| homologous and heterologous immune reactions between venezuelan geographic isolates of anaplasma marginale. | | 2000 | 11193694 |
| analysis of the 16s rrna gene sequence of anaplasma centrale and its phylogenetic relatedness to other ehrlichiae. | the nucleotide sequence of the anaplasma centrale 16s rrna gene was determined and compared with the sequences of ehrlichial bacteria. the sequence of a. centrale was closely related to anaplasma marginale by both level-of-similarity (98.08% identical) and distance analysis. a species-specific pcr was developed based upon the alignment data. the pcr can detect a. centrale dna extracted from 10 infected bovine red blood cells in a reaction mixture. a. centrale dna was amplified in the reaction, b ... | 2001 | 11238202 |
| differential adhesion of major surface proteins 1a and 1b of the ehrlichial cattle pathogen anaplasma marginale to bovine erythrocytes and tick cells. | anaplasma marginale is a tick-borne ehrlichial pathogen of cattle for which six major surface proteins (msps) have been described. the msp1 complex, a heterodimer composed of msp1a and msp1b, was shown to induce a protective immune response in cattle and both proteins have been identified as putative adhesins for bovine erythrocytes. in this study the role of msp1a and msp1b as adhesins for bovine erythrocytes and tick cells was defined. msp1alpha and msp1beta1 genes from the oklahoma isolate of ... | 2001 | 11239934 |
| identification of antigenic differences that discriminate between cattle vaccinated with anaplasma centrale and cattle naturally infected with anaplasma marginale. | monoclonal antibodies were raised against the vaccine strain of anaplasma centrale used in australia. a monoclonal antibody that reacted with an 80 kda antigen was used to develop an a. centrale-specific fluorescent antibody test that will be useful for confirming species identity in patent infections. another monoclonal antibody that reacted with a 116 kda antigen was used to develop an a. centrale-specific competitive inhibition enzyme-linked immunosorbent assay (elisa) for the serological ide ... | 2001 | 11239938 |
| sensitivity and specificity of the complement fixation test for detection of cattle persistently infected with anaplasma marginale. | the complement fixation (cf) test commonly is used to identify cattle infected with anaplasma marginale prior to interstate or international movement. estimates of the accuracy of the cf test in detecting animals persistently infected with a. marginale vary widely. in this study, the sensitivity and specificity of the cf test for detection of carrier animals was determined using serum from 232 cattle previously defined as a. marginale positive or negative by nested polymerase chain reaction meth ... | 2001 | 11243370 |
| efficient use of a small genome to generate antigenic diversity in tick-borne ehrlichial pathogens. | ehrlichiae are responsible for important tick-transmitted diseases, including anaplasmosis, the most prevalent tick-borne infection of livestock worldwide, and the emerging human diseases monocytic and granulocytic ehrlichiosis. antigenic variation of major surface proteins is a key feature of these pathogens that allows persistence in the mammalian host, a requisite for subsequent tick transmission. in anaplasma marginale pseudogenes for two antigenically variable gene families, msp2 and msp3, ... | 2001 | 11274438 |
| [molecular tools in the epidemiology of tick-borne bacterial diseases]. | molecular tools have been used to detect rickettsiae in ticks. in ixodes ricinus ticks collected in france, we detected for the first time there an emerging pathogen, rickettsia helvetica, and an ehrlichia sp, closely related to the agent of human granulocytic ehrlichiosis. in guadeloupe (french west indies), we described the occurrence of african tick-bite fever due to rickettsia africae, which had been previously reported in sub-saharan africa only. in africa, we completed our knowledge about ... | 2001 | 11282521 |
| antigenic variation of anaplasma marginale: major surface protein 2 diversity during cyclic transmission between ticks and cattle. | the rickettsial pathogen anaplasma marginale expresses a variable immunodominant outer membrane protein, major surface protein 2 (msp2), involved in antigenic variation and long-term persistence of the organism in carrier animals. msp2 contains a central hypervariable region of about 100 amino acids that encodes immunogenic b-cell epitopes that induce variant-specific antibodies during infection. previously, we have shown that msp2 is encoded on a polycistronic mrna transcript in erythrocyte sta ... | 2001 | 11292724 |
| use of repetitive dna elements to define genetic relationships among anaplasma marginale isolates. | anaplasma marginale genomic dna was tested for the presence of repetitive extragenic palindromic (rep) and enterobacterial repetitive intergenic consensus (eric)-like sequences in order to evaluate the genetic diversity of multiple a. marginale isolates. a. marginale isolates were obtained from cattle of six different states of brazil, from the us and an anaplasma centrale strain was obtained from uruguay. patterns obtained from a. marginale isolates varied from 14 to 17 fragments by rep-polymer ... | 2001 | 11313126 |
| molecular phylogeny and biogeography of north american isolates of anaplasma marginale (rickettsiaceae: ehrlichieae). | anaplasma marginale (a. marginale) is a tick-borne ehrlichial pathogen of cattle that causes the disease anaplasmosis. six major surface proteins (msps) have been identified on a. marginale from cattle and ticks of which three, msp1a, msp4 and msp5, are from single genes and do not vary within isolates. the other three, msp1b, msp2 and msp3, are from multigene families and may vary antigenically in persistently infected cattle. several geographic isolates have been identified in the united state ... | 2001 | 11337128 |
| phylogenetic relationships of anaplasma marginale and 'ehrlichia platys' to other ehrlichia species determined by groel amino acid sequences. | the heat-shock protein (groel) genes of anaplasma marginale, ehrlichia muris and 'ehrlichia platys' were sequenced and compared with the groel of other species of ehrlichia. the groel amino acid sequences of a. marginale and 'e. platys' were most similar to the groel sequence of ehrlichia phagocytophila, with which they formed one group with 6-10% divergence. the e. muris groel was most closely related to the groel of two unclassified strains (hf-565 and anan), then to ehrlichia chaffeensis, ehr ... | 2001 | 11414267 |
| expression of anaplasma marginale major surface protein 2 variants in persistently infected ticks. | anaplasma marginale, an intraerythrocytic ehrlichial pathogen of cattle, establishes persistent infections in both vertebrate (cattle) and invertebrate (tick) hosts. the ability of a. marginale to persist in cattle has been shown to be due, in part, to major surface protein 2 (msp2) variants which are hypothesized to emerge in response to the bovine immune response. msp2 antigenic variation has not been studied in persistently infected ticks. in this study we analyzed msp2 in a. marginale popula ... | 2001 | 11447197 |
