Publications

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
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
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
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
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
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
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
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
an incidental case of tick paralysis in a holstein calf exposed to dermacentor andersoni.		1992	17423967
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
real-time pcr for francisella tularensis types a and b.		2006	17283646
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
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
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
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
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
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
importance of ticks and their chemical and immunological control in livestock.	the medical and economic importance of ticks has long been recognized due to their ability to transmit diseases to humans and animals. ticks cause great economic losses to livestock, and adversely affect livestock hosts in several ways. loss of blood is a direct effect of ticks acting as potential vector for haemo-protozoa and helminth parasites. blood sucking by large numbers of ticks causes reduction in live weight and anemia among domestic animals, while their bites also reduce the quality of ...	0	17048307
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
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
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
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
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
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
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
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
the microbial flora of the rocky mountain wood tick, dermacentor andersoni stiles.		1942	16560577
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
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
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
dermatologic emergencies.		2005	16301696
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
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
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 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
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
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
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
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
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
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
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
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
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
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
ehrlichia prevalence in amblyomma americanum, central texas.		2004	15338551
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
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
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
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
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
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
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
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
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
anaplasma marginale theiler observed in the gut and excreta of dermacentor andersoni stiles (dermacentor venustus marx).		1964	14204828
nonpathogenic rickettsias related to the spotted fever group isolated from ticks, dermacentor variabilis and dermacentor andersoni from eastern montana.		1963	14053295
morphology and functioning of the mouthparts of dermacentor andersoni stiles.		1960	13851716
isolation of a virus closely related to powassan virus from dermacentor andersoni collected along north cache la poudre river, colo.		1960	13838002
the possible role of ticks as vectors of leptospire. ii. infection of the ixodid ticks, dermacentor andersoni and amblyomma maculatum, with leptospira pomona.		1959	13806052
identification of rickettsia rickettsii in the wood tick, dermacentor andersoni, by means of fluorescent antibody.		1960	13688983
development of colorado tick fever virus in the rocky mountain wood tick, dermacentor andersoni.		1959	13626953
transmission of anaplasma marginale by boophilus microplus: retention of vector competence in the absence of vector-pathogen interaction.	whether arthropod vectors retain competence for transmission of infectious agents in the long-term absence of vector-pathogen interaction is unknown. we addressed this question by quantifying the vector competence of two tick vectors, with mutually exclusive tropical- versus temperate-region distributions, for genetically distinct tropical- and temperate-region strains of the cattle pathogen anaplasma marginale. the tropical cattle tick boophilus microplus, which has been eradicated from the con ...	2003	12904396
