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highly prevalent coxiella sp. bacterium in the tick vector amblyomma americanum.laboratory-reared and field-collected amblyomma americanum ticks were hosts of a coxiella sp. and a rickettsia sp. while the coxiella sp. was detected in 50 of 50 field-collected ticks, the rickettsia sp. was absent from 32% of ticks. the coxiella sp. showed evidence of a reduced genome and may be an obligate endosymbiont.200717085709
functional evolution of the vitamin d and pregnane x receptors.the vitamin d receptor (vdr) and pregnane x receptor (pxr) are nuclear hormone receptors of the nr1i subfamily that show contrasting patterns of cross-species variation. vdr and pxr are thought to have arisen from duplication of an ancestral gene, evident now as a single gene in the genome of the chordate invertebrate ciona intestinalis (sea squirt). vdr genes have been detected in a wide range of vertebrates including jawless fish. to date, pxr genes have not been found in cartilaginous fish. i ...200717997857
repellency of two terpenoid compounds isolated from callicarpa americana (lamiaceae) against ixodes scapularis and amblyomma americanum ticks.callicarpenal (13, 14, 15, 16-tetranor-3-cleroden-12-al) and intermedeol [(4s,5s,7r,10s)-eudesm-11-en-4-ol], isolated from american beautyberry, callicarpa americana (lamiaceae), were evaluated in laboratory bioassays for repellent activity against host-seeking nymphs of the blacklegged tick, ixodes scapularis, and lone star tick, amblyomma americanum. a strip of organdy cloth treated with test solution was doubly wrapped (treatment on outer layer) around the middle phalanx of a forefinger and t ...200717380408
evolution of the iron-responsive element.an rna hairpin structure referred to as the iron-responsive element (ire) and iron regulatory proteins (irps) are key players in the control of iron metabolism in animal cells. they regulate translation initiation or mrna stability, and the ire is found in a variety of mrnas, such as those encoding ferritin, transferrin receptor (tfr), erythroid aminolevulinic acid synthase (ealas), mitochondrial aconitase (maco), ferroportin, and divalent metal transporter 1 (dmt1). we have studied the evolutio ...200717513696
surface-exposed proteins of ehrlichia chaffeensis.the surface proteins of ehrlichia chaffeensis provide an important interface for pathogen-host interactions. to investigate the surface proteins of e. chaffeensis, membrane-impermeable, cleavable sulfo-nhs-ss-biotin was used to label intact bacteria. the biotinylated bacterial surface proteins were isolated by streptavidin-agarose affinity purification. the affinity-captured proteins were separated by electrophoresis, and five relatively abundant protein bands containing immunoreactive proteins ...200717517859
purification and characterization of two larval glycoproteins from the cattle tick, boophilus annulatus.the present study was conducted to identify new target immunogenic molecules from the larval stage of the cattle tick, boophilus annulatus (acari: ixodidae). two specific larval glycoproteins (glps) were isolated by two-step affinity chromatography. the larval immunogens were first purified with cnbr-sepharose coupled to rabbit anti-larval immunoglobulins, and the glycoproteins were then purified with con-a sepharose. these glycoproteins have molecular weights of approximately 32 and 15 kda with ...200717519572
virulence potential of ehrlichia chaffeensis strains of distinct genome sequences.human monocytic ehrlichiosis, one of the most frequent life-threatening tick-borne zoonoses, is caused by ehrlichia chaffeensis that lacks endotoxin and peptidoglycan. while sequence polymorphisms in several genes in e. chaffeensis strains have been reported, global genomic divergence and biological differences among strains are unknown. the objectives of the present study were to compare the genome sequences of strains of e. chaffeensis and to examine the virulence potentials of the strains wit ...200717438035
scafos: a tool for selection, concatenation and fusion of sequences for phylogenomics.phylogenetic analyses based on datasets rich in both genes and species (phylogenomics) are becoming a standard approach to resolve evolutionary questions. however, several difficulties are associated with the assembly of large datasets, such as multiple copies of a gene per species (paralogous or xenologous genes), lack of some genes for a given species, or partial sequences. the use of undetected paralogous or xenologous genes in phylogenetic inference can lead to inaccurate results, and the us ...200717288575
gene knockdown by rnai in the pea aphid acyrthosiphon pisum.rna interference (rnai) is a powerful method to inhibit gene expression in a sequence specific manner.200717903251
structural and functional characterization of a novel type of ligand-independent rxr-usp receptor.retinoid x receptor (rxr) and ultraspiracle (usp) play a central role as ubiquitous heterodimerization partners of many nuclear receptors. while it has long been accepted that a wide range of ligands can activate vertebrate/mollusc rxrs, the existence and necessity of specific endogenous ligands activating rxr-usp in vivo is still matter of intense debate. here we report the existence of a novel type of rxr-usp with a ligand-independent functional conformation. our studies involved tribolium usp ...200717673910
key biosynthetic gene subfamily recruited for pheromone production prior to the extensive radiation of lepidoptera.moths have evolved highly successful mating systems, relying on species-specific mixtures of sex pheromone components for long-distance mate communication. acyl-coa desaturases are key enzymes in the biosynthesis of these compounds and to a large extent they account for the great diversity of pheromone structures in lepidoptera. a novel desaturase gene subfamily that displays delta11 catalytic activities has been highlighted to account for most of the unique pheromone signatures of the taxonomic ...200818831750
relaxation of selective constraints causes independent selenoprotein extinction in insect genomes.selenoproteins are a diverse family of proteins notable for the presence of the 21st amino acid, selenocysteine. until very recently, all metazoan genomes investigated encoded selenoproteins, and these proteins had therefore been believed to be essential for animal life. challenging this assumption, recent comparative analyses of insect genomes have revealed that some insect genomes appear to have lost selenoprotein genes.200818698431
revealing pancrustacean relationships: phylogenetic analysis of ribosomal protein genes places collembola (springtails) in a monophyletic hexapoda and reinforces the discrepancy between mitochondrial and nuclear dna markers.in recent years, several new hypotheses on phylogenetic relations among arthropods have been proposed on the basis of dna sequences. one of the challenged hypotheses is the monophyly of hexapods. this discussion originated from analyses based on mitochondrial dna datasets that, due to an unusual positioning of collembola, suggested that the hexapod body plan evolved at least twice. here, we re-evaluate the position of collembola using ribosomal protein gene sequences.200818366624
