| 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 ... | 2003 | 14680102 |
| 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 ... | 2003 | 14680122 |
| the effects of bird feeders on lyme disease prevalence and density of ixodes scapularis (acari: ixodidae) in a residential area of dutchess county, new york. | the effects of bird feeders on local densities of ixodes scapularis ticks and prevalence of lyme disease were examined in residential areas of dutchess county, ny. ticks were collected, counted, and analyzed for borrelia burgdorferi spirochetes in 2001-2002 on residential properties with and without bird feeders. tick densities and infection prevalence were not significantly different on properties with and without bird feeders. furthermore, analysis of a questionnaire, administered to 580 local ... | 2003 | 14680124 |
| prevalence of borrelia burgdorferi (spirochaetales: spirochaetaceae) in ixodes scapularis (acari: ixodidae) adults in new jersey, 2000-2001. | using polymerase chain reaction, we analyzed 529 ixodes scapularis say adults collected from 16 of new jersey's 21 counties for the presence of borrelia burgdorferi, the etiological agent of lyme disease. overall, 261 (49.3%) were positive. b. burgdorferi was detected in ticks obtained from each county and from 53 of the 58 (93.1%) municipalities surveyed. the observed statewide prevalence in new jersey is similar to those reported from other northeastern and mid-atlantic states. | 2003 | 14680126 |
| geographic information systems and spatial analysis of adult ixodes scapularis (acari: ixodidae) in the middle atlantic region of the u.s.a. | in the middle atlantic region of the u.s.a., the vector of lyme disease, human granulocytic ehrlichiosis, babesiosis, and other human and veterinary pathogens is the black-legged tick, ixodes scapularis say. in 1997 and 1998, 663 adult i. scapularis ticks were collected from 320 transects spanning 66,400 km2 in five states of the middle atlantic region. tick abundance patterns were clustered, with relatively high numbers along the coastal plain of the chesapeake bay, decreasing to the west and s ... | 2003 | 14680128 |
| intracellular symbionts and other bacteria associated with deer ticks (ixodes scapularis) from nantucket and wellfleet, cape cod, massachusetts. | the diversity of bacteria associated with the deer tick (ixodes scapularis) was assessed using pcr amplification, cloning, and sequencing of 16s rrna genes originating from seven ticks collected from nantucket island and wellfleet, cape cod, mass. the majority of sequences obtained originated from gram-negative proteobacteria. four intracellular bacteria were detected including strains of ehrlichia, rickettsia, and wolbachia and an organism related to intracellular insect symbionts from the cyto ... | 2004 | 14711698 |
| the western black-legged tick, ixodes pacificus, in the sutter buttes. | the western black-legged tick, ixodes pacificus, was collected from huff canyon in the sutter buttes in north central california, sutter county. the sutter buttes are within the sacramento valley and outside the normal distribution of i. pacificus in california. adult i. pacificus were collected via flagging as they quested along deer trails; subadult life stages were collected from three species of lizard, elgaria multicarinata, sceloporus occidentalis, and s. graciosus. adult ticks were tested ... | 2003 | 14714665 |
| 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 ... | 2003 | 14714667 |
| ospc facilitates borrelia burgdorferi invasion of ixodes scapularis salivary glands. | outer surface protein c (ospc) is a differentially expressed major surface lipoprotein of borrelia burgdorferi. ospc is swiftly upregulated when spirochetes leave the ixodes scapularis tick gut, migrate to the salivary gland, and exit the arthropod vector. here we show that ospc strongly binds to the tick salivary gland, suggesting a role for ospc in spirochete adherence to this tissue. in vivo studies using a murine model of lyme borreliosis showed that while ospc f(ab)(2) fragments did not inf ... | 2004 | 14722614 |
| global change and human vulnerability to vector-borne diseases. | global change includes climate change and climate variability, land use, water storage and irrigation, human population growth and urbanization, trade and travel, and chemical pollution. impacts on vector-borne diseases, including malaria, dengue fever, infections by other arboviruses, schistosomiasis, trypanosomiasis, onchocerciasis, and leishmaniasis are reviewed. while climate change is global in nature and poses unknown future risks to humans and natural ecosystems, other local changes are o ... | 2004 | 14726459 |
| sequence analysis of p44 homologs expressed by anaplasma phagocytophilum in infected ticks feeding on naive hosts and in mice infected by tick attachment. | the 44-kda immunodominant outer membrane proteins (p44 proteins) of anaplasma phagocytophilum are encoded by the p44 polymorphic multigene family. the present study examined p44 expression and analyzed the cdna sequences of various p44 transcripts from the spleens and blood of mice infected by the bites of ticks infected with the a. phagocytophilum ntn-1 strain or of naturally infected nymphal ticks and in the salivary glands and midgut tissues of these ticks. a total of 300 p44 cdnas were subje ... | 2004 | 14742506 |
| an effective second-generation outer surface protein a-derived lyme vaccine that eliminates a potentially autoreactive t cell epitope. | the antigenic component of a common lyme disease vaccine is recombinant outer surface protein a (rospa) of borrelia burgdorferi (bb), the causative agent of lyme disease. coincidentally, patients with chronic, treatment-resistant lyme arthritis develop an immune response against ospa, whereas those with acute lyme disease usually do not. treatment-resistant lyme arthritis occurs in a subset of lyme arthritis patients and is linked to hla.drb1*0401 (dr4) and related alleles. recent work from our ... | 2004 | 14742868 |
| 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 ... | 2004 | 14745044 |
| chemical composition of some components of the arrestment pheromone of the black-legged tick, ixodes scapularis (acari: ixodidae) and their use in tick control. | chemical analysis (high-performance liquid chromatography) and bioassay demonstrated the presence of compounds that seem to be components of the ixodes scapularis arrestment pheromone. only two purines, guanine and xanthine, were found in acidified saline extracts made from cast skins after molting of fed nymphs, fed larvae, and fecal/excretory exudates deposited by unfed adults on substrates in their environment. the ratio of guanine to xanthine was 10.6:1 in an extract from the nymphal skins v ... | 2003 | 14765662 |
