy. However, prompt antibiotic therapy is advised prior to serologic studies, especially in immunocompromised individuals, splenectomized persons, and patients with AIDS-who may develop a more overwhelming rickettsial infection.     

Epidemiology of Ehrlichiosis and Anaplasmosis among American Indians in the United States, 2000-2007

Abstract. Ehrlichiosis and anaplasmosis infections among American Indians (AIs) have never been specifically examined, despite high rates of other tick-borne rickettsial diseases among AIs. The epidemiology of ehrlichiosis and anaplasmosis among AIs was analyzed using the National Electronic Telecommunications System for Surveillance (NETSS), Case Report Forms (CRFs), and Indian Health Service (IHS) inpatient and outpatient visits. The 2000-2007 average annual ehrlichiosis and anaplasmosis incidence among AIs reported to NETSS was almost 4-fold lower (4.0/1,000,000) than that using IHS data (14.9). American Indian cases reported from CRFs had a higher proportion of hospitalization (44%) compared with IHS (10%). American Indian incidence of ehrlichiosis and anaplasmosis was higher and showed a different age and geographical distribution than other races. These results highlight the need to improve collaboration between the ehrlichiosis and anaplasmosis surveillance systems for AIs so as to develop interventions that target the unique epidemiology and mitigate the burden of disease among this high-risk population.     

Incidence and Prevalence of Infection with Human Granulocytic Ehrlichiosis Agent in Germany. A Prospective Study in Young Healthy Subjects

Background: Only limited data are available on incidence and prevalence of infection with the human granulocytic ehrlichiosis (HGE) agent in a healthy population. Materials and Methods: In a prospective study, we tested 361 male soldiers (age 18–29 years) from southwestern Germany for the HGE agent immunoglobulin G (IgG) using an indirect immunofluorescence antibody assay and for Borrelia burgdorferi IgG with an ELISA at the beginning and the end of their 10-month military service. Using a standardized questionnaire, the subjects were asked about clinical symptoms at the beginning and the end of the observation period. Results: Of these 361 subjects, 14.9% were HGE agent IgG positive at study entry. 19 participants (5.3%) seroconverted from IgG negative to positive during the observation period resulting in an incidence rate of 6.4% per year. 20 subjects converted from initially HGE agent. IgG positive to negative resulting in a reconversion rate of 6.6% per year. Concurrence of Borrelia IgG and HGE agent IgG was observed in 21.1%, whereas 13.7% were HGE agent IgG positive but Borrelia IgG negative (not significant). Clinical symptoms associated with HGE were not present in seroconverting subjects. Conclusion: Infection with the HGE agent occurs frequently in southwestern Germany but was asymptomatic in these young subjects. Received: January 11, 2001 · Revision accepted: July 12, 2001     

Ehrlichiosis in a recent kidney transplant recipient: The repellent that did not repel! A case report and literature review of ehrlichiosis in solid organ transplant patients

Ehrlichiosis has been infrequently reported in immunosuppressed patients such as solid organ transplants (SOT). We report a case of Ehrlichia chaffeensis infection in an immunosuppressed woman four months after deceased donor kidney transplantation. The diagnosis was confirmed by PCR testing in serum, and the patient responded promptly to treatment with doxycycline. To supplement our Case Report, a literature review encompassing 1995 to present was also performed using PubMed as the search vehicle. Search terms that were utilized include: ehrlichiosis, HME, E chaffeensis, kidney transplant(ation), renal transplant(ation), solid organ transplant(ation), and immunosuppression. The diagnosis of ehrlichiosis can be challenging in SOT patients since ehrlichiosis is not a classic opportunistic infection in SOT. Transplant physicians must have a high clinical suspicion for the diagnosis in patients with an acute febrile illness accompanied by headache, worsening cytopenias, and transaminitis who live in endemic areas, especially if they have tick exposure.