| health protocol for translocation of free-ranging elk. | when considering an elk (cervus elaphus) restoration program, wildlife managers must evaluate the positive and negative elements of translocation. we prepared this protocol to give an overview of health considerations associated with translocation of elk, with an emphasis on movement of free-ranging elk from western north america to the southeastern usa. we evaluated infectious agents and ectoparasites reported in elk from two perspectives. first, we made a qualitative estimate of the ability of ... | 2001 | 11504216 |
| detection of haemoparasites in cattle by reverse line blot hybridisation with a note on the distribution of ticks in sicily. | a reverse line blot hybridisation (rlb) of 21 oligonucleotides with polymerase chain reaction (pcr) amplified regions of 16s rrna (ehrlichia/anaplasma group) or 18s rrna (babesia/theileria group) genes of haemoparasites detected theileria annulata, t. buffeli/orientalis, babesia bovis, b. bigemina, b. divergens, ehrlichia bovis, anaplasma marginale, a. centrale and unknown species within the rickettsia tribe.a very high prevalence of mixed infections was detected, which indicated that animals in ... | 2001 | 11511414 |
| ingenious gene generation. | | 2001 | 11514195 |
| citrate synthase gene sequence: a new tool for phylogenetic analysis and identification of ehrlichia. | the sequence of the citrate synthase gene (glta) of 13 ehrlichial species (ehrlichia chaffeensis, ehrlichia canis, ehrlichia muris, an ehrlichia species recently detected from ixodes ovatus, cowdria ruminantium, ehrlichia phagocytophila, ehrlichia equi, the human granulocytic ehrlichiosis [hge] agent, anaplasma marginale, anaplasma centrale, ehrlichia sennetsu, ehrlichia risticii, and neorickettsia helminthoeca) have been determined by degenerate pcr and the genome walker method. the ehrlichial ... | 2001 | 11526124 |
| seroprevalences of vector-transmitted infections of small-holder dairy cattle in coastal kenya. | a cross-sectional study was carried out from july to september 1989 in kaloleni division, coast province, kenya to estimate the prevalence of vector-transmitted diseases in small-holder dairy cattle and to identify the risk factors associated with different management systems. one hundred and thirty of the 157 herds with dairy cattle in kaloleni division were surveyed. these were from three agro-ecological zones (coconut-cassava, cashew nut-cassava and livestock-millet), comprised two management ... | 2001 | 11566374 |
| cd4(+) t lymphocytes from calves immunized with anaplasma marginale major surface protein 1 (msp1), a heteromeric complex of msp1a and msp1b, preferentially recognize the msp1a carboxyl terminus that is conserved among strains. | native major surface protein 1 (msp1) of the ehrlichial pathogen anaplasma marginale induces protective immunity in calves challenged with homologous and heterologous strains. msp1 is a heteromeric complex of a single msp1a protein covalently associated with msp1b polypeptides, of which at least two (designated msp1f1 and msp1f3) in the florida strain are expressed. immunization with recombinant msp1a and msp1b alone or in combination fails to provide protection. the protective immunity in calve ... | 2001 | 11598059 |
| population structure of plasmodium falciparum isolates during an epidemic in southern mauritania. | while the population structure of plasmodium falciparum is well analysed in selected areas with high malaria endemicity in east and west africa, only limited data are available for low endemicity regions bordering the saharan desert. this is one of the first studies for the sahel, where atypically strong rainfalls in 1998 and 1999 led to a severe outbreak of falciparum malaria in south-east mauritania. during a study on in vivo-drug resistance against chloroquine we collected blood samples of pa ... | 2001 | 11679123 |
| immunization of cattle with anaplasma marginale derived from tick cell culture. | anaplasmosis is a hemolytic disease of cattle caused by the ehrlichial tick-borne pathogen anaplasma marginale. killed vaccines used for control of anaplasmosis in the us used antigen harvested from infected bovine erythrocytes which was often contaminated with bovine cells and other pathogens. in this study, we performed an initial cattle trial to test a. marginale harvested from tick cell culture as an immunogen for cattle. eleven yearling holstein cattle were immunized with the cell culture-d ... | 2001 | 11705661 |
| major surface protein 1a effects tick infection and transmission of anaplasma marginale. | anaplasma marginale, an ehrlichial pathogen of cattle and wild ruminants, is transmitted biologically by ticks. a developmental cycle of a. marginale occurs in a tick that begins in gut cells followed by infection of salivary glands, which are the site of transmission to cattle. geographic isolates of a. marginale vary in their ability to be transmitted by ticks. in these experiments we studied transmission of two recent field isolates of a. marginale, an oklahoma isolate from wetumka, ok, and a ... | 2001 | 11730800 |
| specific expression of anaplasma marginale major surface protein 2 salivary gland variants occurs in the midgut and is an early event during tick transmission. | infectivity of anaplasma spp. develops when infected ticks feed on a mammalian host (transmission feed). specific anaplasma marginale major surface protein 2 (msp2) variants are selected for within the tick and are expressed within the salivary glands. the aims of this study were to determine when and where msp2 variant selection occurs in the tick, how msp2 expression is regulated in salivary glands of transmission-feeding ticks, and whether the number of a. marginale organisms per salivary gla ... | 2002 | 11748171 |
| mapping antigenic sites of an immunodominant surface lipoprotein of mycoplasma agalactiae, avgc, with the use of synthetic peptides. | as a first step toward the design of an epitope vaccine to prevent contagious agalactia, the strongly immunogenic 55-kda protein of mycoplasma agalactiae was studied and found to correspond to the avgc protein encoded by the avgc gene. the avg genes of m. agalactiae, which encode four variable surface lipoproteins, display a significant homology to the vsp (variable membrane surface lipoproteins) genes of the bovine pathogen mycoplasma bovis at their promoter region as well as their n-terminus-e ... | 2002 | 11748179 |
| reorganization of genera in the families rickettsiaceae and anaplasmataceae in the order rickettsiales: unification of some species of ehrlichia with anaplasma, cowdria with ehrlichia and ehrlichia with neorickettsia, descriptions of six new species combinations and designation of ehrlichia equi and 'hge agent' as subjective synonyms of ehrlichia phagocytophila. | the genera anaplasma, ehrlichia, cowdria, neorickettsia and wolbachia encompass a group of obligate intracellular bacteria that reside in vacuoles of eukaryotic cells and were previously placed in taxa based upon morphological, ecological, epidemiological and clinical characteristics. recent genetic analyses of 16s rrna genes, groesl and surface protein genes have indicated that the existing taxa designations are flawed. all 16s rrna gene and groesl sequences deposited in genbank prior to 2000 a ... | 2001 | 11760958 |
| expression of major surface protein 2 variants with conserved t-cell epitopes in anaplasma centrale vaccinates. | major surface protein 2 (msp-2), identified as a protection-inducing immunogen against anaplasma marginale challenge, is an immunodominant outer membrane protein with orthologues in all examined anaplasma species. although immunization with live anaplasma centrale has long been used to induce protection against acute disease upon challenge with virulent a. marginale, its msp-2 structure and whether msp-2 variants are generated during persistence of the vaccine strain was unknown. in this study, ... | 2002 | 11796593 |
