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lack of susceptibility of guinea pigs and gerbils to experimental infection with ehrlichia chaffeensis.guinea pigs and mongolian gerbils were experimentally infected with ehrlichia chaffeensis (st. vincent strain, 10 passages in vitro). the infection was monitored by serial blood sampling for pcr and by xenodiagnosis with amblyomma americanum larvae. exposure to the pathogen was confirmed using serology. neither guinea pigs nor gerbils were susceptible to infection with e. chaffeensis, and ticks fed upon these animals did not become infected with the pathogen.200415682515
disease agents in amblyomma americanum from northeastern georgia.amblyomma americanum (lone star tick) is known or suspected to vector several organisms that are implicated as human pathogens, including ehrlichia chaffeensis, e. ewingii, and borrelia lonestari. these three agents have also been detected in white-tailed deer (odocoileus virginianus). because northeastern georgia has a high abundance of both lone star ticks and white-tailed deer, and one of these organisms, e. chaffeensis, is already known to be endemic in the area, we assayed individual adult ...200415311471
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
an in vitro larval immersion microassay for identifying and characterizing candidate acaricides.we have optimized a larval immersion microassay (lim) that offers superior sensitivity, flexibility to accommodate multiple formulations, and a robust capability for rapidly screening many compounds with a minimal requirement of test article for evaluation. dose-response studies were conducted for representative members from the organophosphate, pyrethroid, pyrazole, carbamate, macrocyclic lactone, and formamidine chemistries against amblyomma americanum (l.). time-response experiments revealed ...200415605642
detection of ehrlichia chaffeensis in adult and nymphal amblyomma americanum (acari: ixodidae) ticks from long island, new york.the lone star tick, amblyomma americanum (l.), has increased in abundance in several regions of the northeastern united states, including areas of long island, ny. adult and nymphal stage a. americanum collected from several sites on long island were evaluated for infection with ehrlichia chaffeensis, the causative agent of human monocytic ehrlichiosis (hme), by using a nested polymerase chain reaction assay. fifty-nine (12.5%) of 473 adults and eight of 113 pools of five nymphs each (estimated ...200415605650
susceptibility of mice (mus musculus) to repeated infestation with amblyomma americanum (acari: ixodidae) ticks.laboratory mice, mus musculus (l.), balb/c strain, were assessed for their ability to develop resistance to repeated infestation by amblyomma americanum (l.) ticks. mice were infested five consecutive times with a. americanum nymphs. no decrease in tick viability was seen after five infestations, suggesting that balb/c mice do not develop immune-mediated resistance to a. americanum. in contrast, tick viability was significantly reduced in the second infestation of a new zealand white rabbit, a l ...200415605656
evaluation of immunocompetent and immunocompromised mice (mus musculus) for infection with ehrlichia chaffeensis and transmission to amblyomma americanum ticks.experiments on the natural history of ehrlichia chaffeensis, the agent of human monocytic ehrlichiosis (hme), would be facilitated by the availability of a laboratory animal model for transmission to vector ticks. five strains of mice were evaluated for their susceptibility to infection with e. chaffeensis and transmission competence: c57bl/6 mice, inducible nitric oxide synthase (inos) deficient mice, mhc i deficient (beta2m /) mice, mhc ii deficient mice (abb /), and b and t cell deficient (ra ...200415671738
molecular differentiation of metastriate tick immatures.hard ticks, family ixodidae, are divided into two groups, the metastriata and the prostriata, based on morphological differences. in the united states, there are four medically important genera of the ixodidae: ixodes, amblyomma, dermacentor, and rhipicephalus. ixodes is the only genus in and representative of the prostriata, whereas the latter three genera are members of the metastriata. all developmental stages of the prostriata can be easily differentiated from the metastriata using morpholog ...200415682516
amblyomma americanum salivary glands: double-stranded rna-mediated gene silencing of synaptobrevin homologue and inhibition of pge2 stimulated protein secretion.protein secretion into the saliva from the tick salivary glands is due to exocytosis of vesicular membrane bound granular material regulated by snare complex proteins after salivary gland stimulation by pge2 [insect biochem. mol. biol. 32 (2002) 1711]. proteins associated with vesicles (v-snares) are essential components of the exocytotic process. synaptobrevin is a key v-snare in all secreting cells studied to date. a vesicle-associated synaptobrevin cdna fragment homologue from the salivary gl ...200415041024
ehrlichia chaffeensis: a prevalent, life-threatening, emerging pathogen.ehrlichia chaffeensis are small, obligately intracellular, endosomal bacteria with tropism for macrophages. persistent infection in reservoir white-tailed deer is transmitted by lone star ticks. flu-like illness can progress to severe multisystem disease with toxic shock-like syndrome, meningitis, or ards. the case-fatality rate is 2.7%. leukopenia and thrombocytopenia are diagnostically useful. granulomas are associated with control of the infection. ehrlichial proteins and glycoproteins have b ...200417060980
rnai-mediated gene silencing to assess the role of synaptobrevin and cystatin in tick blood feeding.in addition to being the conduit for pathogens into hosts, tick saliva contains a broad array of secretory products that facilitate prolonged tick attachment and blood feeding. proteins found in tick saliva modulate host hemostasis and immune responses. however, it is not clear whether ticks manipulate the immune responses of their hosts by disrupting the antigen-processing pathways of the hosts. protein secretion into tick saliva from the salivary glands is due to exocytosis of vesicular membra ...200516040003
factors influencing in vitro infectivity and growth of rickettsia peacockii (rickettsiales: rickettsiaceae), an endosymbiont of the rocky mountain wood tick, dermacentor andersoni (acari, ixodidae).rickettsia peacockii, a spotted fever group rickettsia, is a transovarially transmitted endosymbiont of rocky mountain wood ticks, dermacentor andersoni. this rickettsia, formerly known as the east side agent and restricted to female ticks, was detected in a chronically infected embryonic cell line, dae100, from d. andersoni. we examined infectivity, ability to induce cytopathic effect (cpe) and host cell specificity of r. peacockii using cultured arthropod and mammalian cells. aposymbiotic dae1 ...200516288906