arbobacteria - pathogens transmittable by arthropods. 200821512627
prevention of lyme disease and other tick-borne infections.prevention is the best method for avoiding potentially serious complications of lyme and other tick-borne diseases. in this article, we discuss preventative measures that can be used by individuals or communities. among the topics discussed are personal protective measures, tick reduction, reservoir reduction, and vaccination. additionally, new preventative measures that are in development-including new lyme disease vaccines, antitick vaccines, and reservoir-targeted vaccination-are discussed.200818755380
larval keys to the genera of ixodidae (acari) and species of ixodes (latreille) ticks established in california.in california, hard (ixodidae) ticks transmit at least 8 zoonotic disease agents (1 virus, 6 bacteria, 1 protozoan) to humans or other animals. the correct taxonomic identification of all 3 parasitic stages (larvae, nymphs, adults) of ticks is integral to understanding host-tick associations and disease dynamics, but immature ticks, especially the larvae, can be difficult to identify. here, we present larval keys to the 4 genera of ixodidae (dermacentorkoch, 1844; haemaphysaliskoch, 1844; ixodes ...200820027236
a critical analysis of disease-associated dna polymorphisms in the genes of cattle, goat, sheep, and pig.genetic variations through their effects on gene expression and protein function underlie disease susceptibility in farm animal species. the variations are in the form of single nucleotide polymorphisms, deletions/insertions of nucleotides or whole genes, gene or whole chromosomal rearrangements, gene duplications, and copy number polymorphisms or variants. they exert varying degrees of effects on gene action, such as substitution of an amino acid for another, shift in reading frame and prematur ...200818350334
tick-borne diseases in north carolina: is "rickettsia amblyommii" a possible cause of rickettsiosis reported as rocky mountain spotted fever?cases of rocky mountain spotted fever (rmsf) in north carolina have escalated markedly since 2000. in 2005, we identified a county in the piedmont region with high case numbers of rmsf. we collected ticks and examined them for bacterial pathogens using molecular methods to determine if a novel tick vector or spotted fever group rickettsiae (sfgr) might be emerging. amblyomma americanum, the lone star tick, comprised 99.6% of 6,502 specimens collected in suburban landscapes. in contrast, dermacen ...200818447622
two usa ehrlichia spp. cause febrile illness in goats.ehrlichia spp. are not currently recognized as a cause of illness in goats in the usa, but three ehrlichia are enzootic in lone star ticks (amblyomma americanum) in the eastern usa, and related bacteria in other countries cause illness in goats. we exposed naïve goats to ehrlichia-infected amblyomma and demonstrated that infection and clinical illness can be caused by two usa species, e. ewingii and the recently discovered panola mountain ehrlichia sp. clinical features in all five goats are des ...200818328644
ligand specificity and evolution of liver x receptors.liver x receptors (lxrs) are key regulators of lipid and cholesterol metabolism in mammals. little is known, however, about the function and evolution of lxrs in non-mammalian species. the present study reports the cloning of lxrs from african clawed frog (xenopus laevis), western clawed frog (xenopus tropicalis), and zebrafish (danio rerio), and their functional characterization and comparison with human and mouse lxrs. additionally, an ortholog of lxr in the chordate invertebrate ciona intesti ...200818395439
characterization of rickettsial infection in amblyomma americanum (acari: ixodidae) by quantitative real-time polymerase chain reaction.several species of the spotted fever group rickettsia (sfgr), with considerable variation in vertebrate host pathogenicity, are present in ticks in the united states. in this study, quantitative real-time pcr (qpcr) was used to characterize the growth and the distribution of rickettsia amblyommii in selected tissues (salivary glands, gut, and ovaries) of naturally infected amblyomma americanum (l.) (acari: ixodidae), during bloodmeal acquisition and throughout vertical transmission to eggs and p ...200818402143
geographic distribution and genetic diversity of the ehrlichia sp. from panola mountain in amblyomma americanum.a novel ehrlichia, closely related to ehrlichia ruminantium, was recently discovered from panola mountain state park, ga, usa. we conducted a study to determine if this agent was recently introduced into the united states.200818433500
natural and experimental infection of white-tailed deer (odocoileus virginianus) from the united states with an ehrlichia sp. closely related to ehrlichia ruminantium.an ehrlichia sp. (panola mountain [pm] ehrlichia sp.) closely related to ehrlichia ruminantium was recently detected in a domestic goat experimentally infested with lone star ticks (lsts, amblyomma americanum) collected from georgia, usa. the infected goat exhibited pyrexia and mild clinical pathologic abnormalities consistent with ehrlichiosis. at least two other ehrlichia species (ehrlichia chaffeensis and ehrlichia ewingii) are maintained in nature by a cycle involving lsts as the primary vec ...200818436670
identification of 19 polymorphic major outer membrane protein genes and their immunogenic peptides in ehrlichia ewingii for use in a serodiagnostic assay.ehrlichia ewingii, a tick-transmitted rickettsia previously known only as a canine pathogen, was recently recognized as a human pathogen. e. ewingii has yet to be cultivated, and there is no serologic test available to diagnose e. ewingii infection. previously, a fragment (505 bp) of a single e. ewingii gene homologous to 1 of 22 genes encoding ehrlichia chaffeensis immunodominant major outer membrane proteins 1 (omp-1s)/p28s was identified. the purposes of the present study were to (i) determin ...200818094116
prevalence and infection load dynamics of rickettsia felis in actively feeding cat fleas.rickettsia felis is a flea-associated rickettsial pathogen recurrently identified in both colonized and wild-caught cat fleas, ctenocephalides felis. we hypothesized that within colonized fleas, the intimate relationship between r. felis and c. felis allows for the coordination of rickettsial replication and metabolically active periods during flea bloodmeal acquisition and oogenesis.200818665265
a novel clade of cysteinyl leukotriene scavengers in soft ticks.inflammation is an important vertebrate defense mechanism against ecto-parasites for which ticks have evolved numerous mechanisms of modulation. am-33 and tsgp4, related lipocalins from the soft ticks argas monolakensis and ornithodoros savignyi bind cysteinyl leukotrienes with high affinity as measured by isothermal titration calorimetry. this was confirmed in a smooth muscle bioassay that measured contraction of guinea pig ileum induced by leukotriene c4 where both proteins inhibited contracti ...200818675910