| characterisation of the 33kda piroplasm surface antigen of theileria orientalis/sergenti/buffeli isolates from west java, indonesia. | the immunodominant 33/35kda antigen of a theileria isolate from west java, indonesia, was characterised and immuno-affinity purified by use of a monoclonal antibody, kul-a4, and was shown to be representative of the t. orientalis/sergenti/buffeli group. the aminoterminal sequence of the purified 35kda peptide (20 residues) was determined by automated edman degradation and found to correspond to the predicted amino acid sequence of a prospective p33 gene previously sequenced from the same isolate ... | 2002 | 11809330 |
| conservation of major surface protein 1 genes of anaplasma marginale during cyclic transmission between ticks and cattle. | bovine anaplasmosis is a rickettsial disease of world-wide economic importance caused by anaplasma marginale. several major surface proteins with conserved gene sequences have been examined as potential candidates for vaccines and/or diagnostic assays. major surface protein 1 (msp1) is composed of polypeptides msp1a and msp1b. msp1a is expressed from the single copy gene msp1 alpha and msp1b is expressed by members of the msp1 beta multigene family. in order to determine if the msp1 genes are co ... | 2002 | 11814681 |
| evolution and function of tandem repeats in the major surface protein 1a of the ehrlichial pathogen anaplasma marginale. | the major surface protein (msp) 1a of the ehrlichial cattle pathogen anaplasma marginale, encoded by the single-copy gene msp1alpha, has been shown to have a neutralization-sensitive epitope and to be an adhesin for bovine erythrocytes and tick cells. msp1alpha has been found to be a stable genetic marker for the identification of geographic isolates of a. marginale throughout development in acutely and persistently infected cattle and in ticks. the molecular weight of msp1a varies among geograp ... | 2001 | 11831437 |
| immunity following use of australian tick fever vaccine: a review of the evidence. | to review the evidence available on the degree and duration of immunity provided by australian tick fever vaccines against babesia bovis, b. bigemina and anaplasma marginale infections in australia and overseas. | 2001 | 11837905 |
| transcript heterogeneity of the p44 multigene family in a human granulocytic ehrlichiosis agent transmitted by ticks. | human granulocytic ehrlichiosis (hge) is an emerging tick-borne zoonosis caused by a strain of anaplasma phagocytophila called the hge agent, an obligatory intracellular bacterium. the agent expresses immunodominant 44-kda outer membrane proteins (p44s) encoded by a multigene family. the present study established an experimental process for transmission of the hge agent from infected mice (a reservoir model) to nymphal ixodes scapularis ticks (a biological vector) and subsequently to horses (a p ... | 2002 | 11854198 |
| genetic variability and stability of anaplasma phagocytophila msp2 (p44). | anaplasma (ehrlichia) phagocytophila's major immunodominant surface protein antigen, msp2 (p44, 44-kda antigen), is encoded by a family of paralogous genes characterized by conserved sequences flanking a hypervariable region. the antigenic profiles of most strains of a. phagocytophila are different, and the differences are principally related to msp2 expression. to date, multiple unique msp2 gene paralogs have been found in a. phagocytophila isolates, but the overall number in the genome of a si ... | 2002 | 11854205 |
| effects of anaplasma phagocytophila on nadph oxidase components in human neutrophils and hl-60 cells. | the human granulocytic ehrlichiosis agent, anaplasma phagocytophila, resides and multiplies exclusively in cytoplasmic vacuoles of granulocytes. a. phagocytophila rapidly inhibits the superoxide anion (o(2)(-)) generation by human neutrophils in response to various stimuli. to determine the inhibitory mechanism, the influence of a. phagocytophila on protein levels and localization of components of the nadph oxidase were examined. a. phagocytophila decreased levels of p22(phox), but not gp91(phox ... | 2002 | 11854221 |
| merozoite surface protein 3 and protection against malaria in aotus nancymai monkeys. | a blood-stage vaccine based on plasmodium falciparum merozoite surface protein 3 (msp3) was tested for efficacy in a primate model. aotus nancymai monkeys were vaccinated with yeast-expressed msp3 before a lethal challenge with plasmodium falciparum parasites. five of 7 control monkeys had acute infections and required treatment to control parasitemia. only 1 of 7 monkeys vaccinated with msp3 required this treatment. the efficacy of the msp3 vaccination appeared to be comparable to that of msp1( ... | 2002 | 11865423 |
| the highest priority: what microbial genomes are telling us about immunity. | study of microbial genomes has provided new insight into the functions that pathogens require for survival in the animal host. small genome bacterial pathogens, defined as those < or = 1/3 the size of escherichia coli, include chlamydiae, rickettsiae and ehrlichiae, mycoplasmas, and spirochetes. the small genome size is believed to result from reductive evolution, a process of initial mutation with loss of function followed by progressive accumulation of mutations and eventual gene deletion. thi ... | 2002 | 11867162 |
| selective in vivo depletion of cd4(+) t lymphocytes with anti-cd4 monoclonal antibody during acute infection of calves with anaplasma marginale. | to investigate the in vivo role of cd4(+) t lymphocytes during acute anaplasmosis, thymectomized calves were selectively depleted of cd4(+) t lymphocytes by treatment with anti-cd4 monoclonal antibody (mab) and were then infected with the florida strain of anaplasma marginale in two sequential experiments (experiments 1 and 2). treatment of thymectomized calves with a total of 5.0 mg of anti-cd4 mab/kg of body weight during the 1st week followed by 0.3-mg/kg doses administered twice weekly for 7 ... | 2002 | 11874888 |
| characterization and transcriptional analysis of gene clusters for a type iv secretion machinery in human granulocytic and monocytic ehrlichiosis agents. | anaplasma (ehrlichia) phagocytophila and ehrlichia chaffeensis, the etiologic agents of granulocytic and monocytic ehrlichioses, respectively, are obligatory intracellular bacteria that cause febrile systemic illness in humans. we identified and characterized clusters of genes for a type iv secretion machinery in these two bacteria, and analyzed their gene expression in cell culture and mammalian hosts. eight virb and vird genes were found in each bacterial genome, and all of the genes were tran ... | 2002 | 11895979 |
| antigenic variation of anaplasma marginale msp2 occurs by combinatorial gene conversion. | the rickettsial pathogen anaplasma marginale establishes lifelong persistent infection in the mammalian reservoir host, during which time immune escape variants continually arise in part because of variation in the expressed copy of the immunodominant outer membrane protein msp2. a key question is how the small 1.2 mb a. marginale genome generates sufficient variants to allow long-term persistence in an immunocompetent reservoir host. the recombination of whole pseudogenes into the single msp2 e ... | 2002 | 11918803 |
