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contrasts in tick innate immune responses to borrelia burgdorferi challenge: immunotolerance in ixodes scapularis versus immunocompetence in dermacentor variabilis (acari: ixodidae).the blacklegged tick, ixodes scapularis say, transmits the lyme disease spirochete borrelia burgdorferi, whereas the american dog tick, dermacentor variabilis (say), is unable to transmit the bacterium. we compared the innate immune response of these ticks against spirochetes directly inoculated into the hemocoel cavity of ticks. in i. scapularis, some borrelia were found associated with hemocytes, while numerous other spiral-shaped, intact bacteria remained free in the hemolymph. in contrast, i ...200111268698
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 ...200314680128
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 ...200414722614
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
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 ...200314765677
purification and characterization of borrelia burgdorferi from feeding nymphal ticks (ixodes scapularis).here we describe a protocol for purifying borrelia burgdorferi from feeding ticks by velocity centrifugation and percoll density gradient centrifugation. the purified spirochetes were motile and 10- to 20-fold purer than the bacteria in crude tick homogenates. the purified bacteria were present in sufficient quantity for protein and gene expression studies. in comparison to culture-grown bacteria, tick-borne spirochetes had several proteins that were upregulated and a few that were downregulated ...200111349010
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 ...200415061282
lyme disease.lyme disease, which is caused by borrelia burgdorferi and transmitted in the united states primarily by ixodes scapularis (the deer tick), is the most common vector borne disease in the united states. its most frequent manifestation, a characteristic, expanding annular rash (erythema migrans), sometimes accompanied by myalgia, arthralgia, and malaise, occurs in nearly 90% of persons with symptomatic infection. other manifestations of lyme disease include seventh cranial nerve palsy, aseptic meni ...200010987718
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.200415184475
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 ...200415184561
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.200415200875
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 ...200015218912
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 ...200415228814
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 ...200415243077
genetic diversity of the outer surface protein c gene of southern borrelia isolates and its possible epidemiological, clinical, and pathogenetic implications.the ospc genes of 20 southern borrelia strains were sequenced. the strains consisted of b. burgdorferi sensu stricto, b. andersonii, b. bissettii, one undescribed genospecies, mi-8, and one probably new borrelia species, txw-1. a high degree of similarity exists between b. burgdorferi sensu stricto and b. bissettii and between b. bissettii and b. andersonii. lateral transfers of the ospc gene probably occurred between b. burgdorferi sensu stricto and b. bissettii and between b. bissettii and b. ...200212089279
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 ...200415311475
natural antibody affects survival of the spirochete borrelia burgdorferi within feeding ticks.natural antibodies are those immunoglobulin molecules found in mammalian serum that arise in the absence of exposure to environmental pathogens and may comprise an early host defense against invading pathogens. the spirochete borrelia burgdorferi first encounters natural antibodies when its arthropod vector, ixodes scapularis, begins feeding on a mammalian host. natural antibodies may therefore have an impact on pathogens within blood-sucking vectors, prior to pathogen transmission to the mammal ...200111553590
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. ...200415381804
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 ...200415528545
attachment of borrelia burgdorferi within ixodes scapularis mediated by outer surface protein a.borrelia burgdorferi outer surface protein (osp) a has been used as a lyme disease vaccine that blocks transmission: ospa antibodies of immune hosts enter ticks during blood feeding and destroy spirochetes before transmission to the host can occur. b. burgdorferi produce ospa in the gut of unfed ixodes scapularis ticks, and many spirochetes repress ospa production during the feeding process. this preferential expression suggests that ospa may have an important function in the vector. here we sho ...200010953031
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 ...200415537536
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 ...200415605643
experimental infection of dogs with borrelia burgdorferi sensu stricto using ixodes scapularis ticks artificially infected by capillary feeding.specific pathogen-free dogs were experimentally infected with borrelia burgdorferi sensu stricto using nymphal or adult female ixodes scapularis ticks artificially infected with spirochetes by capillary feeding. the ticks were capillary fed b. burgdorferi isolate 610, previously isolated from a dog with lyme disease and grown in bsk medium. this isolate induced clinical signs in the dogs similar to those for dogs infested with ticks naturally infected with b. burgdorferi. adult ticks were more e ...200412884036