characterization of a recombinant immunomodulatory protein from the salivary glands of dermacentor andersoni.	the gene encoding a 36-kda (p36) immunomodulatory protein present in saliva of dermacentor andersoni was cloned in prokaryotic and eukaryotic expression vectors. a polymerase chain reaction (pcr)-generated cdna lacking signal peptide was cloned into the escherichia coli expression vector pet28 and a similar sequence was cloned into pib/v5-his-topo expression vector for stable transfection of insect cells, high 5 trade mark. the 26-kda molecular mass of p36 expressed by bacteria is in agreement w ...	2003	12791102
recombinant vp7-based enzyme-linked immunosorbent assay for detection of immunoglobulin g antibodies to colorado tick fever virus.	vp6, vp7, vp9, vp10, vp11, and vp12 of colorado tick fever virus (ctf virus), a virus member of the genus coltivirus, family reoviridae, were expressed in bacteria with the pgex-4t-2 vector. a partial sequence of vp7 (designated pvp7) was chosen to elaborate an enzyme-linked immunosorbent assay (elisa) for detecting anti-ctf virus immunoglobulin g (igg) antibodies in humans. this was based on two observations: (i) among all expressed proteins, pvp7 showed the highest immunoreactivity to an anti- ...	2003	12734255
increasing the paralyzing ability of a laboratory colony of dermacentor andersoni stiles.	field-collected rocky mountain wood ticks dermacentor andersoni stiles from british columbia caused limited paralysis in hamsters at high doses, but not at lower doses, while ticks collected from alberta failed to cause paralysis. this prompted development of a laboratory strain of ticks with a more consistent ability to cause paralysis. progeny of ticks that paralyzed a cow near walhachin, british columbia were reared and assayed for paralyzing ability. a high-virulence colony was selected for ...	2003	12693847
findings of scientific misconduct.		0	12666658
bartonella henselae in ixodes ricinus ticks (acari: ixodida) removed from humans, belluno province, italy.	the potential role of ticks as vectors of bartonella species has recently been suggested. in this study, we investigated the presence of bartonella species in 271 ticks removed from humans in belluno province, italy. by using primers derived from the 60-kda heat shock protein gene sequences, bartonella dna was amplified and sequenced from four ixodes ricinus ticks (1.48%). to confirm this finding, we performed amplification and partial sequencing of the pap31 protein and the cell division protei ...	2003	12643827
antigenic classification of rickettsia felis by using monoclonal and polyclonal antibodies.	rickettsia felis is a flea-transmitted rickettsia. there is a discrepancy between its reported phylogenic and phenotypic identifications. following the first report of r. felis, it was considered by tests with serologic reagents to be closely related to another recognized flea-transmitted rickettia, r. typhi. subsequently, it appeared to be more closely related to spotted fever group (sfg) rickettsiae by genetic analysis. in the present work, r. felis was studied by microimmunofluorescence (mif) ...	2003	12626446
expression of anaplasma marginale major surface protein 2 operon-associated proteins during mammalian and arthropod infection.	the antigenically variant major surface protein 2 (msp2) of anaplasma marginale is expressed from a 3.5-kb operon that contains, in a 5'-to-3' direction, four open reading frames, opag3, opag2, opag1, and msp2. this operon structure was shown to be conserved among genotypically and phenotypically distinct a. marginale, a. ovis, and a. centrale strains. the individual opag amino acid sequences are highly conserved among a. marginale strains, with identities ranging from 95 to 99%. opag2 and opag3 ...	2002	12379676
tularemia.	francisella tularensis is the etiological agent of tularemia, a serious and occasionally fatal disease of humans and animals. in humans, ulceroglandular tularemia is the most common form of the disease and is usually a consequence of a bite from an arthropod vector which has previously fed on an infected animal. the pneumonic form of the disease occurs rarely but is the likely form of the disease should this bacterium be used as a bioterrorism agent. the diagnosis of disease is not straightforwa ...	2002	12364373
detection of rickettsia prowazekii in body lice and their feces by using monoclonal antibodies.	in order to identify rickettsia prowazekii in lice, we developed a panel of 29 representative monoclonal antibodies selected from 187 positive hybridomas made by fusing splenocytes of immunized mice with sp2/0-ag14 myeloma cells. immunoblotting revealed that 15 monoclonal antibodies reacted with the lipopolysaccharide-like (lps-l) antigen and 14 reacted with the epitopes of a 120-kda protein. only typhus group rickettsiae reacted with the monoclonal antibodies against lps-l. r. felis, a recently ...	2002	12202579
rickettsia monacensis sp. nov., a spotted fever group rickettsia, from ticks (ixodes ricinus) collected in a european city park.	we describe the isolation and characterization of rickettsia monacensis sp. nov. (type strain, irr/munich(t)) from an ixodes ricinus tick collected in a city park, the english garden in munich, germany. rickettsiae were propagated in vitro with ixodes scapularis cell line ise6. blast analysis of the 16s rrna, the citrate synthase, and the partial 190-kda rickettsial outer membrane protein a (rompa) gene sequences demonstrated that the isolate was a spotted fever group (sfg) rickettsia closely re ...	2002	12200314
