查菲埃立克体P28蛋白抗原免疫印迹调查犬单核细胞埃立克体病

目的　以查菲埃立克体P2 8蛋白抗原免疫印迹法对犬单核细胞埃立克体病作流行病学调查 ,为该病的防治提供依据。方法　收集广东犬埃立克体病发生地的犬血清 ,用基因工程制备的查菲埃立克体P2 8融合蛋白抗原与犬血清作免疫印迹 ,检测犬血清中的抗P2 8抗体。结果　 2 12份犬血清行免疫印迹 ,89份 (42 % )阳性 ;这些阳性反应的血清绝大部分来自广州市和深圳市的野外工作犬 ,而南海市观赏犬的血清均为阴性。广西省南宁市的野外工作犬的 36份标本仅 3份为弱阳性。高水平的P2 8抗体出现在 4～ 10月 ,与当地蜱的活动期平行。结论　犬单核细胞埃立克体病在我国为局部流行 ,蜱可能是该病的传播媒介     

查菲埃立克体重组120kDa抗原的初步应用研究

目的　克隆查菲埃立克体 12 0kDa膜表面抗原蛋白基因 ,获得纯化的重组蛋白。方法　根据查菲埃立克体(91HE17) 12 0kDa抗原蛋白基因序列设计特异性引物 ,PCR扩增查菲埃立克体 12 0kDa抗原蛋白的基因片段 ;用限制性内切酶酶切PCR扩增产物后与 pUC18载体相连接 ,经酶切和序列分析证实后 ,将目标片段定向插入原核表达载体pProEXHTB中构建pProEXHTB/ p12 0重组质粒 ;将重组质粒转化E coliDH5α ,并使转化子在IPTG的诱导下进行蛋白质表达 ;运用亲和层析和电洗脱法对重组蛋白进行纯化。结果　克隆到一大小为 10 80bp的查菲埃立克体 12 0kDa抗原蛋白的基因片段 ,用该基因与表达质粒连接 ,成功构建了重组表达质粒 ;SDS -PAGE分析显示 :在IPTG诱导下 ,重组表达质粒转化的大肠杆菌产生一分子量为 4 7kDa的目标蛋白 ,免疫印迹证明该重组蛋白能与查菲埃立克体免疫血清发生反应。用纯化的重组蛋白作免疫斑点分析 ,76份被检血清中有 2份为可疑阳性 ,但经IFA复核为阴性。结论　查菲埃立克体 12 0kDa重组抗原蛋白具有免疫反应活性 ,为以重组蛋白为基础的人单核细胞埃立克体病的血清学诊断试剂盒制备和疫苗的研制奠定了基础。     

查菲埃立克体120kDa抗原蛋白基因的克隆与表达

目的 克隆查菲埃立克体120kDa膜表面免疫决定性蛋白基因,并使之在原核表达系统中表达。方法 查菲埃立克体分离株（91HE17）感染DH82细胞40天后收集DH82细胞。根据查菲埃立克体P120蛋白基因序列设计特异性引物,套式PCR扩增查菲埃立允体P120蛋白基因部分片段,将PCR扩增产物用BamHⅠ和EcoRⅠ限制性内切酶双酶切后与pUC18载体连接,在获得阳性克隆子后用限制性内切酶将克隆片段切下,定向手稿原核表达载体pProEX HTb构建pProEX HTb/P120重组质粒。将重组质粒转化E.coli DH5α,并使之在IPTG的诱导下进行蛋白质表达。结果 裁短成1080bp的查菲埃立克体P120蛋白基因克隆到pUC18载体,用IPTG诱导pProEX HTb/P120重组质粒转化的E.coli DH5α,表达一分子量大小约为47kDa的融合蛋白。结论 查菲埃立克体120kDa抗原蛋白基因能在原核表达系统中表达,为诊断试剂盒的研制及其它研究工作提供了基础。     

查菲埃立克体28kD表面抗原基因的克隆与表达

目的 克隆和高效表达查菲埃立克体（Ehrlichia chaffensis)28kD表面抗原基因。方法 依据书籍的查菲埃立克体28kD表面抗原基因设计引物，用PCR从查菲埃立克体基因组中克隆该基因片段（531bp），再将该基因片段定向插入表达载体（PinPoint^TMXa-3）中，然后将该重组质粒转化E.coli JM109细胞。结果 经SDS-PAGE分析，转化子所产生的融合蛋白分子量为32kD，与预期的结果相一致；在37℃用0.1Mn IPTG诱导转化子12h，融合蛋白量达到细菌总蛋白量的35.8%。结论 查菲埃立克体28～kD表面抗原基因在E.coli JM109细胞内得到高效率表达，从而为该抗原的大量制备奠定了基础。     