hypersensitivity to ticks and lyme disease risk.although residents of lyme disease-endemic regions describe frequent exposure to ticks, lyme disease develops in relatively few. to determine whether people who experience cutaneous hypersensitivity against tick bite have fewer episodes of lyme disease than those who do not, we examined several factors that might restrict the incidence of lyme disease among residents of block island, rhode island. of 1,498 study participants, 27% (95% confidence interval [ci] 23%-31%) reported > or = 1 tick bite ...200515705320
protection against lyme disease spirochete transmission provided by prompt removal of nymphal ixodes scapularis (acari: ixodidae).public health recommendations for lyme disease prevention generally include daily tick checks and prompt removal of attached ticks as a means of decreasing the risk of acquiring lyme disease in highly endemic regions. in the current study, we determined whether crushing nymphal ticks during removal with forceps increased the risk of b. burgdorferi transmission, what degree of protection from transmission of b. burgdorferi was provided by removal of nymphal ixodes scapularis say at specific inter ...200212061448
analysis of borrelia burgdorferi gene expression during life cycle phases of the tick vector ixodes scapularis.borrelia burgdorferi exists in nature via an enzootic cycle whereby the organism must adapt to the diverse environmental conditions provided inside the arthropod transmission vector and the mammalian reservoir hosts. b. burgdorferi genes shown to be regulated by temperature, ph and/or cell density during the organism's growth in culture medium were assayed for expression during various stages of the tick feeding cycle by reverse transcription-polymerase chain reaction (rt-pcr). ospa, ospc, flab, ...200111580974
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
geographic uniformity of the lyme disease spirochete (borrelia burgdorferi) and its shared history with tick vector (ixodes scapularis) in the northeastern united states.over 80% of reported cases of lyme disease in the united states occur in coastal regions of northeastern and mid-atlantic states. the genetic structure of the lyme disease spirochete (borrelia burgdorferi) and its main tick vector (ixodes scapularis) was studied concurrently and comparatively by sampling natural populations of i. scapularis ticks along the east coast from 1996 to 1998. borrelia is genetically highly diverse at the outer surface protein ospc. since borrelia is highly clonal, the ...200211901105
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
dynamic changes in borrelia burgdorferi populations in ixodes scapularis (acari: ixodidae) during transmission: studies at the mrna level.many b. burgdorferi genes are regulated at the level of transcription during b. burgdorferi passage from ticks to mammals. particular spirochete outer surface proteins of interest are ospa, ospc, and vlse. the messenger rna (mrna) levels produced by these three genes were determined by a quantitative reverse transcription pcr (q-rt-pcr) procedure for spirochete populations in nymphal i. scapularis midguts and salivary glands at specific intervals during the feeding process. the mrna values were ...200314511582
presence of borrelia burgdorferi (spirochaetales: spirochaetaceae) in southern kettle moraine state forest, wisconsin, and characterization of strain w97f51.lyme disease, caused by borrelia burgdorferi johnson, schmidt, hyde, steigerwalt & brenner; babesiosis, caused by babesia microti franca; and human granulocytic ehrlichiosis, caused by anaplasma phagocytophilum bakken & dumler have been reported in wisconsin, mainly in the endemic areas of the northwestern part of the state. people exposed to blacklegged ticks, ixodes scapularis say, from this region can potentially contract one or all of these diseases concurrently. within the past several year ...200515962800
protection against tick-transmitted lyme disease in dogs vaccinated with a multiantigenic vaccine.in an effort to develop a safe and effective vaccine for the prevention of lyme borreliosis that addresses concerns raised over currently available vaccines, dogs were vaccinated twice with a multiantigenic preparation of borrelia burgdorferi, strain n40, on days 0 and 20 of the experiment. about 70 and 154 days after the first immunization, dogs were challenged by exposing them to field-collected ixodes scapularis ticks harboring b. burgdorferi. vaccinated dogs were completely protected from in ...200111567763
capillary feeding of specific dsrna induces silencing of the isac gene in nymphal ixodes scapularis ticks.ixodes scapularis transmits several pathogens including borrelia burgdorferi. bioactive compounds in tick saliva support tick feeding and influence pathogen transmission to the mammalian host. these studies utilized oral delivery of dsrna to silence an anticomplement gene (isac) in i. scapularis nymphs. silencing of isac significantly reduced fed-tick weight compared to delivery of control lacz dsrna, and immunoblots specific for flab protein indicated a reduction in spirochete load in isac-sile ...200516033437
detection of attenuated, noninfectious spirochetes in borrelia burgdorferi-infected mice after antibiotic treatment.xenodiagnosis by ticks was used to determine whether spirochetes persist in mice after 1 month of antibiotic therapy for vectorborne borrelia burgdorferi infection. immunofluorescence and polymerase chain reaction (pcr) were used to show that spirochetes could be found in ixodes scapularis ticks feeding on 4 of 10 antibiotic-treated mice up to 3 months after therapy. these spirochetes could not be transmitted to naive mice, and some lacked genes on plasmids correlating with infectivity. by 6 mon ...200212404158