| ixodes scapularis ticks (acari: ixodidae) from louisiana are competent to transmit borrelia burgdorferi, the agent of lyme borreliosis. | the principal vector of borrelia burgdorferi, the lyme borreliosis spirochete, in the northeast and midwestern regions of the united states is the blacklegged tick ixodes scapularis. because of a favorable environment, i. scapularis is also plentiful in the south; however, a correlation with lyme borreliosis cases does not exist in this region of the united states. concern existed that something intrinsic to ticks found in louisiana could mitigate their ability to transmit b. burgdorferi. theref ... | 2003 | 14765677 |
| identification of a new type of babesia species in wild rats (bandicota indica) in chiang mai province, thailand. | a new type of rodent babesia, which resembled babesia microti but was phylogenetically placed closest, with the highest level of statistical support, to babesia canis, a canine babesia, was identified in thai bandicota indica in thai provinces to which malaria is endemic. close watch should be kept on human babesiosis in thailand. | 2004 | 14766871 |
| outer-surface protein c of the lyme disease spirochete: a protein induced in ticks for infection of mammals. | environmentally responsive synthesis of surface proteins represents a hallmark of the infectious cycle of the lyme disease agent, borrelia burgdorferi. here we created and analyzed a b. burgdorferi mutant lacking outer-surface protein c (ospc), an abundant osp that spirochetes normally synthesize in the tick vector during the blood meal and down-regulate after transmission to the mammal. we demonstrate that b. burgdorferi strictly requires ospc to infect mice but not to localize or migrate appro ... | 2004 | 14970347 |
| ospb antibody prevents borrelia burgdorferi colonization of ixodes scapularis. | borrelia burgdorferi outer surface protein ospb is expressed by spirochetes in the ixodes scapularis gut. ospb is transcribed from a bicistronic operon with ospa, a known spirochete adhesion gene in the tick gut. here we examine whether ospb also has a specific function in ticks. ospb specifically binds to a protein or protein complex within the tick gut. we also assessed whether selected nonborreliacidal ospb antibodies or f(ab)(2) fragments interfere with b. burgdorferi-tick attachment in vivo ... | 2004 | 14977984 |
| essential role for ospa/b in the life cycle of the lyme disease spirochete. | the molecular basis of how borrelia burgdorferi (bb), the lyme disease spirochete, maintains itself in nature via a complex life cycle in ticks and mammals is poorly understood. outer surface (lipo)protein a (ospa) of bb has been the most intensively studied of all borrelial molecular constituents, and hence, much has been speculated about the potential role(s) of ospa in the life cycle of bb. however, the precise function of ospa (along with that of its close relative and operonic partner, oute ... | 2004 | 14981112 |
| isolation and characterization of borrelia hermsii associated with two foci of tick-borne relapsing fever in california. | relapsing fever, caused by the spirochete borrelia hermsii and transmitted by the soft tick ornithodoros hermsi, is endemic in many rural mountainous areas of california. between 1996 and 1998, 12 cases of relapsing fever associated with two exposure sites in northern california were investigated. follow-up at exposure sites included collection of soft ticks and serum specimens from sylvatic rodents. attempts to cultivate spirochetes were made through inoculation of patient blood into mice and b ... | 2004 | 15004063 |
| 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 ... | 2004 | 15004069 |
| evaluation of groel gene analysis for identification of borrelia burgdorferi sensu lato. | the nucleotide sequences of the groel genes, the flagellin genes, and the 16s rrna genes from 22 reference strains of borrelia were compared. groel sequence analysis is useful not only in interspecies differentiation but also in intraspecies differentiation of borrelia afzelii and borrelia garinii isolates. | 2004 | 15004091 |
| 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 ... | 2004 | 15009442 |
| acquisition of different isolates of anaplasma phagocytophilum by ixodes scapularis from a model animal. | the prevalence of etiologic agents in ticks reflects the intensity of their transmission in natural cycles and is an important measure of their potential to cause human disease. the distribution of anaplasma phagocytophilum within the range of its primary vectors is patchy. even nearby sites differ dramatically in the prevalence of anaplasma in questing ticks. we hypothesized that this irregular distribution may be due in part to variations in acquisition rates of different isolates of a. phagoc ... | 2004 | 15018773 |
| cloning and sequencing of putative calreticulin complementary dnas from four hard tick species. | calreticulin (crt) is a calcium-binding protein and has many functions in eukaryotic cells. crt is possibly involved in parasite host immune system evasion. to better understand the molecular basis of crt in ticks, we cloned and sequenced 4 full-length complementary dnas (cdnas) from the hard tick species, dermacentor variabilis, haemaphysalis longicornis, ixodes scapularis, and rhipicephalus sanguineus, using the technique of rapid amplification of cdna ends. the deduced amino acid sequences sh ... | 2004 | 15040669 |
| ehrlichia ruminantium grows in cell lines from four ixodid tick genera. | continuous cell lines from the ticks amblyomma variegatum, boophilus decoloratus, boophilus microplus, hyalomma anatolicum anatolicum, ixodes scapularis, ixodes ricinus and rhipicephalus appendiculatus were tested for ability to support growth of the rickettsial pathogen ehrlichia (previously cowdria) ruminantium. five e.ruminantium isolates, from west africa, south africa and the french west indies, were used. twelve tick cell lines were inoculated with e.ruminantium derived either from culture ... | 2004 | 15053931 |
| lyme disease spirochete, borrelia burgdorferi, endemic in epicenter at turkey point, ontario. | the lyme disease spirochete, borrelia burgdorferi johnson, schmidt, hyde, steigerwalt, and brenner, was discovered in blacklegged ticks, ixodes scapularis say at turkey point, ontario, canada. we report the first isolation of b. burgdorferi from a vertebrate animal collected on mainland ontario. during this 2-yr study, spirochetes were isolated from the white-footed mouse, peromyscus leucopus rafinesque, and attached i. scapularis larvae. similarly, isolates of b. burgdorferi were cultured from ... | 2004 | 15061282 |