capillary tube feeding system for studying tick-pathogen interactions of dermacentor variabilis (acari: ixodidae) and anaplasma marginale (rickettsiales: anaplasmataceae).a capillary tube feeding (ctf) system was adapted for studying the interaction between dermacentor variabilis (say) and the rickettsial cattle pathogen anaplasma marginale theiler. a. marginale undergoes a complex developmental cycle in ticks that begins in midguts and ends by transmission from salivary glands. in this ctf system, male d. variabilis were fed a. marginale-infected blood or cultured tick cells. ticks that fed on highly rickettsemic calves developed midgut and salivary gland infect ...200516366000
influence of meso- and microscale habitat structure on focal distribution of sympatric ixodes scapularis and amblyomma americanum (acari: ixodidae).we compared the distribution of sympatric ixodes scapularis say and amblyomma americanum (l.) within several suitable forested habitats at different spatial scales and characterized differences in microhabitat features accounting for the observed distribution of questing ticks. we used automatic data loggers placed in the shrub and litter layers to contrast mesoclimate and microclimate conditions experienced by questing ticks. larger numbers of i. scapularis were collected at sites where the for ...200515962776
distribution of borreliae among ticks collected from eastern states.lyme disease is the most commonly reported vector-borne disease in the united states and is transmitted by borrelia burgdorferi-infected ixodes species. the disease is typically characterized by an erythema migrans (em) rash at the site of tick feeding. em rashes have also been associated with feeding by amblyomma americanum ticks despite evidence suggesting that they are incompetent vectors for lyme disease. in 1996, a borrelia organism only recently cultivated in the laboratory was described i ...200516417434
the fc fragment mediates the uptake of immunoglobulin c from the midgut to hemolymph in the ixodid tick amblyomma americanum (acari: ixodidae).the phenomenon of immunoglobulin uptake from the midgut into the hemolymph has been observed in both argasid and ixodid ticks, but the mechanism of the uptake is not known. using capillary feeding of adult amblyomma americanum (l.) female ticks, we investigated the role of immunoglobulin g fc and fab fragments in the uptake process. intact igg and fragments labeled with 125i were introduced alone or as a mixture with a 10-fold molar excess of unlabeled compounds into ticks, and then the concentr ...200515962788
theileriosis in a white-tailed deer (odocoileus virginianus) fawn.a white-tailed deer (odocoileus virginianus) fawn was collected in missouri (usa) and submitted for diagnostic evaluation. necropsy and histologic examination revealed severe amblyomma americanum infestation, pronounced icterus, and marked hemosiderin deposition in the liver and spleen. whole blood evaluation revealed a normocytic normochromic anemia and a piroplasm parasitemia of approximately 70%. the piroplasm was identified as theileria cervi by polymerase chain reaction and sequencing of th ...200516456174
novel spotted fever group rickettsiae (sfgr) infecting amblyomma americanum ticks in ohio, usa. 200516481541
overcoming barriers to the transformation of the genus ehrlichia.while bacterial transformation has evolved since the early 20th century to allow for the genetic manipulation of a variety of microbial agents, rickettsial organisms have proved resistant to such advances until only recently. the ehrlichia are small, gram-negative, obligately intracellular bacterial parasites, which belong to the family anaplasmataceae and cause a variety of infections in human and animal hosts. e. chaffeensis is the causative agent of human monocytotropic ehrlichiosis and is tr ...200516481548
tick infestations of the eastern cottontail rabbit (sylvilagus floridanus) and small rodentia in northwest alabama and implications for disease transmission.studies were conducted over a four-county area of northwest alabama to determine the association of eastern cottontail rabbits with dermacentor variabilis, the eastern united states vector of rocky mountain spotted fever. a secondary objective was to compare infestations of this tick on rabbits with infestations on commonly encountered rodent species as a means of determining the relative importance of each in the disease transmission cycle. these epidemiologic surveys were conducted in response ...200516599149
francisella tularensis in the united states.the causative agent of tularemia, francisella tularensis, is a formidable biologic agent that occurs naturally throughout north america. we examined genetic and spatial diversity patterns among 161 us f. tularensis isolates by using a 24-marker multiple-locus variable-number tandem repeat analysis (mlva) system. mlva identified 126 unique genotypes. phylogenetic analyses showed patterns similar to recently reported global-scale analyses. we observed clustering by subspecies, low genetic diversit ...200516485467
genetic variants of anaplasma phagocytophilum infecting dogs in western washington state.eight dogs from western washington state suspected of being infected with anaplasma phagocytophilum because of the finding of morulae in peripheral blood neutrophils were studied for determination of the etiologic agent of disease. all cases were diagnosed between april 2003 and april 2004. six of the eight dogs had no travel history during the 6 months prior to presentation. two dogs had traveled within the northwest united states and canada. fever, lethargy, and anorexia were the most common c ...200515695682
the molecular and biological analysis of ixodid ticks histamine release factors.we previously described a dermacentor varibialis (dv) cdna that encodes a ubiquitously expressed and tick saliva-secreted functional histamine release factor (hrf) homolog. in this study gene specific primers based on dvhrf open reading frame nucleotide sequence were utilized to amplify three orthologs, from the wood tick, d. andersoni (da), the black legged tick, the southern cattle tick, boophilus microplus (bm) and the lone star tick, amblyomma americanum (aa). at nucleotide level, sequence c ...200516323052
bartonella henselae in porpoise blood.we report detection of bartonella henselae dna in blood samples from 2 harbor porpoises (phocoena phocoena). by using real-time polymerase chain reaction, we directly amplified bartonella species dna from blood of a harbor porpoise stranded along the northern north carolina coast and from a pre-enrichment blood culture from a second harbor porpoise. the second porpoise was captured out of habitat (in a low-salinity canal along the northern north carolina coast) and relocated back into the ocean. ...200516485476