the efficacy of co-feeding as a means of maintaining borrelia burgdorferi: a north american model system.although research on co-feeding as a means of maintaining tick-borne pathogens has focused chiefly on viruses, recent interest has been directed toward the importance of this phenomenon in maintaining the lyme disease spirochete, borrelia burgdorferi. in the current study, an experimental model was developed to determine under what conditions immature co-feeding ticks exchange b. burgdorferi using the principal north american vector (ixodes scapularis) and reservoir (peromyscus leucopus) species ...200111813659
backbone dynamics and thermodynamics of borrelia outer surface protein a.nuclear spin relaxation experiments performed at 298k, 308k and 318k are used to characterize the intramolecular dynamics and thermodynamics of outer surface protein a (ospa), a key protein in the life-cycle of borrelia burgdorferi, the causative agent of lyme disease. it has recently been demonstrated that ospa specifically binds to the gut of the intermediate tick host (ixodes scapularis), and that this interaction is mediated, at least in part, by residues in the c-terminal domain of ospa tha ...200212470954
defining plasmids required by borrelia burgdorferi for colonization of tick vector ixodes scapularis (acari: ixodidae).maintenance in nature of borrelia burgdorferi, the pathogenic bacterium that causes lyme disease, requires transmission through an infectious cycle that includes a tick vector and a mammalian host. the genetic requirements for persistence in these disparate environments have not been well defined. b. burgdorferi has a complex genome composed of a chromosome and >20 plasmids. previous work has demonstrated that b. burgdorferi requires two plasmids, lp25 and lp28-1, in the mammalian host. to inves ...200516119559
tick exposure and lyme disease at a summer camp in maryland.after investigating an outbreak of lyme disease among counselors at a summer camp in kent county, maryland in 1994, we wanted to determine the incidence of lyme disease (ld) at the camp the following summer and identify risk factors for tick exposure. any ticks that were detected on campers' skin or clothing were collected by the camp nurse and we studied them for infection with borrelia burgdorferi. in addition, we sent detailed questionnaires home with the 1,623 campers. a total of 537 campers ...200516161531
the abcs of lyme disease spirochaetes in ticks. 200516168758
borrelia burgdorferi-specific monoclonal antibodies derived from mice primed with lyme disease spirochete-infected ixodes scapularis ticks.we have generated a panel of igg monoclonal antibodies (mabs) directed against borrelia burgdorferi strain b31 antigens, using a method whereby mice were primed with organisms naturally inoculated by ixodes scapularis nymphal ticks. western blot analysis showed that these mabs recognized several b. burgdorferi b31 antigens, including the complement inhibitor factor h-binding proteins erpa/i/n and erpc. two other mabs were specific for the reva protein, and have enabled characterization of that p ...200212165143
geographic distribution of ticks (acari: ixodidae) in iowa with emphasis on ixodes scapularis and their infection with borrelia burgdorferi.in 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
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 ...200415073690
seroprevalence of antibodies against borrelia burgdorferi and anaplasma phagocytophilum in cats.to determine whether cats in the northeastern united states develop serum antibodies against antigens of borrelia burgdorferi and anaplasma phagocytophilum and whether coinfection with the 2 organisms occurs.200516334946
borrelia burgdorferi sigma54 is required for mammalian infection and vector transmission but not for tick colonization.previous studies have shown that a sigma54-sigma(s) cascade regulates the expression of a few key lipoproteins in borrelia burgdorferi, the agent of lyme disease. here, we demonstrate that these sigma factors, both together and independently, regulate a much more extensive number of genes and cellular processes. microarray analyses of sigma54 and sigma(s) mutant strains identified 305 genes regulated by sigma54 and 145 regulated by sigma(s), whereas the sigma54-sigma(s) regulatory cascade appear ...200515743918
three multiplex assays for detection of borrelia burgdorferi sensu lato and borrelia miyamotoi sensu lato in field-collected ixodes nymphs in north america.two hundred fifty new jersey field-collected ixodes scapularis say ticks and 17 colorado ixodes spinipalpis hadwen & nuttall ticks were tested using three separate multiplex real-time polymerase chain reaction (pcr) assays. one assay targets the rrs-rrla igs region of borrelia spp. to detect borrelia burgdorferi sensu lato (s.l.) and borrelia miyamotoi s.l. the second assay targets the ospa region of b. burgdorferi s.l. to detect b. burgdorferi sensu stricto (s.s.), borrelia bissettii, and borre ...200516465748
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
strategies for reducing the risk of lyme borreliosis in north america.the incidence of lyme borreliosis continues to increase in the united states. in 1991, when lyme borreliosis first became a nationally reportable disease to the centers for disease control and prevention (cdc), a total of 9470 cases were reported; in contrast, by 2002 a total of 23,763 cases were reported, >2.5x the total in 1991. area-wide acaricides can be highly effective in killing nymphal ixodes scapularis, with >95% of nymphs killed in studies using cyfluthrin, deltamethrin, or carbaryl. t ...200616524769
myd88 deficiency enhances acquisition and transmission of borrelia burgdorferi by ixodes scapularis ticks.borrelia burgdorferi strains exhibit various degrees of infectivity and pathogenicity in mammals, which may be due to their relative ability to evade initial host immunity. innate immune cells recognize b. burgdorferi by toll-like receptors (tlrs) that use the intracellular molecule myd88 to mediate effector functions. to determine whether impaired tlr signaling enhances ixodes scapularis acquisition of b. burgdorferi, we fed nymphs on wild-type (wt) and myd88-/- mice previously infected with tw ...200616552045
