ehrlichia chaffeensis: a prototypical emerging pathogen.ehrlichia chaffeensis is an obligately intracellular, tick-transmitted bacterium that is maintained in nature in a cycle involving at least one and perhaps several vertebrate reservoir hosts. the moderate to severe disease caused by e. chaffeensis in humans, first identified in 1986 and reported for more than 1,000 patients through 2000, represents a prototypical "emerging infection." knowledge of the biology and natural history of e. chaffeensis, and of the epidemiology, clinical features, and ...200312525424
effect of deer exclusion by fencing on abundance of amblyomma americanum (acari: ixodidae) on fire island, new york, usa.the effects of deer exclusion on northern populations of lone star ticks, amblyomma americanum, were tested at the lighthouse tract, fire island, ny, usa, where densities of this species have increased recently. game fencing was erected to exclude deer from two sites of roughly one ha each, and populations of nymphal and adult a. americanum within were compared with those at control sites outside the exclosures. percent control of nymphs within vs. outside the exclosures averaged 48.4% in the fo ...200212546457
detection of borrelia lonestari in amblyomma americanum (acari: ixodidae) from tennessee.genetic sequences characteristic of borrelia lonestari (barbour et al. 1996) were detected in two pools of adult amblyomma americanum (l.) from tennessee, corresponding to an estimated minimum field infection rate of 8.4 infected ticks/1000 adults. dna amplification was conducted using primers derived from the b. lonestari flagellin gene that would also amplify borrelia burgdorferi (johnson, schmid, hyde, steigerwalt, and brenner). species-specific, internal probes were then used to differentiat ...200312597661
infection rates of amblyomma americanum and dermacentor variabilis by ehrlichia chaffeensis and ehrlichia ewingii in southwest missouri.both ehrlichia chaffeensis and ehrlichia ewingii are causative agents of human ehrlichiosis. both pathogens are transmitted to humans through the bite of an infected lone star tick (amblyomma americanum). since missouri has a high incidence of human monocytic ehrlichiosis, we investigated the prevalence of e. chaffeensis- and e. ewingii-infected a. americanum and dermacentor variabilis (american dog tick) ticks to help assess the relative risk for humans exposed to these vectors. we used a neste ...200212653298
rna interference in ticks: a study using histamine binding protein dsrna in the female tick amblyomma americanum.rna interference (rnai), a gene silencing process, has been recently exploited to determine gene function by degrading specific mrnas in several eukaryotic organisms. we constructed a double stranded rna (dsrna) from a previously cloned putative amblyomma americanum histamine binding protein (hbp) to test the significance of using this methodology in the assessment of the function and importance of gene products in ectoparasitic ticks. the female salivary glands incubated in vitro with hbp dsrna ...200312752664
efficacy of two 65% permethrin spot-on formulations against induced infestations of ctenocephalides felis (insecta: siphonaptera) and amblyomma americanum (acari: ixodidae) on beagles.the efficacy of two formulations of a topically applied 65% permethrin spot-on (defend exspot treatment for dogs, schering-plough animal health) was evaluated against experimental infestations of the cat flea ctenocephalides felis and the lone star tick amblyomma americanum in dogs. eighteen dogs were randomly assigned to treatment with 65% permethrin in either diethylene glycol monomethyl ether (dgme; original formulation) or propylene glycol monomethyl ether (pgme) or to be untreated as a cont ...200312756635
comprehensive analysis of the factor h binding capabilities of borrelia species associated with lyme disease: delineation of two distinct classes of factor h binding proteins.some lyme disease spirochete isolates can bind complement regulatory protein factor h (fh), a process that may allow evasion of complement-mediated killing. here we demonstrate significant differences in the fh binding capabilities of species of the borrelia burgdorferi sensu lato complex. the percentages of b. burgdorferi, b. afzelii, and b. garinii bacteria that bound fh in either enzyme-linked immunosorbent assays or affinity ligand binding immunoblot assays were 100, 83, and 29%, respectivel ...200312761145
impact of feeding, molting and relative humidity on cuticular wax deposition and water loss in the lone star tick, amblyomma determine whether there is a correlation between the amount of lipids on the surface of ticks and their permeability to water, we quantified cuticular surface wax and measured water-loss rates in the ixodid tick amblyomma americanum from nonfed nymph to egg-laying female. ticks deposited no extra cuticular lipids during feeding, permitting maximum transpiratory water loss that presumably helps to concentrate the bloodmeal; and ticks deposited additional cuticular wax after apolysis that reduc ...199712770417
a method for extraction and analysis of high quality genomic dna from ixodid ticks.currently, no published methods describe the extraction of high molecular weight genomic dna from ixodid ticks (acari: ixodidae) and commonly used methods of extraction are not well adapted for use with members of this family. a method for extraction of minimally degraded genomic dna from ixodid ticks that can be completed in one or two days is described. the method produces dna which is of sufficient size (>24 kb) for use in southern analysis and which is readily digestible by restriction endon ...200312823841
endocannabinoids and related fatty acid amides, and their regulation, in the salivary glands of the lone star tick.the salivary glands and saliva from the lone star tick amblyomma americanum (l.) were analyzed for the presence of the two endogenous agonists of cannabinoid receptors, n-arachidonoylethanolamine (anandamide) and 2-arachidonoylglycerol (2-ag), as well as of the anandamide congener, n-palmitoylethanolamine (pea), an anti-inflammatory and analgesic mediator that is inactive at cannabinoid receptors. two very sensitive mass-spectrometric techniques were used for this purpose. both 2-ag and pea, as ...200312842196
a ten-year study of tick biting in mississippi: implications for human disease determine exactly which tick species bit people in mississippi, information was gathered on ticks involved in human biting cases for the ten-year period, january 1, 1990-december 31, 1999. specimens were identified by the author and, in most cases, confirmed by personnel at the institute of arthropodology and parasitology, georgia southern university. a total of 119 ticks were recovered from 73 humans during the study period. seven tick species were represented; most common included the lone ...200212853269
survival, replication, and antibody susceptibility of ehrlichia chaffeensis outside of host cells.ehrlichia chaffeensis, an obligate intracellular, tick-transmitted bacterium, is susceptible to antibody-mediated host defense, but the mechanism by which this occurs is not understood. one possible explanation is that antibodies directly access the bacteria in the extracellular environment of the host, perhaps during bacterial intercellular transfer. accordingly, we investigated whether bacteria could be found outside of host cells during infection. host cell-free plasma obtained from infected ...200312874298