the effects of vegetation density and habitat disturbance on the spatial distribution of ixodid ticks (acari: ixodidae).larval, nymphal, and adult amblyomma americanum (l.), and adult dermacentor variabilis (say) ticks were collected using timed dragging techniques, in an attempt to examine how different habitat variables affect models that describe the distribution of ticks in virginia, usa. tick count data were modeled using two approaches: (i) habitat and edge, and (ii) habitat, edge, vegetation density and levels of disturbance. nymphs and adults tended to follow a forest edge distribution when analysed by ha ...200818686272
function, mechanism and evolution of the moubatin-clade of soft tick lipocalins.the "moubatin-clade" of soft tick lipocalins, although monophyletic, shows clear signs of paralogy as indicated by the various functions associated with this protein family. this includes anti-platelet (moubatin), anti-complement (omci) and toxic (tsgp2) activities in the vertebrate host. in order to understand the evolution of function and how it relates to the various paralogs in this clade, we characterized a number of different proteins in regard to undefined function and mechanism. by utili ...200818694828
exotic grass invasion reduces survival of amblyomma americanum and dermacentor variabilis ticks (acari: ixodidae).exotic plants often invade areas of high human activity, such as along trails, roads, and forest edges, and in disturbed riparian areas. these same habitat types are also favored by ticks. this convergence suggests that habitat modifications caused by exotic plant invasions may mediate disease vector habitat quality, indirectly affecting human disease risk at the local spatial scale. we tested the hypothesis that experimental invasions of japanese stiltgrass, microstegium vimineum (trin.) a. cam ...200818826028
molecular and biological characterization of the amblyomma americanum organic anion transporter polypeptide.the organic anion transporting polypeptides (oatps in rodents and other organism; oatps in human) are na(+)-independent transporters that shuttle a wide range of endogenous and xenobotic amphipathic compounds across plasma membranes. we previously discovered an amblyomma americanum tick (aam) oatp cdna among genes that were upregulated or induced in ticks that were stimulated to start feeding. in this study, we have characterized a 2860 bp full-length cdna that encode a 724 amino acid putative p ...200818931313
intracellular infection of tick cell lines by the entomopathogenic fungus metarhizium anisopliae.several fungal pathogens are able to enter and persist within eukaryotic cells as part of their infectious life cycle. metarhizium anisopliae is a saprophytic entomopathogenic fungus virulent towards numerous tick species, including those within the genera ixodes and amblyomma. infection of the target organism by this fungus proceeds via several steps, including adhesion and penetration of the host cuticle, proliferation within tissues and the haemolymph, and eventual eruption through the host c ...200818524924
twelve-hour duration testing of cream formulations of three repellents against amblyomma americanum.the repellent efficacies of the u.s. military repellent 33% n,n-diethyl-3-methylbenzamide (deet), 10% and 20% (1s, 2's) 2-methylpiperidinyl-3-cyclohexene-1-carboxamide (ss220) and 10% and 20% 1-methyl-propyl-2-(hydroxyethyl)-1-piperidinecarboxylate (bayrepel) cream formulations on human volunteers against the lone star tick amblyomma americanum (l.) were evaluated in a simulated forest floor environment over a 12-h testing period. at 2-h intervals, volunteers, with repellent applied in a 5-cm-wi ...200818498614
microbial communities and interactions in the lone star tick, amblyomma americanum.to quantify microbial composition and interactions, we identified prokaryotic communities in the lone star tick (amblyomma americanum) based on 16s rrna gene sequences and direct probing. the lone star tick is the vector of emerging diseases and host to additional symbionts of unknown activity, and is representative of other blood-sucking arthropods. we evaluated the potential for vertical (transovarial) transmission by molecular analysis of microbial symbionts from egg and larval clutches. dire ...200819378409
enhanced spatial models for predicting the geographic distributions of tick-borne pathogens.disease maps are used increasingly in the health sciences, with applications ranging from the diagnosis of individual cases to regional and global assessments of public health. however, data on the distributions of emerging infectious diseases are often available from only a limited number of samples. we compared several spatial modelling approaches for predicting the geographic distributions of two tick-borne pathogens: ehrlichia chaffeensis, the causative agent of human monocytotropic ehrlichi ...200818412972
experimental and field studies on the suitability of raccoons (procyon lotor) as hosts for tick-borne pathogens.we investigated the experimental susceptibility and natural exposure of raccoons (procyon lotor) to five tick-borne pathogens of human and veterinary importance, ehrlichia canis, e. chaffeensis, e. ewingii, anaplasma phagocytophilum (apvariant 1 and ap-ha hge-1 strains), and borrelia lonestari. infections were assessed by polymerase chain reaction (pcr), indirect fluorescent antibody (ifa) testing, and/or culture isolation methods for at least 30 days postinoculation (dpi). two e. chaffeensis-in ...200818429696
expression and porin activity of p28 and omp-1f during intracellular ehrlichia chaffeensis development.ehrlichia chaffeensis, an obligatory intracellular gram-negative bacterium, must take up various nutrients and metabolic compounds because it lacks many genes involved in metabolism. nutrient uptake by a gram-negative bacterium occurs primarily through pores or channels in the bacterial outer membrane. here we demonstrate that isolated e. chaffeensis outer membranes have porin activities, as determined by a proteoliposome swelling assay. the activity was partially blocked by an antibody that rec ...200818359808
rnai-mediated gene silencing in tick synganglia: a proof of concept study.progress in generating comprehensive est libraries and genome sequencing is setting the stage for reverse genetic approaches to gene function studies in the blacklegged tick (ixodes scapularis). however, proving that rnai can work in nervous tissue has been problematic. developing an ability to manipulate gene expression in the tick synganglia likely would accelerate understanding of tick neurobiology. here, we assess gene silencing by rna interference in the adult female black-legged tick synga ...200818366768