a reverse transcriptase-polymerase chain reaction assay of borrelia burgdorferi 16s rrna for highly sensitive quantification of pathogen load in a vector.we developed a real-time quantitative detection assay for the pathogen borrelia burgdorferi, a lyme borreliosis (lb) agent, using reverse transcription-polymerase chain reaction (rt-pcr) with primers and probe for a borrelia genus-specific region of 16s ribosomal rna. the standard curve of the assay was linear by semi-log plot over more than five orders of magnitude, and the detection limit of the assay was one thousandth of a single cell of b. burgdorferi. the minimum target level for detection ...200616584333
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
spatiotemporal patterns of host-seeking ixodes scapularis nymphs (acari: ixodidae) in the united states.the risk of lyme disease for humans in the eastern united states is dependent on the density of host-seeking ixodes scapularis say nymphal stage ticks infected with borrelia burgdorferi. although many local and regional studies have estimated lyme disease risk using these parameters, this is the first large-scale study using a standardized methodology. density of host-seeking i. scapularis nymphs was measured by drag sampling of closed canopy deciduous forest habitats in 95 locations spaced amon ...200616619595
molecular analysis of microbial communities identified in different developmental stages of ixodes scapularis ticks from westchester and dutchess counties, new york.ixodes scapularis ticks play an important role in the transmission of a wide variety of pathogens between various mammalian species, including humans. pathogens transmitted by ticks include borrelia, anaplasma and babesia. although ticks may harbour both pathogenic and non-pathogenic microflora, little is known about how the diversity of the microflora within ticks may influence the transmission of pathogens. to begin addressing this question, we examined the composition of bacterial communities ...200616623735
climate, deer, rodents, and acorns as determinants of variation in lyme-disease risk.risk of human exposure to vector-borne zoonotic pathogens is a function of the abundance and infection prevalence of vectors. we assessed the determinants of lyme-disease risk (density and borrelia burgdorferi-infection prevalence of nymphal ixodes scapularis ticks) over 13 y on several field plots within eastern deciduous forests in the epicenter of us lyme disease (dutchess county, new york). we used a model comparison approach to simultaneously test the importance of ambient growing-season te ...200616669698
infectivity of the highly transformable bbe02- lp56- mutant of borrelia burgdorferi, the lyme disease spirochete, via ticks.infectious borrelia burgdorferi strains that have increased transformability with the shuttle vector pbsv2 were recently constructed by inactivating the gene encoding bbe02, a putative restriction-modification gene product expressed by the linear plasmid lp25 (kawabata et al., infect. immun. 72:7147-7154, 2004). the absence of the linear plasmid lp56, which carries another putative restriction-modification gene, further enhanced transformation rates. the infectivity of these mutants was assessed ...200616714602
an analysis of spirochete load, strain, and pathology in a model of tick-transmitted lyme borreliosis.four laboratory-grown, low-passage isolates of borrelia burgdorferi sensu stricto, b31, jd-1, 910255, and n40, were incorporated into ixodes scapularis ticks to examine the pathogenesis of these isolates in mice after tick transmission. all isolates induced multifocal, lymphoid nodular cystitis, subacute, multifocal, necrotizing myocarditis, and a localized periostitis and arthritis of the femorotibial joint 6-18 weeks after tick infestation. in terms of the number of mice that demonstrated path ...200112653134
borrelia burgdorferi in ixodes scapularis ticks, chicago area. 200616752480
genetic diversity of borrelia burgdorferi sensu stricto in peromyscus leucopus, the primary reservoir of lyme disease in a region of endemicity in southern maryland.in the north central and northeastern united states, borrelia burgdorferi sensu stricto, the etiologic agent of lyme disease (ld), is maintained in an enzootic cycle between the vector, ixodes scapularis, and the primary reservoir host, peromyscus leucopus. genetic diversity of the pathogen based on sequencing of two plasmid-located genes, those for outer surface protein a (ospa) and outer surface protein c (ospc), has been examined in both tick and human specimens at local, regional, and worldw ...200616885284
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.200415271949
effects of acorn production and mouse abundance on abundance and borrelia burgdorferi infection prevalence of nymphal ixodes scapularis ticks.risk of exposure to lyme disease is a function of the local abundance of nymphal ixodes ticks that are infected with the etiological agent, the spirochete borrelia burgdorferi. we monitored abundance of white-footed mice (the principal b. burgdorferi reservoir in the eastern and central united states) and acorns (a critical food resource for mice), and ixodes scapularis ticks, as well as ambient temperature (cumulative growing degree days) and growing season precipitation, in a forested landscap ...200112653136
