Publications

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
dermatologic emergencies.		2005	16301696
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
clinical manifestations of tick-borne infections in children.		2000	10882645
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
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
successive tick infestations selectively promote a t-helper 2 cytokine profile in mice.	several studies have revealed that t lymphocytes and cytokines play a crucial role in determining the outcome of parasitic infections in terms of protective immunity. in this study we found that rhipicephalus sanguineus tick saliva stimulates transforming growth factor-beta (tgf-beta), and reduces interleukin-12 (il-12) secretion by cells from normal c3h/hej mice. moreover, murine lymph node cells harvested 6 days after the fourth infestation with ticks presented an 82.4% decrease in their proli ...	1999	10233725
detection and identification of ehrlichia, borrelia burgdorferi sensu lato, and bartonella species in dutch ixodes ricinus ticks.	a sensitive and specific pcr hybridization assay was developed for the simultaneous detection and identification of ehrlichia and borrelia burgdorferi sensu lato. in separate assays the 16s rrna gene of ehrlichia species and the 23s-5s rrna spacer region of b. burgdorferi sensu lato were amplified and labeled by pcr. these pcr products were used in a reverse line blot hybridization assay in which oligonucleotide probes are covalently linked to a membrane in parallel lines. hybridization of the s ...	1999	10364588
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
body lice as tools for diagnosis and surveillance of reemerging diseases.	body lice are vectors of three bacteria which cause human disease: rickettsia prowazekii, the agent of epidemic typhus; bartonella quintana, the agent of trench fever; and borrelia recurrentis, the agent of relapsing fever. a recrudescence of body lice is being observed as the numbers of individuals living under social conditions which predispose individuals to infestation have increased. because this phenomenon may lead to the reemergence of infections transmitted by body lice, we aimed to asse ...	1999	9986818
comparison of ehrlichia muris strains isolated from wild mice and ticks and serologic survey of humans and animals with e. muris as antigen.	in metropolitan tokyo, the ehrlichia muris seropositivity rate of 24 wild mice was 63% in hinohara village, but in the surrounding areas, it was 0 to 5%. this finding suggests that the reservoir of e. muris is focal. among the 15 seropositive mice, ehrlichiae were isolated from 9 apodemus speciosus mice and 1 a. argenteus mouse, respectively. five ehrlichial isolates were obtained from 10 ticks (haemaphysalis flava) collected in asuke town, aichi prefecture, where the e. muris type strain had be ...	1999	10074536
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
comparison of surface proteins of anaplasma marginale grown in tick cell culture, tick salivary glands, and cattle.	anaplasma marginale, a tick-borne rickettsial pathogen of cattle, infects bovine erythrocytes, resulting in mild to severe hemolytic disease that causes economic losses in domestic livestock worldwide. recently, the virginia isolate of a. marginale was propagated in a continuous tick cell line, ide8, derived from embryonic ixodes scapularis. development of a. marginale in cell culture was morphologically similar to that described previously in ticks. in order to evaluate the potential of the cel ...	1999	9864202
restriction of major surface protein 2 (msp2) variants during tick transmission of the ehrlichia anaplasma marginale.	anaplasma marginale is an ehrlichial pathogen of cattle that establishes lifelong persistent infection. persistence is characterized by rickettsemic cycles in which new a. marginale variant types, defined by the sequence of the expressed msp2 transcripts, emerge. the polymorphic msp2 transcripts encode structurally distinct msp2 proteins and result in an antigenically diverse and continually changing a. marginale population within the blood. in this manuscript, we used sequence analysis of msp2 ...	1999	10077656
