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Lijuan Zhang,
Hong Liu,
Bianli Xu,
Qunying Lu,
Liang Li,
Litao Chang,
Xiuchun Zhang,
Desheng Fan,
Guohua Li,
Yuming Jin,
Feng Cui,
Yonglin Shi,
Weihong Li,
Jianguo Xu, Xue Jie Yu
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ABSTRACT: A nationwide epidemiologic investigation of domestic animal infections has been conducted in nine provinces and one city during 2007-2010. Serum samples from a total of 707 goats, 433 cattle, and 219 dogs were collected for detecting Anaplasma phagocytophilum IgG antibody by immunofluorescence assays and the average seroprevalences were 10.05% for dogs, 3.82% for goats, and 0.69% for cattle, respectively. A total of 472 goats, 201 cattle, 102 dog blood clots, and 1,580 ticks were collected for polymerase chain reaction (PCR) amplifying A. phagocytophilum 16S rRNA genes and the PCR-positive rates were 26.69% for goats, 23.38% for cattle, and 10.89% for dogs. Six species were identified and the average PCR-positive rates were 58.3% for Dermacentor silvarum, 43.9% for Haemaphysalis longicornis, 12.5% for Ixodes persulcatus, 7.5% (3 of 40) for Boophilus microplus, and 5.2% for Rhipicephalus sanguineus, respectively. The evidence in the study indicated the zoonotic Rickettsia is highly prevalent in China.
The American journal of tropical medicine and hygiene 07/2012; 87(1):185-9. · 2.59 Impact Factor
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ABSTRACT: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease caused by a newly discovered bunyavirus, SFTS virus (SFTSV), and causes high fatality (12% on average and as high as 30%). The objective of this study was to determine whether SFTSV could be transmitted from person to person. We analyzed sera of 13 patients from two clusters of unknown infectious diseases that occurred between September and November of 2006 in Anhui Province of China for SFTSV antibody by indirect immunofluorescence assay and for SFTSV RNA by RT-PCR. We found that all patients (n=14) had typical clinical symptoms of SFTS including fever, thrombocytopenia, and leukopenia and all secondary patients in both clusters got sick at 6-13 days after contacting or exposing to blood of index patients. We demonstrated that all patients in cluster 1 including the index patient and nine secondary patients and all three secondary patients in cluster 2 had seroconversion or fourfold increases in antibody titer to SFTSV and/or by RT-PCR amplification of SFTSV RNA from the acute serum. The index patient in cluster 2 was not analyzed because of lack of serum. No person who contacted the index patient during the same period, but were not exposed to the index patient blood, had got illness. We concluded that SFTSV can be transmitted from person to person through contacting patient's blood.
Vector borne and zoonotic diseases (Larchmont, N.Y.) 09/2011; 12(2):156-60. · 2.61 Impact Factor
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Xue-Jie Yu,
Mi-Fang Liang,
Shou-Yin Zhang,
Yan Liu,
Jian-Dong Li,
Yu-Lan Sun,
Lihong Zhang,
Quan-Fu Zhang,
Vsevolod L Popov,
Chuan Li, [......],
Xiu-Ping Fu,
Li-Na Sun,
Xiao-Ping Dong,
Zi-Jian Feng,
Wei-Zhong Yang,
Tao Hong,
Yu Zhang,
David H Walker,
Yu Wang,
De-Xin Li
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ABSTRACT: Heightened surveillance of acute febrile illness in China since 2009 has led to the identification of a severe fever with thrombocytopenia syndrome (SFTS) with an unknown cause. Infection with Anaplasma phagocytophilum has been suggested as a cause, but the pathogen has not been detected in most patients on laboratory testing.
We obtained blood samples from patients with the case definition of SFTS in six provinces in China. The blood samples were used to isolate the causal pathogen by inoculation of cell culture and for detection of viral RNA on polymerase-chain-reaction assay. The pathogen was characterized on electron microscopy and nucleic acid sequencing. We used enzyme-linked immunosorbent assay, indirect immunofluorescence assay, and neutralization testing to analyze the level of virus-specific antibody in patients' serum samples.
We isolated a novel virus, designated SFTS bunyavirus, from patients who presented with fever, thrombocytopenia, leukocytopenia, and multiorgan dysfunction. RNA sequence analysis revealed that the virus was a newly identified member of the genus phlebovirus in the Bunyaviridae family. Electron-microscopical examination revealed virions with the morphologic characteristics of a bunyavirus. The presence of the virus was confirmed in 171 patients with SFTS from six provinces by detection of viral RNA, specific antibodies to the virus in blood, or both. Serologic assays showed a virus-specific immune response in all 35 pairs of serum samples collected from patients during the acute and convalescent phases of the illness.