vector seasonality, host infection dynamics and fitness of pathogens transmitted by the tick ixodes scapularis.fitness of tick-borne pathogens may be determined by the degree to which their infection dynamics in vertebrate hosts permits transmission cycles if infective and uninfected tick stages are active at different times of the year. to investigate this hypothesis we developed a simulation model that integrates the transmission pattern imposed by seasonally asynchronous nymphal and larval ixodes scapularis ticks in northeastern north america, with a model of infection in white-footed mice (peromyscus ...200717032476
disruption of the salivary protein 14 in ixodes scapularis nymphs and impact on pathogen acquisition.we previously examined the physiological role of the anticoagulant salivary protein 14 (salp14) in adult ixodes scapularis and showed that salp14 played a role in tick feeding and engorgement. we now analyze whether the disruption of the salp14 family expression by rna interference affects tick weight in naïve nymph i. scapularis. salp14 expression after dsrna injection was significantly reduced, as shown by mrna and protein analysis. however, nymph engorgement weight was not altered in salp9pac ...200617038693
migratory songbirds disperse ticks across canada, and first isolation of the lyme disease spirochete, borrelia burgdorferi, from the avian tick, ixodes auritulus.during a 3-yr comprehensive study, 196 ixodid ticks (9 species) were collected from 89 passerine birds (32 species) from 25 localities across canada to determine the distribution of avian-associated tick species and endogenous lyme disease spirochetes, borrelia burgdorferi johnson, schmid, hyde, steigerwalt, and brenner. we report the following first records of tick parasitism on avian hosts: the rabbit-associated tick, ixodes dentatus marx, from manitoba and ontario; the mouse tick, ixodes muri ...200517089744
ospa immunization decreases transmission of borrelia burgdorferi spirochetes from infected peromyscus leucopus mice to larval ixodes scapularis ticks.recombinant outer surface protein a (ospa) vaccination of wild animal reservoirs has potential application for reducing borrelia burgdorferi transmission in nature and subsequent risk of human infection. as a major reservoir host, the white-footed mouse (peromyscus leucopus) is a candidate for a vaccination program designed to reduce infection prevalence in vector ticks. in this study we characterized the effect of various levels of immunization with recombinant ospa-glutathione transferase fusi ...200112653137
mammal diversity and infection prevalence in the maintenance of enzootic borrelia burgdorferi along the western coastal plains of maryland.the primary vector of borrelia burgdorferi in north america, ixodes scapularis, feeds on various mammalian, avian, and reptilian hosts. several small mammal hosts; peromyscus leucopus, tamias striatus, microtus pennsylvanicus, and blarina spp. can serve as reservoirs in an enzootic cycle of lyme disease. the primary reservoir in the northeast united states is the white-footed mouse, p. leucopus. the infection prevalence of this reservoir as well as the roles of potential secondary reservoirs has ...200617187577
assessing peridomestic entomological factors as predictors for lyme disease.the roles of entomologic risk factors, including density of nymphal blacklegged ticks (ixodes scapularis), prevalence of nymphal infection with the etiologic agent (borrelia burgdorferi), and density of infected nymphs, in determining the risk of human lyme disease were assessed at residences in the endemic community of south kingstown, ri. nymphs were sampled between may and july from the wooded edge around 51 and 47 residential properties in 2002 and 2003, respectively. nymphs were collected f ...200617249354
outer surface protein b is critical for borrelia burgdorferi adherence and survival within ixodes ticks.survival of borrelia burgdorferi in ticks and mammals is facilitated, at least in part, by the selective expression of lipoproteins. outer surface protein (osp) a participates in spirochete adherence to the tick gut. as ospb is expressed on a bicistronic operon with ospa, we have now investigated the role of ospb by generating an ospb-deficient b. burgdorferi and examining its phenotype throughout the spirochete life cycle. similar to wild-type isolates, the ospb-deficient b. burgdorferi were ab ...200717352535
immunity against ixodes scapularis salivary proteins expressed within 24 hours of attachment thwarts tick feeding and impairs borrelia transmission.in north america, the black-legged tick, ixodes scapularis, an obligate haematophagus arthropod, is a vector of several human pathogens including borrelia burgdorferi, the lyme disease agent. in this report, we show that the tick salivary gland transcriptome and proteome is dynamic and changes during the process of engorgement. we demonstrate, using a guinea pig model of i. scapularis feeding and b. burgdorferi transmission, that immunity directed against salivary proteins expressed in the first ...200717505544
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.200314680126
biochemical and functional characterization of salp20, an ixodes scapularis tick salivary protein that inhibits the complement pathway.ixodes ticks are vectors of several pathogens including borrelia burgdorferi. tick saliva contains numerous molecules that facilitate blood feeding without host immune recognition and rejection. we have expressed, purified, and characterized ixodes scapularis salivary protein 20 (salp20), a potential inhibitor of the alternative complement pathway that shares homology with the isac protein family. when analysed by sds-page and size exclusion chromatography, salp20 was approximately 48 kda, more ...200717651236