identification of a new borrelia species among small mammals in areas of northern spain where lyme disease is endemic.the role of small mammals as reservoir hosts for borrelia burgdorferi was investigated in several areas where lyme disease is endemic in northern spain. a low rate of infestation by ixodes ricinus nymphs was found in the small mammal populations studied that correlated with the near-absence of b. burgdorferi sensu lato in 184 animals tested and with the lack of transmission of b. burgdorferi sensu lato to i. ricinus larvae that fed on them. in contrast, questing ticks collected at the same time ...200515746336
possible tick-borne human enterovirus resulting in aseptic meningitis.enterovirus-specific genetic sequences were isolated from two amblyomma americanum tick pools. identical genetic sequences were later obtained from cerebrospinal fluid of a patient with aseptic meningitis and a recent history of tick attachment. these observations suggest the possibility of an emerging tick-borne human enterovirus associated with aseptic meningitis.200516000481
rapid detection methods and prevalence estimation for borrelia lonestari glpq in amblyomma americanum (acari: ixodidae) pools of unequal size.dna was extracted from pools of amblyomma americanum ticks collected from vegetation at two sites in fort leonard wood, missouri and tested for the presence of borrelia spp. two new methods were developed to detect borrelia lonestari dna by targeting the glycerophosphodiester phosphodiesterase (glpq) gene. the first method detected b. lonestari dna using a sybr green i melting curve analysis of the pcr product obtained with glpq gene primers. the second method, a glpq taqman assay, detected and ...200516011431
detection of ehrlichia spp. in raccoons (procyon lotor) from georgia.raccoons (procyonis lotor) and opossums (didelphis virginianus) acquired from six contiguous counties in the piedmont physiographic region of georgia were investigated for their potential role in the epidemiology of ehrlichial and anaplasmal species. serum was tested by indirect fluorescent antibody (ifa) assay for the presence of antibodies reactive to ehrlichia chaffeensis, e. canis, and anaplasma phagocytophilum (hga agent). nested polymerase chain reaction (pcr) assay was used to test whole ...200516011433
epidemiology and transmission dynamics of west nile virus disease.from 1937 until 1999, west nile virus (wnv) garnered scant medical attention as the cause of febrile illness and sporadic encephalitis in parts of africa, asia, and europe. after the surprising detection of wnv in new york city in 1999, the virus has spread dramatically westward across the united states, southward into central america and the caribbean, and northward into canada, resulting in the largest epidemics of neuroinvasive wnv disease ever reported. from 1999 to 2004, >7,000 neuroinvasiv ...200516102302
ehrlichial infection in cameroonian canines by ehrlichia canis and ehrlichia ewingii.ehrlichia chaffeensis and ehrlichia ewingii are agents of emerging human ehrlichioses in north america and are transmitted primarily by amblyomma americanum ticks, while ehrlichia canis is the globally distributed cause of canine monocytic ehrlichiosis (cme) and is transmitted by the brown dog tick, rhipicephalus sanguineus. although e. canis and ehrlichia ruminantium are endemic in africa, the presence of ehrlichial agents in dogs and ticks in cameroon has not been investigated. the objective o ...200516181750
comparison of in vitro and in vivo ectoparasiticide activity of experimental benzimidazole-carbamate with permethrin and amitraz.a series of in vitro and in vivo bioassays were conducted to assess the ectoparasiticide activity of isopropyl-4-nitro-2,6-bis(trifluoromethyl)-1-benzimidazole-carbamate, an experimental benzimidazole-carbamate class compound. this compound was less potent than permethrin against ectoparasiticide-susceptible larvae of the lone star tick, amblyomma americanum (l.) (acari: ixodidae); larvae of the southern cattle tick, boophilus microplus (canestrini); and adult stable fly, stomoxys calcitrans (l. ...200515799532
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
relative encounter frequencies and prevalence of selected borrelia, ehrlichia, and anaplasma infections in amblyomma americanum and ixodes scapularis (acari: ixodidae) ticks from central new jersey.to evaluate their relative importance in tick-borne disease transmission in new jersey, host-seeking amblyomma americanum (l.) and ixodes scapularis say adults and nymphs were collected during spring activity periods in 2003 and 2004 to determine relative frequencies at which these ticks were encountered from an area known to be hyperendemic for lyme disease. although similar numbers of the two species were encountered during early spring of both years, a. americanum were encountered more often ...200515962799
sequence variation of the ribosomal dna second internal transcribed spacer region in two spatially-distinct populations of amblyomma americanum (l.) (acari: ixodidae).sequence analysis of the ribosomal dna second internal transcribed spacer (its 2) region in 2 spatially distinct populations of amblyomma americanum (l.) revealed intraspecific variation. nucleotide sequences from multiple dna extractions and several polymerase chain reaction amplifications of eggs from mixed-parentage samples from both populations of ticks revealed that 12 of 1,145 (1.0%) sites varied. three of the 12 sites of variation were distinct between the 2 a. americanum populations, whi ...200515986597
polymerase chain reaction detection of cytauxzoon felis from field-collected ticks and sequence analysis of the small subunit and internal transcribed spacer 1 region of the ribosomal rna gene.cytauxzoon felis produces a disease in domestic cats in the midwest (u.s.a.), which often leads to a fatal outcome. although the clinical disease process is well described, there are still many unanswered questions about this organism. for example, it is unknown whether species of ticks other than dermacentor variabilis can serve as vectors for transmission. with recent reports of surviving cats from limited geographic areas, another relevant question is the potential for genetically less virule ...200515986625
failure of ticks to transmit scopulariopsis brevicaulis (deuteromycota), a common filamentous fungal commensal of ticks.the capacity of ticks to transmit a fungus was examined by analyzing tick saliva, host tissue from feeding sites, and host blood for presence of scopulariopsis brevicaulis (sacc.) bainier, an internal mycosymbiont of the american dog tick, dermacentor variabilis (say), and lone star tick, amnblyomma americanum (l.). although >85% of ticks were infected with s. brevicaulis, conidia presence was low (0-5% of samples) in microscopic observations and mycological culturing of saliva expressed from la ...200515962791
tick-borne rickettsioses around the world: emerging diseases challenging old concepts.during most of the 20th century, the epidemiology of tick-borne rickettsioses could be summarized as the occurrence of a single pathogenic rickettsia on each continent. an element of this paradigm suggested that the many other characterized and noncharacterized rickettsiae isolated from ticks were not pathogenic to humans. in this context, it was considered that relatively few tick-borne rickettsiae caused human disease. this concept was modified extensively from 1984 through 2005 by the identif ...200516223955