molecular genetics and evolution of pheromone biosynthesis in lepidoptera.a great diversity of pheromone structures are used by moth species (insecta: lepidoptera) for long-distance mating signals. the signal/response channel seems to be narrow for each species, and a major conundrum is how signal divergence has occurred in the face of strong selection pressures against small changes in the signal. observations of various closely related and morphologically similar species that use pheromone components biosynthesized by different enzymes and biosynthetic routes unders ...200312876197
enzootic transmission of anaplasma bovis in nantucket cottontail rabbits.serological studies of cottontail rabbits sampled from nantucket island, mass., have suggested exposure to at least two ehrlichiae. the agent of human granulocytic ehrlichiosis (anaplasma phagocytophilum) is intensely enzootic in rabbits there, but the identity of the other ehrlichial infection remains undescribed. we sampled rabbits over five transmission seasons and tested their blood and tissues for evidence of infection using pcr targeting an ehrlichia genus-wide 16s rdna target. sequence an ...200312904385
quantitative real-time pcr assay for detection of ehrlichia chaffeensis.a real-time pcr assay was developed for the detection of ehrlichia chaffeensis. the assay is species specific and provides quantitative results in the range 10 to 10(10) gene copies. the assay is not inhibited by the presence of tick, human, or mouse dna and is compatible with high sample throughput. the assay was compared with previously described assays for e. chaffeensis.200312904406
isolation of an anaplasma sp. organism from white-tailed deer by tick cell culture.we used tick cell culture to isolate a bacterium previously referred to as the "white-tailed deer (wtd) agent" from two captive fawns inoculated with blood from wild wtd (odocoileus virginianus). buffy coat cells were added to ise6 tick cell cultures and incubated at 34 degrees c, and 8 days later, anaplasma-like inclusions were demonstrated in giemsa-stained culture samples. the microbes became established and could be continuously passaged in tick cells. the identity of a culture isolate desig ...200312958265
development of a polyclonal competitive enzyme-linked immunosorbent assay for detection of antibodies to ehrlichia ruminantium.a polyclonal competitive enzyme-linked immunosorbent assay (pc-elisa) is described for detection of antibodies to ehrlichia (cowdria) ruminantium by using a soluble extract of endothelial cell culture-derived e. ruminantium as the antigen and biotin-labeled polyclonal goat immunoglobulins as the competitor. for goats, the diagnostic sensitivity and specificity were both 100% with a cutoff of 80% inhibition (80 pi), with detection of antibodies for 550 days postinfection. for cattle, diagnostic s ...200312965926
natural occurrence of tularemia in the lone star tick, amblyomma americanus (linn.), and in dogs in arkansas. 195413138839
allergy in a horse due to amblyomma americanum. 196514296518
the multiplication of tularemia organisms in the lone star tick. 195514376386
ehrlichia chaffeensis infections among hiv-infected patients in a human monocytic ehrlichiosis-endemic area.manifestations of human monocytic ehrlichiosis (hme), a tick-borne infection caused by ehrlichia chaffeensis, range from asymptomatic disease to fulminant infection and may be particularly severe in persons infected with hiv. we conducted a serologic study to determine the epidemiology of hme in hiv-positive patients residing in an hme-endemic area. we reviewed charts from a cohort of 133 hiv-positive patients who were seen during the 1999 tick season with symptoms compatible with hme (n=36) or ...200314519250
a proteomics approach to characterizing tick salivary secretions.the saliva of ticks contains a complex mixture of bioactive molecules including proteins that modulate host responses ensuring successful feeding. the limited amount of saliva that can be obtained from ticks has hampered characterization of salivary proteins using traditional protein chemistry. recent improvements in two-dimensional gel electrophoresis, mass spectrometry, and bioinformatics provide new tools to characterize small amounts of protein. these methods were employed to characterize sa ...200214570118
how specific are host-produced kairomones to host-seeking ixodid ticks?ixodid ticks respond to host-produced substances (kairomones) that influence the ticks' host-finding behavior. in the laboratory adult blacklegged ticks, ixodes scapularis say, lone star ticks, amblyomma americanum l., and american dog ticks, dermacentor variabilis (say) became akinetic on residues rubbed from their principal hosts (deer for the former two species and dogs for the latter). however, arrestment also occurred when adults of these species were tested using the same method bioassay, ...200214570126
control of ixodes scapularis and amblyomma americanum through use of the '4-poster' treatment device on deer in maryland.deer self-treatment devices ('4-posters') were evaluated for their efficacy in reducing populations of blacklegged ticks, ixodes scapularis, and lone star ticks, amblyomma americanum. at each of three locations in maryland, 25 '4-posters' were operated in study areas of approximately 5.18 km2. populations of host-seeking ticks were monitored by flagging of treated areas and similar untreated control areas without '4-posters.' from 1998 to 2002 the percent mortalities achieved were 69, 75.8 and 8 ...200214570143
experimental infection of lone star ticks, amblyomma americanum (l.), with rickettsia parkeri and exposure of guinea pigs to the agent.the maculatum agent, rickettsia parkeri (a member of the spotted fever group rickettsiae), was inoculated into a colony of the lone star tick, amblyomma americanum, and followed for two tick generations. in addition, guinea pigs were exposed to the agent by direct injection and by feeding infected ticks on them. eighty (53%) of 150 nymphal a. americanum that were inoculated with suspensions of r. parkeri were positive by hemolymph test and fluorescent antibody test for rickettsial infection when ...200314596284
a cautionary note: survival of nymphs of two species of ticks (acari: ixodidae) among clothes laundered in an automatic ticks often remain on clothing of persons returning home from work or recreation in tick habitats, and can pose at least a temporary risk to people and pets in these homes. laundering clothing has been one of the recommendations to reduce tick exposure. host-seeking lone star tick, amblyomma americanum (l.), and blacklegged tick, ixodes scapularis say, nymphs confined in polyester mesh packets, were included with laundry in cold, warm, and hot wash cycles of an automatic clothes was ...200314596290
molecular variation in the variable-length pcr target and 120-kilodalton antigen genes of ehrlichia chaffeensis from white-tailed deer (odocoileus virginianus).genes encoding two surface-expressed antigens of ehrlichia chaffeensis, the variable-length pcr target (vlpt) and the 120-kda antigen, which contain variable numbers of tandem repeats, were characterized for e. chaffeensis from white-tailed deer (odocoileus virginianus). both genes from infected deer contained numbers of repeats similar to those reported in genes from humans and ticks, although a new variant of the 120-kda antigen gene containing five repeat units and coinfection with multiple v ...200314605163