identity and transfer of male reproductive gland proteins of the dengue vector mosquito, aedes aegypti: potential tools for control of female feeding and reproduction.male reproductive gland proteins (mrgps) impact the physiology and/or behavior of mated females in a broad range of organisms. we sought to identify mrgps of the yellow fever mosquito, aedes aegypti, the primary vector of dengue and yellow fever viruses. earlier studies with ae. aegypti demonstrated that "matrone" (a partially purified male reproductive accessory gland substance) or male accessory gland fluid injected into virgin female ae. aegypti affect female sexual refractoriness, blood feed ...200818207079
ehrlichia chaffeensis in child, venezuela. 200818325283
plasmids of the prm/prf family occur in diverse rickettsia species.the recent discoveries of the prf and prm plasmids of rickettsia felis and r. monacensis have contravened the long-held dogma that plasmids are not present in the bacterial genus rickettsia (rickettsiales; rickettsiaceae). we report the existence of plasmids in r. helvetica, r. peacockii, r. amblyommii, and r. massiliae isolates from ixodid ticks and in an r. hoogstraalii isolate from an argasid tick. r. peacockii and four isolates of r. amblyommii from widely separated geographic locations cont ...200818065613
variability and action mechanism of a family of anticomplement proteins in ixodes ricinus.ticks are blood feeding arachnids that characteristically take a long blood meal. they must therefore counteract host defence mechanisms such as hemostasis, inflammation and the immune response. this is achieved by expressing batteries of salivary proteins coded by multigene families.200818167559
detection of two bartonella tamiae-like sequences in amblyomma americanum (acari: ixodidae) using 16s-23s intergenic spacer region-specific primers.four hundred and sixty-six questing amblyomma americanum (l.) (acari: ixodidae) from carolina county, va, and 98 questing a. americanum from chatham county, nc, were screened by polymerase chain reaction (pcr) for the bartonella 16s-23s intergenic spacer region. two amplicons, approximately 270-280 bp, were detected in two ticks from virginia. based upon pcr and sequencing, an adult male and adult female tick harbored dna sequences closely related to bartonella tamiae (dq395180). bartonella dna ...200818283962
evolution of pharmacologic specificity in the pregnane x receptor.the pregnane x receptor (pxr) shows the highest degree of cross-species sequence diversity of any of the vertebrate nuclear hormone receptors. in this study, we determined the pharmacophores for activation of human, mouse, rat, rabbit, chicken, and zebrafish pxrs, using a common set of sixteen ligands. in addition, we compared in detail the selectivity of human and zebrafish pxrs for steroidal compounds and xenobiotics. the ligand activation properties of the western clawed frog (xenopus tropica ...200818384689
an insight into the sialome of the soft tick, ornithodorus parkeri.while hard ticks (ixodidae) take several days to feed on their hosts, soft ticks (argasidae) feed faster, usually taking less than 1h per meal. saliva assists in the feeding process by providing a cocktail of anti-hemostatic, anti-inflammatory and immunomodullatory compounds. saliva of hard ticks has been shown to contain several families of genes each having multiple members, while those of soft ticks are relatively unexplored. analysis of the salivary transcriptome of the soft tick ornithodoru ...200818070662
comparative sialomics between hard and soft ticks: implications for the evolution of blood-feeding behavior.ticks evolved various mechanisms to modulate their host's hemostatic and immune defenses. differences in the anti-hemostatic repertoires suggest that hard and soft ticks evolved anti-hemostatic mechanisms independently, but raise questions on the conservation of salivary gland proteins in the ancestral tick lineage. to address this issue, the sialome (salivary gland secretory proteome) from the soft tick, argas monolakensis, was determined by proteomic analysis and cdna library construction of s ...200818070664
host surveys, ixodid tick biology and transmission scenarios as related to the tick-borne pathogen, ehrlichia canis.the ehrlichioses have been subject to increasing interest from veterinary and public health perspectives, but experimental studies of these diseases and their etiologic agents can be challenging. ehrlichia canis, the primary etiologic agent of canine monocytic ehrlichiosis, is relatively well characterized and offers unique advantages and opportunities to study interactions between a monocytotropic pathogen and both its vertebrate and invertebrate hosts. historically, advances in tick-borne dise ...200818963493
exploring the mialome of ticks: an annotated catalogue of midgut transcripts from the hard tick, dermacentor variabilis (acari: ixodidae).ticks are obligate blood feeders. the midgut is the first major region of the body where blood and microbes ingested with the blood meal come in contact with the tick's internal tissues. little is known about protein expression in the digestive tract of ticks. in this study, for analysis of global gene expression during tick attachment and feeding, we generated and sequenced 1,679 random transcripts (ests) from cdna libraries from the midguts of female ticks at varying stages of feeding.200819021911
defining the immune response to ehrlichia species using murine models.pathogenic bacteria belonging to the family anaplasmataceae include species of the genera ehrlichia and anaplasma. ehrlichia chaffeensis, first known as the causative agent of human monocytic ehrlichiosis, also infects several vertebrate hosts including white-tailed deer, dogs, coyotes and goats. e. chaffeensis is transmitted from the bite of an infected hard tick, such as amblyomma americanum. e. chaffeensis and other tick-transmitted pathogens have adapted to both the tick and vertebrate host ...200819028013
failure by engorged stages of the lone star tick, amblyomma americanum, to react to assembly pheromone, guanine and uric acid.response to tick-exposed filter paper discs (tick excreta) by fed and non-fed stages of the lone star tick amblyomma americanum (l.) (acari: ixodidae) was examined from larva to adult. by contrast with engorged stages, each non-fed stage exhibited a classic arrestment response to assembly pheromone, characterized by lack of movement, retraction of legs and formation of small groups; this response was seen in approximately 75% of ticks that made contact with pheromone-treated surfaces. less prono ...200818498612
a leishmania ortholog of macrophage migration inhibitory factor modulates host macrophage responses.parasitic organisms have evolved specialized strategies to evade immune defense mechanisms. we describe herein an ortholog of the cytokine, macrophage migration inhibitory factor (mif), which is produced by the obligate intracellular parasite, leishmania major. the leishmania mif protein, lm1740mif, shows significant structural homology with human mif as revealed by a high-resolution x-ray crystal structure (1.03 a). differences between the two proteins in the n-terminal tautomerization site are ...200818523291