| human behaviors elevating exposure to ixodes pacificus (acari: ixodidae) nymphs and their associated bacterial zoonotic agents in a hardwood forest. | epidemiological evidence suggests that the nymph of the western black-legged tick, ixodes pacificus cooley and kohls, is the primary vector of the lyme disease spirochete, borrelia burgdorferi johnson, schmid, hyde, steigerwalt, and brenner, to humans in northwestern california. in spring 2002, six different human behaviors were evaluated as potential risk factors for acquiring i. pacificus nymphs in a deciduous woodland in mendocino county, california. also, the prevalence of b. burgdorferi sen ... | 2004 | 15061284 |
| 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 ... | 2004 | 15061285 |
| borrelia burgdorferi infection in a natural population of peromyscus leucopus mice: a longitudinal study in an area where lyme borreliosis is highly endemic. | blood samples from peromyscus leucopus mice captured at an enzootic site in connecticut were examined for antibodies to and dna of borrelia burgdorferi, to characterize the dynamics of infection in this reservoir population. from trappings conducted over the course of 2 transmission seasons, 598 (75%) of 801 serum samples from 514 mice were found to be positive by enzyme immunoassay. seropositivity correlated with date of capture and mouse age, was similar among locations within the site, increa ... | 2004 | 15073690 |
| the emergence of lyme disease. | since its identification nearly 30 years ago, lyme disease has continued to spread, and there have been increasing numbers of cases in the northeastern and north central us. the lyme disease agent, borrelia burgdorferi, causes infection by migration through tissues, adhesion to host cells, and evasion of immune clearance. both innate and adaptive immune responses, especially macrophage- and antibody-mediated killing, are required for optimal control of the infection and spirochetal eradication. ... | 2004 | 15085185 |
| tick saliva reduces adherence and area of human neutrophils. | during natural infection with the agent of lyme disease, borrelia burgdorferi, spirochetes are delivered with vector saliva, which contains anti-inflammatory and antihemostatic activities. we show here that the saliva of ixodid ticks reduces polymorphonuclear leukocyte (pmn) adhesion via downregulation of beta2-integrins and decreases the efficiency of pmn in the uptake and killing of spirochetes. inhibition of integrin adhesion and signaling reduces anti-inflammatory functions of pmn. these eff ... | 2004 | 15102811 |
| glycosylation of anaplasma marginale major surface protein 1a and its putative role in adhesion to tick cells. | anaplasma marginale, the causative agent of bovine anaplasmosis, is a tick-borne rickettsial pathogen of cattle that multiplies in erythrocytes and tick cells. major surface protein 1a (msp1a) and msp1b form the msp1 complex of a. marginale, which is involved in adhesion of the pathogen to host cells. in this study we tested the hypothesis that msp1a and msp1b were glycosylated, because the observed molecular weights of both proteins were greater than the deduced molecular masses. we further hyp ... | 2004 | 15102815 |
| penthalaris, a novel recombinant five-kunitz tissue factor pathway inhibitor (tfpi) from the salivary gland of the tick vector of lyme disease, ixodes scapularis. | tick saliva is a rich source of molecules with antiinflammatory, antihemostatic and immunosupressive properties. in this paper, a novel tick salivary gland cdna with sequence homology to tissue factor pathway inhibitor (tfpi) and coding for a protein called penthalaris has been characterized from the lyme disease vector, ixodes scapularis. penthalaris is structurally unique and distinct from tfpi or tfpi-like molecules described so far, including ixolaris, napc2, tfpi-1 and tfpi-2. penthalaris i ... | 2004 | 15116248 |
| babesiosis in fairfield county, connecticut. | | 2004 | 15116708 |
| identifying the vector of lyme disease. | lyme disease is the most common vector-borne illness in the united states. it is caused by the spirochete borrelia burgdorferi, which is transmitted by the deer tick. deer ticks have a four-stage life cycle (egg, larva, nymph, and adult), and nymphal ticks transmit b. burgdorferi to humans more frequently than adult ticks. transmission of this spirochete typically requires a minimum of 24 to 48 hours of tick attachment. early stages of lyme disease are characterized by a hallmark rash, erythema ... | 2004 | 15117014 |
| a novel alpha-proteobacterium resides in the mitochondria of ovarian cells of the tick ixodes ricinus. | an intracellular bacterium from ixodes ricinus ticks collected in italy was characterized by electron microscopy (em), pcr sequencing of the 16s rrna gene, molecular phylogenetic analysis, and in situ hybridization (ish). this bacterium was shown by em to be present in the cytoplasm, as well as in the mitochondria of ovarian cells. when universal 16s rrna bacterial primers were used, pcr amplification of ovarian dna followed by cloning and sequencing resulted in the same sequence being found in ... | 2004 | 15128508 |
| survey of rodents and ticks in human babesiosis emergence area in japan: first detection of babesia microti-like parasites in ixodes ovatus. | babesia microti-like parasites were detected for the first time in ixodes ovatus in hyogo prefecture, japan, where two reported types of b. microti-like parasites were recognized in many rodents. of 80 adult i. ovatus ticks collected, 5 possessed the reported type and 1 possessed a new type of b. microti-like parasite. | 2004 | 15131209 |
| 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. | 2004 | 15131225 |
| identification of four genes expressed by feeding female ixodes scapularis, including three with sequence similarity to previously recognized genes. | we created a cdna library from feeding, female ixodes scapularis ticks and screened the library with a subtracted probe to eliminate most genes common to feeding female and mating male i. scapularis ticks. four unique genes were identified in this screen. one gene, is 9, (represented by 16 cdnas) was more highly expressed in female ticks. this gene encodes a putative glycine-rich protein, which matched a number of glycine-rich proteins including attachment cement proteins from rhipicephalus appe ... | 2004 | 15139276 |