detection of antibodies to anaplasma phagocytophilum and ehrlichia chaffeensis antigens in sera of korean patients by western immunoblotting and indirect immunofluorescence assays.two hundred seventy one serum samples from south korean patients were tested to detect antibodies against anaplasma phagocytophilum (the human granulocytic ehrlichiosis agent) and ehrlichia chaffeensis (the human monocytic ehrlichiosis agent) by indirect fluorescent-antibody assay (ifa) and the western blot assay. these sera were collected from patients with symptoms of high fever. the rate of seropositivity for orientia tsutsugamushi was 50.9% by ifa at the public health & environmental researc ...200314607867
evaluation of a pcr assay for quantitation of rickettsia rickettsii and closely related spotted fever group rickettsiae.a spotted fever rickettsia quantitative pcr assay (sq-pcr) was developed for the detection and enumeration of rickettsia rickettsii and other closely related spotted fever group rickettsiae. the assay is based on fluorescence detection of sybr green dye intercalation in a 154-bp fragment of the rompa gene during amplification by pcr. as few as 5 copies of the rompa gene of r. rickettsii can be detected. sq-pcr is suitable for quantitation of r. rickettsii and 10 other genotypes of spotted fever ...200314662926
evidence of borrelia lonestari dna in amblyomma americanum (acari: ixodidae) removed from humans.we used a nested pcr with borrelia flagellin gene (flab) primers and dna sequencing to determine if borrelia lonestari was present in amblyomma americanum ticks removed from military personnel and sent to the tick-borne disease laboratory of the u.s. army center for health promotion and preventive medicine. in our preliminary investigation, we detected borrelia sequences in 19 of 510 a. americanum adults and nymphs from ft. a. p. hill, va. during the 2001 tick season, the flab primers were used ...200314662940
meteorologically mediated diurnal questing of ixodes scapularis and amblyomma americanum (acari: ixodidae) nymphs.questing ixodes scapularis say and amblyomma americanum (l.) nymphs were collected in the field by drag sampling to determine whether ticks would be collected in greater numbers during certain times of the day and under certain ambient meteorological conditions. ticks were collected hourly for 16 h on 4 d and counts were contrasted with simultaneous measurements of ambient temperature and relative humidity, and with similar measurements made within the leaf litter. peak numbers of questing i. sc ...200314680102
transstadial transfer of west nile virus by three species of ixodid ticks (acari: ixodidae).larvae and/or nymphs of four species of ixodid ticks, ixodes scapularis say, amblyomma americanum (l.), dermacentor andersoni stiles, and dermacentor variabilis say, were fed to completion on laboratory hamsters or mice which had been inoculated with a west nile (wn) virus isolate from culex pipiens l. captured in connecticut usa. maximum titers in mice and hamsters were approximately 5 and two logs, respectively, lower than recorded (10 logs) in a naturally infected american crow, corvus brachy ...200314680122
dna evidence of borrelia lonestari in amblyomma americanum (acari: ixodidae) in southeast missouri.amblyomma americanum collected near lake wappapello, missouri, tested positive for borrelia lonestari using polymerase chain reaction and sequence analyses of b. lonestari 16s rrna and flagellin (flab) genes. twelve pools containing a total of 214 nymph or adult ticks contained evidence of infection with b. lonestari (minimum prevalence 5.6%). these data suggest that persons in southeast missouri are at risk for exposure to b. lonestari after a. americanum tick bite, a possible cause of erythema ...200314680133
survey of ticks collected in mississippi for rickettsia, ehrlichia, and borrelia species.from november 1999 through october 2000, we tested ticks collected from vegetation as well as from deer, dogs, and humans for spotted fever group (sfg) rickettsiae, ehrlichia chaffeensis, and borrelia spp. spirochetes. a total of 149 adult ticks representing four species was collected from 11 collection sites from southwestern to northern mississippi. amblyomma americanum was most commonly collected (n=68), followed by ixodes scapularis (n=53). the bird tick, ixodes brunneus (usually rare), was ...200314714667
human monocytotropic ehrlichiosis, determine the incidence, clinical and laboratory characteristics, and utility of molecular diagnosis of human monocytotropic ehrlichiosis (hme) in the primary care setting, we conducted a prospective study in an outpatient primary care clinic in cape girardeau, missouri. one hundred and two patients with a history of fever for 3 days (>37.7 degrees c), tick bite or exposure, and no other infectious disease diagnosis were enrolled between march 1997 and december 1999. hme was diagnosed in 29 p ...200314720399
evaluation of a prototype ehrlichia chaffeensis surveillance system using white-tailed deer (odocoileus virginianus) as natural sentinels.the natural history of ehrlichia chaffeensis, the causative agent of human monocytotropic ehrlichiosis, includes the lone star tick (lst, amblyomma americanum) as a vector and white-tailed deer (wtd; odocoileus virginianus) as both a natural reservoir of e. chaffeensis and a major host of lst. the goal of the current study was to implement and evaluate a prototype surveillance system to delineate the geographic distribution of e. chaffeensis using wtd as natural sentinels. to accomplish this goa ...200314733672
disruption of ixodes scapularis anticoagulation by using rna interference.ixodes scapularis ticks transmit many pathogens, including borrelia burgdorferi, anaplasma phagocytophilum, and babesia microti. vaccines directed against arthropod proteins injected into the host during tick engorgement could prevent numerous infectious diseases. salp14, a salivary anticoagulant, poses a key target for such intervention. salp14 is the prototypic member of a family of potential i. scapularis anticoagulants, expressed and secreted in tick saliva during tick feeding. rna interfere ...200414745044
evaluation of transovarial transmission and transmissibility of ehrlichia chaffeensis (rickettsiales: anaplasmataceae) in amblyomma americanum (acari: ixodidae).it has long been assumed that ehrlichia chaffeensis (anderson, dawson & wilson), is not transmitted transovarially in the lone star tick vector amblyomma americanum (l.). to test this hypothesis, three beagle dogs, canis familiaris (l.) (carnivora: canidae), were subcutaneously infected with e. chaffeensis (arkansas strain). uninfected nymphal lone star ticks were placed on the infected dogs and allowed to feed to repletion. these nymphal ticks were allowed to molt, and five of five adult female ...200314765684