total, membrane, and immunogenic proteomes of macrophage- and tick cell-derived ehrlichia chaffeensis evaluated by liquid chromatography-tandem mass spectrometry and maldi-tof methods.ehrlichia chaffeensis, a tick-transmitted rickettsial, is the causative agent of human monocytic ehrlichiosis. to examine protein expression patterns, we analyzed total, membrane, and immunogenic proteomes of e. chaffeensis originating from macrophage and tick cell cultures. total proteins resolved by one-dimensional gel electrophoresis and subjected to liquid chromatography-electrospray ionization ion trap mass spectrometry allowed identification of 134 and 116 proteins from macrophage- and tic ...200818710870
evidence of the importance of host habitat use in predicting the dilution effect of wild boar for deer exposure to anaplasma spp.foci of tick-borne pathogens occur at fine spatial scales, and depend upon a complex arrangement of factors involving climate, host abundance and landscape composition. it has been proposed that the presence of hosts that support tick feeding but not pathogen multiplication may dilute the transmission of the pathogen. however, models need to consider the spatial component to adequately explain how hosts, ticks and pathogens are distributed into the landscape. in this study, a novel, lattice-deri ...200818714379
an insight into the salivary transcriptome and proteome of the soft tick and vector of epizootic bovine abortion, ornithodoros coriaceus.the salivary glands of blood-sucking arthropods contain a redundant 'magic potion' that counteracts their vertebrate host's hemostasis, inflammation, and immunity. we here describe the salivary transcriptome and proteomics (sialome) of the soft tick ornithodoros coriaceus. the resulting analysis helps to consolidate the classification of common proteins found in both soft and hard ticks, such as the lipocalins, kunitz, cystatin, basic tail, hebraein, defensin, til domain, metalloprotease, 5'-nuc ...200818725333
laboratory maintenance of ehrlichia chaffeensis and ehrlichia canis and recovery of organisms for molecular biology and proteomics studies.tick-borne illnesses are emerging as a major concern for human health in recent years. these include the human monocytic ehrlichiosis caused by the amblyomma americanum tick-transmitted bacterium, ehrlichia chaffeensis; human ewingii ehrlichiosis caused by ehrlichia ewingii (also transmitted by a. americanum ticks); and human granulocytic anaplasmosis caused by the ixodes scapularis tick-transmitted pathogen, anaplasma phagocytophilum. likewise, tick-borne rickettsial pathogens are also a major ...200818770537
rickettsia amblyommii infecting amblyomma americanum larvae.polymerase chain reaction analysis of amblyomma americanum adults, nymphs, and larvae from aberdeen proving ground, md (apg), revealed a very high prevalence of a spotted fever group (sfg) rickettsia. restriction fragment length polymorphism (rflp) and sequence analysis identified "rickettsia amblyommii." this organism is not yet described or well studied, and its pathogenicity is unknown; however, investigations of the organism are warranted because of its high prevalence in a. americanum. this ...200818171102
identification of residual blood proteins in ticks by mass spectrometry proteomics.mass spectrometry-based proteomics of individual ticks demonstrated persistence of mammalian host blood components, including alpha- and beta-globin chains, histones, and mitochondrial enzymes, in ixodes scapularis and amblyomma americanum ticks for months after molting. residual host proteins may identify sources of infection for ticks.200818680654
use of drosophila s2 cells as a model for studying ehrlichia chaffeensis infections.ehrlichia chaffeensis is an obligate intracellular bacterium and the causative agent of human monocytic ehrlichiosis. although this pathogen grows in several mammalian cell lines, no general model for eukaryotic cellular requirements for bacteria replication has yet been proposed. we found that drosophila s2 cells are permissive for the growth of e. chaffeensis. we saw morulae (aggregates of bacteria) by microscopy, detected the e. chaffeensis 16s rrna gene by reverse transcriptase pcr, and used ...200818245255
the first report of human illness associated with the panola mountain ehrlichia species: a case report.two species of ehrlichia are known to cause human illness. several other species have been discovered in ticks and animals, and recent reports suggest that some of these ehrlichia species might be human pathogens. we report here the first association of a recently discovered pathogen, the panola mountain ehrlichia species, with a case of human illness.200818447934
stari, or masters disease: lone star tick-vectored lyme-like illness.lyme-like illness (also known as southern tick-associated rash illness [stari] or masters disease) is vectored by the lone star tick (amblyomma americanum). lyme-like illness lesions, which are similar to the erythema migrans rash of lyme disease, tend to have lymphocytic dermal infiltrates. with the exception of borrelia lonestari, the possible causative agent or agents of lyme-like illness have not been cultured. more research is needed to fully understand this newly recognized zoonosis. clini ...200818452807
insight into the sialome of the castor bean tick, ixodes ricinus.in recent years, there have been several sialome projects revealing transcripts expressed in the salivary glands of ticks, which are important vectors of several human diseases. here, we focused on the sialome of the european vector of lyme disease, ixodes ricinus.200818489795
neuropeptide discovery in ixodoidea: an in silico investigation using publicly accessible expressed sequence tags.the ixodoidea (ticks) are important vectors in the transmission of many human diseases; for example, the blacklegged tick ixodes scapularis is the major vector in the transmission of lyme disease, the most frequently reported vector-borne illness in the united states. the development of expressed sequence tags (ests) for ixodoidean cdna libraries, and their public deposition, has generated a rich resource for protein discovery in members of this taxon, thereby providing an opportunity for better ...200818495123
a possible canine tick-bite reaction to ixodes muris.an airedale terrier became acutely ill following attachment of an ixodes muris tick. clinical signs waned within hours of tick removal, similar to a pattern previously documented in animals harboring i. muris. this supports the theory that i. muris can induce a noninfectious, severe inflammatory reaction in domestic animals.200818390101
detection of tick-borne pathogens by masstag polymerase chain reaction.masstag polymerase chain reaction (pcr) is a platform that enables microbe detection using primers labeled through a photocleavable link with tags that vary in molecular weight. after multiplex pcr, tags are released by ultraviolet irradiation and analyzed by mass spectroscopy. the identification of a microbe in a sample is determined by its cognate tags. here we describe establishment and implementation of a masstag pcr panel for surveillance of microbes implicated in tick-vectored infectious d ...200918800864