A novel phlebovirus was identified in patients with a life-threatening illness associated with fever and thrombocytopenia in China. (Funded by the China Mega-Project for Infectious Diseases and others.).
New England Journal of Medicine 03/2011; 364(16):1523-32. · 53.30 Impact Factor
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ABSTRACT: Ehrlichia are obligately intracellular bacteria that reside in a vacuole in the cytoplasm of phagocytes. We determined by confocal microscopy the interaction between Ehrlichia and mitochondria in DH82 cells to investigate the mechanism of Ehrlichia survival inside the phagocyte. The most remarkable finding of our study was that Ehrlichia morulae interacted with mitochondria and inhibited mitochondrial metabolism. We showed that in Ehrlichia chaffeensis-infected DH82 cells, mitochondria did not incorporate BrdU and transcriptional level of the mitochondrial gene NADPH2 was significantly reduced, indicating the inhibition of mitochondrial metabolism. This study demonstrates that Ehrlichia are able to inhibit mitochondrial activities, and it opens up a new avenue for the study of Ehrlichia pathogenesis.
Microbes and Infection 11/2010; 13(3):232-8. · 3.10 Impact Factor
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ABSTRACT: Ehrlichia chaffeensis is an obligately intracellular bacterium that exhibits tropism for mononuclear phagocytes and survives by reprogramming the host cell. Here we review new information regarding the newly characterized effector molecules and the complex network of molecular host-pathogen interactions that the organism exploits enabling it to thrive and persist intracellularly.
Microbes and Infection 05/2010; 12(5):337-45. · 3.10 Impact Factor
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Shouyin Zhang,
Hongbin Song,
Yan Liu,
Qun Li,
Yong Wang,
Jiabin Wu,
Junfeng Wan,
Guolan Li,
Changjun Yu,
Xiuyong Li, [......],
Kanglin Wan,
Guichang Li,
Xiuping Fu,
Jingshan Zhang,
Jinrong He,
Rong Hai,
Dongzheng Yu,
David H Walker,
Jianguo Xu, Xue-Jie Yu
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ABSTRACT: Scrub typhus, caused by Orientia tsutsugamushi, has emerged recently in areas of northern China where the disease had not been known to exist. We analyzed epidemiological, clinical, and laboratory data for 104 patients who were admitted to a hospital in Fuyang City between 26 September and 1 November 2008. We showed that the major clinical manifestations of the patients were fever (100%), headache (82%), myalgias (77%), eschar (67%), rash (52%), and unusual facial flushing (62%). Among the 104 patients, the sera of 98% contained IgM antibodies to O. tsutsugamushi detected by indirect immunofluorescence assays (IFA), and DNA of the O. tsutsugamushi 56-kDa gene was amplified by PCR from the blood of 36 patients. We conclude that 104 patients were infected with scrub typhus in Fuyang City, Anhui Province. Our study indicates that physicians need to consider the diagnosis of scrub typhus for febrile patients living in northern China, where scrub typhus had not been considered to exist in the past.
Journal of clinical microbiology 04/2010; 48(4):1241-4. · 4.16 Impact Factor
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Ying Liang,
Xuexin Hou,
Yanhua Wang,
Zhigang Cui,
Zhikai Zhang,
Xiaoyu Zhu,
Lianxu Xia,
Xiaona Shen,
Hong Cai,
Jian Wang,
Donglei Xu,
Enmin Zhang,
Huijuan Zhang,
Jianchun Wei,
Jinrong He,
Zhizhong Song, Xue-jie Yu,
Dongzheng Yu,
Rong Hai
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ABSTRACT: Yersinia pestis has caused three worldwide plagues in human history that have led to innumerable deaths. We have completely sequenced the genomes of two strains (D106004 and D182038) of Y. pestis isolated from Yunnan Province of China. The most striking finding of our study is that large amounts of genome rearrangement events exist between the genomes of two Yunnan strains despite being isolated from two foci only 50 kilometers apart. When we compared the genome sequences of the Yunnan strains with six strains (CO92, KIM, 91001, Antiqua, Nepal516, and Pestoides F) of Y. pestis sequenced previously, we found that the genomes of Y. pestis were divided into 61 relatively independent segments. Pairwise comparisons of all 61 segments among eight strains showed that the Yunnan strains were most closely related to strain CO92. We concluded that Y. pestis genomes consist of segments that can change their positions and directions within the genomes caused by genome rearrangements, and our study confirmed the inference that the third plague pandemic originated in Yunnan since the genome sequences of Yunnan strains were closest to the strain CO92 isolated from the United States.
