| isolation of a virus closely related to powassan virus from dermacentor andersoni collected along north cache la poudre river, colo. | | 1960 | 13838002 |
| morphology and functioning of the mouthparts of dermacentor andersoni stiles. | | 1960 | 13851716 |
| nonpathogenic rickettsias related to the spotted fever group isolated from ticks, dermacentor variabilis and dermacentor andersoni from eastern montana. | | 1963 | 14053295 |
| anaplasma marginale theiler observed in the gut and excreta of dermacentor andersoni stiles (dermacentor venustus marx). | | 1964 | 14204828 |
| difference of sites of attachment of dermacentor andersoni stiles to cattle in southeastern alberta and in south central british columbia, in relation to possible existence of genetically different strains of ticks. | | 1965 | 14328661 |
| site and mechanism of tick paralysis. | a neurophysiological investigation indicates that the paralysis produced in the dog by the wood tick, dermacentor andersoni stiles, is due to failure in the liberation of acetylcholine at the neuromuscular junction because of a conduction block in the somatic motor fibers produced by the tick "toxin". | 1960 | 14425361 |
| antigens and alternatives for control of anaplasma marginale infection in cattle. | anaplasmosis, a tick-borne cattle disease caused by the rickettsia anaplasma marginale, is endemic in tropical and subtropical areas of the world. the disease causes considerable economic loss to both the dairy and beef industries worldwide. analyses of 16s rrna, groesl, and surface proteins have resulted in the recent reclassification of the order rickettsiales. the genus anaplasma, of which a. marginale is the type species, now also includes a. bovis, a. platys, and a. phagocytophilum, which w ... | 2003 | 14557295 |
| simultaneous variation of the immunodominant outer membrane proteins, msp2 and msp3, during anaplasma marginale persistence in vivo. | vector-borne bacterial pathogens persist in the mammalian host by varying surface antigens to evade the existing immune response. to test whether the model of surface coat switching and immune evasion can be extended to a vector-borne bacterial pathogen with multiple immunodominant surface proteins, we examined anaplasma marginale, a rickettsia with two highly immunogenic outer membrane proteins, major surface protein 2 (msp2) and msp3. the simultaneous clearance of variants of the two most immu ... | 2003 | 14573687 |
| transstadial transfer of west nile virus by three species of ixodid ticks (acari: ixodidae). | larvae and/or nymphs of four species of ixodid ticks, ixodes scapularis say, amblyomma americanum (l.), dermacentor andersoni stiles, and dermacentor variabilis say, were fed to completion on laboratory hamsters or mice which had been inoculated with a west nile (wn) virus isolate from culex pipiens l. captured in connecticut usa. maximum titers in mice and hamsters were approximately 5 and two logs, respectively, lower than recorded (10 logs) in a naturally infected american crow, corvus brachy ... | 2003 | 14680122 |
| rickettsia species infecting amblyomma cooperi ticks from an area in the state of são paulo, brazil, where brazilian spotted fever is endemic. | owing to the potential role of the tick amblyomma cooperi in the enzootic cycle of rickettsia rickettsii, the etiologic agent of brazilian spotted fever (bsf), this study evaluated infection by rickettsia species in a. cooperi ticks collected from an area in brazil where bsf is endemic. among a total of 40 a. cooperi adult ticks collected in an area of bsf endemicity in the state of são paulo, pcr analysis detected dna of rickettsia bellii in 16 ticks (40%), and 3 other ticks (7.5%) were positiv ... | 2004 | 14715737 |
| an immune responsive factor d-like serine proteinase homologue identified from the american dog tick, dermacentor variabilis. | a dermacentor variabilis cdna encoding a clip-domain serine proteinase homologue with glycine replacing the catalytic serine was identified from tick haemocytes. the d. variabilis product was most similar to tachypleus tridentatus haemocyte antimicrobial factor d and shared significant homologies with a number of immune-responsive gene products of arthropods, including insect prophenoloxidase-activating cofactors. northern blotting analyses confirmed that the tick serine proteinase homologue exp ... | 2004 | 14728664 |
| tick paralysis presenting in an urban environment. | we report the case of a 17-month-old female with tick paralysis presenting to an urban los angeles emergency department. the tick was later identified as the north american wood tick, dermacentor andersoni, and was likely obtained while the family was vacationing on a dude ranch in montana. we discuss the epidemiology of tick paralysis, a differential diagnosis for health care providers, and methods of detection and removal. given the increasing popularity of outdoor activities and ease of trave ... | 2004 | 14984905 |
| development of a p28-based pcr assay for ehrlichia chaffeensis. | detection of ehrlichia chaffeensis is necessary to study interactions between the parasite and its vertebrate and invertebrate hosts. the purpose of this study was to develop a sensitive, specific pcr assay for e. chaffeensis based on the outer membrane protein gene, p28. candidate primer sets were identified and ranked based on annealing scores, similarities to three major p28 sequence clusters, dissimilarity to e. canis p30, an ortholog of p28, and the proximities of flanking primer sequences ... | 2004 | 15051120 |
| ehrlichia prevalence in amblyomma americanum, central texas. | | 2004 | 15338551 |
| sequence and expression analysis of the ompa gene of rickettsia peacockii, an endosymbiont of the rocky mountain wood tick, dermacentor andersoni. | the transmission dynamics of rocky mountain spotted fever in montana appears to be regulated by rickettsia peacockii, a tick symbiotic rickettsia that interferes with transmission of virulent rickettsia rickettsii. to elucidate the molecular relationships between the two rickettsiae and glean information on how to possibly exploit this interference phenomenon, we studied a major rickettsial outer membrane protein gene, ompa, presumed to be involved in infection and pathogenesis of spotted fever ... | 2004 | 15528527 |