| a msp1alpha polymerase chain reaction assay for specific detection and differentiation of anaplasma marginale isolates. | anaplasma marginale is the causative agent of bovine anaplasmosis, a disease which can be protected by vaccination with the less pathogenic anaplasma species, a. centrale. currently, there is no polymerase chain reaction (pcr) assay available which differentiates between different species of anaplasma or which can differentiate isolates of a. marginale within outbreaks and between different countries. a molecular test specific for a. marginale would be ideal for the identification of anaplasma s ... | 2002 | 11955782 |
| human ehrlichioses. | human ehrlichioses represent one of the best examples of newly emergent infectious diseases in which the classic triad of host, infectious agent, and environment are intertwined closely. these pathogens have existed for eons on the planet, and some were described as veterinary pathogens decades ago. because of dramatic increases of deer and small mammal populations in certain areas and the subsequent increased populations of particular blood-feeding ticks, the risk of developing these diseases i ... | 2002 | 11982308 |
| infection of tick cells and bovine erythrocytes with one genotype of the intracellular ehrlichia anaplasma marginale excludes infection with other genotypes. | anaplasma marginale, a tick-borne rickettsial pathogen of cattle, is endemic in several areas of the united states. many geographic isolates of a. marginale that occur in the united states are characterized by the major surface protein 1a, which varies in sequence and molecular weight due to different numbers of tandem repeats of 28 or 29 amino acids. recent studies (g. h. palmer, f. r. rurangirwa, and t. f. mcelwain, j. clin. microbiol. 39:631-635, 2001) of an a. marginale-infected herd of catt ... | 2002 | 11986275 |
| molecular epidemiology of plasmodium falciparum infections among asymptomatic inhabitants of a holoendemic malarious area in northern ghana. | age dependence of malaria infection was assessed in an age-stratified cluster sample of 308 individuals from kassena-nankana district of northern ghana during june and july 2000. overall prevalence of plasmodium falciparum by microscopy was 70%, with the maximum among 5-9 year olds. parasite density was highest (geometric mean 1922/microl blood) in 1-2 year olds. eighty-two per cent of samples were positive by polymerase chain reaction (pcr), and restriction fragment length polymorphism typing o ... | 2002 | 12000651 |
| antigenic characterization of anaplasma marginale isolates from different regions of brazil. | antigenic characterization of a. marginale isolates has contributed to identifying the presence of common and restricts epitopes of major surface proteins (msps). the data may improve vaccine development to protect against a. marginale isolates from different regions. brazilian a. marginale isolates were characterized antigenically by western blot with monoclonal antibodies (mabs) against msps and rabbit anti-msp-4 from florida strain. six a. marginale isolates from ms, mg (aufv1), sp, pr-l1, pr ... | 2002 | 12034541 |
| molecular diagnosis of theileriosis and heartwater in bovines in africa. | the advent of the polymerase chain reaction (pcr) coupled with the specificity of deoxyribocucleic acid (dna)-dna hybridization has led to the development of specific and sensitive molecular diagnostic tests to detect and characterize the organisms that cause theileriosis and heartwater. theileriosis is a widespread disease of wild and domestic ruminants caused by apicomplexan parasites of the genus theileria. species-specific variations in small subunit ribosomal ribonucleic acid genes (ssurrna ... | 2002 | 12055842 |
| effect of tetracycline on development of anaplasma marginale in cultured ixodes scapularis cells. | infections of the tick-borne ehrlichial pathogen, anaplasma marginale, in cattle have been controlled, in part, by administration of low doses of tetracycline. recently, a cell culture system was developed for a. marginale using a tick cell line derived from embryonic ixodes scapularis. this study was designed to determine the effect of tetracycline on a. marginale propagated in a tick cell culture assay. various concentrations of tetracycline (0, 0.01, 0.10, 1.0, 5, 10, 20 or 100 microg/ml) wer ... | 2002 | 12072219 |
| antigenic characterization of morphologically distinct anaplasma marginale isolates using a panel of monoclonal antibodies. | the present study, describes the antigenic characterization of a brazilian isolate of anaplasma marginale with appendage (tail). a panel of monoclonal antibodies (mcabs) was produced and tested by the indirect fluorescent antibody test (ifat), elisa and western blotting, and used to characterize two isolates of a. marginale (one with appendage and another without appendage). among the clones produced, eight recognized antigenic proteins, with molecular weights varying from 18.4 to 66kda. in west ... | 2002 | 12072223 |
| seroprevalence of antibodies that react with anaplasma phagocytophila, the agent of human granulocytic ehrlichiosis, in different populations in westchester county, new york. | we determined the frequencies of antibodies to anaplasma phagocytophila, the agent of human granulocytic ehrlichiosis (hge), in different groups of adults and children from westchester county, new york. the groups included 159 adult blood donors and 215 children who were seronegative for borrelia burgdorferi antibodies, 118 adult patients and 57 children who were seropositive for b. burgdorferi antibodies, and 42 adult patients with culture-confirmed erythema migrans. eighteen (11.3%) of the blo ... | 2002 | 12089287 |
| detection of the anaplasma centralevaccine strain and specific differentiation from anaplasma marginale in vaccinated and infected cattle. | bovine anaplasmosis caused by the intraerythrocytic rickettsia anaplasma marginale is the most prevalent tick-borne disease of cattle worldwide. the most efficient method to control anaplasmosis is by vaccination using live anaplasma centrale, a closely related species or subspecies of low pathogenicity that is capable of inducing significant protection against the more virulent a. marginale. in the present study, we applied pcr assays to detect and discriminate field infection with a. marginale ... | 2002 | 12107477 |
| roles of p38 mitogen-activated protein kinase, nf-kappab, and protein kinase c in proinflammatory cytokine mrna expression by human peripheral blood leukocytes, monocytes, and neutrophils in response to anaplasma phagocytophila. | anaplasma phagocytophila, an obligately intracellular bacterium of granulocytes, causes human granulocytic ehrlichiosis. within 2 h after addition of a. phagocytophila, interleukin-1beta (il-1beta), tumor necrosis factor alpha (tnf-alpha), and il-6 mrnas are induced in human peripheral blood leukocytes (pbls) or monocytes in vitro. however, neutrophils generate only il-1beta mrna. in the present study, signaling pathways for induction of these three cytokines were examined. tnf-alpha and il-6 mr ... | 2002 | 12117921 |