| borrelia burgdorferi binds to, invades, and colonizes native type i collagen lattices. | borrelia burgdorferi binds strongly to the extracellular matrix and cells of the connective tissue, a binding apparently mediated by specific proteins and proteoglycans. we investigated the interactions between b. burgdorferi cells and intact type i collagen using hydrated lattices that reproduce features of in vivo collagen matrices. b. burgdorferi cells of several strains adhered avidly to these acellular matrices by a mechanism that was not mediated by decorin or other proteoglycans. moreover ... | 2004 | 15155615 |
| delivery of the immunosuppressive antigen salp15 to antigen-presenting cells by salmonella enterica serovar typhimurium aroa mutants. | a salmonella enterica serovar typhimurium aroa-deficient delivery system was used to target the immunosuppressive protein salp15 to antigen-presenting cells. in vitro and in vivo infections with salp15-containing salmonella resulted in an impaired cd4(+)-t-cell activation, suggesting that the protein was produced by antigen-presenting cells in a physiologically active form. | 2004 | 15155675 |
| prevalence of borrelia burgdorferi, bartonella spp., babesia microti, and anaplasma phagocytophila in ixodes scapularis ticks collected in northern new jersey. | pcr analysis of ixodes scapularis ticks collected in new jersey identified infections with borrelia burgdorferi (33.6%), babesia microti (8.4%), anaplasma phagocytophila (1.9%), and bartonella spp. (34.5%). the i. scapularis tick is a potential pathogen vector that can cause coinfection and contribute to the variety of clinical responses noted in some tick-borne disease patients. | 2004 | 15184475 |
| sequence typing reveals extensive strain diversity of the lyme borreliosis agents borrelia burgdorferi in north america and borrelia afzelii in europe. | the genetic polymorphism of borrelia burgdorferi and borrelia afzelii, two species that cause lyme borreliosis, was estimated by sequence typing of four loci: the rrs-rrla intergenic spacer (igs) and the outer-membrane-protein gene p66 on the chromosome, and the outer-membrane-protein genes ospa and ospc on plasmids. the major sources of dna for pcr amplification and sequencing were samples of the b. burgdorferi tick vector ixodes scapularis, collected at a field site in an endemic region of the ... | 2004 | 15184561 |
| effects of anaplasma phagocytophilum infection on the molting success of ixodes scapularis (acari: ixodidae) larvae. | we assessed the effects of sympatric (occupying the same or overlapping geographic areas) and allopatric (occurring in separate geographic areas) isolates of anaplasma phagocytophilum on the survival of ixodes scapularis say larvae that were derived from ticks collected in bridgeport, ct. seven isolates of a. phagocytophilum, originating from different geographic regions of the united states, were tested: four isolates from the northeast (bridgeport, dawson, gaillard, and ny-8), two from the mid ... | 2004 | 15185953 |
| babesia divergens-like infection, washington state. | most reported u.s. zoonotic cases of babesiosis have occurred in the northeast and been caused by babesia microti. in washington state, three cases of babesiosis have been reported previously, which were caused by wa1 (for "washington 1")-type parasites. we investigated a case of babesiosis in washington in an 82-year-old man whose spleen had been removed and whose parasitemia level was 41.4%. the complete 18s ribosomal rna gene of the parasite was amplified from specimens of his whole blood by ... | 2004 | 15200851 |
| anaplasma phagocytophilum, babesia microti, and borrelia burgdorferi in ixodes scapularis, southern coastal maine. | ixodes scapularis (deer ticks) from maine were tested for multiple infections by polymerase chain reaction and immunofluorescence. in 1995, 29.5%, 9.5%, and 1.9% of deer ticks were infected with borrelia burgdorferi, anaplasma phagocytophilum, and babesia microti, respectively. in 1996 and 1997, the number of a. phagocytophilum-infected ticks markedly declined. in 1995 through 1996, 4 (1.3%) of 301 were co-infected. | 2004 | 15200875 |
| telomere exchange between linear replicons of borrelia burgdorferi. | spirochetes in the genus borrelia carry a linear chromosome and numerous linear plasmids that have covalently closed hairpin telomeres. the overall organization of the large chromosome of borrelia burgdorferi appears to have been quite stable over recent evolutionary time; however, a large fraction of natural isolates carry differing lengths of dna that extend the right end of the chromosome between about 7 and 20 kbp relative to the shortest chromosomes. we present evidence here that a rather r ... | 2004 | 15205414 |
| anaplasma phagocytophilum has a functional msp2 gene that is distinct from p44. | the msp2 and p44 genes encode polymorphic major outer membrane proteins that are considered unique to the intraerythrocytic agent of anaplasma marginale and the intragranulocytic agent of anaplasma phagocytophilum, respectively. in the present study, however, we found an msp2 gene in a. phagocytophilum that was remarkably conserved among a. phagocytophilum strains from human granulocytic anaplasmosis (hga) patients, ticks, and a horse from various regions in the united states, but the gene was d ... | 2004 | 15213131 |
| direct detection of borrelia burgdorferi in ixodes scapularis (acari: ixodidae) nymphs by hybridization to ribosomal rna. | a method for direct detection of borrelia burgdorferi johnson, schmid, hyde, steigerwalt & brenner has been developed. cells are lysed to facilitate release of ribosomal rna. lysates are filtered onto nylon membranes that are hybridized with probes specific for sequences in b. burgdorferi 23s rrna. the technique is rapid and does not require any enzymatic amplification steps. with the use of a cocktail containing five different probes, approximately 1,000 organisms could be detected. the assay w ... | 2000 | 15218912 |
| 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 ... | 2000 | 15218915 |
| relationship between weights of the engorged nymphal stage and resultant sexes in ixodes scapularis and dermacentor variabilis (acari: ixodidae) ticks. | the relationship between weights of the nymphal stage and their resultant sexes in ixodes scapularis say and dermacentor variabilis (say) was examined under laboratory conditions. nymphs were fed to repletion on laboratory white mice, weighed individually, and held until they molted. fully engorged i. scapularis nymphs that subsequently molted to females weighed between 3.8 and 6.4 mg (n = 64). those nymphs that molted to males weighed between 2.0 and 3.2 mg (n = 57). body weights of engorged ny ... | 2000 | 15218928 |