transstadial and intrastadial experimental transmission of ehrlichia canis by male rhipicephalus sanguineus.the acquisition and transmission of rickettsial pathogens by different tick developmental stages has important epidemiological implications. the purpose of this study was to determine if male rhipicephalus sanguineus can experimentally acquire and transmit ehrlichia canis in the absence of female ticks. two trials were performed where nymphal and male r. sanguineus were simultaneously acquisition fed on the same infected donor hosts, and transstadially or intrastadially exposed male ticks were f ...200515941624
ehrlichia chaffeensis expresses macrophage- and tick cell-specific 28-kilodalton outer membrane proteins.ehrlichia chaffeensis, a tick-transmitted rickettsial agent, causes human monocyte/macrophage-tropic ehrlichiosis. in this study, proteomic approaches were used to demonstrate host cell-specific antigenic expression by e. chaffeensis. the differentially expressed antigens include those from the 28-kda outer membrane protein (p28-omp) multigene locus. the proteins expressed in infected macrophages are the products of p28-omp19 and p28-omp20 genes, whereas in tick cells, the protein expressed is t ...200515618143
microbiologic evaluation of patients from missouri with erythema migrans.borrelia lonestari infects amblyomma americanum, the tick species that is the most common cause of tick bites in southeast and south-central united states, and this spirochete has been detected in an erythema migrans (em)-like skin rash in 1 patient. therefore, b. lonestari is considered to be a leading candidate for the etiologic agent of em in this region.200515668867
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
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
ehrlichia under our noses and no one notices.ehrlichia chaffeensis, an obligately intracellular bacterium, resides within a cytoplasmic vacuole in macrophages, establishes persistent infection in natural hosts such as white-tailed deer and canids, and is transmitted transstadially and during feeding by ticks, particularly amblyomma americanum. ehrlichial cell walls contain glycoproteins and a family of divergent 28 kda proteins, but no peptidoglycan or lipopolysaccharide. the dense-cored ultrastructural form preferentially expresses certai ...200516358425
transcription analysis of the major antigenic protein 1 multigene family of three in vitro-cultured ehrlichia ruminantium isolates.ehrlichia ruminantium, an obligate intracellular bacterium transmitted by ticks of the genus amblyomma, causes heartwater disease in ruminants. the gene coding for the major antigenic protein map1 is part of a multigene family consisting of a cluster containing 16 paralogs. in the search for differentially regulated genes between e. ruminantium grown in endothelial and tick cell lines that could be used in vaccine development and to determine if differences in the map1 gene cluster exist between ...200515995193
detection and identification of ehrlichia spp. in ticks collected in tunisia and morocco.a broad-range 16s rrna gene pcr assay followed by partial sequencing of the 16s rrna gene was used for the detection of members of the family anaplasmataceae in ticks in north africa. a total of 418 questing ixodes ricinus ticks collected in tunisia and morocco, as well as 188 rhipicephalus ticks from dogs and 52 hyalomma ticks from bovines in tunisia, were included in this study. of 324 adult i. ricinus ticks, 16.3% were positive for ehrlichia spp., whereas only 3.4 and 2.8% of nymphs and larva ...200515750072
borreliacidal activity of saliva of the tick amblyomma americanum.amblyomma americanum (linneaus) (acari: ixodidae), an important tick vector of human and animal disease, is not a competent vector of the bacterial agent of lyme disease, borrelia burgdorferi, although its range overlaps the geographical distribution of lyme disease within the united states. a possible mechanism that could prevent acquisition of b. burgdorferi spirochetes from infected hosts is the toxic effect of a. americanum saliva on b. burgdorferi. the data presented here indicate that afte ...200515752182
repellency of deet and ss220 applied to skin involves olfactory sensing by two species of ticks.responses of host-seeking nymphs of the blacklegged tick, ixodes scapularis say and lone star tick, amblyomma americanum (linnaeus) (acari: ixodidae) to the repellents n,n-diethyl-3-methylbenzamide (deet) and (1s, 2's)-2-methylpiperidinyl-3-cyclohexene-1-carboxamide (ss220) were studied using fingertip laboratory bioassays. ethanol solutions of both compounds applied to the skin strongly repelled both species of ticks at 0.8 and 1.6 micromole of compound/cm2 skin. the ticks were also repelled wh ...200515752184
babesia microti, upstate new york.five cases of human babesiosis were reported in the lower hudson valley region of new york state in 2001. an investigation to determine if babesia microti was present in local ixodes scapularis ticks yielded 5 positive pools in 123 pools tested, the first detection of b. microti from field-collected i. scapularis in upstate new york.200515757571
ticks (acari: ixodoidea: argasidae, ixodidae) of chile.the tick species recorded from chile can be listed under the following headings: (1) endemic or established: argas keiransi estrada-peña, venzal and gonzalez-acuña, a. neghmei kohls and hoogstraal; ornithodoros amblus chamberlin; otobius megnini (dugès); amblyomma parvitarsum neumann; a. tigrinum koch; ixodes auritulus neumann; i. chilensis kohls; i. cornuae arthur, i. sigelos keirans, clifford and corwin; i. stilesi neumann; i. uriae white; rhipicephalus sanguineus koch. (2) probably establishe ...200515777007
anointing chemicals and ectoparasites: effects of benzoquinones from millipedes on the lone star tick, amblyomma americanum.many mammals and birds roll on or rub themselves with millipedes that discharge benzoquinones. chemicals transferred from millipedes onto the integument of anointing animals are thought to deter ectoparasites. we tested the lone star tick, amblyomma americanum (l.), for responses to three widespread components of millipede defensive secretions, 1,4-benzoquinone; 2-methyl-1,4-benzoquinone (toluquinone); and 2-methoxy-3-methyl-1,4-benzoquinone (mmb). in toxicity tests, ticks were confined for 1 hr ...200515839480
efficacy of imidacloprid (8.8% w/w) plus permethrin (44% w/w) spot-on topical solution against amblyomma americanum infesting dogs using a natural tick exposure model.this study evaluated the efficacy of an imidacloprid 8.8% w/w + permethrin 44% w/w spot-on topical solution (k9 advantix, bayer animal health) against amblyomma americanum using a natural field exposure model. sixteen beagles were divided into two groups of eight dogs each. one group of dogs was treated with k9 advantix and the other group served as untreated controls. on day -1 and at 3, 7, 14, 21 and 28 days after treatment, the dogs were walked for 80 minutes in an a. americanum-infested habi ...200616871491