| identification and characterization of a site-specific tyrosine recombinase within the variable loci of mycoplasma bovis, mycoplasma pulmonis and mycoplasma agalactiae. | three highly mutable loci of the wall-less pathogens mycoplasma bovis, mycoplasma pulmonis and mycoplasma agalactiae undergo high-frequency genomic rearrangements and generate extensive antigenic variation of major surface lipoproteins. adjacent to each locus, an open reading frame exists as a single chromosomal copy and is predicted to encode a site-specific dna recombinase exhibiting high homology to the recombinases xerd of escherichia coli and codv of bacillus subtilis. each of the mycoplasm ... | 2002 | 12119115 |
| superoxide anion production during anaplasma phagocytophila infection. | anaplasma phagocytophila persists within neutrophils and prevents the respiratory burst by inhibiting gp91(phox). mutations in gp91(phox) result in chronic granulomatous disease (cgd), which is diagnosed by use of the nitroblue tetrazolium (nbt) and fc-oxyburst assays that examine whether cells produce o2-. this study assessed whether the nbt and fc-oxyburst assays could detect a respiratory burst during a. phagocytophila infection. o2- production was inhibited in hl-60 cells and neutrophils inf ... | 2002 | 12134266 |
| ehrlichia equi (anaplasma phagocytophila) infection in an adult horse in france. | | 2002 | 12135075 |
| ehrlichiosis in ixodes ricinus and wild mammals. | | 2002 | 12141732 |
| pcr-elisa for diagnosis of trypanosoma evansi in animals and vector. | a highly sensitive and specific polymerase chain reaction (pcr) based assay for the detection of trypanosoma evansi present in the blood of different animals and vector was developed. a simple lysis method was used to remove of the red blood cells to facilitate direct input of samples into the pcr reactions. the primer set was designed and synthesized to amplify a single band of 257 bp pcr product that was subsequently examined by enzyme-linked immunosorbent assay (elisa). the sensitivity limit ... | 2002 | 12144767 |
| conservation of the unique rickettsial rrna gene arrangement in anaplasma. | the organization of the rrna genes of anaplasma marginale, the type species of the genus anaplasma, was identified to determine if the atypical rrna gene arrangement identified in rickettsiae preceded divergence of the order rickettsiales into the families anaplasmataceae and rickettsiaceae. the rrna genes are encoded by two unlinked units, each present in a single copy per a. marginale genome. the 16s rrna gene is separated from the linked 23s and 5s rrna genes by a minimum of 100 kb. similar t ... | 2002 | 12148657 |
| analysis of sequences and loci of p44 homologs expressed by anaplasma phagocytophila in acutely infected patients. | anaplasma phagocytophila is an obligatory intragranulocytic bacterium that causes human granulocytic ehrlichiosis. immunodominant 44-kda outer membrane proteins of a. phagocytophila are encoded by a p44 multigene family. in the present study, expression profiles of p44 genes in the blood of acutely infected patients in the year 2000 were characterized. a single p44 gene was predominantly expressed in peripheral blood leukocytes from one patient, while up to 17 different p44 genes were transcribe ... | 2002 | 12149362 |
| serologic and molecular detection of ehrlichia chaffeensis and anaplasma phagocytophila (human granulocytic ehrlichiosis agent) in korean patients. | sera from 491 korean patients with acute febrile diseases were tested for ehrlichia chaffeensis and anaplasma phagocytophila antibodies by indirect immunofluorescence assay (ifa), western blotting, and taqman real-time pcr. overall, 0.4% of sera reacted with e. chaffeensis, and 1.8% reacted with a. phagocytophila in ifas. this is the first report of detection of antibodies to a. phagocytophila and e. chaffeensis in korea and suggests the presence of a. phagocytophila and e. chaffeensis or antige ... | 2002 | 12149387 |
| phylogeography of new world isolates of anaplasma marginale based on major surface protein sequences. | gene and protein sequences of major surface proteins (msp) 1a and 4 of anaplasma marginale (rickettsiales: anaplasmataceae) were used to infer phylogenetic relationships between new world isolates from argentina, brazil, mexico and the united states. seventeen isolates of a. marginale plus two outgroup taxa (a. centrale and a. ovis) were used for maximum-parsimony analysis of msp4, while 20 isolates were used for phylogenetic analysis of msp1a. msp4 analysis provided strong bootstrap support for ... | 2002 | 12151201 |
| agents of ehrlichia phagocytophila group and other microorganisms co-infecting ticks in southwestern slovakia. | | 2002 | 12197635 |
| epidemiology of bovine tick-borne diseases in southern italy. | this investigation was carried out in an area covering part of three southern italian regions: campania, basilicata and apulia. eighty-one farms were involved using the formula suggested by thrusfield; they were equally distributed over the area which was subdivided into 81 geo-referenced sub-areas. in may and june 1999 from a total of 506 cattle, older than 18 months, blood-samples were taken and ticks were collected and identified. serum samples were tested for antibodies of bahesia bigemina, ... | 2002 | 12199369 |
| identification of anaplasma phagocytophila (formerly ehrlichia phagocytophila) variants in blood from sheep in norway. | a total of 41 blood samples were collected from 40 anaplasma phagocytophila-infected sheep in 11 sheep flocks from four different counties of southern norway. the presence and nature of the anaplasma species were identified by microscopic detection of morulae, pcr, reverse line blot hybridization, and 16s rrna gene sequencing. a. phagocytophila was identified in all of the samples, and sequencing of the 16s rrna gene revealed the presence of four variants of a. phagocytophila. two of these varia ... | 2002 | 12202552 |
| simultaneous detection of anaplasma marginale and a new ehrlichia species closely related to ehrlichia chaffeensis by sequence analyses of 16s ribosomal dna in boophilus microplus ticks from tibet. | to identify ehrlichial agents in boophilus microplus ticks, dna samples of b. microplus collected from the tibet autonomous region and sichuan province of china were screened by a nested pcr. sixteen of 43 (37%) dna samples of b. microplus from tibet were positive in nested pcr analysis. all 27 samples from sichuan were negative. the screen identified two ehrlichial agents based on different 16s rrna genes that were found after amplifying and sequencing the 5'-end fragments of the 16s rrna genes ... | 2002 | 12202567 |
| cytokine gene expression by peripheral blood leukocytes in horses experimentally infected with anaplasma phagocytophila. | human granulocytic ehrlichiosis (hge), a tick-borne zoonosis, is caused by an obligatory intragranulocytic bacterium, the hge agent, a strain of anaplasma phagocytophila. the equine model of hge is considered valuable in understanding pathogenic and immune mechanisms of hge. in the present study, cytokine mrna expression by peripheral blood leukocytes (pbls) in horses was examined during the course of infection by intravenous inoculation of a. phagocytophila or by allowing feeding by infected ti ... | 2002 | 12204963 |
| determination of the nucleotide sequences of heat shock operon groesl and the citrate synthase gene (glta) of anaplasma (ehrlichia) platys for phylogenetic and diagnostic studies. | the 1,670-bp nucleotide sequence of the heat shock operon groesl and the 1,236-bp sequence of the citrate synthase gene (glta) of anaplasma (ehrlichia) platys were determined. the topology of the groel- and glta-based phylogenetic tree was similar to that derived from 16s rrna gene analyses with distances. both groesl- and glta-based pcrs specific to a. platys were also developed based upon the alignment data. | 2002 | 12204973 |