| complete genome sequencing of anaplasma marginale reveals that the surface is skewed to two superfamilies of outer membrane proteins. | the rickettsia anaplasma marginale is the most prevalent tick-borne livestock pathogen worldwide and is a severe constraint to animal health. a. marginale establishes lifelong persistence in infected ruminants and these animals serve as a reservoir for ticks to acquire and transmit the pathogen. within the mammalian host, a. marginale generates antigenic variants by changing a surface coat composed of numerous proteins. by sequencing and annotating the complete 1,197,687-bp genome of the st. mar ... | 2004 | 15618402 |
| characterization of genetic diversity in dermacentor andersoni (acari: ixodidae) with body size and weight polymorphism. | morphological and discrete genetic differences are found between geographically isolated, allopatric, tick populations. however, we have found differences in sympatric tick populations. notable differences were found in the body size and weight of dermacentor andersoni collected from a single location in montana, usa. these ticks were separated in groups consisting of big (b) and small (s) individuals. the objectives of this study were: (a) to characterize genetic diversity in b and s d. anderso ... | 2004 | 15639135 |
| tick saliva inhibits differentiation, maturation and function of murine bone-marrow-derived dendritic cells. | haematophagous arthropod vectors such as mosquitoes, tsetse flies, sandflies and ticks have evolved salivary immunomodulatory factors that prevent the vertebrate host from rejecting them meanwhile enhancing pathogen transmission. as dendritic cells (dc) play a major role in host immune responses, we studied the effects of rhipicephalus sanguineus tick saliva on dc differentiation and maturation. flow cytometry analysis revealed that the addition of saliva to bone marrow cells inhibits the differ ... | 2005 | 15667568 |
| molecular differentiation of metastriate tick immatures. | hard ticks, family ixodidae, are divided into two groups, the metastriata and the prostriata, based on morphological differences. in the united states, there are four medically important genera of the ixodidae: ixodes, amblyomma, dermacentor, and rhipicephalus. ixodes is the only genus in and representative of the prostriata, whereas the latter three genera are members of the metastriata. all developmental stages of the prostriata can be easily differentiated from the metastriata using morpholog ... | 2004 | 15682516 |
| variation among geographically separated populations of dermacentor andersoni (acari: ixodidae) in midgut susceptibility to anaplasma marginale (rickettsiales: anaplasmataceae). | anaplasma marginale is a tick-borne rickettsial pathogen of cattle that is endemic throughout large areas of the united states. cattle that survive acute infection become life-long persistently infected carriers. in the intermountain west the rocky mountain wood tick, dermacentor andersoni stiles, is the most common vector of a. marginale. male d. andersoni acquire a. marginale when feeding on persistently infected cattle and biologically transmit it when they transfer from infected to susceptib ... | 2005 | 15799524 |
| 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 ... | 2005 | 15941624 |
| prefeeding dermacentor andersoni (acari: ixodidae) on cattle with prior tick exposure may inhibit detection of tick paralysis by using hamster bioassay. | the effect of prefeeding dermacentor andersoni stiles on naive and previously challenged cattle before conducting virulence assays by using hamsters was examined. in an initial observational trial, ticks prefed on a previously challenged heifer did not cause paralysis after transfer to hamsters, whereas ticks from the same lot that were prefed on a naive heifer did cause paralysis. subsequent paired trails were conducted to simultaneously compare paralysis after feeding on naive and previously c ... | 2005 | 15962790 |
| murine extramedullary erythropoiesis induced by tick infestation. | tick saliva contains molecules that modulate the haemostasis, pain/itch responses, wound healing and immune defences of the host. using balb/c mice that were each infested with 10 nymphs of dermacentor andersoni stiles (acari: ixodidae), an attempt has now been made to determine the influence of tick infestation on the expression of leucocyte adhesion molecules in the host. the ticks became fully engorged by the fourth to sixth day of infestation. on the fourth day of infestation, the results of ... | 2005 | 16004711 |
| relative efficiency of biological transmission of anaplasma marginale (rickettsiales: anaplasmataceae) by dermacentor andersoni (acari: ixodidae) compared with mechanical transmission by stomoxys calcitrans (diptera: muscidae). | anaplasma marginale theiler is a tick-borne intraerythrocytic rickettsial pathogen of cattle that also can be mechanically transmitted by biting flies. rickettsemia during the acute phase of infection may reach as high as 10(9) infected erythrocytes (ies) per milliliter of blood. animals that survive acute infection develop a life-long persistent infection that cycles between 10(2.5) and 10(7) ie/ ml of blood. we compared stable fly stomoxys calcitrans (l.) -borne mechanical transmission during ... | 2005 | 16119558 |
| tick modulation of the in-vitro expression of adhesion molecules by skin-derived endothelial cells. | as a tick feeds, its saliva induces innate and acquired immune responses in the host, including leucocyte infiltration into the bite site. tick salivary glands produce molecules, however, that counteract many host defences against blood feeding. the effects of salivary-gland extracts (sge) of dermacentor andersoni and ixodes scapularis on the expression of various adhesion molecules [e-selectin, p-selectin, intercellular adhesion molecule 1 (icam-1) and vascular cell adhesion molecule 1 (vcam-1) ... | 2005 | 16212800 |
| transcription of the rickettsia felis ompa gene in naturally infected fleas. | rickettsia felis is maintained transovarially in ctenocephalides felis fleas in a widespread geographic distribution and is transmitted to humans and animals, including opossums. this rickettsia is phylogenetically a member of the spotted fever group, most closely related to rickettsia akari and r. australis. an unusual feature of this rickettsia is that the gene for the outer membrane protein a (ompa) is interrupted by stop codons. to determine if this putatively dying gene is expressed, mrna w ... | 2005 | 16222005 |