isolation and identification of rickettsia massiliae from rhipicephalus sanguineus ticks collected in arizona.twenty rhipicephalus sanguineus ticks collected in eastern arizona were tested by pcr assay to establish their infection rate with spotted fever group rickettsiae. with a nested pcr assay which detects a fragment of the rickettsia genus-specific 17-kda antigen gene (htra), five ticks (25%) were found to contain rickettsial dna. one rickettsial isolate was obtained from these ticks by inoculating a suspension of a triturated tick into monolayers of vero e6 monkey kidney cells and xtc-2 clawed toa ...200616885311
the emerging diversity of rickettsia.the best-known members of the bacterial genus rickettsia are associates of blood-feeding arthropods that are pathogenic when transmitted to vertebrates. these species include the agents of acute human disease such as typhus and rocky mountain spotted fever. however, many other rickettsia have been uncovered in recent surveys of bacteria associated with arthropods and other invertebrates; the hosts of these bacteria have no relationship with vertebrates. it is therefore perhaps more appropriate t ...200616901827
serologic evaluation of patients from missouri with erythema migrans-like skin lesions with the c6 lyme test.southern tick-associated rash illness (stari), also known as masters disease, affects people predominantly in the southeast and south central united states. these patients exhibit skin lesions that resemble erythema migrans (em), the characteristic skin lesion in early lyme disease. the etiology of stari remains unknown, and no serologic test is available to aid in its diagnosis. the c6 lyme enzyme-linked immunosorbent assay was used to evaluate coded serum specimens from patients with stari at ...200617028220
evaluation of an imidacloprid (8.8% w/w)--permethrin (44.0% w/w) topical spot-on and a fipronil (9.8% w/w)--(s)-methoprene (8.8% w/w) topical spot-on to repel, prevent attachment, and kill adult ixodes scapularis and amblyomma americanum ticks on dogs.this study evaluated the effectiveness of two topical spot-on formulations -- imidacloprid(8.8% w/w)-permethrin (44.0% w/w) and fipronil (9.8% w/w)-(s)-methoprene (8.8% w/w)--to repel, prevent the attachment of, and kill adult ixodes scapularis and amblyomma americanum on dogs. twelve purpose-bred beagles were distributed into three groups of four dogs each; one group served as untreated controls, and each of the other two groups received one of the test products. dogs were exposed to 25 adult t ...200617039440
protective efficacy of an oral vaccine to reduce carriage of borrelia burgdorferi (strain n40) in mouse and tick reservoirs.lyme disease is caused by the spirochete borrelia burgdorferi, which is transmitted through the bite of infected ixodes ticks. vaccination of mice with outer surface protein a (ospa) of b. burgdorferi has been shown to both protect mice against b. burgdorferi infection and reduce carriage of the organism in feeding ticks. here we report the development of a murine-targeted ospa vaccine utilizing vaccinia virus to interrupt transmission of disease in the reservoir hosts, thus reducing incidence o ...200616300863
unique macrophage and tick cell-specific protein expression from the p28/p30-outer membrane protein multigene locus in ehrlichia chaffeensis and ehrlichia canis.ehrlichia chaffeensis and ehrlichia canis are tick-transmitted rickettsial pathogens that cause human and canine monocytic ehrlichiosis respectively. we tested the hypothesis that these pathogens express unique proteins in response to their growth in vertebrate and tick host cells and that this differential expression is similar in closely related ehrlichia species. evaluation of nine e. chaffeensis isolates and one e. canis isolate demonstrated that protein expression was host cell-dependent. t ...200616922866
confirmation of tick bite by detection of antibody to ixodes calreticulin salivary protein.ticks introduce a variety of pharmacologically active molecules into their host during attachment and feeding in order to obtain a blood meal. people who are repeatedly exposed to ticks may develop an immune response to tick salivary proteins. despite this response, people usually are unaware of having been bitten, especially if they are not repeatedly exposed to ticks. in order to develop a laboratory marker of tick exposure that would be useful in understanding the epidemiology of tick-borne i ...200616928887
tick-borne rickettsial pathogens in ticks and small mammals in korea.in order to investigate the prevalence of tick-borne infectious agents among ticks, ticks comprising five species from two genera (hemaphysalis spp. and ixodes spp.) were screened using molecular techniques. ticks (3,135) were collected from small wild-caught mammals or by dragging/flagging in the republic of korea (rok) and were pooled into a total of 1,638 samples (1 to 27 ticks per pool). from the 1,638 tick samples, species-specific fragments of anaplasma phagocytophilum (1 sample), anaplasm ...200616957192
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
comparative genomics of emerging human ehrlichiosis agents.anaplasma (formerly ehrlichia) phagocytophilum, ehrlichia chaffeensis, and neorickettsia (formerly ehrlichia) sennetsu are intracellular vector-borne pathogens that cause human ehrlichiosis, an emerging infectious disease. we present the complete genome sequences of these organisms along with comparisons to other organisms in the rickettsiales order. ehrlichia spp. and anaplasma spp. display a unique large expansion of immunodominant outer membrane proteins facilitating antigenic variation. all ...200616482227
multiple pruritic papules from lone star tick larvae bites.ticks are the second most common vectors of human infectious diseases in the world. in addition to their role as vectors, ticks and their larvae can also produce primary skin manifestations. infestation by the larvae of ticks is not commonly recognized, with only 3 cases reported in the literature. the presence of multiple lesions and partially burrowed 6-legged tick larvae can present a diagnostic challenge for clinicians.200616618870
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
prevalence of ehrlichia, borrelia, and rickettsial agents in amblyomma americanum (acari: ixodidae) collected from nine states.ambyomma americanum (l.) (acari: ixodidae) is an aggressive tick that feeds on humans during all postembryonic life stages. in many regions of the united states, it is the tick most commonly found attached to humans. public health interest has grown recently, due to the recognition of new human pathogens transmitted by a. americanum and the expanding distribution of the tick. a. americanum is a vector of several bacteria pathogenic to humans. ehrlichia chaffeensis and ehrlichia ewingii cause mod ...200617162962