| evaluation of sensitivity and specificity of a mycoplasma haemomuris-specific polymerase chain reaction test. | mycoplasma haemomuris, a small pleomorphic bacterium parasitic of red blood cells, often causes chronic and subclinical infection of rodents. mycoplasma haemomuris is uncultivable, and a serologic testing method is not readily available. the purpose of the study reported here was to develop a sensitive and specific polymerase chain reaction (pcr) test for detection of m. haemomuris in blood samples. | 2002 | 12211273 |
| characterization of the rrna genes of ehrlichia chaffeensis and anaplasma phagocytophila. | the rrna genes of ehrlichia chaffeensis and anaplasma phagocytophila have been analyzed. the 16s rrna genes were previously characterized for both of these agents. southern hybridization was used to show that there are single copies of both the 16s and 23s rrna genes in the genomes of each organism, and that the 16s rrna genes were upstream from the 23s rrna genes by at least 16 and 11 kb for e. chaffeensis and a. phagocytophila, respectively. pcr amplification and gene walking was used to seque ... | 2002 | 12215262 |
| major histocompatibility complex class ii dr-restricted memory cd4(+) t lymphocytes recognize conserved immunodominant epitopes of anaplasma marginale major surface protein 1a. | native major surface protein 1 (msp1) of anaplasma marginale, composed of covalently associated msp1a and msp1b proteins, stimulates protective immunity in cattle against homologous and heterologous strain challenge. protective immunity against pathogens in the family anaplasmataceae involves both cd4(+) t cells and neutralizing immunoglobulin g. thus, an effective vaccine should contain both cd4(+) t- and b-lymphocyte epitopes that will elicit strong memory responses upon infection with homolog ... | 2002 | 12228278 |
| occurrence of concurrent trypanosomosis, theileriosis, anaplasmosis and helminthosis in friesian, zebu and sahiwal cattle in uganda. | an epidemiological investigation was conducted on farms in tororo and soroti districts of uganda from january to february 2000 to determine the cause of reported persistent mortality of cattle. blood and faecal material of 98 cattle comprising of 33 friesians, 58 zebu and 7 sahiwal were examined. results revealed that seven (7.1 %) cattle had trypanosome infection, mainly due to trypanosoma vivax and t. brucei, 17 (17.3%) fasciola infection, 28 (28.6%) gastrointestinal nematode infection, 33 (33 ... | 2002 | 12233999 |
| simultaneous detection of anaplasma and ehrlichia species in ruminants and detection of ehrlichia ruminantium in amblyomma variegatum ticks by reverse line blot hybridization. | the detection of anaplasma and ehrlichia species is usually based on species-specific pcr assays, since no assay is yet available which can detect and identify these species simultaneously. to this end, we developed a reverse line blot (rlb) assay for simultaneous detection and identification of anaplasma and ehrlichia species in domestic ruminants and ticks. in a pcr the hypervariable v1 region of the 16s ribosomal rna (rrna) gene was amplified with a set of primers unique for members of the ge ... | 2002 | 12243899 |
| vaccination of cattle with anaplasma marginale derived from tick cell culture and bovine erythrocytes followed by challenge-exposure with infected ticks. | anaplasmosis, a hemolytic disease of cattle caused by the tick-borne pathogen anaplasma marginale (rickettsiales: anaplasmataceae) has been controlled using killed vaccines made with antigen harvested from infected bovine erythrocytes. we recently developed a cell culture system for propagation of a. marginale in a continuous tick cell line. in this study, we performed a cattle trial to compare the bovine response to vaccination with a. marginale harvested from tick cell culture or bovine erythr ... | 2002 | 12243900 |
| dna-encoded fetal liver tyrosine kinase 3 ligand and granulocyte macrophage-colony-stimulating factor increase dendritic cell recruitment to the inoculation site and enhance antigen-specific cd4+ t cell responses induced by dna vaccination of outbred animals. | dna-based immunization is a contemporary strategy for developing vaccines to prevent infectious diseases in animals and humans. translating the efficacy of dna immunization demonstrated in murine models to the animal species that represent the actual populations to be protected remains a significant challenge. we tested two hypotheses directed at enhancing dna vaccine efficacy in outbred animals. the first hypothesis, that dna-encoding fetal liver tyrosine kinase 3 ligand (flt3l) and gm-csf incr ... | 2002 | 12244180 |
| cultivation of an ovine strain of ehrlichia phagocytophila in tick cell cultures. | ehrlichia phagocytophila (previously known as cytoecetes phagocytophila) which causes tick-borne fever (tbf) in sheep and pasture fever in cattle in the uk and mainland europe is transmitted by the temperate hard tick ixodes ricinus. the disease in sheep is characterized by fever, leucopenia and immunosuppression. studies on the pathogenesis and other aspects of the disease have been hampered because the organism has not been cultivated in continuous or primary cell culture systems. this paper d ... | 2002 | 12354525 |
| activation of a p44 pseudogene in anaplasma phagocytophila by bacterial rna splicing: a novel mechanism for post-transcriptional regulation of a multigene family encoding immunodominant major outer membrane proteins. | immunodominant 44 kda major outer membrane proteins of anaplasma phagocytophila (human granulocytic ehrlichiosis agent) are encoded by the p44 multigene family. one of the paralogues, p44-18 is predominantly expressed by a. phagocytophila in mammalian hosts, but is downregulated in the arthropod vector. the expression of p44-18 was upregulated in a. phagocytophila cultivated in hl-60 cells at 37 degrees c compared with 24 degrees c. however, the molecular mechanism of such gene expression was un ... | 2002 | 12366837 |
| expression of anaplasma marginale major surface protein 2 operon-associated proteins during mammalian and arthropod infection. | the antigenically variant major surface protein 2 (msp2) of anaplasma marginale is expressed from a 3.5-kb operon that contains, in a 5'-to-3' direction, four open reading frames, opag3, opag2, opag1, and msp2. this operon structure was shown to be conserved among genotypically and phenotypically distinct a. marginale, a. ovis, and a. centrale strains. the individual opag amino acid sequences are highly conserved among a. marginale strains, with identities ranging from 95 to 99%. opag2 and opag3 ... | 2002 | 12379676 |
| tick-borne diseases (tbds) of dairy cows in a mediterranean environment: a clinical, serological, and hematological study. | a longitudinal study of tick-borne diseases (tbds) in southern italy was carried out by monitoring two dairy farms (a and b) located in the apulia region. on each farm ten calves and ten heifers were observed monthly from may 1999 to february 2001 for clinical signs and blood parameters; antibodies against babesia bigemina and anaplasma marginale using an elisa test were also monitored for the first eight months of the study. totals of 28 and 14 cases of tbds were observed in the complete herds ... | 2002 | 12381611 |