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     

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…     

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。     

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。     

广州市郊鼠中检出埃立克体样微生物

目的　了解曾经两次暴发犬埃立克体病流行的广州市郊某养犬基地野生啮齿动物感染埃立克体情况。方法　用 16SrRNA基因埃立克体属特异引物对抓捕的动物全血及脾脏样本进行PCR检测 ,阳性样本克隆测序 ,所得序列与Gen Bank中注册的核苷酸序列进行比较。结果　在所抓捕的 2 6只野生啮齿动物中 ,3份褐家鼠全血样本和一份脾样本检出埃立克体特异阳性带。序列测定结果显示 ,这 3只鼠所携带的埃立克体样微生物基因完全一致。该基因与核酸数据库中的埃立克体Schotti株有最大同源性 (99 0 4 % )。结论　此次发现的埃立克体与该基地流行的犬埃立克体Gzh982株和扁平埃立克体Gzh981株有很大差异。该菌在流行病学上的意义有待进一步研究。     

东北林区啮齿动物的查菲埃立克体核酸检测

目的 调查东北林区啮齿动物的查菲埃立克体感染水平。方法 采用巢式PCR检测吉林省集安和辽宁省宽甸林区野鼠脾脏样本的查菲埃立克体16S rRNA DNA;对阳性扩增产物作DNA序列测定,并对测定的序列进行同源性比较和聚类分析。结果 检测两地野鼠132只,阳性19只,阳性率14.39%。其中,集安野鼠阳性率 7.58%(5/66),宽甸野鼠阳性率 21.21%(14/66), 宽甸野鼠阳性率明显高于集安(χ²=3.9348, P=0.0473)。不同鼠种查菲埃立克体阳性率无明显差异。扩增阳性DNA片段测序后与GenBank中注册的埃立克体16S rRNA基因对应序列进行同源性比较, JA-m51(集安株)、KD-m18(宽甸株)二者基因序列相差4个核苷酸,而JA-m51与查菲埃立克体美国株及我国云南株核苷酸序列完全一致,进化树分析显示JA-m51、KD-m18与查菲埃立克体同属一个分支。结论 辽宁省、吉林省林区野鼠查菲埃立克体感染较普遍,该地区存在单核细胞埃立克体病的自然疫源地。     

Ehrlichia species in Rhipicephalus sanguineus ticks in Cameroon

Ehrlichia and Anaplasma species are tick-transmitted obligately intracellular bacteria that commonly cause disease in dogs worldwide. In addition to causing disease in canines, Ehrlichia chaffeensis, Ehrlichia ewingii, and Anaplasma phagocytophilum are responsible for emerging and life-threatening human zoonoses in the United States. We previously reported a high prevalence of E. canis infection in Cameroonian dogs based on serologic and molecular evidence. This study was undertaken to determine the Ehrlichia species (E. canis, E. chaffeensis, E. ewingii) present in Rhipicephalus sanguineus ticks (n = 92) collected from those dogs (n = 51). Ehrlichial DNA was detected by real-time polymerase chain reaction (PCR) in 28 (30%) unengorged R. sanguineus ticks attached to dogs. E. canis, the causative agent of canine monocytic ehrlichiosis, was detected in 19 (21%) ticks from 15 dogs, E. ewingii was detected in six (6%) ticks from 6 dogs, and E. chaffeensis, the etiologic agent of human monocytotropic ehrlichiosis, was detected in 4 (4%) ticks. Notably, 2 ticks were coinfected with E. chaffeensis and E. canis, one tick with E. canis and E. ewingii, and one tick with E. chaffeensis and E. ewingii. These findings further support our previous conclusion that multiple Ehrlichia species are present in Cameroon and identify R. sanguineus ticks primarily infected with E. canis, but suggest that they may be infected with and transmit other ehrlichial agents in Cameroon, potentially to humans.     

Ehrlichia chaffeensis infection in dogs in South Korea

Ehrlichia chaffeensis is one of the causative agents of canine ehrlichiosis and human monocytic ehrlichiosis (HME). Canine ehrlichiosis caused by E. chaffeensis was diagnosed in two dogs in South Korea based on clinical findings, and the diagnosis was confirmed by polymerase chain reaction (PCR) and DNA sequencing. A 5-year-old intact male American Pit bull terrier allowed outdoors was found to be concurrently infected with Babesia gibsoni and E. chaffeensis. The major clinical findings were lethargy and reddish urine, and laboratory analysis revealed severe hematuria and thrombocytopenia. In addition, a 3-year-old neutered male Shih-tzu was also found to be infected with E. chaffeensis. Although this dog was an indoor companion animal, he was frequently allowed outside for exercise. The clinical signs observed in this dog included generalized purpura with petechiae and ecchymoses due to thrombocytopenia. A 390-bp partial portion of E. chaffeensis 16S rRNA gene was amplified in both cases, and nucleotide sequence analysis revealed 99% homology of this fragment with other E. chaffeensis isolates. These findings demonstrate the presence of E. chaffeensis infection in dogs in South Korea, and this is the first report to confirm clinical cases of E. chaffeensis infection in dogs.     