| 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 ... | 2005 | 16223955 |
| 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 ... | 2005 | 16288906 |
| coltiviruses and seadornaviruses in north america, europe, and asia. | coltiviruses are tickborne viruses of the genus coltivirus. the type species, colorado tick fever virus (from north america), has been isolated from patients with flulike syndromes, meningitis, encephalitis, and other severe complications. another coltivirus, eyach virus, has been isolated from ticks in france and germany and incriminated in febrile illnesses and neurologic syndromes. seadornaviruses are endemic in southeast asia, particularly indonesia and china. the prototype virus of the genu ... | 2005 | 16318717 |
| a novel bacteroidetes symbiont is localized in scaphoideus titanus, the insect vector of flavescence dorée in vitis vinifera. | flavescence dorée (fd) is a grapevine disease that afflicts several wine production areas in europe, from portugal to serbia. fd is caused by a bacterium, "candidatus phytoplasma vitis," which is spread throughout the vineyards by a leafhopper, scaphoideus titanus (cicadellidae). after collection of s. titanus specimens from fd-contaminated vineyards in three different areas in the piedmont region of italy, we performed a survey to characterize the bacterial microflora associated with this insec ... | 2006 | 16461701 |
| distribution, seasonality, and hosts of the rocky mountain wood tick in the united states. | anaplasma marginale theiler is a tick-borne pathogen that causes anaplasmosis in cattle. there are approximately 20 tick species worldwide that are implicated as vectors of this pathogen. in the united states, dermacentor andersoni stiles and dermacentor variabilis (say) are the principal vectors. the risk of transmission of anaplasmosis to cattle has been largely based on the distribution of d. andersoni in the united states. we developed a centralized geographic database that incorporates coll ... | 2006 | 16506443 |
| the microbial flora of the rocky mountain wood tick, dermacentor andersoni stiles. | | 1942 | 16560577 |
| differential expression and sequence conservation of the anaplasma marginale msp2 gene superfamily outer membrane proteins. | bacterial pathogens in the genera anaplasma and ehrlichia encode a protein superfamily, pfam01617, which includes the predominant outer membrane proteins (omps) of each species, major surface protein 2 (msp2) and msp3 of anaplasma marginale and anaplasma ovis, anaplasma phagocytophilum msp2 (p44), ehrlichia chaffeensis p28-omp, ehrlichia canis p30, and ehrlichia ruminantium map1, and has been shown to be involved in both antigenic variation within the mammalian host and differential expression b ... | 2006 | 16714578 |
| analysis of the anaplasma marginale major surface protein 1 complex protein composition by tandem mass spectrometry. | the protective major surface protein 1 (msp1) complex of anaplasma marginale is a heteromer of msp1a and msp1b, encoded by a multigene family. the msp1beta sequences were highly conserved throughout infection. however, liquid chromatography-tandem mass spectrometry analysis identified only a single msp1b protein, msp1b1, within the msp1 complex. | 2006 | 16788207 |
| 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 ... | 2006 | 16885311 |
| rickettsia felis from cat fleas: isolation and culture in a tick-derived cell line. | rickettsia felis, the etiologic agent of spotted fever, is maintained in cat fleas by vertical transmission and resembles other tick-borne spotted fever group rickettsiae. in the present study, we utilized an ixodes scapularis-derived tick cell line, ise6, to achieve isolation and propagation of r. felis. a cytopathic effect of increased vacuolization was commonly observed in r. felis-infected cells, while lysis of host cells was not evident despite large numbers of rickettsiae. electron microsc ... | 2006 | 16885313 |
| 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 ... | 2006 | 16901827 |
| sarcoptes scabiei (acari: sarcoptidae) mite extract modulates expression of cytokines and adhesion molecules by human dermal microvascular endothelial cells. | the inflammatory and immune responses seen with the worldwide disease scabies, caused by the mite sarcoptes scabiei (de geer) (acari: sarcoptidae), are complex. clinical symptoms are delayed for weeks in patients when they are infested with scabies for the first time. this study was undertaken to elucidate the role of the human dermal microvascular endothelial cell (hmvec-d) in modulating the inflammatory and immune responses in the skin to s. scabiei. extracts of s. scabiei were incubated with ... | 2006 | 17017228 |
| a canadian bison isolate of anaplasma marginale (rickettsiales: anaplasmataceae) is not transmissible by dermacentor andersoni (acari: ixodidae), whereas ticks from two canadian d. andersoni populations are competent vectors of a u.s. strain. | anaplasma marginale theiler is a tick-borne rickettsial pathogen of cattle with a global distribution in both temperate and tropical regions. the pathogen is endemic in regions within the united states, whereas the canadian cattle population is considered to be free ofa. marginale. farmed bison, bison bison l., in central saskatchewan have been found to be infected with a. marginale; however, there is no evidence of transmission from bison to cattle. we tested a saskatchewan bison isolate of a. ... | 2006 | 17017236 |
| coinfections acquired from ixodes ticks. | the pathogens that cause lyme disease (ld), human anaplasmosis, and babesiosis can coexist in ixodes ticks and cause human coinfections. although the risk of human coinfection differs by geographic location, the true prevalence of coinfecting pathogens among ixodes ticks remains largely unknown for the majority of geographic locations. the prevalence of dually infected ixodes ticks appears highest among ticks from regions of north america and europe where ld is endemic, with reported prevalences ... | 2006 | 17041141 |