Journal of clinical microbiology 03/2010; 48(5):1619-23. · 4.16 Impact Factor
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Zhikai Zhang,
Rong Hai,
Zhizhong Song,
Lianxu Xia,
Yun Liang,
Hong Cai,
Ying Liang,
Xiaona Shen,
Enmin Zhang,
Jianguo Xu,
Dongzheng Yu, Xue-Jie Yu
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ABSTRACT: Yunnan Province of China is considered the site of origin for modern plague. We analyzed the genotypes of eight Yersinia pestis strains isolated from three counties in Yunnan Province by pulse field gel electrophoresis (PFGE). PFGE showed that strains isolated from the same site were identical regardless of hosts or year of isolation. However, Y. pestis strains isolated from geographically distinct loci were genetically divergent. Whole genome sequences of two strains from two foci in Yunnan showed that the genetic variation of Y. pestis strains was caused by genome rearrangement. We concluded that Y. pestis strains in each epidemic focus in Yunnan were a clonal population and selected by host environments. The genomic variability of the Y. pestis strains from different foci were caused by genome rearrangement, which may provide a positive selective advantage for Y. pestis to adapt to its host environments.
The American journal of tropical medicine and hygiene 10/2009; 81(4):714-7. · 2.59 Impact Factor
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Shouyin Zhang,
Rong Hai,
Wenyuan Li,
Guohua Li,
Guangyu Lin,
Jinrong He,
Xiuping Fu,
Jingshan Zhang,
Hong Cai,
Fengqin Ma,
Jianhua Zhang,
Dongzheng Yu, Xue-Jie Yu
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ABSTRACT: Human granulocytic anaplasmosis (HGA) is an emerging tick-borne infectious disease. To determine the prevalence of HGA in central and southeastern China, a total of 323 human sera were collected from individuals at high risk for exposure to ticks and animals. The IgG antibody against the etiologic agent of HGA, Anaplasma phagocytophilum was detected with indirect immunofluorescence assay. The results showed that 20% of the tested individuals (64/323) were positive to A. phagocytophilum and that the incidence was higher in male (22%) than female (16%). We concluded that A. phagocytophilum infection was prevalent in central and southeastern China.
The American journal of tropical medicine and hygiene 09/2009; 81(2):293-5. · 2.59 Impact Factor
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ABSTRACT: Opportunistic pathogenic bacteria continuously live in humans and obligately pathogenic bacteria associate with humans only in the case of diseases. A mystery is whether pathogens can live outside the hosts. We showed here that most human pathogens have lost biosynthetic pathways for amino acids. This condition suggests that most microbial pathogens are obligately host-dependent and they cannot multiply outside their hosts. Further analysis of the genome sizes revealed that the genomes of host-dependent bacteria are smaller than those of free living bacteria, suggesting that reductive evolution of genomes occurs broadly in bacterial pathogens and non-pathogens closely associated with human and animal hosts. The extent of genome reduction appears to depend on the environment in which they reside. The richer the nutrients are in the environment the smaller the genome is in the bacteria.
Infection, genetics and evolution: journal of molecular epidemiology and evolutionary genetics in infectious diseases 08/2009; 9(4):514-7. · 3.22 Impact Factor
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Lijuan Zhang,
Yan Liu,
Daxin Ni,
Qun Li,
Yanlin Yu, Xue-jie Yu,
Kanglin Wan,
Dexin Li,
Guodong Liang,
Xiugao Jiang, [......],
Jing Run,
Mingchun Luan,
Xiuping Fu,
Jingshan Zhang,
Weizhong Yang,
Yu Wang,
J Stephen Dumler,
Zijian Feng,
Jun Ren,
Jianguo Xu
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ABSTRACT: Human granulocytic anaplasmosis (HGA) is an emerging tick-borne disease in China. A cluster of cases among health care workers and family members following exposure to a patient with fulminant disease consistent with HGA prompted investigation.
To investigate the origin and transmission of apparent nosocomial cases of febrile illness in the Anhui Province.
After exposure to an index patient whose fatal illness was characterized by fever and hemorrhage at a primary care hospital and regional tertiary care hospital's isolation ward, secondary cases with febrile illness who were suspected of being exposed were tested for antibodies against Anaplasma phagocytophilum and by polymerase chain reaction (PCR) and DNA sequencing for A. phagocytophilum DNA. Potential sources of exposure were investigated.