first culture isolation of borrelia lonestari, putative agent of southern tick-associated rash illness.southern tick-associated rash illness (stari) is a lyme disease-like infection described in patients in the southeastern and south-central united states, where classic lyme disease is relatively rare. stari develops following the bite of a lone star tick (amblyomma americanum) and is thought to be caused by infection with an "uncultivable" spirochete tentatively named borrelia lonestari. in this study, wild lone star ticks collected from an area where b. lonestari is endemic were cocultured in a ...200415004069
how much pilocarpine contaminates pilocarpine-induced tick saliva?pilocarpine is often applied or injected into ticks to induce salivation, and the resulting saliva used to test for various pharmacological, biochemical and immunological activities. to measure the amount of pilocarpine in pilocarpine-induced tick saliva, an hplc-ms/ms method, based on capillary strong cation exchange chromatography online with an ion trap mass spectrometer, was used to measure pilocarpine in the pg to ng range. results indicate large concentrations of pilocarpine in ixodes scap ...200415009442
amblyomma americanum salivary glands: double-stranded rna-mediated gene silencing of synaptobrevin homologue and inhibition of pge2 stimulated protein secretion.protein secretion into the saliva from the tick salivary glands is due to exocytosis of vesicular membrane bound granular material regulated by snare complex proteins after salivary gland stimulation by pge2 [insect biochem. mol. biol. 32 (2002) 1711]. proteins associated with vesicles (v-snares) are essential components of the exocytotic process. synaptobrevin is a key v-snare in all secreting cells studied to date. a vesicle-associated synaptobrevin cdna fragment homologue from the salivary gl ...200415041024
development of a p28-based pcr assay for ehrlichia chaffeensis.detection of ehrlichia chaffeensis is necessary to study interactions between the parasite and its vertebrate and invertebrate hosts. the purpose of this study was to develop a sensitive, specific pcr assay for e. chaffeensis based on the outer membrane protein gene, p28. candidate primer sets were identified and ranked based on annealing scores, similarities to three major p28 sequence clusters, dissimilarity to e. canis p30, an ortholog of p28, and the proximities of flanking primer sequences ...200415051120
transgenic expression of reca of the spirochetes borrelia burgdorferi and borrelia hermsii in escherichia coli revealed differences in dna repair and recombination phenotypes.after unsuccessful attempts to recover a viable reca-deficient mutant of the lyme borreliosis agent borrelia burgdorferi, we characterized the functional activities of reca of b. burgdorferi, as well as reca of the relapsing fever spirochete borrelia hermsii and the free-living spirochete leptospira biflexa, in a reca mutant of escherichia coli. as a control, e. coli reca was expressed from the same plasmid vector. dna damage repair activity was assessed after exposure of the transgenic cells to ...200415060027
comparative activity of deet and ai3-37220 repellents against the ticks ixodes scapularis and amblyomma americanum (acari: ixodidae) in laboratory bioassays.the repellents n,n-diethyl-3-methylbenzamide (deet) and racemic 2-methylpiperidinyl-3-cyclohexene-1-carboxamide (ai3-37220) were evaluated using two different laboratory bioassays to determine their relative effectiveness against host-seeking nymphs of the blacklegged tick, ixodes scapularis say, and the lone star tick, amblyomma americanum (l.). in a petri dish bioassay, ticks were released within a ring of repellent on a horizontal filter paper disk. in the second bioassay, ticks were allowed ...200415061285
invasion of the central nervous system by intracellular bacteria.infection of the central nervous system (cns) is a severe and frequently fatal event during the course of many diseases caused by microbes with predominantly intracellular life cycles. examples of these include the facultative intracellular bacteria listeria monocytogenes, mycobacterium tuberculosis, and brucella and salmonella spp. and obligate intracellular microbes of the rickettsiaceae family and tropheryma whipplei. unfortunately, the mechanisms used by intracellular bacterial pathogens to ...200415084504
detection of pathogenic ehrlichia in ticks collected at acquisition sites of human ehrlichiosis in missouri.we collected 385 ticks from sites in missouri associated with human monocytic ehrlichiosis. using pcr, we detected e. chaffeensis or e. ewingii in 2 of 19 pools of adult amblyomma americanum, 0 of 32 pools of dermacentor variabilis, and 6 (18%) of 39 pools of unspeciated nymphal ticks from 3 of 6 sites associated with disease and one site not associated with disease. we also detected a variant of a. phagocytophila in one nymph pool.200415119113
glycerophosphodiester phosphodiesterase gene (glpq) of borrelia lonestari identified as a target for differentiating borrelia species associated with hard ticks (acari:ixodidae).a glpq ortholog was identified in dna from borrelia lonestari-positive amblyomma americanum, providing further evidence that b. lonestari is more closely related to the relapsing fever group spirochetes than to borreliae that cause lyme disease. this finding provides a basis for developing diagnostic assays to differentiate species of borrelia transmitted by hard ticks.200415131225
a proteomics approach to characterizing tick salivary secretions.the saliva of ticks contains a complex mixture of bioactive molecules including proteins that modulate host responses ensuring successful feeding. the limited amount of saliva that can be obtained from ticks has hampered characterization of salivary proteins using traditional protein chemistry. recent improvements in two-dimensional gel electrophoresis, mass spectrometry, and bioinformatics provide new tools to characterize small amounts of protein. these methods were employed to characterize sa ...200415198089
effects of granular carbaryl application on sympatric populations of ixodes scapularis and amblyomma americanum (acari: ixodidae) nymphs.a single application of granular carbaryl approaching the lowest recommended rate to the shrub layer of a forested area in late spring significantly reduced the abundance of ixodes scapularis say nymphs throughout their peak activity period, but had little effect on amblyomma americanum l. nymphs. factors influencing the efficacy of the application are discussed. the possible explanations for the lack of efficacy of granular carbaryl against a. americanum, including behavior, formulation, and ap ...200015218915
ectoparasites of gray squirrels in two different habitats and screening of selected ectoparasites for bartonellae.gray squirrels, sciurus carolinensis, were livetrapped in 2 different habitat types, woodland (67 squirrels) and parkland (53 squirrels), in southeastern georgia. ectoparasites were recovered from anesthetized squirrels and compared between hosts from the 2 habitats. because of the absence of low vegetation in parkland habitats, it was hypothesized that the ectoparasite fauna, especially ticks and chiggers, would be more diverse on woodland squirrels. the results were generally in agreement with ...200415270090
disease agents in amblyomma americanum from northeastern georgia.amblyomma americanum (lone star tick) is known or suspected to vector several organisms that are implicated as human pathogens, including ehrlichia chaffeensis, e. ewingii, and borrelia lonestari. these three agents have also been detected in white-tailed deer (odocoileus virginianus). because northeastern georgia has a high abundance of both lone star ticks and white-tailed deer, and one of these organisms, e. chaffeensis, is already known to be endemic in the area, we assayed individual adult ...200415311471