Surveillance for zoonotic vector-borne infections using sick dogs from southeastern Brazil

For many vector-borne organisms, dogs can be used as sentinels to estimate the risk of human infection. The objective of this study was to use dogs as sentinels for multiple vector-borne organisms in order to evaluate the potential for human infection with these agents in southeastern Brazil. Blood from 198 sick dogs with clinicopathological abnormalities consistent with tick-borne infections were selected at the S?o Paulo State University Veterinary Teaching Hospital in Botucatu and tested for DNA and/or antibodies against specific vector-borne pathogens. At least one organism was detected in 88% of the dogs, and Ehrlichia canis DNA was amplified from 78% of the blood samples. Bartonella spp. seroreactivity was found in 3.6%. Leishmania chagasi antibodies were detected in 1% of the dogs. There was no serological or polymerase chain reaction evidence of infection with Anaplasma phagocytophilum, Borrelia burgdorferi, Ehrlichia chaffeensis, Ehrlichia ewingii, and Rickettsia rickettsii. The full E. canis 16S rRNA gene sequence of one of the Brazilian strains obtained in this study was identical to the causative agent of human ehrlichiosis in Venezuela. Ehrlichia canis may pose a human health hazard and may be undiagnosed in southeastern Brazil, whereas exposure to the other organisms examined in this study is presumably infrequent.     

Seroprevalence and geographic distribution of Dirofilaria immitis and tick-borne infections (Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato, and Ehrlichia canis) in dogs from Romania

Tick-borne diseases are of great concern worldwide. Despite this, in Romania there is only limited information regarding the prevalence of vector-borne pathogens in dogs. In all, 1146 serum samples were tested by SNAP(?) 4Dx(?) (IDEXX Laboratories, Inc., Westbrook, ME) for Anaplasma phagocytophilum, Borrelia burgdorferi, and Ehrlichia canis antibodies, and for Dirofilaria immitis antigen. The correlation between positive cases and their geographic distribution, as well as potential risk factors (age, sex, breed, type of dog, habitat, and prophylactic treatments) were evaluated. Overall, 129 dogs (11.3%) were serologically-positive to one or more of the tested pathogens. The seroprevalence for the four infectious agents were: A. phagocytophilum 5.5% (63/1146), D. immitis 3.3% (38/1146), E. canis 2.1% (24/1146), and B. burgdorferi 0.5% (6/1146). Co-infection with E. canis and A. phagocytophilum was registered in 2 dogs (0.2%). The geographical distribution of the seropositive cases suggests clustered foci in southern regions and in the western part of the country for D. immitis, and in the southeastern region (Constan?a County) for E. canis. A. phagocytophilum and B. burgdorferi showed a homogenous distribution, with a tendency for Lyme-positive samples to concentrate in central Romania. For D. immitis, A. phagocytophilum, and E. canis, administering prophylactic treatments was a risk factor associated with infection. Another associated risk factor was the type of dog (stray dogs were at risk being positive for D. immitis, shelter dogs for E. canis, and hunting dogs for B. burgdorferi). The prevalence of D. immitis was significantly higher in males and in dogs older than 2 years. This survey represents the first data detailing A. phagocytophilum and E. canis seroprevalence in Romanian dogs, and the most comprehensive epidemiological study on vector-borne infections in dogs from this country.     

Ehrlichia canis: a tick-borne rickettsial-like infection in humans living in the southeastern United States

During the past two years, sporadic cases of a rickettsial-like illness were reported in humans living in the Southeastern United States. The illness was serologically similar to Ehrlichia canis infections in dogs. It resembled spotless Rocky Mountain Spotted Fever but was differentiated from this infection serologically with acute and convalescent sera showing increasing titers to Ehrlichia canis. E. canis infection should be suspected in patients with fever, headache, malaise, myalgia, gastrointestinal symptoms, relative bradycardia, leukopenia, thrombocytopenia, and a recent exposure to either dogs or ticks. Although recovery has been observed in humans without treatment, prompt therapy with tetracycline is advised before obtaining results of serologic studies because an immunologically similar illness in untreated dogs has been lethal.     