| gene expression in male tick salivary glands is affected by feeding in the presence of females. | in this study, we have compared gene expression in the salivary glands of male dermacentor andersoni ticks fed in the presence or absence of females to that in unfed males. we have established that the patterns of expression are different using arbitrarily primed polymerase chain reaction following reverse transcription of rna (rap-pcr) and differential display. our results indicate a significant difference in salivary gland gene expression between fed and unfed males and also between males fed ... | 2006 | 17103403 |
| molecular typing of novel rickettsia rickettsii isolates from arizona. | seven isolates of rickettsia rickettsii were obtained from a skin biopsy, two whole-blood specimens, and from rhipicephalus sanguineus ticks from eastern arizona. molecular typing of seven isolates of r. rickettsii and dna samples from two other rh. sanguineus ticks infected with r. rickettsii was conducted by pcr and dna sequencing of rompa and 12 variable-number tandem repeat regions (vntrs). all dna specimens from arizona were identical to each other and to reference human and dermacentor and ... | 2006 | 17114781 |
| 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 ... | 2007 | 17125789 |
| isolation of rickettsia rhipicephali and rickettsia bellii from haemaphysalis juxtakochi ticks in the state of são paulo, brazil. | in the present study, attempts to isolate rickettsia in cell culture were performed individually in seven specimens of haemaphysalis juxtakochi ticks collected in the state of são paulo (southeastern brazil). rickettsia was successfully isolated by the shell vial technique and established in vero cell culture from six ticks (six isolates). dna extracted from infected cells of these isolates was tested by pcr and dna sequencing, using genus-specific rickettsia primers targeting the genes glta, ht ... | 2007 | 17142361 |
| transcriptome analysis of the salivary glands of dermacentor andersoni stiles (acari: ixodidae). | amongst blood-feeding arthropods, ticks of the family ixodidae (hard ticks) are vectors and reservoirs of a greater variety of infectious agents than any other ectoparasite. salivary glands of ixodid ticks secrete a large number of pharmacologically active molecules that not only facilitate feeding but also promote establishment of infectious agents. genomic, proteomic and immunologic characterization of bioactive salivary gland molecules are, therefore, important as they offer new insights into ... | 2007 | 17175446 |
| selection for simple major surface protein 2 variants during anaplasma marginale transmission to immunologically naïve animals. | anaplasma marginale, a rickettsial pathogen, evades clearance in the animal host by antigenic variation. under immune selection, a. marginale expresses complex major surface protein 2 mosaics, derived from multiple donor sequences. however, these mosaics have a selective advantage only in the presence of adaptive immunity and are rapidly replaced by simple variants following transmission. | 2007 | 17178787 |
| real-time pcr for francisella tularensis types a and b. | | 2006 | 17283646 |
| identification of midgut and salivary glands as specific and distinct barriers to efficient tick-borne transmission of anaplasma marginale. | understanding the determinants of efficient tick-borne microbial transmission is needed to better predict the emergence of highly transmissible pathogen strains and disease outbreaks. although the basic developmental cycle of anaplasma and ehrlichia spp. within the tick has been delineated, there are marked differences in the ability of specific strains to be efficiently tick transmitted. using the highly transmissible st. maries strain of anaplasma marginale in dermacentor andersoni as a positi ... | 2007 | 17420231 |
| an incidental case of tick paralysis in a holstein calf exposed to dermacentor andersoni. | | 1992 | 17423967 |
| seasonal pattern of host-seeking activity by the human-biting adult life stage of dermacentor andersoni (acari: ixodidae). | nonremoval drag sampling was conducted in multiple sites in larimer county, co, from march to july 2006 to determine the seasonal pattern of host-seeking activity by the human-biting adult life stage of the rocky mountain wood tick, dermacentor andersoni stiles (acari: ixodidae). four sites, at elevations ranging from 1,790 to 2,470 m, consistently yielded host-seeking ticks. ticks were active from march until late june; the length of the active period ranged from 84 to 104 d. based on site-spec ... | 2007 | 17427709 |
| rickettsia peacockii, an endosymbiont of dermacentor andersoni, does not elicit or inhibit humoral immune responses from immunocompetent d. andersoni or ixodes scapularis cell lines. | ixodes scapularis and dermacentor andersoni cell lines were stimulated with heat-killed escherichia coli and micrococcus luteus to investigate whether infection by rickettsia peacockii, an endosymbiont of d. andersoni, modifies humoral immune responses. radial diffusion assays, western blotting, flow cytometry, and quantitative reverse-transcription pcr were used to determine if expression of bacteriolytic peptides, including lysozyme and defensin, was upregulated by bacterial stimulation or inf ... | 2007 | 17428539 |
| 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. | 2007 | 17476327 |
| tick-borne flavivirus infection in ixodes scapularis larvae: development of a novel method for synchronous viral infection of ticks. | following a bite from an infected tick, tick-borne flaviviruses cause encephalitis, meningitis and hemorrhagic fever in humans. although these viruses spend most of their time in the tick, little is known regarding the virus-vector interactions. we developed a simple method for synchronously infecting ixodes scapularis larvae with langat virus (lgtv) by immersion in media containing the virus. this technique resulted in approximately 96% of ticks becoming infected. lgtv infection and replication ... | 2007 | 17490700 |
| 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 ... | 2007 | 17505544 |
| differentiation of three species of ixodid tick, dermacentor andersoni, d. variabilis and d. albipictus, by pcr-based approaches using markers in ribosomal dna. | three species of dermacentor, dermacentor albipictus, dermacentor andersoni and dermacentor variabilis, commonly occur in canada. d. andersoni and d. variabilis are morphologically similar and are important vectors of human and animal pathogens. a practical polymerase chain reaction (pcr) assay, based on the amplification of part of the second internal transcribed spacer ribosomal dna (pits-2 rdna), was developed to distinguish d. andersoni from d. variabilis. in addition, single-strand conforma ... | 2007 | 17544620 |