antibody responses of domestic animals to salivary antigens of triatomainfestans as biomarkers for low-level infestation of triatomines.hematophagous arthropods such as triatoma infestans, the vector of trypanosoma cruzi, elicit host-immune responses during feeding. characterization of antibody responses to salivary antigens offers the potential to develop immunologically based monitoring techniques for exposure to re-emergent triatomine bug populations in peridomestic animals. igg-antibody responses to the salivary antigens of t.infestans have been detected in chickens as soon as 2 days after the first exposure to five adult bu ...200919248784
79-year-old man with fever, malaise, and jaundice. 200919252117
a borreliacidal factor in amblyomma americanum saliva is associated with phospholipase a2 activity.previous work in our laboratory described the in vitro killing of borrelia burgdorferi when co-cultured with saliva from adult amblyomma americanum. borreliacidal activity was not evident using ixodes scapularis saliva. mixing trypsin with saliva eliminated the borreliacidal activity of a. americanum saliva, while incorporating a trypsin inhibitor restored all borreliacidal activity, indicating this factor was of protein or peptide origin. one-dimensional page indicated at least 7 major protein ...200919271281
molecular characterization of ehrlichia interactions with tick cells and macrophages.several tick-transmitted anaplasmataceae family rickettsiales of the genera ehrlichia and anaplasma have been discovered in recent years. some species are classified as pathogens causing emerging diseases with growing health concern for people. they include human monocytic ehrlichiosis, human granulocytic ewingii ehrlichiosis and human granulocytic anaplasmosis which are caused by ehrlichia chaffeensis, e. ewingii and anaplasma phagocytophilum, respectively. despite the complex cellular environm ...200919273271
effects of climate change on ticks and tick-borne diseases in europe.zoonotic tick-borne diseases are an increasing health burden in europe and there is speculation that this is partly due to climate change affecting vector biology and disease transmission. data on the vector tick ixodes ricinus suggest that an extension of its northern and altitude range has been accompanied by an increased prevalence of tick-borne encephalitis. climate change may also be partly responsible for the change in distribution of dermacentor reticulatus. increased winter activity of i ...200919277106
isolongifolenone: a novel sesquiterpene repellent of ticks and mosquitoes.a naturally occurring sesquiterpene, isolongifolenone, derivatives of which have been used extensively as ingredients in the cosmetics industry, was discovered to effectively repel blood-feeding arthropods that are important disease vectors. we show that (-)-isolongifolenone deters the biting of the mosquitoes, aedes aegypti (l.) and anopheles stephensi liston, more effectively than the widely used synthetic chemical repellent, n,n-diethyl-3-methyl benzamide (deet), in laboratory bioassays. the ...200919198523
detection of borrelia burgdorferi and borrelia lonestari in birds in tennessee.lyme disease in the united states is caused by the bacterial spirochete borrelia burgdorferi s.s. (johnson, schmid, hyde, steigerwalt, and brenner), which is transmitted by tick vectors ixodes scapularis (say) and i. pacificus (cooley and kohls). borrelia lonestari, transmitted by the tick amblyomma americanum l., may be associated with a related syndrome, southern tick-associated rash illness (stari). borrelia lonestari sequences, reported primarily in the southeastern states, have also been de ...200919198527
conservation and immunogenicity of the mosquito ortholog of the tick-protective antigen, subolesin.the control of arthropod vectors of pathogens that affect human and animal health is important for the eradication of vector-borne diseases. the ortholog of the tick-protective antigen, subolesin, was identified in aedes albopictus and found to have conserved epitopes in ticks and mosquitoes. rna interference with the tick and mosquito double-stranded rna in three tick species resulted in significant gene knockdown and decreased tick weight and/or survival. feeding anopheles atroparvus, aedes ca ...200919229557
promoter analysis of macrophage- and tick cell-specific differentially expressed ehrlichia chaffeensis p28-omp genes.ehrlichia chaffeensis is a rickettsial agent responsible for an emerging tick-borne illness, human monocytic ehrlichiosis. recently, we reported that e. chaffeensis protein expression is influenced by macrophage and tick cell environments. we also demonstrated that host response differs considerably for macrophage and tick cell-derived bacteria with delayed clearance of the pathogen originating from tick cells.200919454021
microarray analysis of gene expression changes in feeding female and male lone star ticks, amblyomma americanum (l).a collection of est clones from female tick amblyomma americanum salivary glands was hybridized to rna from different feeding stages of female tick salivary glands and from unfed or feeding adult male ticks. in the female ticks, the expression patterns changed dramatically upon starting feeding, then changed again towards the end of feeding. on beginning feeding, genes possibly involved in survival on the host increased in expression as did many housekeeping genes. as feeding progressed, some of ...200919514082
a sustained release gel formulation of doramectin for control of lone star ticks (acari: ixodidae) and horn flies (diptera: muscidae) on cattle.a gel formulation formed by incorporating technical doramectin into a 10% hydroxypropyl methylcellulose aqueous solution was used to subcutaneously inject steers at varying dosages. doramectin serum concentration of steers receiving 600 microg (ai)/kg body weight declined from 21.9 ppb at 0.5 wk to below detectable at 8 wk postinjection. the 1,200 microg (ai)/kg injection resulted in serum concentrations of 29.1 ppb at 0.5 wk and declined to 0.5 ppb at 8 wk postinjection. both the 600 and 1,200 ...200919449664
efficacy of eprinomectin and doramectin against amblyomma americanum (acari: ixodidae) on cattle.steers were treated with doramectin or eprinomectin by daily oral capsule for 28 consecutive days. the level of doramectin in the serum of steers treated at 200 microg/kg/d reached a maximum of 104.0 +/- 22.1 ppb at day 21 and declined from 93.3 +/- 20.5 ppb on the final day of treatment to below detectable by day 56. steers treated at 50 microg/kg/d reached a maximum level of doramectin in the serum of 24.7 +/- 1.2 ppb on day 21 and declined from 24.7 +/- 0.6 ppb on the final day of treatment t ...200919449665
a borreliacidal factor in amblyomma americanum saliva is associated with phospholipase a(2) activity.previous work in our laboratory described the in vitro killing of borrelia burgdorferi when co-cultured with saliva from adult amblyomma americanum. borreliacidal activity was not evident using ixodes scapularis saliva. mixing trypsin with saliva eliminated the borreliacidal activity of a. americanum saliva, while incorporating a trypsin inhibitor restored all borreliacidal activity, indicating this factor was of protein or peptide origin. one dimensional page indicated at least 7 major protein ...200919545533