histologic, serologic, and molecular analysis of persistent ehrlichiosis in a murine model.human monocytotropic ehrlichiosis caused by ehrlichia chaffeensis was reported in 1987. an animal model to study acute fatal ehrlichiosis in mice that has been developed closely resembles the fatal form of human monocytotropic ehrlichiosis. however, animal models for persistent infection in the genus ehrlichia in immunocompetent mice have not been characterized. we report the histopathological progression of ehrlichia muris infection in immunocompetent mice (akr and c57bl/6 strains) correlated w ...200415331423
ehrlichia prevalence in amblyomma americanum, central texas. 200415338551
water relations in eggs of the lone star tick, amblyomma americanum, with experimental work on the capacity for water vapor absorption.this study shows that water stress is not countered in eggs of the lone star tick, amblyomma americanum (l.), using water vapor, and suggests involvement of liquid water as a developmental cue. eggs fail to maintain an equilibrium water content in subsaturated air, hence, gain not equal to loss, with net water losses occurring at relative humidities near saturation and these eggs exhibit a three-fold drop in viability, but not incubation period, as compared to eggs held in saturated air. amblyom ...200415347026
structure-based analysis of the ultraspiracle protein and docking studies of putative ligands.the ultraspiracle protein (usp) is the insect ortholog of the mammalian retinoid x receptor (rxr). fundamental questions concern the functional role of usp as the heterodimerization partner of insect nuclear receptors such as the ecdysone receptor. the crystallographic structures of the ligand binding domain of usps of heliothis virescens and drosophila melanogaster solved recently show that helix 12 is locked in an antagonist conformation raising the question whether usps could adopt an agonist ...200215455059
typing of borrelia relapsing fever group strains.partial sequencing of the 16s-23s rdna intergenic spacer showed two to four genotypes each for borrelia hermsii and b. turicatae, both relapsing fever agents transmitted by argasid ticks, and for b. miyamotoi and b. lonestari, transmitted by ixodid ticks. field surveys of ixodes ticks in connecticut and sweden showed limited local diversity for b. miyamotoi.200415498172
characterization of the b-cell inhibitory protein factor in ixodes ricinus tick saliva: a potential role in enhanced borrelia burgdoferi transmission.we recently described the inhibition of host b lymphocytes by ixodes ricinus tick saliva. in this study, we characterized the factor responsible for this activity and examined the modulation of lipopolysaccharide (lps)- and borrelia burgdorferi outer surface protein (osp)-induced proliferation of naive murine b lymphocytes by an enriched fraction of this factor. the b-lymphocyte inhibitory activity was destroyed by trypsin treatment, indicating that a proteinaceous factor was responsible for thi ...200415500628
amblyomma americanum salivary gland homolog of nsec1 is essential for saliva protein secretion.soluble n-ethylmaleimide-sensitive factor attachment protein receptor proteins assemble in tight core complexes which promote fusion of carrier vesicles with target compartments. members of this class of proteins are expressed in all eukaryotic cells and distributed in distinct subcellular compartments. all vesicle transport mechanisms known to date have an essential requirement for a member of the sec1 protein family, including the nsec1 in regulated exocytosis. a homolog of nsec1 was cloned an ...200415504350
sequence and expression analysis of the ompa gene of rickettsia peacockii, an endosymbiont of the rocky mountain wood tick, dermacentor andersoni.the transmission dynamics of rocky mountain spotted fever in montana appears to be regulated by rickettsia peacockii, a tick symbiotic rickettsia that interferes with transmission of virulent rickettsia rickettsii. to elucidate the molecular relationships between the two rickettsiae and glean information on how to possibly exploit this interference phenomenon, we studied a major rickettsial outer membrane protein gene, ompa, presumed to be involved in infection and pathogenesis of spotted fever ...200415528527
borrelia species in host-seeking ticks and small mammals in northern florida.the aim of this study was to improve understanding of several factors related to the ecology and environmental risk of borrelia infection in northern florida. small mammals and host-seeking adult ticks were collected at several sites, and specimens were tested for the presence of borrelia species, primarily by pcr amplification. tissues from some vertebrates and ticks were initially cultured in bsk-h medium to isolate spirochetes, but none were recovered. however, comparison of partial flagellin ...200415528699
ehrlichia chaffeensis (rickettsiales: ehrlichieae) infection in amblyomma americanum (acari: ixodidae) at aberdeen proving ground, maryland.human monocytic ehrlichiosis (hme) is a sometimes fatal, emerging tick-borne disease caused by the bacterium ehrlichia chaffeensis. it is frequently misdiagnosed because its symptoms mimic those of the flu. current evidence indicates that amblyomma americanum (l.), the lone star tick, is the major vector of hme. to determine if e. chaffeensis is present in ticks at aberdeen proving ground, md, questing a. americanum ticks were collected from 33 sites. nucleic acid was extracted from 34 adult and ...200015535577
seasonal distribution and abundance of ticks (acari: ixodidae) in northwestern florida.a 2-yr study was conducted in a northwestern florida state park and recreation area to determine tick species composition, seasonal abundance, and spatial distribution. risk of tick attachment to park visitors was also assessed relative to tick abundance from several habitats. tick collections consisted of weekly cloth drag samples obtained from ground and emergent vegetation along a deer trail, a walking trail located in a 3-mo-old control burned area of forest, a nonburned walking trail, picni ...200015535590
evaluation of antibiotic susceptibilities of ehrlichia canis, ehrlichia chaffeensis, and anaplasma phagocytophilum by real-time pcr.we determined mics of antibiotics against anaplasma phagocytophilum, ehrlichia chaffeensis, and ehrlichia canis by real-time quantitative pcr. the doubling times of the organisms were established: 19 h for e. chaffeensis, 26 h for a. phagocytophilum, and 28 h for e. canis. in comparison to the reference method for determining sensitivities, which uses diff-quick staining, our pcr assay was very sensitive and specific. we confirmed that doxycycline and rifampin are highly active against these bac ...200415561862
an in vitro larval immersion microassay for identifying and characterizing candidate acaricides.we have optimized a larval immersion microassay (lim) that offers superior sensitivity, flexibility to accommodate multiple formulations, and a robust capability for rapidly screening many compounds with a minimal requirement of test article for evaluation. dose-response studies were conducted for representative members from the organophosphate, pyrethroid, pyrazole, carbamate, macrocyclic lactone, and formamidine chemistries against amblyomma americanum (l.). time-response experiments revealed ...200415605642