| conservation of transmission phenotype of anaplasma marginale (rickettsiales: anaplasmataceae) strains among dermacentor and rhipicephalus ticks (acari: ixodidae). | before the eradication of boophilus ticks from the united states, rhipicephalus (boophilus) microplus (canestrini) and rhipicephalus (boophilus) annulatus (say) were important biological vectors of the cattle pathogen anaplasma marginale theiler. in the absence of boophilus ticks, a. marginale continues to be transmitted by dermacentor ticks. however, a few u.s. strains are not transmissible by dermacentor andersoni stiles, dermacentor variabilis (say), or both, raising the question of how these ... | 2007 | 17547235 |
| gulf coast ticks (amblyomma maculatum) and rickettsia parkeri, united states. | geographic distribution of rickettsia parkeri in its us tick vector, amblyomma maculatum, was evaluated by pcr. r. parkeri was detected in ticks from florida, georgia, kentucky, mississippi, oklahoma, and south carolina, which suggests that a. maculatum may be responsible for additional cases of r. parkeri rickettsiosis throughout much of its us range. | 2007 | 17553257 |
| molecular typing of isolates of rickettsia rickettsii by use of dna sequencing of variable intergenic regions. | rickettsia rickettsii, the causative agent of rocky mountain spotted fever, is found throughout the americas, where it is associated with different animal reservoirs and tick vectors. no molecular typing system currently exists to allow for the robust differentiation of isolates of r. rickettsii. analysis of eight completed genome sequences of rickettsial species revealed a high degree of sequence conservation within the coding regions of chromosomes in the genus. intergenic regions between codi ... | 2007 | 17553977 |
| q fever (coxiella burnetii) among man and farm animals in north sinai, egypt. | antibodies against coxiella burnetii were estimated among sheep, goats and camels (190), their owners (150 patients with pyrexia of unknown origin) and 30 normal individuals in north sinai over the 2006 by indirect immounofluorescence assay. nested polymerase chain reaction was used to detect com-1 gene (genetic target of c. burnetii) encoding a 27-kda outer membrane protein in the samples. c. burnetii ifa antibodies (igm & igg) in patients were 8 (5.3%) and a healthy control (3.3%). the overall ... | 2007 | 17580573 |
| abnormal morphology of an adult rocky mountain wood tick, dermacentor andersoni (acari: ixodidae). | during a collection of ticks from vegetation in march 2006, a single adult male rocky mountain wood tick, dermacentor andersoni (stiles, 1908), was collected that exhibited unique morphological anomalies, including the absence of a leg on the right side of the body. coxa iv on the right side also was missing in this specimen. such teratological changes have not been reported previously for d. andersoni. | 2007 | 17626369 |
| identification of rickettsial isolates at the species level using multi-spacer typing. | in order to estimate whether multi-spacer typing (mst), based on the sequencing of variable intergenic spacers, could serve for the identification of rickettsia at the species level, we applied it to 108 rickettsial isolates or arthropod amplicons that include representatives of 23 valid rickettsia species. | 2007 | 17662158 |
| climate-based model predicting acarological risk of encountering the human-biting adult life stage of dermacentor andersoni (acari: ixodidae) in a key habitat type in colorado. | we exploited an elevation (climate) gradient ranging from 1,700 to 2,500 m in poudre canyon of larimer county, co, to determine climatic correlates of abundance per 15-s drag sampling time unit (hereafter referred to as abundance) of the human-biting adult life stage of the rocky mountain wood tick, dermacentor andersoni stiles (acari: ixodidae), in a key risk habitat for tick exposure: south/west-facing, rocky hillsides with mixed grass-brush-conifer vegetation. the relationship between elevati ... | 2007 | 17695027 |
| 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 ... | 2007 | 17720830 |
| propagation of arthropod-borne rickettsia spp. in two mosquito cell lines. | rickettsiae are obligate intracellular alphaproteobacteria that include pathogenic species in the spotted fever, typhus, and transitional groups. the development of a standardized cell line in which diverse rickettsiae can be grown and compared would be highly advantageous to investigate the differences among and between pathogenic and nonpathogenic species of rickettsiae. although several rickettsial species have been grown in tick cells, tick cells are more difficult to maintain and they grow ... | 2007 | 17766452 |
| maintenance of antibody to pathogen epitopes generated by segmental gene conversion is highly dynamic during long-term persistent infection. | multiple bacterial and protozoal pathogens utilize gene conversion to generate rapid intrahost antigenic variation. both large- and small-genome pathogens expand the size of the variant pool via a combinatorial process in which oligonucleotide segments from distinct donor loci are recombined in various combinations into expression sites. although the potential combinatorial diversity generated by this segmental gene conversion mechanism is quite large, the functional variant pool depends on whet ... | 2007 | 17785476 |
| experimental transmission of bovine anaplasmosis (caused by anaplasma marginale) by means of dermacentor variabilis and d. andersoni (ixodidae) collected in western canada. | canadian cattle are free of bovine anaplasmosis, with the exception of 4 isolated incursions since 1968, which were eradicated. it is not known why the disease has not become established in regions of canada adjacent to the united states where it is endemic. to assess the vector competence of wild-caught ticks in cattle-rearing regions, dermacentor variabilis and d. andersoni were collected in western canada and fed on calves experimentally infected with anaplasma marginale (st. maries strain). ... | 2007 | 17955901 |
| experimental infection of dermacentor andersoni stiles with the virus of lymphocytic choriomeningitis. | | 1939 | 18015117 |