metapopulation structure for perpetuation of francisella tularensis tularensis.outbreaks of type a tularemia due to francisella tularensis tularensis are typically sporadic and unstable, greatly hindering identification of the determinants of perpetuation and human risk. martha's vineyard, massachusetts has experienced an outbreak of type a tularemia which has persisted for 9 years. this unique situation has allowed us to conduct long-term eco-epidemiologic studies there. our hypothesis is that the agent of type a tularemia is perpetuated as a metapopulation, with many sma ...200919627585
ehrlichia chaffeensis infections in drosophila melanogaster.ehrlichia chaffeensis is an obligate, intracellular bacterium, transmitted by the tick amblyomma americanum, and is the causative agent of human monocytic ehrlichiosis infections. we previously demonstrated that e. chaffeensis is capable of growing in drosophila s2 cells. therefore, we tested the hypothesis that e. chaffeensis can infect adult drosophila melanogaster. adult drosophila organisms were experimentally challenged with intra-abdominal injections of bacteria. ehrlichia-infected flies s ...200919687202
endemic tickborne infectious diseases in louisiana and the gulf south.most emerging infectious diseases today, such as west nile virus and sudden acute respiratory distress syndrome (sars), arise from zoonotic reservoirs and many are transmitted by arthropod vectors. ticks are among the most competent and versatile arthropod vectors of infectious diseases because ticks of all ages and both sexes remain infectious for generations without having to reacquire infections from reservoir hosts. today, ticks transmit the most common arthropod-borne infectious disease in ...200920108827
efficacy of a topical ectoparasiticide containing dinotefuran, pyriproxyfen, and permethrin against amblyomma americanum (lone star tick) and amblyomma maculatum (gulf coast tick) on dogs.amblyomma americanum (lone star tick) and amblyomma maculatum (gulf coast tick) are important disease vectors for both dogs and humans. this article describes two studies conducted to evaluate the efficacy of a new topical spot-on ectoparasiticide containing dinotefuran, permethrin, and pyriproxyfen (vectra 3d, summit vetpharm) against a. maculatum and a. americanum in dogs. dogs were treated on day 0 and infested on days -1, 7, 14, 21, and 28 with approximately 40 ticks each day. live tick coun ...200919742444
results from a mathematical model for human monocytic ehrlichiosis. 200920584161
amblyomma americanum (l): tick macrophage migration inhibitory factor peptide immunization lengthens lone star tick feeding intervals in vivo.immunizations of new zealand white rabbits with specific macrophage migration inhibitory factor (mif) tick peptide (pep) produced circulating anti-tick pep antibodies in the hosts. antibody titers of greater than 1:5000 to tick mif peptide were observed for crude sera from pep-immunized rabbits. pep- and bsa-vaccinated rabbits were infested with amblyomma americanum adults. feeding intervals, female weights, egg masses and percent egg hatch were measured for ticks feeding on control and immunize ...200919111543
directed evolution of a filamentous fungus for thermotolerance.filamentous fungi are the most widely used eukaryotic biocatalysts in industrial and chemical applications. consequently, there is tremendous interest in methodology that can use the power of genetics to develop strains with improved performance. for example, metarhizium anisopliae is a broad host range entomopathogenic fungus currently under intensive investigation as a biologically based alternative to chemical pesticides. however, it use is limited by the relatively low tolerance of this spec ...200919709419
niche partitioning of borrelia burgdorferi and borrelia miyamotoi in the same tick vector and mammalian reservoir species.the lyme borreliosis agent borrelia burgdorferi and the relapsing fever group species borrelia miyamotoi co-occur in the united states. we used species-specific, quantitative polymerase chain reaction to study both species in the blood and skin of peromyscus leucopus mice and host-seeking ixodes scapularis nymphs at a connecticut site. bacteremias with b. burgdorferi or b. miyamotoi were most prevalent during periods of greatest activity for nymphs or larvae, respectively. whereas b. burgdorferi ...200919996447
burden of tick-borne infections on american companion animals.this review examines the biology of ticks and tick-borne infections in the united states. the most common tick-borne diseases in dogs and cats are discussed. we demonstrate that there is much interest in tick-borne infections at the level of the lay public (pet owners), describe trends in the distribution and prevalence of tick-borne infections in the united states, summarize some issues in understanding the degree of ill health due to tick-borne infections, and suggest some avenues for research ...200919945085
strains of ehrlichia chaffeensis in southern indiana, kentucky, mississippi, and north carolina.rates of infection of amblyomma americanum (l.) by ehrlichia chaffeensis were compared in 100 ticks collected from sites in each of four states: indiana, north carolina, kentucky, and mississippi. the overall infection rates were similar among sites, ranging from 1 to 4%. because pathogenic differences may exist between e. chaffeensis strains, nested polymerase chain reaction (pcr) amplification of the variable-length pcr target (vlpt), and sequencing of the amplicons were performed to different ...200919960699
infection and replication of bartonella species within a tick cell line.bartonella species are fastidious, gram negative bacteria, some of which are transmitted by arthropod vectors, including fleas, sandflies, and lice. there is very little information regarding the interaction and/or transmission capabilities of bartonella species by ticks. in the present study, we demonstrate successful infection of the amblyomma americanum cell line, aae12, by seven bartonella isolates and three candidatus bartonella species by electron or light microscopy. with the exception of ...200919242658
efficacy of the new repellent bioud against three species of ixodid ticks.bioud with the active ingredient 2-undecanone originally derived from wild tomato plants is a new repellent recently registered by the us epa. repellent efficacy of bioud (7.75% 2-undecanone) and deet (98.11%) was examined in the laboratory using a choice test between repellent-treated and control filter paper surfaces for amblyomma americanum, dermacentor variabilis, and ixodes scapularis. bioud provided greater repellency against a. americanum and i. scapularis than deet. no difference was fou ...200919140016