detection of ehrlichia chaffeensis in adult and nymphal amblyomma americanum (acari: ixodidae) ticks from long island, new york.the lone star tick, amblyomma americanum (l.), has increased in abundance in several regions of the northeastern united states, including areas of long island, ny. adult and nymphal stage a. americanum collected from several sites on long island were evaluated for infection with ehrlichia chaffeensis, the causative agent of human monocytic ehrlichiosis (hme), by using a nested polymerase chain reaction assay. fifty-nine (12.5%) of 473 adults and eight of 113 pools of five nymphs each (estimated ...200415605650
susceptibility of mice (mus musculus) to repeated infestation with amblyomma americanum (acari: ixodidae) ticks.laboratory mice, mus musculus (l.), balb/c strain, were assessed for their ability to develop resistance to repeated infestation by amblyomma americanum (l.) ticks. mice were infested five consecutive times with a. americanum nymphs. no decrease in tick viability was seen after five infestations, suggesting that balb/c mice do not develop immune-mediated resistance to a. americanum. in contrast, tick viability was significantly reduced in the second infestation of a new zealand white rabbit, a l ...200415605656
ehrlichia chaffeensis expresses macrophage- and tick cell-specific 28-kilodalton outer membrane proteins.ehrlichia chaffeensis, a tick-transmitted rickettsial agent, causes human monocyte/macrophage-tropic ehrlichiosis. in this study, proteomic approaches were used to demonstrate host cell-specific antigenic expression by e. chaffeensis. the differentially expressed antigens include those from the 28-kda outer membrane protein (p28-omp) multigene locus. the proteins expressed in infected macrophages are the products of p28-omp19 and p28-omp20 genes, whereas in tick cells, the protein expressed is t ...200515618143
microbiologic evaluation of patients from missouri with erythema migrans.borrelia lonestari infects amblyomma americanum, the tick species that is the most common cause of tick bites in southeast and south-central united states, and this spirochete has been detected in an erythema migrans (em)-like skin rash in 1 patient. therefore, b. lonestari is considered to be a leading candidate for the etiologic agent of em in this region.200515668867
evaluation of immunocompetent and immunocompromised mice (mus musculus) for infection with ehrlichia chaffeensis and transmission to amblyomma americanum ticks.experiments on the natural history of ehrlichia chaffeensis, the agent of human monocytic ehrlichiosis (hme), would be facilitated by the availability of a laboratory animal model for transmission to vector ticks. five strains of mice were evaluated for their susceptibility to infection with e. chaffeensis and transmission competence: c57bl/6 mice, inducible nitric oxide synthase (inos) deficient mice, mhc i deficient (beta2m /) mice, mhc ii deficient mice (abb /), and b and t cell deficient (ra ...200415671738
lack of susceptibility of guinea pigs and gerbils to experimental infection with ehrlichia chaffeensis.guinea pigs and mongolian gerbils were experimentally infected with ehrlichia chaffeensis (st. vincent strain, 10 passages in vitro). the infection was monitored by serial blood sampling for pcr and by xenodiagnosis with amblyomma americanum larvae. exposure to the pathogen was confirmed using serology. neither guinea pigs nor gerbils were susceptible to infection with e. chaffeensis, and ticks fed upon these animals did not become infected with the pathogen.200415682515
molecular differentiation of metastriate tick immatures.hard ticks, family ixodidae, are divided into two groups, the metastriata and the prostriata, based on morphological differences. in the united states, there are four medically important genera of the ixodidae: ixodes, amblyomma, dermacentor, and rhipicephalus. ixodes is the only genus in and representative of the prostriata, whereas the latter three genera are members of the metastriata. all developmental stages of the prostriata can be easily differentiated from the metastriata using morpholog ...200415682516
genetic variants of anaplasma phagocytophilum infecting dogs in western washington state.eight dogs from western washington state suspected of being infected with anaplasma phagocytophilum because of the finding of morulae in peripheral blood neutrophils were studied for determination of the etiologic agent of disease. all cases were diagnosed between april 2003 and april 2004. six of the eight dogs had no travel history during the 6 months prior to presentation. two dogs had traveled within the northwest united states and canada. fever, lethargy, and anorexia were the most common c ...200515695682
identification of a new borrelia species among small mammals in areas of northern spain where lyme disease is endemic.the role of small mammals as reservoir hosts for borrelia burgdorferi was investigated in several areas where lyme disease is endemic in northern spain. a low rate of infestation by ixodes ricinus nymphs was found in the small mammal populations studied that correlated with the near-absence of b. burgdorferi sensu lato in 184 animals tested and with the lack of transmission of b. burgdorferi sensu lato to i. ricinus larvae that fed on them. in contrast, questing ticks collected at the same time ...200515746336
detection and identification of ehrlichia spp. in ticks collected in tunisia and morocco.a broad-range 16s rrna gene pcr assay followed by partial sequencing of the 16s rrna gene was used for the detection of members of the family anaplasmataceae in ticks in north africa. a total of 418 questing ixodes ricinus ticks collected in tunisia and morocco, as well as 188 rhipicephalus ticks from dogs and 52 hyalomma ticks from bovines in tunisia, were included in this study. of 324 adult i. ricinus ticks, 16.3% were positive for ehrlichia spp., whereas only 3.4 and 2.8% of nymphs and larva ...200515750072
borreliacidal activity of saliva of the tick amblyomma americanum.amblyomma americanum (linneaus) (acari: ixodidae), an important tick vector of human and animal disease, is not a competent vector of the bacterial agent of lyme disease, borrelia burgdorferi, although its range overlaps the geographical distribution of lyme disease within the united states. a possible mechanism that could prevent acquisition of b. burgdorferi spirochetes from infected hosts is the toxic effect of a. americanum saliva on b. burgdorferi. the data presented here indicate that afte ...200515752182
repellency of deet and ss220 applied to skin involves olfactory sensing by two species of ticks.responses of host-seeking nymphs of the blacklegged tick, ixodes scapularis say and lone star tick, amblyomma americanum (linnaeus) (acari: ixodidae) to the repellents n,n-diethyl-3-methylbenzamide (deet) and (1s, 2's)-2-methylpiperidinyl-3-cyclohexene-1-carboxamide (ss220) were studied using fingertip laboratory bioassays. ethanol solutions of both compounds applied to the skin strongly repelled both species of ticks at 0.8 and 1.6 micromole of compound/cm2 skin. the ticks were also repelled wh ...200515752184