| experimental transmission of anaplasma marginale by male dermacentor reticulatus. | bovine anaplasmosis has been reported in several european countries, but the vector competency of tick species for anaplasma marginale from these localities has not been determined. because of the wide distributional range of dermacentor reticulatus within europe and the major role of dermacentor spp. as a vector of a. marginale in the united states, we tested the vector competency of d. reticulatus for a. marginale. | 2007 | 18053123 |
| an insight into the sialome of the soft tick, ornithodorus parkeri. | while hard ticks (ixodidae) take several days to feed on their hosts, soft ticks (argasidae) feed faster, usually taking less than 1h per meal. saliva assists in the feeding process by providing a cocktail of anti-hemostatic, anti-inflammatory and immunomodullatory compounds. saliva of hard ticks has been shown to contain several families of genes each having multiple members, while those of soft ticks are relatively unexplored. analysis of the salivary transcriptome of the soft tick ornithodoru ... | 2008 | 18070662 |
| comparative sialomics between hard and soft ticks: implications for the evolution of blood-feeding behavior. | ticks evolved various mechanisms to modulate their host's hemostatic and immune defenses. differences in the anti-hemostatic repertoires suggest that hard and soft ticks evolved anti-hemostatic mechanisms independently, but raise questions on the conservation of salivary gland proteins in the ancestral tick lineage. to address this issue, the sialome (salivary gland secretory proteome) from the soft tick, argas monolakensis, was determined by proteomic analysis and cdna library construction of s ... | 2008 | 18070664 |
| variability and action mechanism of a family of anticomplement proteins in ixodes ricinus. | ticks are blood feeding arachnids that characteristically take a long blood meal. they must therefore counteract host defence mechanisms such as hemostasis, inflammation and the immune response. this is achieved by expressing batteries of salivary proteins coded by multigene families. | 2008 | 18167559 |
| comparison of the efficiency of biological transmission of anaplasma marginale (rickettsiales: anaplasmataceae) by dermacentor andersoni stiles (acari: ixodidae) with mechanical transmission by the horse fly, tabanus fuscicostatus hine (diptera: muscidae). | mechanical transmission ofanaplasma marginale by horse flies (tabanidae) is thought to be epidemiologically significant in some areas of the united states. we compared the relative efficiencies of mechanical transmission of anaplasma marginale by the horse fly, tabanus fuscicostatus hine, during acute infection (approximately 10(7) to approximately 10(9) infected erythrocytes [ie]/ml blood) with biological transmission by dermacentor andersoni stiles in the persistent phase of infection (approxi ... | 2008 | 18283950 |
| characterization and growth of polymorphic rickettsia felis in a tick cell line. | morphological differentiation in some arthropod-borne bacteria is correlated with increased bacterial virulence, transmission potential, and/or as a response to environmental stress. in the current study, we utilized an in vitro model to examine rickettsia felis morphology and growth under various culture conditions and bacterial densities to identify potential factors that contribute to polymorphism in rickettsiae. we utilized microscopy (electron microscopy and immunofluorescence), genomic (pc ... | 2008 | 18359823 |
| a possible canine tick-bite reaction to ixodes muris. | an airedale terrier became acutely ill following attachment of an ixodes muris tick. clinical signs waned within hours of tick removal, similar to a pattern previously documented in animals harboring i. muris. this supports the theory that i. muris can induce a noninfectious, severe inflammatory reaction in domestic animals. | 2008 | 18390101 |
| insight into the sialome of the castor bean tick, ixodes ricinus. | in recent years, there have been several sialome projects revealing transcripts expressed in the salivary glands of ticks, which are important vectors of several human diseases. here, we focused on the sialome of the european vector of lyme disease, ixodes ricinus. | 2008 | 18489795 |
| detection and identification of spotted fever group rickettsiae in dermacentor species from southern california. | dermacentor occidentalis marx and dermacentor variabilis (say) commonly bite humans in california. these dermacentor species may play a role in transmitting spotted fever group (sfg) rickettsiae to humans in many parts of the state where dermacentor andersoni stiles, a known vector for the etiologic agent of rocky mountain spotted fever, rickettsia rickettsii, is absent. however, the specific rickettsial agents present in these ticks and their current prevalence are poorly understood. in total, ... | 2008 | 18533446 |
| tick-borne transmission of two genetically distinct anaplasma marginale strains following superinfection of the mammalian reservoir host. | strain superinfection affects the dynamics of epidemiological spread of pathogens through a host population. superinfection has recently been shown to occur for two genetically distinct strains of the tick-borne pathogen anaplasma marginale that encode distinctly different surface protein variants. superinfected animals could serve as a reservoir for onward transmission of both strains if the tick vector is capable of acquiring and transmitting both strains. whether competition among strains dur ... | 2008 | 18573892 |
| transmission of bartonella henselae by ixodes ricinus. | bartonella spp. are facultative intracellular bacteria associated with several emerging diseases in humans and animals. b. henselae causes cat-scratch disease and is increasingly associated with several other syndromes, particularly ocular infections and endocarditis. cats are the main reservoir for b. henselae and the bacteria are transmitted to cats by cat fleas. however, new potential vectors are suspected of transmitting b. henselae, in particular, ixodes ricinus, the most abundant ixodid ti ... | 2008 | 18598628 |