comparison of differentially expressed genes in the salivary glands of male ticks, amblyomma americanum and dermacentor andersoni.	genes expressed differentially in the salivary glands of unfed and fed male ticks, amblyomma americanum (l.), were identified, cloned and sequenced, and some were compared with those expressed in the salivary glands of dermacentor andersoni. total protein and rna increased sixfold in the salivary glands of fed male a. americanum, while in fed male d. andersoni salivary glands, rna increased approximately 3.5 times. feeding d. andersoni in the presence of females increased total rna by 25% over t ...	2002	12020839
infection of tick cells and bovine erythrocytes with one genotype of the intracellular ehrlichia anaplasma marginale excludes infection with other genotypes.	anaplasma marginale, a tick-borne rickettsial pathogen of cattle, is endemic in several areas of the united states. many geographic isolates of a. marginale that occur in the united states are characterized by the major surface protein 1a, which varies in sequence and molecular weight due to different numbers of tandem repeats of 28 or 29 amino acids. recent studies (g. h. palmer, f. r. rurangirwa, and t. f. mcelwain, j. clin. microbiol. 39:631-635, 2001) of an a. marginale-infected herd of catt ...	2002	11986275
colorado tick fever.	colorado tick fever, also known as mountain fever and mountain tick fever, is a well-described, viral, tick-borne disease common to the rocky mountain region of the united states and canada. the rocky mountain wood tick, dermacentor andersoni, is the primary vector. the triad of high fever, severe myalgia, and headache is typical, but not specific. although a self-limited disease in most cases, severe complications may occur. pcr techniques have been developed that allow the diagnosis to be esta ...	2002	11982311
specific expression of anaplasma marginale major surface protein 2 salivary gland variants occurs in the midgut and is an early event during tick transmission.	infectivity of anaplasma spp. develops when infected ticks feed on a mammalian host (transmission feed). specific anaplasma marginale major surface protein 2 (msp2) variants are selected for within the tick and are expressed within the salivary glands. the aims of this study were to determine when and where msp2 variant selection occurs in the tick, how msp2 expression is regulated in salivary glands of transmission-feeding ticks, and whether the number of a. marginale organisms per salivary gla ...	2002	11748171
transcriptional analysis of p30 major outer membrane multigene family of ehrlichia canis in dogs, ticks, and cell culture at different temperatures.	ehrlichia canis, an obligatory intracellular bacterium of monocytes and macrophages, causes canine monocytic ehrlichiosis. e. canis immunodominant 30-kda major outer membrane proteins are encoded by a polymorphic multigene family consisting of more than 20 paralogs. in the present study, we analyzed the mrna expression of 14 paralogs in experimentally infected dogs and rhipicephalus sanguineus ticks by reverse transcription-pcr using gene-specific primers followed by southern blotting. eleven ou ...	2001	11553557
health protocol for translocation of free-ranging elk.	when considering an elk (cervus elaphus) restoration program, wildlife managers must evaluate the positive and negative elements of translocation. we prepared this protocol to give an overview of health considerations associated with translocation of elk, with an emphasis on movement of free-ranging elk from western north america to the southeastern usa. we evaluated infectious agents and ectoparasites reported in elk from two perspectives. first, we made a qualitative estimate of the ability of ...	2001	11504216
dermacentor andersoni: effects of repeated infestations on lymphocyte proliferation, cytokine production, and adhesion-molecule expression by balb/c mice.	the effects of repeated infestations with dermacentor andersoni nymphs on the lymphocyte functions of balb/c mice were investigated. the in-vitro proliferation responses to concanavalin-a or salivary-gland molecules, the production of cytokines, and the expression of two adhesion molecules-leucocyte function-associated antigen-1 (lfa-1) and very late activation-4 (vla-4)-were all studied. in addition, the ability of salivary-gland extract or saliva from d. andersoni to modulate expression of lym ...	2001	11454252
expression of anaplasma marginale major surface protein 2 variants in persistently infected ticks.	anaplasma marginale, an intraerythrocytic ehrlichial pathogen of cattle, establishes persistent infections in both vertebrate (cattle) and invertebrate (tick) hosts. the ability of a. marginale to persist in cattle has been shown to be due, in part, to major surface protein 2 (msp2) variants which are hypothesized to emerge in response to the bovine immune response. msp2 antigenic variation has not been studied in persistently infected ticks. in this study we analyzed msp2 in a. marginale popula ...	2001	11447197