relative abundance and prevalence of selected borrelia infections in ixodes scapularis and amblyomma americanum (acari: ixodidae) from publicly owned lands in monmouth county, new jersey.to evaluate their potential importance in the transmission of ixodid tick-borne borrelioses in monmouth county, nj, we collected host-seeking ixodes scapularis say and amblyomma americanum (l.) (acari: ixodidae) adults and nymphs to determine relative encounter frequencies and the infection prevalence of selected borrelia spp. in their respective tick vectors. we also reviewed records of all ticks submitted for identification by the public in monmouth county during 2001-2005. relative abundance ...200617162963
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
infection of a goat with a tick-transmitted ehrlichia from georgia, u.s.a., that is closely related to ehrlichia ruminantium.we detected a novel tick-transmitted ehrlichia in a goat following exposure to lone star ticks (amblyomma americanum) from a park in the metropolitan area of atlanta, ga, u.s.a. nineteen days after infestation with field-collected adult ticks, the goat developed a fever of two days duration, which coincided with mild clinical pathologic changes and the presence of dna from a novel ehrlichia in peripheral blood. the goat transmitted ehrlichiae to uninfected nymphal a. americanum that fed upon the ...200617249337
white-tailed deer (odocoileus virginianus) develop spirochetemia following experimental infection with borrelia lonestari.borrelia lonestari is considered a putative agent of southern tick-associated rash illness (stari) and is known to occur naturally only in lone star ticks (amblyomma americanum) and white-tailed deer (odocoileus virginianus). we used a low passage isolate of b. lonestari (ls-1) to inoculate white-tailed deer, c3h mice, holstein cattle, and beagles. animals were monitored via examination of giemsa and acridine orange stained blood smears, polymerase chain reaction (pcr), indirect fluorescent anti ...200616459029
orally active acaricidal peptide toxins from spider venom.numerous species of ticks and mites (collectively known as acarines) are serious pests of animals, humans, and crops. there are few commercially available acaricides and major classes of these chemicals continue to be lost from the marketplace due to resistance development or deregistration by regulatory agencies. there is consequently a pressing need to isolate new and safe acaricidal compounds. in this study, we show that two families of peptide neurotoxins isolated from the venom of the austr ...200616330063
an in vivo rodent model for identifying and characterizing acaricides.evaluation of candidate acaricides in livestock or companion animals is expensive, time-consuming, and usually requires large quantities of test material. to identify promising substances at the earliest possible stage of the development process, robust and predictive surrogate animal models, capable of rapidly characterizing potency with minimal compound requirements, are necessary. the objective of this study was to generate an in vivo surrogate animal bioassay capable of rapidly and accuratel ...200616739411
a novel real-time pcr assay for the speciation of medically important ticks.the identification of ticks using morphological characters is a well-established practice, however specimens that are small or damaged are often difficult to speciate. a novel, rapid real-time pcr assay, which targets the second internal transcribed spacer (its2) region in the nuclear ribosomal dna gene, was developed for identification of four tick species of utmost medical importance in the united states: ixodes scapularis, i. pacificus, dermacentor variabilis, and amblyomma americanum. comput ...200616796512
relative abundance and survival of the tick amblyomma americanum collected from sunlit and shaded habitats.the population density of host-searching nymphal and adult lone star ticks, amblyomma americanum (l.) (acari: ixodidae), was determined at the robinson tract of the kansas ecological reserves and a private farm 5 km north-west of the robinson tract using standard drag cloth methods. nymphs, males and females were counted and collected weekly from shaded habitats and adjacent sunlit habitats from mid-may through late july, 2003. of the 1598 nymphs and 549 males collected by drag sampling, 74.0% a ...200616796613
inferring the population structure and demographic history of the tick, amblyomma americanum linnaeus.a hierarchial population genetic study was conducted on 703 individual amblyomma americanum from nine populations in georgia, u.s.a. populations were sampled from the coastal plain, midland piedmont region, and the upper piedmont region. twenty-nine distinct haplotypes were found. a minimum spanning tree was constructed that indicated these haplotypes comprised two lineages, the root of which was distinctly star-like. the majority of the variation found was among ticks within each population, in ...200616859107
lymph node hemophagocytosis in rickettsial diseases: a pathogenetic role for cd8 t lymphocytes in human monocytic ehrlichiosis (hme)?human monocytic ehrlichiosis (hme) and rocky mountain spotted fever (rmsf) are caused by ehrlichia chaffeensis and rickettsia rickettsii, respectively. the pathogenesis of rmsf relates to rickettsia-mediated vascular injury, but it is unclear in hme.200616859547
localization and visualization of a coxiella-type symbiont within the lone star tick, amblyomma americanum.a coxiella-type microbe occurs at 100% frequency in all amblyomma americanum ticks thus far tested. using laboratory-reared ticks free of other microbes, we identified the amblyomma-associated coxiella microbe in several types of tissue and at various stages of the life cycle of a. americanum by 16s rrna gene sequencing and diagnostic pcr. we visualized amblyomma-associated coxiella through the use of a diagnostic fluorescence in situ hybridization (fish) assay supplemented with pcr-based detect ...200717720830
a call for renewed research on tick-borne francisella tularensis in the arkansas-missouri primary national focus of tularemia in humans.arkansas-missouri has emerged as the primary u.s. focus of tularemia, which is caused by the national institute of allergy and infectious diseases category a priority pathogen francisella tularensis, over the past 30 yr. there are several pieces of indirect evidence suggesting that a key role of ticks in the transmission of f. tularensis to humans in arkansas-missouri is the primary reason why tularemia has remained a prominent disease of humans in this two-state area while fading away from othe ...200717547223
haemaphysalis longicornis: molecular characterization of a homologue of the macrophage migration inhibitory factor from the partially fed ticks.the macrophage migration inhibitory factor (mif) has been identified from some vertebrates and invertebrates. mif is related to inflammation, tumor growth, and angiogenesis in vertebrates. here, we report the molecular characterization of a homologue of mif from partially fed haemaphysalis longicornis. the sequence analysis of the h. longicornis mif (hlmif) indicated that its deduced amino acid sequence has an identity of 77% with the mif of the tick amblyomma americanum. western blot analysis u ...200716987517