| ovarian intercellular bridges in dermacentor andersoni stiles (acari : ixodidae). | intercellular bridges are present between oogonia and between oocytes of nymphs and newly molted and fasting adult dermacentor andersoni stiles. during these stages there is synchronous development of oogonia and oocytes. these bridges are unique both in their degree of development and in possessing narrow, elongated invaginations of the plasma membrane around both bases. dictyosomes are frequently present in close proximity to bridge bases and vesicles are often noted in bridges between oocytes ... | 1971 | 18631576 |
| north american encephalitic arboviruses. | arboviruses continue to be a major cause of encephalitis in north america, and west nile virus neuroinvasive disease is now the dominant cause of encephalitis. transmission to humans of north american arboviruses occurs by infected mosquitoes or ticks. most infections are asymptomatic or produce a flulike illness. rapid serum or cerebrospinal fluid igm antibody capture elisa assays are available to diagnosis the acute infection for all north american arboviruses. unfortunately, no antiviral drug ... | 2008 | 18657724 |
| indicators for elevated risk of human exposure to host-seeking adults of the rocky mountain wood tick (dermacentor andersoni) in colorado. | the human-biting adult stage of the rocky mountain wood tick (dermacentor andersoni) can cause tick paralysis in humans and domestic animals and is the primary tick vector in the intermountain west of the pathogens causing colorado tick fever, rocky mountain spotted fever, and tularemia. we conducted drag sampling studies in poudre canyon and rocky mountain national park of larimer county, co, to determine microhabitat use patterns by host-seeking d. andersoni adults and find environmental facto ... | 2008 | 18697314 |
| an insight into the salivary transcriptome and proteome of the soft tick and vector of epizootic bovine abortion, ornithodoros coriaceus. | the salivary glands of blood-sucking arthropods contain a redundant 'magic potion' that counteracts their vertebrate host's hemostasis, inflammation, and immunity. we here describe the salivary transcriptome and proteomics (sialome) of the soft tick ornithodoros coriaceus. the resulting analysis helps to consolidate the classification of common proteins found in both soft and hard ticks, such as the lipocalins, kunitz, cystatin, basic tail, hebraein, defensin, til domain, metalloprotease, 5'-nuc ... | 2008 | 18725333 |
| detection of francisella tularensis in ticks and identification of their genotypes using multiple-locus variable-number tandem repeat analysis. | tularemia was reported in china over 50 years ago, however, many epidemical characteristics remain unclear. in the present study, the prevalence of francisella tularensis in ticks was investigated during an epidemiological surveillance in china and then we measured their genetic diversity by conducting multiple-locus variable- number tandem repeat analysis (mlva). | 2008 | 18798995 |
| detection of tick-borne pathogens by masstag polymerase chain reaction. | masstag polymerase chain reaction (pcr) is a platform that enables microbe detection using primers labeled through a photocleavable link with tags that vary in molecular weight. after multiplex pcr, tags are released by ultraviolet irradiation and analyzed by mass spectroscopy. the identification of a microbe in a sample is determined by its cognate tags. here we describe establishment and implementation of a masstag pcr panel for surveillance of microbes implicated in tick-vectored infectious d ... | 2009 | 18800864 |
| identification of genetic determinants of a tick-borne flavivirus associated with host-specific adaptation and pathogenicity. | tick-borne flaviviruses are maintained in nature in an enzootic cycle involving a tick vector and a vertebrate host. thus, the virus replicates in two disparate hosts, each providing selective pressures that can influence virus replication and pathogenicity. to identify viral determinants associated with replication in the individual hosts, plaque purified langat virus (tp21pp) was adapted to growth in mouse or tick cell lines to generate two virus variants, mnbp20 and isep20, respectively. viru ... | 2008 | 18823640 |
| francisella tularensis: an arthropod-borne pathogen. | arthropod transmission of tularemia occurs throughout the northern hemisphere. few pathogens show the adaptability of francisella tularensis to such a wide array of arthropod vectors. nonetheless, arthropod transmission of f. tularensis was last actively investigated in the first half of the 20th century. this review will focus on arthropod transmission to humans with respect to vector species, modes of transmission, geographic differences and f. tularensis subspecies and clades. | 2009 | 18950590 |
| quantitative differences in salivary pathogen load during tick transmission underlie strain-specific variation in transmission efficiency of anaplasma marginale. | the relative fitness of arthropod-borne pathogens within the vector can be a major determinant of pathogen prevalence within the mammalian host population. strains of the tick-borne rickettsia anaplasma marginale differ markedly in transmission efficiency, with a consequent impact on pathogen strain structure. we have identified two a. marginale strains with significant differences in the transmission phenotype that is effected following infection of the salivary gland. we have proposed competin ... | 2009 | 18955472 |
| host surveys, ixodid tick biology and transmission scenarios as related to the tick-borne pathogen, ehrlichia canis. | the ehrlichioses have been subject to increasing interest from veterinary and public health perspectives, but experimental studies of these diseases and their etiologic agents can be challenging. ehrlichia canis, the primary etiologic agent of canine monocytic ehrlichiosis, is relatively well characterized and offers unique advantages and opportunities to study interactions between a monocytotropic pathogen and both its vertebrate and invertebrate hosts. historically, advances in tick-borne dise ... | 2008 | 18963493 |
| exploring the mialome of ticks: an annotated catalogue of midgut transcripts from the hard tick, dermacentor variabilis (acari: ixodidae). | ticks are obligate blood feeders. the midgut is the first major region of the body where blood and microbes ingested with the blood meal come in contact with the tick's internal tissues. little is known about protein expression in the digestive tract of ticks. in this study, for analysis of global gene expression during tick attachment and feeding, we generated and sequenced 1,679 random transcripts (ests) from cdna libraries from the midguts of female ticks at varying stages of feeding. | 2008 | 19021911 |