| passive tick surveillance, dog seropositivity, and incidence of human lyme disease. | data on nymphal ixodes scapularis ticks submitted by the public to the university of rhode island tick research laboratory for testing from 1991 to 2000 were compared with human case data from the rhode island department of health to determine the efficacy of passive tick surveillance at assessing human risk of lyme disease. numbers of ticks submitted were highly correlated with human cases by county (r = 0.998, n = 5 counties) and by town (r = 0.916, n = 37 towns), as were the numbers of positi ... | 2004 | 15228814 |
| multiplex real-time pcr for detection of anaplasma phagocytophilum and borrelia burgdorferi. | a multiplex real-time pcr assay was developed for the simultaneous detection of anaplasma phagocytophilum and borrelia burgdorferi. the assay was tested on various anaplasma, borrelia, erhlichia, and rickettsia species, as well as on bartonella henselae and escherichia coli, and the assay was found to be highly specific for a. phagocytophilum and the borrelia species tested (b. burgdorferi, b. parkeri, b. andersonii, and b. bissettii). the analytical sensitivity of the assay is comparable to tha ... | 2004 | 15243077 |
| thermal accumulation and the early development of ixodes scapularis. | we examined the relationship between the accumulation of thermal energy and the onset of oviposition and eclosion of the northern deer tick, ixodes scapularis, and explored the usefulness of comparing degree days (dd) required for larval emergence with area-wide national weather service (nws) data to construct maps indicating where the establishment of this vector tick would be climatologically constrained. initially, the validity of basal temperatures for egg and larval development was confirme ... | 2004 | 15266754 |
| reinfection with anaplasma phagocytophilum in balb/c mice and cross-protection between two sympatric isolates. | infection with anaplasma phagocytophilum in white-footed mice results in partial protection against reinfection with the same agent. however, humans and domestic animals may be sequentially exposed to different isolates of the agent circulating in the same or adjacent foci. we investigated whether immune response to a tick-borne infection with a. phagocytophilum provides protection against homologous and heterologous challenges. balb/c mice were infected with one of the two sympatric isolates of ... | 2004 | 15271934 |
| the luxs gene is not required for borrelia burgdorferi tick colonization, transmission to a mammalian host, or induction of disease. | luxs mutants of borrelia burgdorferi strain 297 naturally colonized their arthropod (ixodes scapularis) vector, were maintained in ticks throughout the molting process (larvae to nymphs), were tick transmitted to uninfected mice, and elicited histopathology in mice indistinguishable from that induced by wild-type b. burgdorferi. | 2004 | 15271949 |
| investigation of relationships between temperature and developmental rates of tick ixodes scapularis (acari: ixodidae) in the laboratory and field. | relationships between temperature and preoviposition, preeclosion, and premolt developmental periods for the tick ixodes scapularis say were investigated by holding field-collected ticks in the laboratory at temperatures of 0 to 32 degrees c at constant daylength. the duration of these developmental periods decreased significantly with increasing temperature. host of origin, prior storage at 4 degrees c, and season of collection of the ticks were also significantly associated with variations in ... | 2004 | 15311453 |
| pathogenicity of entomopathogenic fungi beauveria bassiana and metarhizium anisopliae to ixodidae tick species dermacentor variabilis, rhipicephalus sanguineus, and ixodes scapularis. | nymphal and adult ticks from three different tick species, dermacentor variabilis say, ixodes scapularis say, and rhipicephalus sanguineus latrielle, were treated with conidia and blastospores of the entomopathogenic fungi beauveria bassiana (bals.) vuill. and metarhizium anisopliae metschnikoff. dose-response experiments indicated that a critical concentration of fungal spores is required for infection and mortality. over a 28-d time course, fungal suspensions of either b. bassiana or m. anisop ... | 2004 | 15311464 |
| abundance of ixodes scapularis (acari: ixodidae) after the complete removal of deer from an isolated offshore island, endemic for lyme disease. | monhegan is an isolated 237-ha island lying 16 km off the coast of maine. introduced to the island in 1955, white-tailed deer, odocoileus virginianus zimmerman, reached a density of approximately 37/km2 by the mid-1990s. black-legged ticks, ixodes scapularis say, first noticed in the late 1980s, flourished thereafter. norway rats (rattus norvegicus berkenhout) on monhegan are highly infected with borrelia burgdorferi johnson, schmidt, hyde, steigerwalt, and brenner, the agent of lyme disease. by ... | 2004 | 15311475 |
| a technique for longitudinally sampling individual adult ixodes scapularis (acari: ixodidae). | the first technique for repeatedly sampling individual ixodes scapularis adult ticks was developed and validated. gut samples from the same individual ticks were removed and analyzed at weekly intervals. multiple analyses were conducted on each gut sample (e.g., total protein concentration, presence of viable b. burgdorferi spirochetes, and concentration of outer surface protein a [ospa]). female i. scapularis survived for up to 25 d after gut sampling. seventy-five percent of females oviposited ... | 2004 | 15311478 |
| comparison of disseminated and nondisseminated strains of borrelia burgdorferi sensu stricto in mice naturally infected by tick bite. | clinical isolates of borrelia burgdorferi sensu stricto have been categorized into disseminated and nondisseminated groups based on distinct ribosomal spacer restriction fragment length polymorphism genotypes (rsts). in order to determine whether transmission by tick bite would alter the dissemination dynamics and disease produced by distinct genotypes, disseminated isolates (rst1), nondisseminated isolates (rst3), and a standard laboratory strain (b-31) were established in a murine cycle utiliz ... | 2004 | 15322021 |
| combined effects of blood and temperature shift on borrelia burgdorferi gene expression as determined by whole genome dna array. | borrelia burgdorferi undergoes differential gene expression during transmission from its tick vector to a vertebrate host. the addition of blood to a spirochete culture at 35 degrees c for 48 h had a dramatic effect on gene expression of this organism. utilizing b. burgdorferi whole genome dna arrays, we compared the transcriptomes of the spirochetes following a 2-day temperature shift with blood and without blood. using combined data from three independent rna isolations we demonstrated that th ... | 2004 | 15322040 |