| the mouse as a model for investigation of human granulocytic ehrlichiosis: current knowledge and future directions. | the use of laboratory mice to investigate correlates of infectious disease, including infection kinetics, cellular alterations, cytokine profiles, and immune response in the context of an intact host has expanded exponentially in the last decade. a marked increase in the availability of transgenic mice and research tools developed specifically for the mouse parallels and enhances this research. human granulocytic ehrlichiosis (hge) is an emerging, zoonotic disease caused by tick-borne bacteria. ... | 2002 | 12405632 |
| epidemiological, clinical and laboratory distinction between human granulocytic ehrlichiosis and the initial phase of tick-borne encephalitis. | to establish epidemiological, clinical and laboratory differences between adult patients with proven acute human granulocytic ehrlichiosis (hge) and patients with the initial phase of tick-borne encephalitis (tbe). | 2002 | 12422617 |
| infection with anaplasma phagocytophila in cervids from slovenia: evidence of two genotypic lineages. | human granulocytic ehrlichiosis (hge) was recently recognized as an emerging tick-borne infection in europe. the disease is caused by anaplasma (previously ehrlichia) phagocytophila. the first confirmed acute human disease caused by a. phagocytophila was reported from slovenia in 1998. the tick ixodes ricinus was identified as the likely vector for this pathogen of humans and animals in europe. in order to assess the possibility that roe and red deer in slovenia serve as potential reservoir host ... | 2002 | 12422618 |
| demonstration of anaplasma (ehrlichia) platys inclusions in peripheral blood platelets of a dog in japan. | a free-roaming dog in okinawa island showed anaplasma (ehrlichia) platys-like inclusions within the platelets of peripheral blood samples. the inclusions were positive in indirect fluorescence test with anti-a. phagocytophila serum. the platelet count of the dog was 170,000 microl(-1). the sequence analysis of the 16s rrna, citrate synthase and heat shock protein genes of dna from the infected platelets confirmed that the inclusions were a. platys. this is the first detection of a. platys inclus ... | 2002 | 12446100 |
| rickettsial, ehrlichial and bartonella infections of the myocardium and pericardium. | myocarditis and pericarditis are uncommon complications of human rickettsial, ehrlichial and bartonella infections. myocardial inflammation usually occurs in the setting of acute disseminated infection. organisms associated with myocarditis include: rickettsia rickettsii, r. conorii, orientia tsutsugamushi, coxiella burnetii, anaplasma phagocytophila (the causative agent of human granulocytic ehrlichiosis) and bartonella henselae. pericarditis has been described in the setting of r. conorii and ... | 2003 | 12456377 |
| characterization of the functional domain of major surface protein 1a involved in adhesion of the rickettsia anaplasma marginale to host cells. | the major surface protein (msp) 1a of the genus type species anaplasma marginale (rickettsiales: anaplasmataceae) has been shown to mediate adhesion, infection and transmission of the organism, as well as to contribute to protective immunity in cattle. msp1a contains a variable number of tandemly repeated peptides in the amino-terminal region, while the remainder of the protein is highly conserved among isolates. the number of repeats varies among geographic isolates of a. marginale but is const ... | 2003 | 12458174 |
| repression of rac2 mrna expression by anaplasma phagocytophila is essential to the inhibition of superoxide production and bacterial proliferation. | anaplasma phagocytophila, the etiologic agent of human granulocytic ehrlichiosis, is an emerging bacterial pathogen that invades neutrophils and can be cultivated in hl-60 cells. infected neutrophils and hl-60 cells fail to produce superoxide anion (o(2)(-)), which is partially attributable to the fact that a. phagocytophila inhibits transcription of gp91(phox), an integral component of nadph oxidase. cdna microarray and rt-pcr analyses demonstrated that transcription of the gene encoding rac2, ... | 2002 | 12471136 |
| relationship between tick bites and the seroprevalence of babesia microti and anaplasma phagocytophila (previously ehrlichia sp.) in blood donors. | tick-borne diseases, particularly babesiosis and ehrlichiosis, represent recently emerging infections. despite an increased recognition of the threat tick-borne agents pose to blood safety, our understanding of the prevalence and transmissibility of these agents in blood donors is limited. | 2002 | 12473139 |
| elimination of erythrocytes from blood prior to dna extraction improves the sensitivity of anaplasma phagocytophila pcr. | | 2002 | 12477341 |
| roles of neutrophil beta 2 integrins in kinetics of bacteremia, extravasation, and tick acquisition of anaplasma phagocytophila in mice. | tick saliva contains anti-inflammatory and immunosuppressive substances that facilitate blood feeding and enhance tick-vectored pathogen transmission, including anaplasma phagocytophila an etiologic agent of granulocytic ehrlichiosis. as such, inflammation at a tick-feeding site is strikingly different than that typically observed at other sites of inflammation. up-regulation of cd11b/cd18 occurs in host granulocytes following interaction or infection with a phagocytophila, and the absence of cd ... | 2003 | 12480703 |
| transmission of anaplasma phagocytophila (human granulocytic ehrlichiosis agent) in horses using experimentally infected ticks (ixodes scapularis). | most human granulocytic ehrlichiosis (hge) studies carried out in horses use needle inoculation of infected leucocytes or cell cultures. this route of inoculation does not accurately reflect natural infection of the tick-borne agent. to investigate whether tick transmission influences the course of granulocytic ehrlichiosis in the horse model, experimental transmission through infected laboratory-reared ixodes scapularis ticks was attempted into two healthy horses. one additional horse served as ... | 2002 | 12485358 |
| phylogenetic analysis of the erythrocytic anaplasma species based on 16s rdna and groel (hsp60) sequences of a. marginale, a. centrale, and a. ovis and the specific detection of a. centrale vaccine strain. | phenotypic criteria for the identification of erythrocytic ruminant anaplasma species has relied on subjective identification methods such as host pathogenicity (virulence for cattle or sheep) and/or the location of anaplasma inclusion bodies within the host's red cells. sequence comparisons of new and available genbank accessions were investigated to elucidate the relationships among these closely related anaplasma species. twenty-one 16s rdna and groel (hsp60) sequences from 13 anaplasma margi ... | 2003 | 12488078 |
| evidence for modulated immune response to anaplasma phagocytophila sensu lato in cats with fiv-induced immunosuppression. | human granulocytic ehrlichiosis (hge) is an emerging infectious disease in which some patients experience unusual opportunistic infections. in this study, cats infected with the hge agent, anaplasma phagocytophila s.l., had clinical granulocytic ehrlichiosis (ge), anti-nuclear antibodies and increased ifn-gamma mrna. in fiv-immunosuppressed cats with ge, there was upregulated il-10 transcription but not ifn-gamma. cats with fiv had poor response to vaccines, regardless of ge status. this prelimi ... | 2003 | 12493491 |