Cases with serological or PCR evidence of HGA were compared with uninfected contacts to define the attack rate, relative risk of illness, and potential risks for exposure during the provision of care to the index patient.
In a regional hospital of Anhui Province, China, between November 9 and 17, 2006, a cluster of 9 febrile patients with leukopenia, thrombocytopenia, and elevated serum aminotransferase levels were diagnosed with HGA by PCR for A. phagocytophilum DNA in peripheral blood and by seroconversion to A. phagocytophilum. No patients had tick bites. All 9 patients had contact with the index patient within 12 hours of her death from suspected fatal HGA while she experienced extensive hemorrhage and underwent endotracheal intubation. The attack rate was 32.1% vs 0% (P = .04) among contacts exposed at 50 cm or closer, 45% vs 0% (P = .001) among those exposed for more than 2 hours, 75% vs 0% (P < .001) among those reporting contact with blood secretions, and 87.5% vs 0% (P = .004) among those reporting contact with respiratory secretions from the index patient.
We report the identification of HGA in China and likely nosocomial transmission of HGA from direct contact with blood or respiratory secretions.
JAMA The Journal of the American Medical Association 11/2008; 300(19):2263-70. · 30.03 Impact Factor
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ABSTRACT: We developed a typing method that can differentiate 8 strains of Rickettsia prowazekii into 7 genotypes. This method can be used to type and trace the origin of R. prowazekii isolated from samples collected during epidemics after a bioterrorism attack.
Emerging Infectious Diseases 09/2008; 14(8):1300-2. · 6.79 Impact Factor
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ABSTRACT: Ehrlichia chaffeensis, an obligatory intracellular bacterium, has two forms in mammalian cells: small dense-cored cells (DC) with dense nucleoid and larger reticulate cells (RC) with uniformly dispersed nucleoid. We have determined by electron microscopy that DC but not RC attaches to and enters into the host cells and RC but not DC multiples inside the host cells. Analysis of outer membrane protein expression by confocal microscopy showed that RC expressed the 28 kDa outer membrane protein (p28), the intermediate form, which were transforming from RC to DC, expressed both gp120 and p28, and the mature DC expressed gp120 only. The TCID50 of DC is 6 log10 higher than RC. We conclude that E. chaffeensis has a developmental cycle, in which the DC attaches to and enters into the host cells, and transforms into RC and the RC multiplies by binary fission for 48 h and then matures into DC at 72 h.
Cellular Microbiology 04/2007; 9(3):610-8. · 5.46 Impact Factor
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ABSTRACT: Ehrlichia are tick-borne gram negative, obligately intracellular bacteria. The 16S rRNA gene DNA sequences are highly conserved among strains of each Ehrlichia species. The 28-kDa/Map-1 outer membrane protein genes are highly diversified among strains of Ehrlichia chaffeensis and E. ruminantium, but are highly conserved among E. canis isolates. The diversity of the immunodominant proteins of E. chaffeensis and E. ruminantium in contrast with the conservation of the immunodominant proteins of E. canis suggests that E. chaffeensis and E. ruminantium face more host immune pressure than E. canis or that E. chaffeensis and E. ruminantium evolved earlier than E. canis and have diverged.
Veterinary Parasitology 03/2007; 143(3-4):337-46. · 2.58 Impact Factor
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ABSTRACT: Rickettsia prowazekii Madrid E (E) strain is an effective vaccine, but can revert to virulent status when passaged in animals. The aim of this study is to identify the reverse mutation that may determine the virulence of R. prowazekii by comparing the genetic structures of E strain and its virulent revertant Evir strain. We determined that the gene (Rp028/Rp027) encoding the methyltransferase was mutated by frameshift in avirulent E strain but not in virulent revertant Evir strain and wild type virulent Breinl strain. We conclude that the mutation in the E strain gene reverts to wild type in the virulent revertant Evir strain. Whether the mutation plays an essential role in the attenuation of E strain needs to be further investigated.
Vaccine 04/2006; 24(13):2317-23. · 3.77 Impact Factor
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Annals of the New York Academy of Sciences 01/2006; 1063:433-5. · 3.15 Impact Factor
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ABSTRACT: Historically, ehrlichioses were tick-borne diseases of veterinary medical importance and are now important emerging infectious diseases in humans. p28s are encoded by multigene families with ORFs tandemly arranged with intergenic spaces of variable lengths. We reported initial sequencing of the Ehrlichia muris p28 locus. A model of persistent infection was described and provided tools for study of persistent ehrlichial infection. We completed the sequence of the E. muris p28 locus and examined mRNA expression.