molecular and clinical evidence of ehrlichia chaffeensis infection in cameroonian patients with undifferentiated febrile illness.in the u.s.a., human monocytotropic ehrlichiosis (hme) caused by ehrlichia chaffeensis is an emerging tick-transmitted zoonosis. in cameroon, where e. canis, e. chaffeensis and e. ewingii have recently been detected in dogs and/or ticks (rhipicephalus sanguineus), the potential exists for human infections. patients from the coastal region of cameroon who had acute fevers of unknown aetiology were therefore checked for ehrlichial infection, using a real-time pcr that amplifies part of a genus-spe ...200920030996
transmission of cytauxzoon felis to a domestic cat by amblyomma americanum.cytauxzoon felis was transmitted to a domestic cat by amblyomma americanum. the infection was produced by the bite of a. americanum adults that were acquisition fed as nymphs on a domestic cat that naturally survived infection of c. felis. fever, inappetence, depression, and lethargy were first noted 11 days post-infestation (dpi). pale mucus membranes, splenomegaly, icterus, and dyspnea were also observed during the course of the disease. the body temperature of the experimentally infected c. f ...200919168288
role of the lone star tick, amblyomma americanum (l.), in human and animal diseases.we reviewed scientific literature pertaining to known and putative disease agents associated with the lone star tick, amblyomma americanum. reports in the literature concerning the role of the lone star tick in the transmission of pathogens of human and animal diseases have sometimes been unclear and even contradictory. this overview has indicated that a. americanum is involved in the ecology of several disease agents of humans and other animals, and the role of this tick as a vector of these di ...200919054615
ability of two natural products, nootkatone and carvacrol, to suppress ixodes scapularis and amblyomma americanum (acari: ixodidae) in a lyme disease endemic area of new jersey.we evaluated the ability of the natural, plant-derived acaricides nootkatone and carvacrol to suppress ixodes scapularis say and amblyomma americanum (l.) (acari: ixodidae). aqueous formulations of 1 and 5% nootkatone applied by backpack sprayer to the forest litter layer completely suppressed i. scapularis nymphs through 2 d. thereafter, the level of reduction gradually declined to < or =50% at 28 d postapplication. against a. americanum nymphs, 1% nootkatone was less effective, but at a 5% con ...200920069863
[ehrlichiosis/anaplasmosis].ehrlichiosis and anaplasmosis are zoonoses caused by bacteria from the family anaplasmataceae, including human and animal pathogens. the human pathogens are ehrlichia chaffeensis, the causative agent of human monocytic ehrlichiosis (hme), anaplasma phagocytophilum, the pathogen causing human granulocytic anaplasmosis (hga), e. ewingii and neorickettsia sennetsu, granulocytotropic and monocytotropic ehrlichia species, respectively. ehrlichia spp. are small, gram-negative, obligate intracellular b ...200920077398
distribution of antibodies reactive to borrelia lonestari and borrelia burgdorferi in white-tailed deer (odocoileus virginianus) populations in the eastern united states.southern tick-associated rash illness is a lyme-like syndrome that occurs in the southern states. borrelia lonestari, which has been suggested as a possible causative agent of southern tick-associated rash illness, naturally infects white-tailed deer (wtd; odocoileus virginianus) and is transmitted by the lone star tick (amblyomma americanum). to better understand the prevalence and distribution of borrelia exposure among wtd, we tested wtd from 21 eastern states for antibodies reactive to b. lo ...200919874183
francisella tularensis: an arthropod-borne pathogen.arthropod transmission of tularemia occurs throughout the northern hemisphere. few pathogens show the adaptability of francisella tularensis to such a wide array of arthropod vectors. nonetheless, arthropod transmission of f. tularensis was last actively investigated in the first half of the 20th century. this review will focus on arthropod transmission to humans with respect to vector species, modes of transmission, geographic differences and f. tularensis subspecies and clades.200918950590
rickettsia parkeri in amblyomma americanum ticks, tennessee and georgia, usa.to determine the geographic distribution of the newly recognized human pathogen rickettsia parkeri, we looked for this organism in ticks from tennessee and georgia, usa. using pcr and sequence analysis, we identified r. parkeri in 2 amblyomma americanum ticks. this rickettsiosis may be underdiagnosed in the eastern united states.200919788817
anaplasmosis and ehrlichiosis - maine, 2008.anaplasmosis and ehrlichiosis are rickettsial tickborne diseases that have had at least a twofold increase in prevalence in the united states since 2000. despite similar clinical presentations, the causative organisms are carried by different ticks with distinct geographic and ecologic associations. surveillance efforts are complicated by ambiguous terminology and serologic testing with antibody cross-reactivity. although anaplasmosis historically has been reported in maine, ehrlichiosis has bee ...200919779398
influence of prescribed burns on the abundance of amblyomma americanum (acari: ixodidae) in the missouri ozarks.the increasingly widespread use of prescribed burns to manage oak (quercus spp.)-hickory (carya spp.) forests in the missouri ozarks, usa, has considerable potential to alter the abundance of amblyomma americanum (l.) (acari: ixodidae), the lone star tick, an important vector of several emerging pathogens. in particular, responses of important tick hosts, primarily white-tailed deer (odocoileus virginianus), to fire management and the resultant changes in the distribution and abundance of a. ame ...200919769033
current management of human granulocytic anaplasmosis, human monocytic ehrlichiosis and ehrlichia ewingii ehrlichiosis.anaplasma phagocytophilum, ehrlichia chaffeensis and ehrlichia ewingii are emerging tick-borne pathogens and are the causative agents of human granulocytic anaplasmosis, human monocytic ehrlichiosis and e. ewingii ehrlichiosis, respectively. collectively, these are referred to as human ehrlichioses. these obligate intracellular bacterial pathogens of the family anaplasmataceae are transmitted by ixodes spp. or amblyomma americanum ticks and infect peripherally circulating leukocytes to cause inf ...200919681699
prospective health assessment of fort campbell, kentucky patrons bitten by ticks.amblyomma americanum is an aggressive human-biting tick that transmits several known human pathogens and is associated with a lyme disease-like illness of unknown etiology. to determine the frequency, distinguishing clinical characteristics, and etiology ofa. americanum-associated illness and identify associated risk factors, a prospective study of adult tick-bite victims was conducted at fort campbell from 2005-2007. forty-two participants submitted ticks, none of which contained borrelia lones ...200919485114
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