| avian reservoirs of the agent of human granulocytic ehrlichiosis? | | 2002 | 12498679 |
| antibiotic susceptibilities of anaplasma (ehrlichia) phagocytophilum strains from various geographic areas in the united states. | we tested the antibiotic susceptibilities of eight strains of anaplasma phagocytophilum (the agent of human granulocytic ehrlichiosis) collected in various geographic areas of the united states, including minnesota, wisconsin, california, and new york. the results are homogeneous and show that doxycycline, rifampin, and levofloxacin are the most active antibiotics against these strains in vitro. | 2003 | 12499227 |
| human granulocytic ehrlichiosis in europe. | ehrlichiosis comprises a group of emerging tick-borne infectious diseases caused by obligate intracellular gram-negative bacteria that infect leukocytes. infections caused by members of the genus ehrlichia have been described in animals and humans, but to date there are no convincing reports of the presence of other types of human ehrlichiosis different from human granulocytic ehrlichiosis (hge) in europe. the european vector is the same as that of lyme borreliosis, the hard tick ixodes ricinus, ... | 2002 | 12519349 |
| infection exclusion of the rickettsial pathogen anaplasma marginale in the tick vector dermacentor variabilis. | anaplasma marginale is a tick-borne, rickettsial cattle pathogen that is endemic in several areas of the united states. recent studies (j. de la fuente, j. c. garcia-garcia, e. f. blouin, j. t. saliki, and k. m. kocan, clin. diagn. lab. immunol. 9:658-668, 2002) demonstrated that infection of cultured tick cells and bovine erythrocytes with one genotype of a. marginale excluded infection with other genotypes, a phenomenon referred to as infection exclusion. the present study was undertaken to co ... | 2003 | 12522060 |
| antibodies to anaplasma marginale major surface proteins 1a and 1b inhibit infectivity for cultured tick cells. | major surface protein 1 (msp1) of the cattle pathogen anaplasma marginale (rickettsiales: anaplasmataceae) is a complex of two proteins, msp1a and msp1b. previous studies demonstrated that msp1a and msp1b are adhesins for bovine erythrocytes, while only msp1a proved to be an adhesin for tick cells. in this study, a tick cell culture system for propagation of a. marginale was used to develop an infection inhibition assay for testing the ability of antisera to block infection of a. marginale for c ... | 2003 | 12531299 |
| [comparison of extraction methods for detection of ehrlichia dna in whole blood using pcr]. | the author compared nine methods for isolation of specific dna of the etiological agent of human granulocytic ehrlichiosis from human blood for examination of the pcr. to full blood of healthy donors a laboratory culture of the agent was added and the effectiveness of isolation an stability of the template was tested under conditions when the blood was fresh or frozen. for universal use qiaamp (qiagen) was most suitable, frozen blood was extracted best using nucleospin tissue (macherey-nagel). | 2002 | 12532899 |
| seasonal dynamics of anaplasma phagocytophila in a rodent-tick (ixodes trianguliceps) system, united kingdom. | we investigated the reservoir role of european wild rodents for anaplasma phagocytophila using polymerase chain reaction (pcr) analysis of blood collected from individually tagged rodents captured monthly over 2 years. the only tick species observed in the woodland study site was ixodes trianguliceps, and ruminant reservoir hosts were not known to occur. a. phagocytophila infections were detected in both bank voles and wood mice but were restricted to periods of peak nymphal and adult tick activ ... | 2003 | 12533283 |
| conservation of a gene conversion mechanism in two distantly related paralogues of anaplasma marginale. | anaplasmataceae, the causative agents of anaplasmosis and ehrlichiosis, persist in the bloodstream of their mammalian hosts, allowing acquisition and transmission by tick vectors. anaplasma marginale establishes persistent infection characterized by sequential cycles of rickettsaemia in which new antigenic variants emerge. the two most immunodominant outer membrane proteins, msp2 and msp3, are paralogues, each encoded by a distinct family of related genes. this study demonstrates that, although ... | 2003 | 12535066 |
| simultaneous infection with borrelia burgdorferi and human granulocytic ehrlichiosis. | a 5-year-old child with simultaneous early lyme disease and human granulocytic ehrlichiosis (hge) is described. because of the shared vector, hge and lyme disease are increasingly identified as coinfections in tick-exposed patients. early recognition of concurrent lyme disease and hge is important because amoxicillin, an antibiotic of choice for young children with early lyme disease, is ineffective for hge. | 2003 | 12553302 |
| comparison of pcr assays for detection of the agent of human granulocytic ehrlichiosis, anaplasma phagocytophilum. | human granulocytic ehrlichiosis is an emerging infectious disease in the united states and europe, and pcr methods have been shown to be effective for the diagnosis of acute infections. numerous pcr assays and primer sets have been reported in the literature. the analytical sensitivities (limits of detection) of 13 published pcr primer sets were compared using dna extracted from serial dilutions of anaplasma phagocytophilum-infected hl-60 cells. the specificity of the assays that were able to de ... | 2003 | 12574272 |
| co-feeding studies of ticks infected with anaplasma marginale. | ticks often cluster at preferred feeding sites on hosts, and the co-feeding of ticks at the same site has been shown to increase feeding success and the transmission of some pathogens. while the major route of infection of ticks with pathogens is via the bloodmeal during feeding on a parasitemic host, non-systemic transmission of viruses and spirochetes has been shown to occur from infected to uninfected ticks at common feeding sites on uninfected hosts. in this research, two separate studies we ... | 2003 | 12623209 |
| detection of ehrlichia spp. in the blood of wild white-tailed deer in missouri by pcr assay and serologic analysis. | blood samples collected from wild deer in missouri in november of 2000 and 2001 were positive by pcr assays for ehrlichia chaffeensis (50 of 217; 23%), ehrlichia ewingii (44 of 217; 20%), and anaplasma species (214 of 217; 99%). nucleotide sequences of selected amplicons from the assay for anaplasma matched sequences of the white-tailed deer agent. serologic analysis of 112 deer sampled in 2000 showed a very high prevalence of antibodies to e. chaffeensis (97 of 112; 87%) and a low prevalence of ... | 2003 | 12624063 |
| ehrlichia platys (anaplasma platys) in dogs from maracaibo, venezuela: an ultrastructural study of experimental and natural infections. | since 1982 ehrlichia platys, now emended as anaplasma platys, has been diagnosed in dogs from maracaibo, venezuela, using buffy coat smears stained with dip quick. three dogs were inoculated with an a. platys strain. when parasitemia reached 60-97%, blood samples obtained from the inoculated dogs and from two naturally infected dogs were centrifuged to obtain platelet-rich plasma, which was mixed with 0.1% glutaraldehyde at 37 c for 10 minutes. platelet pellets were fixed in 3% glutaraldehyde fo ... | 2003 | 12637754 |