the lyme disease agent exploits a tick protein to infect the mammalian host.the lyme disease agent, borrelia burgdorferi, is maintained in a tick-mouse cycle. here we show that b. burgdorferi usurps a tick salivary protein, salp15 (ref. 3), to facilitate the infection of mice. the level of salp15 expression was selectively enhanced by the presence of b. burgdorferi in ixodes scapularis, first indicating that spirochaetes might use salp15 during transmission. salp15 was then shown to adhere to the spirochaete, both in vitro and in vivo, and specifically interacted with b ...200516049492
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 ...200415608069
histopathological studies of experimental lyme disease in the dog.experimental borrelia infection was induced in 62 specific--pathogen-free beagle dogs by exposure to ixodes scapularis ticks harbouring the spirochaete borrelia burgdorferi. clinical signs of lyme disease occurred in 39/62 dogs, the remaining 23 being subclinically infected. clinical signs consisted of one to six episodes of transitory lameness with joint swelling and pain, most commonly affecting the elbow or shoulder joints. the polymerase chain reaction and culture demonstrated that the dogs ...200515904927
identification of salp15 homologues in ixodes ricinus ticks.the 15-kda ixodes scapularis salivary gland protein salp15 protects borrelia burgdorferi sensu stricto from antibody-mediated killing and facilitates infection of the mammalian host. in addition, salp 15 has been shown to inhibit t-cell activation. we determined whether ixodes ricinus, the major vector for lyme borreliosis in western europe, also express salp15-related genes. we show that engorged i. ricinus express salp15 and we have identified three salp15 homologues within these ticks by reve ...200717896872
the prevalence of borrelia burgdorfieri (spirochaetales: spirochaetaceae) and the agent of human granulocytic ehrlichiosis (rickettsiaceae: ehrlichieae) in ixodes scapularis (acari:ixodidae) collected during 1998 and 1999 from minnesota.we tested 103 adult ixodes scapularis say from 12 counties in minnesota for the presence of borrelia burgdorferi and the causative agent of human granulocytic ehrlichiosis (hge), using polymerase chain reaction (pcr). a total of 17 ticks (16.5%) was positive for b. burgdoiferi using nested pcr for the flagellin gene. or both pcr for the ospa gene and nested pcr for the flagellin gene. a total of four ticks (3.8%) was positive for the agent of hge using nested pcr for 16s rdna. counties in minnes ...200211931260
role of migratory birds in introduction and range expansion of ixodes scapularis ticks and of borrelia burgdorferi and anaplasma phagocytophilum in canada.during the spring in 2005 and 2006, 39,095 northward-migrating land birds were captured at 12 bird observatories in eastern canada to investigate the role of migratory birds in northward range expansion of lyme borreliosis, human granulocytic anaplasmosis, and their tick vector, ixodes scapularis. the prevalence of birds carrying i. scapularis ticks (mostly nymphs) was 0.35% (95% confidence interval [ci] = 0.30 to 0.42), but a nested study by experienced observers suggested a more realistic infe ...200818245258
co-circulating microorganisms in questing ixodes scapularis nymphs in maryland.ixodes scapularis can be infected with borrelia burgdorferi, anaplasma phagocytophilum, bartonella spp., babesia microti, and rickettsia spp., including spotted-fever group rickettsia. as all of these microorganisms have been reported in maryland, the potential for these ticks to have concurrent infections exists in this region. to assess the frequency of these complex infections, 348 i. scapularis nymphs collected in 2003 were screened for these microorganisms by pcr with positives being confir ...200718260514
examination of the borrelia burgdorferi transcriptome in ixodes scapularis during feeding.borrelia burgdorferi gene expression within the guts of engorging ixodes scapularis ticks was examined by use of differential immunoscreening and differential expression with a customized amplified library. fourteen chromosomal genes involved in energy metabolism, substrate transport, and signal transduction and 10 (4 chromosomal and 6 plasmid) genes encoding putative lipoproteins and periplasmic proteins were preferentially expressed in engorging ticks. these data demonstrate a new approach to ...200212003955
evaluation of venezuelan equine encephalitis (vee) replicon-based outer surface protein a (ospa) vaccines in a tick challenge mouse model of lyme disease.venezuelan equine encephalitis (vee) virus replicon particles (vrps) encoding borrelia burgdorferi outer surface protein a (ospa) were evaluated for their ability to induce an immune response and provide protection from tick-borne spirochetes. vrps expressing ospa that accumulated intracellularly (vrp ospa) or that was secreted from host cells (vrp tpa-ospa) were tested. both vrp ospa and vrp tpa-ospa expressed ospa in immunized mice. mice vaccinated with vrps expressing secreted ospa produced s ...200312922122
infection and co-infection rates of anaplasma phagocytophilum variants, babesia spp., borrelia burgdorferi, and the rickettsial endosymbiont in ixodes scapularis (acari: ixodidae) from sites in indiana, maine, pennsylvania, and wisconsin.in total, 394 questing adult blacklegged ticks, ixodes scapularis say (acari: ixodidae), collected at four sites were analyzed by polymerase chain reaction (pcr) for five microbial species: anaplasma phagocytophilum, babesia microti, babesia odocoilei, borrelia burgdorferi, and the rickettsial i. scapularis endosymbiont. identities of genetic variants of a. phagocytophilum were determined by sequencing a portion of the 16s dna. in 55% of infected ticks (193/351), a single agent was detected. in ...200818402145