Annals of the New York Academy of Sciences 01/2006; 1063:420-4. · 3.15 Impact Factor
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ABSTRACT: Three rickettsial genomes have been sequenced and annotated. Rickettsia prowazekii and R. typhi have similar gene order and content. The few differences between R. prowazekii and R. typhi include a 12-kb insertion in R. prowazekii, a large inversion close to the origin of replication in R. typhi, and loss of the complete cytochrome c oxidase system by R. typhi. R. prowazekii, R. typhi, and R. conorii have 13, 24, and 560 unique genes, respectively, and share 775 genes, most likely their essential genes. The small genomes contain many pseudogenes and much noncoding DNA, reflecting the process of genome decay. R. typhi contains the largest number of pseudogenes (41), and R. conorii the fewest, in accordance with its larger number of genes and smaller proportion of noncoding DNA. Conversely, typhus rickettsiae contain fewer repetitive sequences. These genomes portray the key themes of rickettsial intracellular survival: lack of enzymes for sugar metabolism, lipid biosynthesis, nucleotide synthesis, and amino acid metabolism, suggesting that rickettsiae depend on the host for nutrition and building blocks; enzymes for the complete TCA cycle and several copies of ATP/ADP translocase genes, suggesting independent synthesis of ATP and acquisition of host ATP; and type IV secretion system. All rickettsiae share two outer membrane proteins (OmpB and Sca 4) and LPS biosynthesis machinery. RickA, unique to spotted fever rickettsiae, plays a role in induction of actin polymerization in R. conorii, but not in R. prowazekii or R. typhi. The genome of R. typhi contains four potentially membranolytic genes (tlyA, tlyC, pldA, and pat-1) and five autotransporter genes, sca 1, sca 2, sca 3, ompA, and ompB. The presence of six 50-amino acid repeat units in Sca 2 suggests function as an adhesin. The high laboratory passage of the sequenced strains raises the issue of the occurrence of laboratory mutations in genes not required for growth in cell culture or eggs. Resequencing revealed that eight annotated pseudogenes of E strain are actually intact genes. Comparative genomics of virulent and avirulent strains of rickettsial species may reveal their virulence factors.
Annals of the New York Academy of Sciences 01/2006; 1063:13-25. · 3.15 Impact Factor
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ABSTRACT: While bacterial transformation has evolved since the early 20th century to allow for the genetic manipulation of a variety of microbial agents, rickettsial organisms have proved resistant to such advances until only recently. The Ehrlichia are small, gram-negative, obligately intracellular bacterial parasites, which belong to the family Anaplasmataceae and cause a variety of infections in human and animal hosts. E. chaffeensis is the causative agent of human monocytotropic ehrlichiosis and is transmitted by Amblyomma americanum, the Lone Star tick. In this work, we describe the first report of successful transformation of a closely related ehrlichial species, the murine monocytotropic species E. muris. Application of these techniques should allow for a wide variety of molecular studies to be performed that were previously impossible. This heralds the beginning of a new era in ehrlichial research.
Annals of the New York Academy of Sciences 01/2006; 1063:403-10. · 3.15 Impact Factor
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ABSTRACT: Members of the genus Rickettsia possess the ability to invade host cells and promptly escape from phagosomal vacuoles into the host cell cytosol, thereby avoiding destruction within the endosomal pathway. The mechanism underlying rickettsial phagosomal escape remains unknown, although the genomic sequences of several rickettsial species have allowed for the identification of four genes with potential membranolytic activities (tlyA, tlyC, pat1, and pld). This study was undertaken to determine which of the selected genes of Rickettsia prowazekii mediate the escape process. Quantitative ultrastructural analyses indicated that the period of active phagosomal escape was between 30 and 50 min postinfection. Reverse transcriptase PCR analyses determined that tlyC and pld were transcribed during the period of active phagosomal escape but that tlyA and pat1 were not. The functionality of both tlyC and pld was determined by complementation studies of Salmonella, which replicates within endosomes. Complementation of Salmonella organisms with either tlyC or pld resulted in the escape of transformants from endosomal vacuoles into the host cell cytosol demonstrated by quantitative ultrastructural analyses. These data suggest a role for tlyC and pld in the process of phagosomal escape by R. prowazekii.
Infection and Immunity 11/2005; 73(10):6668-73. · 4.16 Impact Factor