improving the specificity of 16s rdna-based polymerase chain reaction for detecting borrelia burgdorferi sensu lato-causative agents of human lyme disease.16s rdna sequences of borrelia burgdorferi sensu lato were aligned with the 16s rdna sequences of borrelia hermsii, borrelia turicatae, and borrelia lonestari in order to identify primers that might be used to more specifically identify agents of human lyme disease in ticks in human skin samples.200515752343
babesia microti, upstate new york.five cases of human babesiosis were reported in the lower hudson valley region of new york state in 2001. an investigation to determine if babesia microti was present in local ixodes scapularis ticks yielded 5 positive pools in 123 pools tested, the first detection of b. microti from field-collected i. scapularis in upstate new york.200515757571
ticks (acari: ixodoidea: argasidae, ixodidae) of chile.the tick species recorded from chile can be listed under the following headings: (1) endemic or established: argas keiransi estrada-peña, venzal and gonzalez-acuña, a. neghmei kohls and hoogstraal; ornithodoros amblus chamberlin; otobius megnini (dugès); amblyomma parvitarsum neumann; a. tigrinum koch; ixodes auritulus neumann; i. chilensis kohls; i. cornuae arthur, i. sigelos keirans, clifford and corwin; i. stilesi neumann; i. uriae white; rhipicephalus sanguineus koch. (2) probably establishe ...200515777007
comparison of in vitro and in vivo ectoparasiticide activity of experimental benzimidazole-carbamate with permethrin and amitraz.a series of in vitro and in vivo bioassays were conducted to assess the ectoparasiticide activity of isopropyl-4-nitro-2,6-bis(trifluoromethyl)-1-benzimidazole-carbamate, an experimental benzimidazole-carbamate class compound. this compound was less potent than permethrin against ectoparasiticide-susceptible larvae of the lone star tick, amblyomma americanum (l.) (acari: ixodidae); larvae of the southern cattle tick, boophilus microplus (canestrini); and adult stable fly, stomoxys calcitrans (l. ...200515799532
anointing chemicals and ectoparasites: effects of benzoquinones from millipedes on the lone star tick, amblyomma americanum.many mammals and birds roll on or rub themselves with millipedes that discharge benzoquinones. chemicals transferred from millipedes onto the integument of anointing animals are thought to deter ectoparasites. we tested the lone star tick, amblyomma americanum (l.), for responses to three widespread components of millipede defensive secretions, 1,4-benzoquinone; 2-methyl-1,4-benzoquinone (toluquinone); and 2-methoxy-3-methyl-1,4-benzoquinone (mmb). in toxicity tests, ticks were confined for 1 hr ...200515839480
practical uses for ecdysteroids in mammals including humans: an update.ecdysteroids are widely used as inducers for gene-switch systems based on insect ecdysteroid receptors and genes of interest placed under the control of ecdysteroid-response elements. we review here these systems, which are currently mainly used in vitro with cultured cells in order to analyse the role of a wide array of genes, but which are expected to represent the basis for future gene therapy strategies. such developments raise several questions, which are addressed in detail. first, the met ...200315844229
molecular identification and analysis of borrelia burgdorferi sensu lato in lizards in the southeastern united states.lyme borreliosis (lb) group spirochetes, collectively known as borrelia burgdorferi sensu lato, are distributed worldwide. wild rodents are acknowledged as the most important reservoir hosts. ixodes scapularis is the primary vector of b. burgdorferi sensu lato in the eastern united states, and in the southeastern united states, the larvae and nymphs mostly parasitize certain species of lizards. the primary aim of the present study was to determine whether wild lizards in the southeastern united ...200515870353
transstadial and intrastadial experimental transmission of ehrlichia canis by male rhipicephalus sanguineus.the acquisition and transmission of rickettsial pathogens by different tick developmental stages has important epidemiological implications. the purpose of this study was to determine if male rhipicephalus sanguineus can experimentally acquire and transmit ehrlichia canis in the absence of female ticks. two trials were performed where nymphal and male r. sanguineus were simultaneously acquisition fed on the same infected donor hosts, and transstadially or intrastadially exposed male ticks were f ...200515941624
influence of meso- and microscale habitat structure on focal distribution of sympatric ixodes scapularis and amblyomma americanum (acari: ixodidae).we compared the distribution of sympatric ixodes scapularis say and amblyomma americanum (l.) within several suitable forested habitats at different spatial scales and characterized differences in microhabitat features accounting for the observed distribution of questing ticks. we used automatic data loggers placed in the shrub and litter layers to contrast mesoclimate and microclimate conditions experienced by questing ticks. larger numbers of i. scapularis were collected at sites where the for ...200515962776
the fc fragment mediates the uptake of immunoglobulin c from the midgut to hemolymph in the ixodid tick amblyomma americanum (acari: ixodidae).the phenomenon of immunoglobulin uptake from the midgut into the hemolymph has been observed in both argasid and ixodid ticks, but the mechanism of the uptake is not known. using capillary feeding of adult amblyomma americanum (l.) female ticks, we investigated the role of immunoglobulin g fc and fab fragments in the uptake process. intact igg and fragments labeled with 125i were introduced alone or as a mixture with a 10-fold molar excess of unlabeled compounds into ticks, and then the concentr ...200515962788
failure of ticks to transmit scopulariopsis brevicaulis (deuteromycota), a common filamentous fungal commensal of ticks.the capacity of ticks to transmit a fungus was examined by analyzing tick saliva, host tissue from feeding sites, and host blood for presence of scopulariopsis brevicaulis (sacc.) bainier, an internal mycosymbiont of the american dog tick, dermacentor variabilis (say), and lone star tick, amnblyomma americanum (l.). although >85% of ticks were infected with s. brevicaulis, conidia presence was low (0-5% of samples) in microscopic observations and mycological culturing of saliva expressed from la ...200515962791
relative encounter frequencies and prevalence of selected borrelia, ehrlichia, and anaplasma infections in amblyomma americanum and ixodes scapularis (acari: ixodidae) ticks from central new evaluate their relative importance in tick-borne disease transmission in new jersey, host-seeking amblyomma americanum (l.) and ixodes scapularis say adults and nymphs were collected during spring activity periods in 2003 and 2004 to determine relative frequencies at which these ticks were encountered from an area known to be hyperendemic for lyme disease. although similar numbers of the two species were encountered during early spring of both years, a. americanum were encountered more often ...200515962799