fecal nirs: detection of tick infestations in cattle and horses.anti-tick treatments are often applied concurrent to routine livestock management practices with little regard to actual infestation levels. prescription treatments against ticks on grazing cattle would be facilitated by non-invasive detection methods. one such method is fecal near infrared spectroscopy (nirs). four studies utilizing cattle (bos spp.) and one with horses (equus caballus) fed varying diets and infested with either amblyomma americanum, a. maculatum, a. cajennense or dermacentor a ...200717097809
infection of ixodes scapularis ticks with rickettsia monacensis expressing green fluorescent protein: a model system.ticks (acari: ixodidae) are ubiquitous hosts of rickettsiae (rickettsiaceae: rickettsia), obligate intracellular bacteria that occur as a continuum from nonpathogenic arthropod endosymbionts to virulent pathogens of both arthropod vectors and vertebrates. visualization of rickettsiae in hosts has traditionally been limited to techniques utilizing fixed tissues. we report epifluorescence microscopy observations of unfixed tick tissues infected with a spotted fever group endosymbiont, rickettsia m ...200717125789
functional evolution of the vitamin d and pregnane x receptors.the vitamin d receptor (vdr) and pregnane x receptor (pxr) are nuclear hormone receptors of the nr1i subfamily that show contrasting patterns of cross-species variation. vdr and pxr are thought to have arisen from duplication of an ancestral gene, evident now as a single gene in the genome of the chordate invertebrate ciona intestinalis (sea squirt). vdr genes have been detected in a wide range of vertebrates including jawless fish. to date, pxr genes have not been found in cartilaginous fish. i ...200717997857
antibiotic treatment of the tick vector amblyomma americanum reduced reproductive fitness.the lone star tick amblyomma americanum is a common pest and vector of infectious diseases for humans and other mammals in the southern and eastern united states. a coxiella sp. bacterial endosymbiont was highly prevalent in both laboratory-reared and field-collected a. americanum. the coxiella sp. was demonstrated in all stages of tick and in greatest densities in nymphs and adult females, while a rickettsia sp. was less prevalent and in lower densities when present.200717476327
gene silencing of the tick protective antigens, bm86, bm91 and subolesin, in the one-host tick boophilus microplus by rna interference.the use of rna interference (rnai) to assess gene function has been demonstrated in several three-host tick species but adaptation of rnai to the one-host tick, boophilus microplus, has not been reported. we evaluated the application of rnai in b. microplus and the effect of gene silencing on three tick-protective antigens: bm86, bm91 and subolesin. gene-specific double-stranded (dsrna) was injected into two tick stages, freshly molted unfed and engorged females, and specific gene silencing was ...200717196597
association of the bovine leukocyte antigen major histocompatibility complex class ii drb3*4401 allele with host resistance to the lone star tick, amblyomma americanum.the mhc of cattle, known as the bovine leukocyte antigen (bola) complex, plays an integral role in disease and parasite susceptibility, and immune responsiveness of the host. while susceptibility to tick infestation in cattle is believed to be heritable, genes that may be responsible for the manifestation of this phenotype remain elusive. in an effort to analyze the role that genes within the bola complex may play in host resistance to ticks, we have evaluated components of this system within a ...200717208379
surface-exposed proteins of ehrlichia chaffeensis.the surface proteins of ehrlichia chaffeensis provide an important interface for pathogen-host interactions. to investigate the surface proteins of e. chaffeensis, membrane-impermeable, cleavable sulfo-nhs-ss-biotin was used to label intact bacteria. the biotinylated bacterial surface proteins were isolated by streptavidin-agarose affinity purification. the affinity-captured proteins were separated by electrophoresis, and five relatively abundant protein bands containing immunoreactive proteins ...200717517859
evidence for a population expansion in the west nile virus vector culex tarsalis.population genetic structure of the west nile virus vector culex tarsalis was investigated in 5 states in the western united states using 5 microsatellite loci and a fragment of the mitochondrial reduced form of nicotinamide adenine dinucleotide dehydrogenase 4 (nd4) gene. nd4 sequence analysis revealed a lack of isolation by distance, panmixia across all populations, an excess of rare haplotypes, and a star-like phylogeny. microsatellites revealed moderate genetic differentiation and isolation ...200717339636
transovarial silencing of the subolesin gene in three-host ixodid tick species after injection of replete females with subolesin dsrna.rna interference (rnai) has become the most powerful experimental tool for the study of gene function in ticks. subolesin, initially called 4d8, was found to be protective against tick infestations when used as a vaccine and was shown to be highly conserved among ixodid tick species at the nucleotide and protein levels. rnai caused systemic silencing of subolesin and demonstrated that this protein is involved in regulation of tick feeding, reproduction, and development. recently, these results w ...200717372765
highly prevalent coxiella sp. bacterium in the tick vector amblyomma americanum.laboratory-reared and field-collected amblyomma americanum ticks were hosts of a coxiella sp. and a rickettsia sp. while the coxiella sp. was detected in 50 of 50 field-collected ticks, the rickettsia sp. was absent from 32% of ticks. the coxiella sp. showed evidence of a reduced genome and may be an obligate endosymbiont.200717085709
new tick defensin isoform and antimicrobial gene expression in response to rickettsia montanensis challenge.recent studies aimed at elucidating the rickettsia-tick interaction have discovered that the spotted fever group rickettsia rickettsia montanensis, a relative of r. rickettsii, the etiologic agent of rocky mountain spotted fever, induces differential gene expression patterns in the ovaries of the hard tick dermacentor variabilis. here we describe a new defensin isoform, defensin-2, and the expression patterns of genes for three antimicrobials, defensin-1 (vsna1), defensin-2, and lysozyme, in the ...200717261604