| effects of ambient temperature and cattle skin temperature on engorgement of dermacentor andersoni. | experiments were conducted to determine whether changes in skin temperature of cattle held at ambient temperatures ranging from 10 degrees c to 30 degrees c influenced engorgement of female dermacentor andersoni (stiles). average skin temperature of angus cattle increased from 29 degrees c to 34 degrees c, whereas skin temperature of holstein cattle increased from 32 degrees c to 35 degrees c over the range of ambient temperatures. changes in skin and ambient temperature strongly influenced the ... | 2008 | 19058622 |
| reproductive compatibility of prairie and montane populations of dermacentor andersoni. | genetic analysis of prairie and montane populations of dermacentor andersoni (stiles) originating from alberta (ab) and british columbia (bc), canada, respectively, indicated limited gene flow (nm <1) and a large amount of genetic differentiation (fst = 0.49) between the populations. the prairie population also had a greater level of genetic diversity. mating experiments indicated that females of geographically heterogeneous crosses had similar engorgement and oviposition failure as homogenous c ... | 2008 | 19058630 |
| field collection and genetic classification of tick-borne rickettsiae and rickettsiae-like pathogens from south texas: coxiella burnetii isolated from field-collected amblyomma cajennense. | we are reporting the first known isolation of the q-fever agent coxiella burnetii from field-collected cayenne ticks amblyomma cajennense in north america. q-fever affects a number of domestic ungulates where it can lead to abortion in sheep and goats. there is far less known about the disease's effects on wild species, primarily because of the tendency of the disease to self resolve and to provide long-term immunity to subsequent infections. the first recovery of c. burnetii in north america wa ... | 2008 | 19120212 |
| conservation in the face of diversity: multistrain analysis of an intracellular bacterium. | with the recent completion of numerous sequenced bacterial genomes, notable advances have been made in understanding the level of conservation between various species. however, relatively little is known about the genomic diversity among strains. we determined the complete genome sequence of the florida strain of anaplasma marginale, and near complete (>96%) sequences for an additional three strains, for comparative analysis with the previously fully sequenced st. maries strain genome. | 2009 | 19134224 |
| prevalence of rickettsia species in canadian populations of dermacentor andersoni and d. variabilis. | we determined the prevalence of rickettsiae in dermacentor adults at 15 localities in canada. rickettsia rickettsii was not detected in any tick, whereas rickettsia peacockii was present in 76% of dermacentor andersoni adults and rickettsia montanensis in 8% of dermacentor variabilis adults. this host specificity was maintained in localities where both tick species occurred in sympatry. | 2009 | 19151178 |
| rickettsia phylogenomics: unwinding the intricacies of obligate intracellular life. | completed genome sequences are rapidly increasing for rickettsia, obligate intracellular alpha-proteobacteria responsible for various human diseases, including epidemic typhus and rocky mountain spotted fever. in light of phylogeny, the establishment of orthologous groups (ogs) of open reading frames (orfs) will distinguish the core rickettsial genes and other group specific genes (class 1 ogs or c1ogs) from those distributed indiscriminately throughout the rickettsial tree (class 2 og or c2ogs) ... | 2008 | 19194535 |
| 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 ... | 2009 | 19196014 |
| allopatric speciation in ticks: genetic and reproductive divergence between geographic strains of rhipicephalus (boophilus) microplus. | the cattle tick, rhipicephalus (boophilus) microplus, economically impact cattle industry in tropical and subtropical regions of the world. the morphological and genetic differences among r. microplus strains have been documented in the literature, suggesting that biogeographical and ecological separation may have resulted in boophilid ticks from america/africa and those from australia being different species. to test the hypothesis of the presence of different boophilid species, herein we perfo ... | 2009 | 19243585 |
| nonrandom distribution of vector ticks (dermacentor variabilis) infected by francisella tularensis. | the island of martha's vineyard, massachusetts, is the site of a sustained outbreak of tularemia due to francisella tularensis tularensis. dog ticks, dermacentor variabilis, appear to be critical in the perpetuation of the agent there. tularemia has long been characterized as an agent of natural focality, stably persisting in characteristic sites of transmission, but this suggestion has never been rigorously tested. accordingly, we sought to identify a natural focus of transmission of the agent ... | 2009 | 19247435 |
| cell lines from the soft tick ornithodoros moubata. | primary cell cultures (n = 16) were initiated from tissues of embryonic and neonatal larval ornithodoros moubata following methods developed for hard ticks. after maintenance for 20-25 months in vitro, cell multiplication commenced in surviving cultures, leading to the establishment of six cell lines designated ome/ctvm21, 22, 24, 25, 26 and 27. all lines are maintained at 28 degrees c, with subculture at 2-8 week intervals. the cultures comprise heterogeneous populations of large cells of 15-10 ... | 2009 | 19252822 |
| a novel sphingomyelinase-like enzyme in ixodes scapularis tick saliva drives host cd4 t cells to express il-4. | tick feeding modulates host immune responses. tick-induced skewing of host cd4(+) t cells towards a th2 cytokine profile facilitates transmission of tick-borne pathogens that would otherwise be neutralized by th1 cytokines. tick-derived factors that drive this th2 response have not previously been characterized. in the current study, we examined an i. scapularis cdna library prepared at 18-24 h of feeding and identified and expressed a tick gene with homology to loxosceles spider venom proteins ... | 2009 | 19292772 |