lethal effect of rickettsia rickettsii on its tick vector (dermacentor andersoni).	rickettsia rickettsii, the causative agent of rocky mountain spotted fever, was lethal for the majority of experimentally and transovarially infected rocky mountain wood ticks (dermacentor andersoni). overall, 94.1% of nymphs infected as larvae by feeding on rickettsemic guinea pigs died during the molt into adults and 88. 3% of adult female ticks infected as nymphs died prior to feeding. in contrast, only 2.8% of uninfected larvae failed to develop into adults over two generations. infected fem ...	1999	9925615
detection of cattle naturally infected with anaplasma marginale in a region of endemicity by nested pcr and a competitive enzyme-linked immunosorbent assay using recombinant major surface protein 5.	a competitive enzyme-linked immunosorbent assay using recombinant major surface protein 5 (rmsp5-celisa) of anaplasma marginale was validated in a naturally infected cattle herd in an area of eastern oregon where a. marginale is endemic. the true positive and negative a. marginale infection status of 235 randomly selected cattle was determined by using a nested pcr (npcr) coupled with msp5 sequence analysis and hybridization. judgment of the reliability of the npcr and hybridization for detectio ...	1998	9508311
persistence of anaplasma ovis infection and conservation of the msp-2 and msp-3 multigene families within the genus anaplasma.	goats which have recovered from acute anaplasma ovis infection remain seropositive, although infected erythrocytes cannot be detected by microscopic examination. persistence of a. ovis 17 to 21 months following experimental infection was demonstrated by pcr detection of the msp-5 gene. quantitative analysis of persistent rickettsemia over time showed that all levels were below the limit of microscopic detection and ranged from a low of 10(2) organisms/ml to peaks of 10(6) organisms/ml. two patte ...	1998	9826393
taxonomic relationships among spotted fever group rickettsiae as revealed by antigenic analysis with monoclonal antibodies.	the spotted fever group (sfg) is made up of more than 20 different rickettsial species and strains. study of the taxonomic relationships among the group has been attempted by phenotypic, genotypic, and phylogenetic analyses. in this study, we determined taxonomic relationships among the sfg rickettsiae by comparative analysis of immunogenic epitopes reactive against a panel of monoclonal antibodies. a total of 98 monoclonal antibodies, which were directed against epitopes on the major immunodomi ...	1998	9542904
in vitro susceptibilities of 27 rickettsiae to 13 antimicrobials.	the mics of 13 antibiotics (doxycycline, thiamphenicol, rifampin, amoxicillin, gentamicin, co-trimoxazole, ciprofloxacin, pefloxacin, ofloxacin, erythromycin, josamycin, clarithromycin, and pristinamycin) were determined for 27 available rickettsial species or strains. we used two in vitro cell culture methods described previously: the plaque assay and the microplaque colorimetric assay. our results confirm the susceptibilities of rickettsiae to doxycycline, thiamphenicol, and fluoroquinolones. ...	1998	9660979
development of a non-radioactive dna probe and in situ hybridization for detection of anaplasma marginale in ticks and cattle.	a non-radioactive dna probe was developed for detection of anaplasma marginale in ticks and cattle. the probe was labeled with digoxigenin 11-dutp by polymerase chain reaction. the probe was tested on bovine blood and was found to be a sensitive and specific detection method for a. marginale in cattle. the dna probe was then adapted for in situ hybridization (ish) of a. marginale in dermacentor andersoni and d. variabilis ticks infected either as nymphs or adults. one-half of each tick was studi ...	1998	9668458
tick-borne relapsing fever in british columbia, canada: first isolation of borrelia hermsii.	the spirochete that causes tick-borne relapsing fever, borrelia hermsii, was isolated in pure culture during 1995 and 1996 from three acutely ill human patients infected in southern british columbia, canada. the geographic area of exposure is a known focus of this disease dating back to 1930 when the first case was recognized in a human. analyses of plasmid dna, protein profiles, and reactivity with a species-specific monoclonal antibody identified the new isolates of spirochetes as b. hermsii, ...	1998	9817862
phylogenetic placement of rickettsiae from the ticks amblyomma americanum and ixodes scapularis.	a rickettsial isolate (isolate moaa) belonging to the spotted fever group (sfg) was obtained from the lone star tick amblyomma americanum. we used pcr to characterize the genes for the rickettsial outer membrane proteins rompa and rompb. we sequenced the pcr products (domains i of both the rompa gene and the rompb gene) of moaa and wb-8-2, another rickettsial isolate from a. americanum. to place moaa and wb-8-2 and two other nonpathogenic isolates (rickettsia rickettsii hip2 and rickettsia monta ...	1998	9574696