quantitative analyses of variations in the injury of endothelial cells elicited by 11 isolates of rickettsia rickettsii.	eleven isolates of spotted fever group rickettsiae from the blood of patients or ixodid ticks from north and south america were characterized. all isolates were identified as rickettsia rickettsii using restriction fragment length polymorphism analysis of a 532-bp rompa gene fragment obtained by pcr. the ability of the r. rickettsii isolates to elicit cytopathic effects and parameters of oxidative injury were examined in cultured human ea.hy 926 endothelial cells. cytopathic effects were determi ...	2001	11427428
antigenic variation of anaplasma marginale: major surface protein 2 diversity during cyclic transmission between ticks and cattle.	the rickettsial pathogen anaplasma marginale expresses a variable immunodominant outer membrane protein, major surface protein 2 (msp2), involved in antigenic variation and long-term persistence of the organism in carrier animals. msp2 contains a central hypervariable region of about 100 amino acids that encodes immunogenic b-cell epitopes that induce variant-specific antibodies during infection. previously, we have shown that msp2 is encoded on a polycistronic mrna transcript in erythrocyte sta ...	2001	11292724
molecular evidence of bartonella spp. in questing adult ixodes pacificus ticks in california.	ticks are the vectors of many zoonotic diseases in the united states, including lyme disease, human monocytic and granulocytic ehrlichioses, and rocky mountain spotted fever. most known bartonella species are arthropod borne. therefore, it is important to determine if some bartonella species, which are emerging pathogens, could be carried or transmitted by ticks. in this study, adult ixodes pacificus ticks were collected by flagging vegetation in three sites in santa clara county, calif. pcr-res ...	2001	11283031
what's eating you? dermacentor andersoni.		2001	11236219
neuropathogenic properties of argas (persicargas) walkerae larval homogenates.	several tick species have been demonstrated, described, or suspected to cause paralysis in their host during the repletion process, presumably by impairing neurotransmission. the resulting polyneuropathy gradually spreads to the upper limbs causing incoordination and ends in respiratory failure. this form of paralysis is commonly confused with guillain-barrè syndrome, botulism and myasthenia gravis and although the clinical symptoms of these diseases are similar, it is not clear whether the path ...	2001	11223384
strain composition of the ehrlichia anaplasma marginale within persistently infected cattle, a mammalian reservoir for tick transmission.	tick-borne ehrlichial pathogens of animals and humans require a mammalian reservoir of infection from which ticks acquire the organism for subsequent transmission. in the present study, we examined the strain structure of anaplasma marginale, a genogroup ii ehrlichial pathogen, in both an acute outbreak and in persistently infected cattle that serve as a reservoir for tick transmission. using the msp1alpha genotype as a stable strain marker, only a single genotype was detected in a disease outbr ...	2001	11158120
isolation of a spotted fever group rickettsia, rickettsia peacockii, in a rocky mountain wood tick, dermacentor andersoni, cell line.	an embryonic cell line (dae100) of the rocky mountain wood tick, dermacentor andersoni, was observed by microscopy to be chronically infected with a rickettsialike organism. the organism was identified as a spotted fever group (sfg) rickettsia by pcr amplification and sequencing of portions of the 16s rrna, citrate synthase, rickettsia genus-specific 17-kda antigen, and sfg-specific 190-kda outer membrane protein a (rompa) genes. sequence analysis of a partial rompa gene pcr fragment and indirec ...	2001	11157215
evaluation of pcr-based methods for discrimination of francisella species and subspecies and development of a specific pcr that distinguishes the two major subspecies of francisella tularensis.	previous studies have demonstrated that the four subspecies of the human pathogen francisella tularensis, despite showing marked variations in their virulence for mammals and originating from different regions in the northern hemisphere, display a very close phylogenetic relationship. this property has hampered the development of generally applicable typing methods. to overcome this problem, we evaluated the use of pcr for discrimination of the subspecies using various forms of long arbitrary pr ...	2000	11060087
antigenic variation of anaplasma marginale by expression of msp2 mosaics.	anaplasma marginale is a tick-borne pathogen, one of several closely related ehrlichial organisms that cause disease in animals and humans. these ehrlichia species have complex life cycles that require, in addition to replication and development within the tick vector, evasion of the immune system in order to persist in the mammalian reservoir host. this complexity requires efficient use of the small ehrlichial genome. a. marginale and related ehrlichiae express immunoprotective, variable outer ...	2000	11035716