sequence variation of the ribosomal dna second internal transcribed spacer region in two spatially-distinct populations of amblyomma americanum (l.) (acari: ixodidae).sequence analysis of the ribosomal dna second internal transcribed spacer (its 2) region in 2 spatially distinct populations of amblyomma americanum (l.) revealed intraspecific variation. nucleotide sequences from multiple dna extractions and several polymerase chain reaction amplifications of eggs from mixed-parentage samples from both populations of ticks revealed that 12 of 1,145 (1.0%) sites varied. three of the 12 sites of variation were distinct between the 2 a. americanum populations, whi ...200515986597
polymerase chain reaction detection of cytauxzoon felis from field-collected ticks and sequence analysis of the small subunit and internal transcribed spacer 1 region of the ribosomal rna gene.cytauxzoon felis produces a disease in domestic cats in the midwest (u.s.a.), which often leads to a fatal outcome. although the clinical disease process is well described, there are still many unanswered questions about this organism. for example, it is unknown whether species of ticks other than dermacentor variabilis can serve as vectors for transmission. with recent reports of surviving cats from limited geographic areas, another relevant question is the potential for genetically less virule ...200515986625
transcription analysis of the major antigenic protein 1 multigene family of three in vitro-cultured ehrlichia ruminantium isolates.ehrlichia ruminantium, an obligate intracellular bacterium transmitted by ticks of the genus amblyomma, causes heartwater disease in ruminants. the gene coding for the major antigenic protein map1 is part of a multigene family consisting of a cluster containing 16 paralogs. in the search for differentially regulated genes between e. ruminantium grown in endothelial and tick cell lines that could be used in vaccine development and to determine if differences in the map1 gene cluster exist between ...200515995193
possible tick-borne human enterovirus resulting in aseptic meningitis.enterovirus-specific genetic sequences were isolated from two amblyomma americanum tick pools. identical genetic sequences were later obtained from cerebrospinal fluid of a patient with aseptic meningitis and a recent history of tick attachment. these observations suggest the possibility of an emerging tick-borne human enterovirus associated with aseptic meningitis.200516000481
rapid detection methods and prevalence estimation for borrelia lonestari glpq in amblyomma americanum (acari: ixodidae) pools of unequal size.dna was extracted from pools of amblyomma americanum ticks collected from vegetation at two sites in fort leonard wood, missouri and tested for the presence of borrelia spp. two new methods were developed to detect borrelia lonestari dna by targeting the glycerophosphodiester phosphodiesterase (glpq) gene. the first method detected b. lonestari dna using a sybr green i melting curve analysis of the pcr product obtained with glpq gene primers. the second method, a glpq taqman assay, detected and ...200516011431
detection of ehrlichia spp. in raccoons (procyon lotor) from georgia.raccoons (procyonis lotor) and opossums (didelphis virginianus) acquired from six contiguous counties in the piedmont physiographic region of georgia were investigated for their potential role in the epidemiology of ehrlichial and anaplasmal species. serum was tested by indirect fluorescent antibody (ifa) assay for the presence of antibodies reactive to ehrlichia chaffeensis, e. canis, and anaplasma phagocytophilum (hga agent). nested polymerase chain reaction (pcr) assay was used to test whole ...200516011433
rnai-mediated gene silencing to assess the role of synaptobrevin and cystatin in tick blood addition to being the conduit for pathogens into hosts, tick saliva contains a broad array of secretory products that facilitate prolonged tick attachment and blood feeding. proteins found in tick saliva modulate host hemostasis and immune responses. however, it is not clear whether ticks manipulate the immune responses of their hosts by disrupting the antigen-processing pathways of the hosts. protein secretion into tick saliva from the salivary glands is due to exocytosis of vesicular membra ...200516040003
epidemiology and transmission dynamics of west nile virus disease.from 1937 until 1999, west nile virus (wnv) garnered scant medical attention as the cause of febrile illness and sporadic encephalitis in parts of africa, asia, and europe. after the surprising detection of wnv in new york city in 1999, the virus has spread dramatically westward across the united states, southward into central america and the caribbean, and northward into canada, resulting in the largest epidemics of neuroinvasive wnv disease ever reported. from 1999 to 2004, >7,000 neuroinvasiv ...200516102302
ehrlichial infection in cameroonian canines by ehrlichia canis and ehrlichia ewingii.ehrlichia chaffeensis and ehrlichia ewingii are agents of emerging human ehrlichioses in north america and are transmitted primarily by amblyomma americanum ticks, while ehrlichia canis is the globally distributed cause of canine monocytic ehrlichiosis (cme) and is transmitted by the brown dog tick, rhipicephalus sanguineus. although e. canis and ehrlichia ruminantium are endemic in africa, the presence of ehrlichial agents in dogs and ticks in cameroon has not been investigated. the objective o ...200516181750
geographic distribution of ticks (acari: ixodidae) in iowa with emphasis on ixodes scapularis and their infection with borrelia iowa, public concern regarding lyme disease has increased markedly over the last decade. in response to these concerns, a statewide surveillance program was initiated in 1990 based on ticks received by the department of entomology at iowa state university. ticks were received from health care professionals, state government agencies, and the general public. a total of 5,343 ticks from all 99 iowa counties were identified during the 12 years of this study. dermacentor variabilis was the most n ...200516187889
tick-borne rickettsioses around the world: emerging diseases challenging old concepts.during most of the 20th century, the epidemiology of tick-borne rickettsioses could be summarized as the occurrence of a single pathogenic rickettsia on each continent. an element of this paradigm suggested that the many other characterized and noncharacterized rickettsiae isolated from ticks were not pathogenic to humans. in this context, it was considered that relatively few tick-borne rickettsiae caused human disease. this concept was modified extensively from 1984 through 2005 by the identif ...200516223955
factors influencing in vitro infectivity and growth of rickettsia peacockii (rickettsiales: rickettsiaceae), an endosymbiont of the rocky mountain wood tick, dermacentor andersoni (acari, ixodidae).rickettsia peacockii, a spotted fever group rickettsia, is a transovarially transmitted endosymbiont of rocky mountain wood ticks, dermacentor andersoni. this rickettsia, formerly known as the east side agent and restricted to female ticks, was detected in a chronically infected embryonic cell line, dae100, from d. andersoni. we examined infectivity, ability to induce cytopathic effect (cpe) and host cell specificity of r. peacockii using cultured arthropod and mammalian cells. aposymbiotic dae1 ...200516288906
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