the tick salivary protein salp15 inhibits the killing of serum-sensitive borrelia burgdorferi sensu lato isolates.borrelia burgdorferi, the agent of lyme disease, is transmitted by ticks. during transmission from the tick to the host, spirochetes are delivered with tick saliva, which contains the salivary protein salp15. salp15 has been shown to protect spirochetes against b. burgdorferi-specific antibodies. we now show that salp15 from both ixodes ricinus and ixodes scapularis protects serum-sensitive isolates of borrelia burgdorferi sensu lato against complement-mediated killing. i. ricinus salp15 showed ...200818426890
differential infectivity of the lyme disease spirochete borrelia burgdorferi derived from ixodes scapularis salivary glands and midgut.blood fed nymphal ixodes scapularis say infected with borrelia burgdorferi were dissected to obtain salivary gland and midgut extracts. extracts were inoculated into c3h/hej mice, and ear, heart, and bladder were cultured to determine comparative infectivity. aliquots of extracts were then analyzed by quantitative polymerase chain reaction to determine the number of spirochetes inoculated into mice. a comparative median infectious dose (id50) was determined for both salivary gland and midgut ext ...200515962807
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 ...200414977984
borrelia burgdorferi sensu stricto is clonal in patients with early lyme borreliosis.lyme borreliosis, the most commonly reported vector-borne disease in north america, is caused by the spirochete borrelia burgdorferi. given the extensive genetic polymorphism of b. burgdorferi, elucidation of the population genetic structure of the bacterium in clinical samples may be relevant for understanding disease pathogenesis and may have applicability for the development of diagnostic tests and vaccine preparations. in this investigation, the genetic polymorphism of the 16s-23s rrna (rrs- ...200818539816
comparison of the spirochete borrelia burgdorferi s. l. isolated from the tick ixodes scapularis in southeastern and northeastern united states.thirty-five strains of the lyme disease spirochete borrelia burgdorferi sensu lato (b. burgdorferi s. l.) were isolated from the blacklegged tick vector ixodes scapularis in south carolina, georgia, florida, and rhode island. they were characterized by pcr-restriction fragment length polymorphism (rflp) analysis of rrf (5s)-rrl (23s) intergenic spacer amplicons. pcr-rflp analysis indicated that the strains represented at least 3 genospecies (including a possible novel genospecies) and 4 differen ...200818576863
projected effects of climate change on tick phenology and fitness of pathogens transmitted by the north american tick ixodes scapularis.ixodes scapularis is the principal tick vector of the lyme borreliosis agent borrelia burgdorferi and other tick-borne zoonoses in northeastern north america. the degree of seasonal synchrony of nymphal and larval ticks may be important in influencing the basic reproductive number of the pathogens transmitted by i. scapularis. because the seasonal phenology of tick vectors is partly controlled by ambient temperature, climate and climate change could shape the population biology of tick-borne pat ...200818634803
forest fragmentation predicts local scale heterogeneity of lyme disease risk.fragmentation of the landscape has been proposed to play an important role in defining local scale heterogeneity in lyme disease risk through influence on mammalian host density and species composition. we tested this observed relationship in a suburban region around lyme, connecticut, where we collected data on the density of the tick vector, ixodes scapularis and prevalence of the lyme bacterium, borrelia burgdorferi at 30 sites. analysis of the landscape pattern of forest patches was performe ...200516187106
transmission dynamics of borrelia burgdorferi s.s. during the key third day of feeding by nymphal ixodes scapularis (acari: ixodidae).nymphal ixodes scapularis say are the principal vectors of lyme disease spirochetes (borrelia burgdorferi sensu stricto) in the eastern united states. physicians frequently face the decision of whether or not to administer prophylactic antibiotics to human tick bite victims in lyme disease endemic regions, based on the overall probability that such bites will result in infection with b. burgdorferi s.s. we evaluated the transmission dynamics of b. burgdorferi s.s. during the key third day of nym ...200818714875
lyme disease agent borrows a practical coat. 200516079876
spatial dynamics of lyme disease: a review.lyme disease (ld), the most frequently reported vector-borne disease in the united states, requires that humans, infected vector ticks, and infected hosts all occur in close spatial proximity. understanding the spatial dynamics of ld requires an understanding of the spatial determinants of each of these organisms. we review the literature on spatial patterns and environmental correlates of human cases of ld and the vector ticks, ixodes scapularis in the northeastern and midwestern united states ...200818787920
production of outer surface protein a by borrelia burgdorferi during transmission from infected mammals to feeding ticks is insufficient to trigger ospa seroconversion.the lyme disease spirochete, borrelia burgdorferi, produces two outer surface lipoproteins, ospa and ospb, that are essential for colonization of tick vectors. both proteins are highly expressed during transmission from infected mammals to feeding ticks and during colonization of tick midguts, but are repressed when bacteria are transmitted from ticks to mammals. humans and other infected mammals generally do not produce antibodies against either protein, although some lyme disease patients do s ...200818793197