| a comparison of serologic tests for the detection of serum antibodies to whole-cell and recombinant borrelia burgdorferi antigens in cattle. | serum samples from healthy dairy and beef cattle, living in tick-infested areas of connecticut, usa, were analyzed by polyvalent enzyme-linked immunosorbent assays (elisa), indirect fluorescent antibody (ifa) staining methods, or western blot procedures to detect antibodies to tick-borne agents. of the 80 sera tested by elisa with whole-cell or 10 separate recombinant antigens (fusion proteins) of borrelia burgdorferi sensu stricto, 57 (71%) were positive to 1 or more antigens, while 36 (45%) re ... | 2004 | 15368740 |
| genetic exchange and plasmid transfers in borrelia burgdorferi sensu stricto revealed by three-way genome comparisons and multilocus sequence typing. | comparative genomics of closely related bacterial isolates is a powerful method for uncovering virulence and other important genome elements. we determined draft sequences (8-fold coverage) of the genomes of strains jd1 and n40 of borrelia burgdorferi sensu stricto, the causative agent of lyme disease, and we compared the predicted genes from the two genomes with those from the previously sequenced b31 genome. the three genomes are closely related and are evolutionarily approximately equidistant ... | 2004 | 15375210 |
| short report: duration of tick attachment required for transmission of powassan virus by deer ticks. | infected deer ticks (ixodes scapularis) were allowed to attach to naive mice for variable lengths of time to determine the duration of tick attachment required for powassan (pow) virus transmission to occur. viral load in engorged larvae detaching from viremic mice and in resulting nymphs was also monitored. ninety percent of larval ticks acquired pow virus from mice that had been intraperitoneally inoculated with 10(5) plaque-forming units (pfu). engorged larvae contained approximately 10 pfu. ... | 2004 | 15381804 |
| polymorphism and transcription at the p44-1/p44-18 genomic locus in anaplasma phagocytophilum strains from diverse geographic regions. | a polymorphic multigene family (p44) of anaplasma phagocytophilum encodes the immunodominant 44-kda major outer membrane proteins. with p44-specific pcr and gene-specific probes, p44-1 was found in all human isolates from new york state but not in isolates from minnesota, whereas p44-18 and two other p44 species were found in isolates from both regions. we therefore sequenced the genomic locus corresponding to the p44-1/p44-18 tandem locus of a. phagocytophilum hz in 14 other geographically dive ... | 2004 | 15385454 |
| experimental assessment of the roles of linear plasmids lp25 and lp28-1 of borrelia burgdorferi throughout the infectious cycle. | borrelia burgdorferi, which causes lyme disease in humans, has an unusual genome composed of a linear chromosome and up to 21 extrachromosomal elements. experimental data suggest that two of these elements, linear plasmids lp25 and lp28-1, play essential roles for infectivity in mice. in this study, we prove the essential natures of these two plasmids by selectively displacing lp25 or lp28-1 in an infectious wild-type clone with incompatible shuttle vectors derived from the native plasmids, rend ... | 2004 | 15385497 |
| outer membrane proteins of pathogenic spirochetes. | pathogenic spirochetes are the causative agents of several important diseases including syphilis, lyme disease, leptospirosis, swine dysentery, periodontal disease and some forms of relapsing fever. spirochetal bacteria possess two membranes and the proteins present in the outer membrane are at the site of interaction with host tissue and the immune system. this review describes the current knowledge in the field of spirochetal outer membrane protein (omp) biology. what is known concerning bioge ... | 2004 | 15449605 |
| molecular and serologic evidence of anaplasma phagocytophilum infection in cats in north america. | anaplasma phagocytophilum dna was detected in blood of clinically ill cats from massachusetts (n = 4) and connecticut (1) by use of polymerase chain reaction assay and dna sequencing. all 5 cats were allowed outdoors, and ixodes scapularis were found on 3 cats. clinical signs of fever, anorexia, and lethargy resolved quickly after treatment with doxycycline or tetracycline. serum samples from each cat reacted with a. phagocytophilum morulae via an indirect fluorescent antibody assay; positive an ... | 2004 | 15485049 |
| 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 ... | 2004 | 15500628 |
| effects of vlse complementation on the infectivity of borrelia burgdorferi lacking the linear plasmid lp28-1. | the loss of linear plasmid lp28-1, which contains the vls antigenic variation locus, is associated with reduced infectivity of borrelia burgdorferi in immunocompetent mice. the recombinant shuttle vector pbbe22, which includes the virulence determinant bbe22 from lp25 and restores infectivity to readily transformable b. burgdorferi lacking lp25 and lp56, was used to determine the effect of trans expression of vlse on virulence. spirochetes lacking lp28-1 were complemented with the plasmid pbbe22 ... | 2004 | 15501789 |
| variations in barbour-stoenner-kelly culture medium modulate infectivity and pathogenicity of borrelia burgdorferi clinical isolates. | the effects of variations in barbour-stoenner-kelly (bsk) medium on the infectivity and pathogenicity of borrelia burgdorferi clinical isolates were assessed by retrospective and prospective studies using a murine model of lyme borreliosis. thirty of 35 (86%) mice infected with any of six virulent b. burgdorferi clinical isolates grown in a bsk-h medium developed clinically apparent arthritis. by contrast, arthritis was observed in only 25 of 60 (42%) mice inoculated with two of these b. burgdor ... | 2004 | 15501807 |
| a thrombin inhibitor from the ixodid tick, amblyomma hebraeum. | a novel thrombin inhibitor named amblin was identified from the haemolymph of the ixodid (hard) tick, amblyomma hebraeum, and the coding cdna was isolated from a tick cdna library. this cdna codes for a preprotein of 166 amino acids, including a predicted signal peptide composed of 15 amino acids n-terminal to the mature amblin. the 151-amino-acid mature amblin contains 14 cysteines and two kunitz-like domains. it displays high sequence similarity with a tissue factor pathway inhibitor (tfpi), i ... | 2004 | 15527983 |