Molecular survey of Anaplasma and Ehrlichia infections of feral raccoons (Procyon lotor) in Hokkaido, Japan

Infection by Anaplasma and Ehrlichia in feral raccoons (Procyon lotor) in Hokkaido, Japan, was examined by molecular methods. A polymerase chain reaction (PCR) screen for Anaplasmataceae, based on 16S rRNA, showed that 38 (5.4%) of 699 raccoons examined were positive. These 38 positive samples were examined for Anaplasma phagocytophilum, Anaplasma bovis, Ehrlichia chaffeensis, and Ehrlichia canis infection by species-specific nested PCR. Nested PCR results indicated that 36 of the 38 samples were positive for A. bovis. All 38 samples were PCR negative for A. phagocytophilum, E. chaffeensis, and E. canis. This is the first report of the detection of A. bovis in the peripheral blood of raccoons. A total of 124 raccoons were infested with ticks, including Ixodes ovatus, Ixodes persulcatus, and Haemaphysalis spp. The rate of A. bovis infection in raccoons infested with Haemaphysalis spp. (46.7%, 7/15) was significantly higher than that in raccoons without Haemaphysalis spp. infestation (3.7%, 4/109, p?相似文献   

Canine infection by rickettsiae and ehrlichiae in southern Brazil

This study evaluated the infection caused by Rickettsia and Ehrlichia agents among dogs in southern Brazil. A total of 389 dogs were tested by the indirect immunofluorescence assay (IFA) for Rickettsia rickettsii, Rickettsia parkeri, Rickettsia amblyommii, Rickettsia rhipicephali, Rickettsia bellii, and Ehrlichia canis. Overall, 42.4% (165/389) of the dogs were seroreactive to at least one Rickettsia species, but only 11 canine sera reacted with another Rickettsia species without reacting with R. parkeri. A total of 100 (25.7%) canine sera showed titers to R. parkeri at least 4-fold higher than those to any of the other rickettsial antigens, allowing us to consider that these dogs were infected by R. parkeri. Dogs that had direct contact with pasture or forest areas were > 2 times more likely to be seroreactive to Rickettsia than dogs with no such direct contact. Only 19 (4.8%) of the 389 dogs were seroreactive to E. canis.     

Specific antibody responses in dogs experimentally infected with Echinococcus granulosus

Six dogs reared helminth-free were divided into 2 groups. Four dogs were infected per os with 200,000 protoscoleces each of Echinococcus granulosus and 2 were kept as uninfected controls. All the dogs were kept together until 32 days after infection, when 1 infected dog was killed, its intestine removed and the contents examined to confirm that the infection with E. granulosus had been successful. The remaining 3 infected dogs were transferred to high security housing and their feces inspected daily to establish the time infections became patent. The infected and control dogs were bled every 5 days for 75 days from the time of infection and the sera were stored at -70 degrees C. Sera were tested by the enzyme-linked immunosorbent assay (ELISA) for antibodies to E. granulosus scolex excretory/secretory (ES) antigen, protoscolex antigen and oncosphere antigen. Antibodies to scolex ES antigen and protoscolex antigen were detected in the sera of infected dogs within 2 weeks of infection. Antibody titers rose rapidly and remained at a high level until the dogs were killed 75 days after infection. Antibodies in these sera did not cross react with antigens prepared from Taenia ovis, T. hydatigena, T. pisiformis, Ancylostoma caninum, Trichuris vulpis and Toxocara canis.     

Serological and molecular prevalence of Borrelia burgdorferi, Anaplasma phagocytophilum, and Ehrlichia species in dogs from Minnesota

A population of 731 naturally exposed pet dogs examined at a private practice in Baxter, Minnesota, an area endemic for Lyme disease and anaplasmosis, was tested by serological and molecular methods for evidence of exposure to or infection with selected vector-borne pathogens. Serum samples were tested by enzyme-linked immunosorbent assay (ELISA) for Anaplasma phagocytophilum, Borrelia burgdorferi, and Ehrlichia canis antibodies and for Dirofilaria immitis antigen. Blood samples from 273 dogs were also analyzed by polymerase chain reaction (PCR) for Anaplasma and Ehrlichia species DNA. Based on the owner history and the attending veterinarian's physical examination findings, dogs exhibiting illness compatible with anaplasmosis or borreliosis were considered clinical cases, and their results were compared to the healthy dog population. Antibodies to only A. phagocytophilum were detected in 217 (29%) dogs; to only B. burgdorferi, in 80 (11%) dogs; and seroreactivity to both organisms, in 188 (25%) dogs. Of 89 suspected cases of canine anaplasmosis or borreliosis, A. phagocytophilum or B. burgdorferi antibodies were detected in 22 dogs (25%) and 8 dogs (9%) respectively, whereas antibodies to both organisms were found in 38 dogs (43%). Ehrlichia canis antibodies and D. immitis antigen were each detected in 11 (1.5%) dogs. Anaplasma phagocytophilum DNA was amplified from 7 of 222 (3%) healthy dogs and 19 of 51 (37%) clinical cases. Seroreactivity to both A. phagocytophilum and B. burgdorferi was detected more frequently in suspected cases of anaplasmosis and/or borreliosis than seroreactivity to either organism alone. Based on PCR testing, A. phagocytophilum DNA was more prevalent in suspected cases of anaplasmosis or borreliosis than in healthy dogs from the same region.