surveillance for lyme disease--united states, 1992-2006.lyme disease is a multisystem disease that occurs in north america, europe, and asia. in the united states, the etiologic agent is borrelia burgdorferi sensu stricto, a spirochete transmitted to humans by infected ixodes scapularis and i. pacificus ticks. the majority of patients with lyme disease develop a characteristic rash, erythema migrans (em), accompanied by symptoms of fever, malaise, fatigue, headache, myalgia, or arthralgia. other manifestations of infection can include arthritis, card ...200818830214
bacterin that induces anti-ospa and anti-ospc borreliacidal antibodies provides a high level of protection against canine lyme disease.groups of 15 laboratory-bred beagles were vaccinated and boosted with either a placebo or adjuvanted bivalent bacterin comprised of a traditional borrelia burgdorferi strain and a unique ospa- and ospb-negative b. burgdorferi strain that expressed high levels of ospc and then challenged with b. burgdorferi-infected ixodes scapularis ticks. the vaccinated dogs produced high titers of anti-ospa and anti-ospc borreliacidal antibodies, including borreliacidal antibodies specific for an epitope withi ...200919052162
use of tick surveys and serosurveys to evaluate pet dogs as a sentinel species for emerging lyme disease.to evaluate dogs as a sentinel species for emergence of lyme disease in a region undergoing invasion by ixodes scapularis.200919119948
positive selection in tick saliva proteins of the salp15 family.when taking their blood meal on the mammalian host, ticks transfer a multitude of different proteins from their saliva into the host. some of these proteins are hijacked by pathogens for their own purposes. borrelia burgdorferi, the lyme disease agent, is critically dependent on the presence of the tick protein salp15 when infecting the host. similarly, anaplasma phagocytophilum, which causes anaplasmosis, needs salp16, a homologue of salp15, to get transferred from the host into the tick. here ...200919159966
dermatologic changes induced by repeated ixodes scapularis bites and implications for prevention of tick-borne infection.previous studies in rodents and people have demonstrated that repeated tick exposure is associated with reduced borrelia burgdorferi transmission but the mechanism of prevention remains unclear. we examined the acute histopathologic reactions to initial and repeated ixodes scapularis bites in balb/c mice and in people. skin biopsies of balb/c mice infested for the first time by i. scapularis nymphs revealed vascular dilatation and an accumulation of inflammatory cells adjacent to the bite site b ...200919196014
detection of borrelia burgdorferi and borrelia lonestari in birds in tennessee.lyme disease in the united states is caused by the bacterial spirochete borrelia burgdorferi s.s. (johnson, schmid, hyde, steigerwalt, and brenner), which is transmitted by tick vectors ixodes scapularis (say) and i. pacificus (cooley and kohls). borrelia lonestari, transmitted by the tick amblyomma americanum l., may be associated with a related syndrome, southern tick-associated rash illness (stari). borrelia lonestari sequences, reported primarily in the southeastern states, have also been de ...200919198527
kinetics of borrelia burgdorferi infection in larvae of refractory and competent tick vectors.the acquisition of borrelia burgdorferi by the larvae of competent and refractory ixodid ticks was assessed by quantitative polymerase chain reaction (pcr). larvae were fed on infected mice, and the spirochete loads were determined during feeding and up to 93 d postfeeding. amblyomma americanum (l.) was refractory to b. burgdorferi infection, with almost no detection of spirochete dna during or postfeeding. in contrast, ixodes scapularis say supported high loads of spirochetes (10(3)-10(4) per l ...200616506448
a modest model explains the distribution and abundance of borrelia burgdorferi strains.the distribution and abundance of borrelia burgdorferi, including human lyme disease strains, is a function of its interactions with vertebrate species. we present a mathematical model describing important ecologic interactions affecting the distribution and abundance of b. burgdorferi strains, marked by the allele at the outer surface protein c locus, in ixodes scapularis ticks, the principal vector. the frequency of each strain in ticks can be explained by the vertebrate species composition, t ...200616606995
the use of harvested white-tailed deer (odocoileus virginianus) and geographic information system (gis) methods to characterize distribution and locate spatial clusters of borrelia burgdorferi and its vector ixodes scapularis in indiana.ixodes scapularis (say) is the vector for borrelia burgdorferi (bb) the causative agent of lyme disease (ld). the increased number and presence of ticks in the environment pose a significant health risk to people and many domestic animals including dogs, cats, and horses. this study characterized the distribution and expansion of i. scapularis and bb and identified areas of increased risk of ld transmission in indiana using geographical information systems (gis) and spatial analysis. a cross-sec ...200919272000
role of borrelia burgdorferi linear plasmid 25 in infection of ixodes scapularis ticks.the tick-borne bacterium borrelia burgdorferi has over 20 different circular and linear plasmids. some b. burgdorferi plasmids are readily lost during in vitro culture or genetic manipulation. linear plasmid 25, which is often lost in laboratory strains, is required for the infection of mice. strains missing linear plasmid 25 (lp25(-)) are able to infect mice if the bbe22 gene on lp25 is provided on a shuttle vector. in this study, we examined the role of lp25 and bbe22 in tick infections. we te ...200516077125
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