| 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 ... | 2004 | 15528527 |
| interaction and transmission of two borrelia burgdorferi sensu stricto strains in a tick-rodent maintenance system. | in the northeastern united states, the lyme disease agent, borrelia burgdorferi sensu stricto, is maintained by enzoonotic transmission, cycling between white-footed mice (peromyscus leucopus) and black-legged ticks (ixodes scapularis). b. burgdorferi sensu stricto is genetically variable and has been divided into three major genotypes based on 16s-23s ribosomal dna spacer (rst) analysis. to better understand how genetic differences in b. burgdorferi sensu stricto may influence transmission dyna ... | 2004 | 15528545 |
| genotypic diversity of francisella tularensis infecting dermacentor variabilis ticks on martha's vineyard, massachusetts. | martha's vineyard, mass., has been the site of two outbreaks of tularemia (1978 and 2000). although most patients from both outbreaks presented with pneumonic disease and although aerosol transmission has been suggested, the bite of a dog tick and exposure to rabbits remain the only proven modes of transmission. the factors that precipitated the tularemia outbreaks or the proximal determinants of human risk remain undescribed. we sought to test the hypothesis that the ongoing outbreak is due to ... | 2004 | 15528681 |
| 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 ... | 2004 | 15528699 |
| estimating population size and drag sampling efficiency for the blacklegged tick (acari: ixodidae). | estimates of absolute density were determined over a 5-yr period (1990-1994) for a population of ixodes scapularis say located in westchester county, ny, by mark-release-recapture (nymphs and adults) and removal (larvae) methods. density estimates for larvae ranged from 5.2 to 16.5/m2 and averaged 11.5/m2. values for nymphs varied as much as fourfold among successive years, ranging from 0.5 to 2.3/m2 and averaging 1.2/m2, whereas adult density ranged from 0.3 to 0.4/m2, averaging 0.33/m2. natura ... | 2000 | 15535578 |
| populations of ixodes scapularis (acari: ixodidae) are modulated by drought at a lyme disease focus in illinois. | from 1990 through 1997, ixodes scapularis say larvae and nymphs were sampled between may and october along a 400-m segment of a nature trail in a lyme disease endemic site in northern illinois. ticks were removed from peromyscus leucopus mice and collected via tick drags at approximately 3-wk intervals. mouse population estimates along the trail varied from 2, in the spring of 1996 following a year of drought, to > 200 in 1993, the wettest year on record. during the 8-yr period, there were major ... | 2000 | 15535585 |
| 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 ... | 2000 | 15535590 |
| responses of adult ixodes scapularis (acari: ixodidae) to urine produced by white-tailed deer of various reproductive conditions. | the responses of adult female blacklegged ticks, ixodes scapularis say, to urine from white-tailed deer, odocoileus virginianus (zimmermann), belonging to 4 reproductive categories (doe in estrous, doe out of season, reproductive [dominant] buck, young buck) and to a mixture of urine from nondominant bucks in rut, young bucks out of rut, and nonestrous does were studied in laboratory behavioral bioassays. in high humidity (approximately 95% rh) in a glove box there were no statistically signific ... | 2000 | 15535595 |
| efficiency of drag sampling for estimating population sizes of ixodes pacificus (acari: ixodidae) nymphs in leaf litter. | drag sampling is a commonly used method to obtain relative estimates of the density of questing nymphal ixodes scapularis say and i pacificus cooley & kohls ticks, which are primary vectors of lyme disease spirochetes to humans in north america. however, the efficiency of drag sampling in determining absolute population densities of questing nymphs has not been evaluated previously. therefore, we assessed the efficiency of a single drag-sampling occasion to estimate the total population size of ... | 2000 | 15535598 |
| a dispersal model for the range expansion of blacklegged tick (acari: ixodidae). | the blacklegged tick, ixodes scapularis say, a vector for the agents of lyme borreliosis and other diseases, has expanded its range dramatically over the past 20 yr. however, the relative contributions of different vertebrate host species to this expansion have remained largely unexplored. to address this issue, we simulated the expansion of a theoretical tick population across a simple landscape by using a deterministic, spatially explicit, cellular automata model. the model incorporates the ec ... | 2004 | 15535611 |
| lack of spatial autocorrelation in fine-scale distributions of ixodes scapularis (acari: ixodidae). | spatial patterns of ixodes scapularis say, the vector of the lyme disease agent, have been examined at various geographic scales, demonstrating that distributions of these ticks are spatially autocorrelated at both national and state scales. we tested the hypothesis that distributions of nymphal i scapularis ticks at the fine scale of an endemic community also are spatially autocorrelated. nymphal tick densities were determined by collecting ticks from 51 and 47 wooded residential properties in ... | 2004 | 15535613 |
| sublethal effects of metarhizium anisopliae (deuteromycetes) on engorged larval, nymphal, and adult ixodes scapularis (acari: ixodidae). | ixodes scapularis say adults, nymphs, and larvae were treated with the entomopathogenic fungus metarhizium anisopliae in a combination of field and laboratory experiments to assess sublethal effects of the fungus on i. scapularis fecundity and body mass. postengorgement and egg mass weights were 33 and 50% lower, respectively, in adult females treated with m. ansiopliae in the field before engorging on laboratory rabbits. m. anisopliae did not significantly reduce egg mass weight, conversion eff ... | 2004 | 15535622 |
| trospa, an ixodes scapularis receptor for borrelia burgdorferi. | the lyme disease agent borrelia burgdorferi naturally persists in a cycle that primarily involves ticks and mammals. we have now identified a tick receptor (trospa) that is required for spirochetal colonization of ixodes scapularis. b. burgdorferi outer surface protein a, which is abundantly expressed on spirochetes within the arthropod and essential for pathogen adherence to the vector, specifically bound to trospa. trospa mrna levels in ticks increased following spirochete infestation and decr ... | 2004 | 15537536 |