ecological havoc, the rise of white-tailed deer, and the emergence of amblyomma americanum-associated zoonoses in the united states.two infectious diseases, and one presumably infectious disease, each vectored by or associated with the bite of the lone star tick (amblyomma americanum), were identified and characterized by clinicians and scientists in the united states during the 1980s and 1990s. these three conditions-human monocytic (or monocytotropic) ehrlichiosis (hme), ehrlichia ewingii ehrlichiosis, and southern tick-associated rash illness (stari)-undoubtedly existed in the united states prior to this time. however, th ...200717848069
confirmation of the efficacy of a novel formulation of metaflumizone plus amitraz for the treatment and control of fleas and ticks on dogs.a novel spot-on formulation containing metaflumizone plus amitraz (promeris/promeris duo for dogs, fort dodge animal health, overland park, ks) was evaluated in four laboratory studies to confirm efficacy against fleas and ticks on dogs for 1 month. three different strains of cat flea (ctenocephalides felis felis) and four tick species were used. rhipicephalus sanguineus and dermacentor variabilis were evaluated concurrently in two studies and ixodes scapularis and amblyomma americanum in one st ...200717923330
bartonella vinsonii subsp. berkhoffii endocarditis in a dog from saskatchewan.a dog referred for lameness was diagnosed with culture-negative endocarditis. antibodies to bartonella spp. were detected. antibiotic treatment resulted in transient clinical improvement, but the dog developed cardiac failure and was euthanized. bartonella vinsonii subsp. berkhoffii genotype iv was identified within the aortic heart valve lesions by pcr amplification and dna sequencing.200717824328
molecular cloning of the ecdysone receptor and the retinoid x receptor from the scorpion liocheles australasiae.cdnas of the ecdysone receptor and the retinoid x receptor were cloned from the japanese scorpion liocheles australasiae, and the amino acid sequences were deduced. the full-length cdna sequences of the l. australasiae ecdysone receptor and the l. australasiae retinoid x receptor were 2881 and 1977 bp in length, respectively, and the open reading frames encoded proteins of 560 and 414 amino acids. the amino acid sequence of the l. australasiae ecdysone receptor was similar to that of the ecdyson ...200718028192
virulence potential of ehrlichia chaffeensis strains of distinct genome sequences.human monocytic ehrlichiosis, one of the most frequent life-threatening tick-borne zoonoses, is caused by ehrlichia chaffeensis that lacks endotoxin and peptidoglycan. while sequence polymorphisms in several genes in e. chaffeensis strains have been reported, global genomic divergence and biological differences among strains are unknown. the objectives of the present study were to compare the genome sequences of strains of e. chaffeensis and to examine the virulence potentials of the strains wit ...200717438035
experimental infection of dairy calves with ehrlichia chaffeensis.human monocytic ehrlichiosis (hme) is a zoonotic emerging tick-borne disease with clinical signs that range from mild symptoms to multiple organ failure and death. ehrlichia chaffeensis, the aetiologic agent of hme, is reported to infect a divergent range of mammals. although cattle are common hosts of the primary vector of this pathogen, the susceptibility of this host to e. chaffeensis has not been reported to date. this study was undertaken to determine if cattle could provide a useful infect ...200718033836
evolution of the iron-responsive element.an rna hairpin structure referred to as the iron-responsive element (ire) and iron regulatory proteins (irps) are key players in the control of iron metabolism in animal cells. they regulate translation initiation or mrna stability, and the ire is found in a variety of mrnas, such as those encoding ferritin, transferrin receptor (tfr), erythroid aminolevulinic acid synthase (ealas), mitochondrial aconitase (maco), ferroportin, and divalent metal transporter 1 (dmt1). we have studied the evolutio ...200717513696
serotonin-like immunoreactivity in the central nervous system of two ixodid tick species.immunocytochemistry was used to describe the distribution of serotonin-like immunoreactive (5ht-ir) neurons and neuronal processes in the central nervous system (cns), the synganglion, of two ixodid tick species; the winter tick, dermacentor albipictus and the lone star tick, amblyomma americanum. 5ht-ir neurons were identified in the synganglion of both tick species. d. albipictus had a significantly higher number of 5ht-ir neurons than a. americanum. the labeling pattern and number of 5ht-ir n ...200718040871
detection of rickettsia amblyommii in association with a tick bite rash.in the summer of 2006, an amblyomma americanum tick was removed from a woman in central north carolina, who subsequently developed a rash at the site of tick attachment. when examined by polymerase chain reaction (pcr) for borrelia, anaplasma, ehrlichia, babesia, rickettsia, and bartonella dna, only the rickettsia primers generated an amplicon, which was identified as "r. amblyommii" by sequencing. to our knowledge, this is the first case in which r. amblyommii was temporally associated with a r ...200718052716
life cycles of seven ixodid tick species (acari: ixodidae) under standardized laboratory conditions.studies of transmission, maintenance, infectivity, virulence, and pathogenicity of tick-borne agents require the use of large numbers of live laboratory-raised ticks. colonies of ixodes scapularis say, ixodes pacificus cooley & kohls, amblyomma americanum (l.), dermacentor occidentalis marx, dermacentor variabilis (say), hemaphysalis leporispalustris (packard), and rhipicephalus sanguineus (latrielle) have been maintained in our laboratory at the centers for disease control and prevention for fi ...200717915502
purification and characterization of two larval glycoproteins from the cattle tick, boophilus annulatus.the present study was conducted to identify new target immunogenic molecules from the larval stage of the cattle tick, boophilus annulatus (acari: ixodidae). two specific larval glycoproteins (glps) were isolated by two-step affinity chromatography. the larval immunogens were first purified with cnbr-sepharose coupled to rabbit anti-larval immunoglobulins, and the glycoproteins were then purified with con-a sepharose. these glycoproteins have molecular weights of approximately 32 and 15 kda with ...200717519572
differential clearance and immune responses to tick cell-derived versus macrophage culture-derived ehrlichia chaffeensis in mice.human monocytic ehrlichiosis is caused by a tick-transmitted rickettsia, ehrlichia chaffeensis. we recently reported that e. chaffeensis grown in tick cells expresses different proteins than bacteria grown in macrophages. therefore, we tested the hypothesis that immune responses against e. chaffeensis would be different if the mice are challenged with bacteria grown in macrophages or tick cells. we assessed the e. chaffeensis clearance from the peritoneum, spleen, and liver by c57bl/6j mice usin ...200717060466
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