influence of soluble proteins from the salivary glands of ixodid ticks on the in-vitro proliferative responses of lymphocytes from balb/c and c3h/hen mice.	in the u.s.a., borrelia burgdorferi, the causative agent of lyme borreliosis, is transmitted to humans by the ticks ixodes scapularis and i. pacificus. tick modulation of host immunity is an important factor in tick transmission of such pathogens. the proliferative responses of lymphocytes from balb/c and c3h/hen mice exposed to the salivary-gland soluble proteins (sgsp) of i. scapularis, i. pacificus or dermacentor andersoni were therefore compared in vitro. this produced the present report, th ...	2000	10983564
a state-by-state survey of ticks recorded from humans in the united states.	based on tick specimens accessioned into the u.s. national tick collection, the species of ticks recorded as ectoparasites of humans are documented and compared for 49 u.s. states. a total of 44 tick species was recorded as parasites of humans, consisting of 11 species of soft ticks (argasidae) and 33 species of hard ticks (ixodidae). four of the hard tick species are not native to the u.s. and were removed from travelers returning from foreign destinations. therefore, we record 40 of the 84 spe ...	2000	10925803
clinical manifestations of tick-borne infections in children.		2000	10882645
isolation and molecular cloning of a secreted immunosuppressant protein from dermacentor andersoni salivary gland.	a 36-kda immunosuppressant protein (da-p36) was isolated from salivary glands of feeding female ixodid ticks dermacentor andersoni, using its affinity for ultralink biosupport medium (pierce, rockford, illinois)/protein complexes. using a nested set of forward degenerate oligonucleotide primers corresponding to da-p36 n-terminal amino acids, a cdna encoding the immunosuppressant protein was isolated by 3' rapid amplification of cdna ends. the resulting 772-base pair cdna encodes a novel protein ...	2000	10864249
strain diversity in major surface protein 2 expression during tick transmission of anaplasma marginale.	specific major surface protein 2 (msp2) variants are expressed by anaplasma marginale within the tick salivary gland and, following transmission, are expressed during acute rickettsemia. in previous work, we have shown that a restricted pattern of msp2 variants is expressed in the salivary glands of dermacentor andersoni ticks infected with the south idaho strain of a. marginale. now we demonstrate that the identical restriction does not apply to two other strains of a. marginale, and that diffe ...	2000	10769008
immunity reduces reservoir host competence of peromyscus leucopus for ehrlichia phagocytophila.	infection with ehrlichia phagocytophila in white-footed mice is transient and followed by a strong immune response. we investigated whether the presence of acquired immunity against e. phagocytophila precludes white-footed mice from further maintenance of this agent in nature. mice were infected with e. phagocytophila via tick bite and challenged either 12 or 16 weeks later by ixodes scapularis nymphs infected with the same agent. xenodiagnostic larvae fed upon each mouse simultaneously with cha ...	2000	10678968
tick paralysis: 33 human cases in washington state, 1946-1996.	tick paralysis is a preventable cause of illness and death that, when diagnosed promptly, requires simple, low-cost intervention (tick removal). we reviewed information on cases of tick paralysis that were reported to the washington state department of health (seattle) during 1946-1996. thirty-three cases of tick paralysis were identified, including 2 in children who died. most of the patients were female (76%), and most cases (82%) occurred in children aged <8 years. nearly all cases with infor ...	1999	10585792
q fever.	q fever is a zoonosis with a worldwide distribution with the exception of new zealand. the disease is caused by coxiella burnetii, a strictly intracellular, gram-negative bacterium. many species of mammals, birds, and ticks are reservoirs of c. burnetii in nature. c. burnetii infection is most often latent in animals, with persistent shedding of bacteria into the environment. however, in females intermittent high-level shedding occurs at the time of parturition, with millions of bacteria being r ...	1999	10515901
characterization of mutations in the rpob gene in naturally rifampin-resistant rickettsia species.	rickettsiae are gram-negative, obligately intracellular bacteria responsible for arthropod-borne spotted fevers and typhus. experimental studies have delineated a cluster of naturally rifampin-resistant spotted fever group species. we sequenced the 4, 122- to 4,125-bp rna polymerase beta-subunit-encoding gene (rpob) from typhus and spotted fever group representatives and obtained partial sequences for all naturally rifampin-resistant species. a single point mutation resulting in a phenylalanine- ...	1999	10508014
invasion and intracellular development of the human granulocytic ehrlichiosis agent in tick cell culture.	human granulocytotropic ehrlichias are tick-borne bacterial pathogens that cause an acute, life-threatening illness, human granulocytic ehrlichiosis (hge). ehrlichias within neutrophil granulocytes that invade tick bite sites are likely ingested by the vector, to be transmitted to another mammalian host during the tick's next blood meal. thus, the cycle of replication and development in the vector is prerequisite to mammalian infection, and yet these events have not been described. we report tic ...	1999	10405394