| rapid sequential changeover of expressed p44 genes during the acute phase of anaplasma phagocytophilum infection in horses. | anaplasma phagocytophilum immunodominant polymorphic major surface protein p44s have been hypothesized to go through antigenic variation, but the within-host dynamics of p44 expression has not been demonstrated. in the present study we investigated the composition and changes of p44 transcripts in the blood during the acute phase of well-defined laboratory a. phagocytophilum infections in naive equine hosts. three traveling waves of sequential population changeovers of the p44 transcript species ... | 2004 | 15557606 |
| use of imidacloprid-permethrin to prevent transmission of anaplasma phagocytophilum from naturally infected ixodes scapularis ticks to dogs. | one group of eight beagles was treated with a combination of imidacloprid and permethrin 7 days before exposure to ixodes scapularis ticks that were naturally infected with anaplasma phagocytophilum. a second group of eight beagles was not treated and was also exposed to infected ticks. seven of eight non-treated dogs--but none of the treated dogs--developed specific antibodies to a. phagocytophilum. results of this study indicate that a combination of imidacloprid and permethrin can prevent tra ... | 2004 | 15578453 |
| control of immature ixodes scapularis (acari: ixodidae) on rodent reservoirs of borrelia burgdorferi in a residential community of southeastern connecticut. | a 3-yr community-based study was conducted on residential properties on mason's island, mystic, ct, to determine the efficacy of a rodent-targeted acaricide (fipronil) to control immature ixodes scapularis (say) on peromyscus leucopus. results indicated that modified commercial bait boxes were effective as an acaricide delivery method for reducing nymphal and larval tick infestations on white-footed mice by 68 and 84%, respectively. passive application of fipronil significantly reduced the infec ... | 2004 | 15605643 |
| identification of novel tick salivary gland proteins for vaccine development. | methods currently used to control ixodes scapularis ticks rely principally on acaricidal applications which suffer from a number of limitations. recently, host vaccination against ticks has been shown to be a promising alternative tick control method. in tick salivary glands, numerous genes are induced during the feeding process. many of these newly expressed proteins are secreted in tick saliva and may play a role in modulating host immune responses and pathogen transmission. we have performed ... | 2005 | 15607754 |
| an ecological approach to preventing human infection: vaccinating wild mouse reservoirs intervenes in the lyme disease cycle. | many pathogens, such as the agents of west nile encephalitis and plague, are maintained in nature by animal reservoirs and transmitted to humans by arthropod vectors. efforts to reduce disease incidence usually rely on vector control or immunization of humans. lyme disease, for which no human vaccine is currently available, is a commonly reported vector-borne disease in north america and europe. in a recently developed, ecological approach to disease prevention, we intervened in the natural cycl ... | 2004 | 15608069 |
| ixolaris: a factor xa heparin-binding exosite inhibitor. | ixolaris is a two-kunitz tfpi (tissue factor pathway inhibitor) from the tick salivary gland. in contrast with human tfpi, ixolaris binds tightly to the zymogen fx (factor x) and to dansyl-glu-gly-arg-chloromethyl ketone-treated fxa (degr-fxa; active-site-blocked fxa), indicating that exosites are involved in the fx(a)-ixolaris interaction. here we provide evidence that ixolaris binds specifically to the fxa hbe (heparin-binding exosite), since (i) it markedly decreases the inhibition of fxa by ... | 2005 | 15617517 |
| 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 ... | 2005 | 15618143 |
| anaplasma phagocytophilum modulates gp91phox gene expression through altered interferon regulatory factor 1 and pu.1 levels and binding of ccaat displacement protein. | infection of neutrophil precursors with anaplasma phagocytophilum, the causative agent of human granulocytic ehrlichiosis, results in downregulation of the gp91(phox) gene, a key component of nadph oxidase. we now show that repression of gp91(phox) gene transcription is associated with reduced expression of interferon regulatory factor 1 (irf-1) and pu.1 in nuclear extracts of a. phagocytophilum-infected cells. loss of pu.1 and irf-1 correlated with increased binding of the repressor, ccaat disp ... | 2005 | 15618156 |
| spatio-temporal analysis of reinfestation by triatoma infestans (hemiptera: reduviidae) following insecticide spraying in a rural community in northwestern argentina. | the spatio-temporal reinfestation patterns by triatoma infestans following a blanket insecticide spraying in the rural community of amama in northwestern argentina were analyzed using a geographic information system, satellite imagery, and spatial statistics. domestic and peridomestic reinfestation by triatomine bugs was monitored from 1993 to 1997. triatoma infestans was detected at least once in 75% of 2,110 sites evaluated. the prevalence of sites positive at least once for t. infestans durin ... | 2004 | 15642975 |
| allergens of the entomopathogenic fungus beauveria bassiana. | background: beauveria bassiana is an important entomopathogenic fungus currently under development as a bio-control agent for a variety of insect pests. although reported to be non-toxic to vertebrates, the potential allergenicity of beauveria species has not been widely studied. methods: ige-reactivity studies were performed using sera from patients displaying mould hypersensitivity by immunoblot and immunoblot inhibition. skin reactivity to b. bassiana extracts was measured using intradermal s ... | 2005 | 15644142 |
| tick saliva inhibits differentiation, maturation and function of murine bone-marrow-derived dendritic cells. | haematophagous arthropod vectors such as mosquitoes, tsetse flies, sandflies and ticks have evolved salivary immunomodulatory factors that prevent the vertebrate host from rejecting them meanwhile enhancing pathogen transmission. as dendritic cells (dc) play a major role in host immune responses, we studied the effects of rhipicephalus sanguineus tick saliva on dc differentiation and maturation. flow cytometry analysis revealed that the addition of saliva to bone marrow cells inhibits the differ ... | 2005 | 15667568 |
| 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 ... | 2004 | 15682516 |
| 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 ... | 2005 | 15695682 |