characterization of an immunosuppressant protein from dermacentor andersoni (acari: ixodidae) salivary glands.	a 36-kda soluble protein was found in the salivary glands of female dermacentor andersoni (stiles) ticks that suppressed the in vitro proliferative response of murine splenocytes to concanavalin a (con a). incubating the purified protein with splenocytes reduced the incorporation of thymidine into the dna of proliferating t-lymphocytes by more than 90% compared with cells exposed to con a and buffer alone. the n-terminal amino acid sequence of the immunosuppressant protein was determined to be n ...	1998	9701936
african swine fever virus infection in the argasid host, ornithodoros porcinus porcinus.	the pathogenesis of african swine fever virus (asfv) infection in ornithodoros porcinus porcinus was examined in nymphal ticks infected with the asfv isolate chiredzi/83/1. at times postinfection (p.i.) ranging from 6 h to 290 days, ticks or dissected tick tissues were titrated for virus and examined ultrastructurally for evidence of virus replication. the asfv infection rate in ticks was 100% in these experiments, and virus infection was not associated with a significant increase in tick mortal ...	1998	9499019
granulocytic ehrlichiosis in tick-immune guinea pigs.	we investigated whether ixodes scapularis-mediated host immunity interrupts transmission of the agent of human granulocytic ehrlichiosis (aohge) to guinea pigs. ticks infected with aohge readily transmitted aohge to tick-immune guinea pigs, despite incomplete tick engorgement and host attachment. although tick immunity can prevent lyme borreliosis, protection is not afforded against granulocytic ehrlichiosis.	1998	9529119
effect of prior exposure to noninfected ticks on susceptibility of mice to lyme disease spirochetes.	to determine whether prior exposure to nearctic ixodes vector ticks protects native reservoir mice from tick-borne infection by lyme disease spirochetes, we compared their infectivities for white-footed mice and laboratory mice that had been repeatedly infested by noninfected deer ticks. nymphal ticks readily engorged on tick-exposed laboratory mice, but their feeding success on white-footed mice progressively declined. tick-borne spirochetes readily infected previously tick-infested mice. thus, ...	1998	9797328
tick-borne diseases of sheep and goats caused by babesia, theileria or anaplasma spp.	a review is given on the babesia, theileria, and anaplasma species infecting sheep and goats. b. ovis is the most important disease agent. it is transmitted by rhipicephalus bursa, r. turanicus, hyalomma anatolicum excavatum, and probably by r. evertsi evertsi b. ovis is widely spread in southern europe, the middle east, and central asia. its geographical distribution in south and east asia and in africa is widely unknown. b. motasi obviously represents several nosodemes in separate regions. it ...	1997	9530692
rickettsia peacockii sp. nov., a new species infecting wood ticks, dermacentor andersoni, in western montana.	rickettsia peacockii, a new species of spotted fever group rickettsiae, was identified from rocky mountain wood ticks (dermacentor andersoni) collected in the sapphire mountain range on the eastern side of bitterroot valley, montana. dna from r. peacockii skalkahot (t = type strain) in naturally infected tick tissue was amplified by a pcr assay with primer sets derived from eubacterial 16s ribosomal dna (rdna), rickettsial citrate synthase, and 190-kda surface antigen (rompa) genes. partial 16s ...	1997	9103635
vector competence of ixodes scapularis, i. spinipalpis, and dermacentor andersoni (acari:ixodidae) in transmitting borrelia burgdorferi, the etiologic agent of lyme disease.	this report describes the vector competence of 3 ixodid tick species, ixodes scapularis (say), i. spinipalpis (nuttall), and dermacentor andersoni (stiles), for borrelia burgdorferi in colorado. the study was based on preliminary field work performed in 6 colorado counties, where rodents and ticks were collected and assayed for the presence of b. burgdorferi. four of the 6 counties produced 52 rodent and 39 i. spinipalpis isolates of b. burgdorferi. two b. burgdorferi isolates were tested under ...	1997	9103755
characterization of an endosymbiont infecting wood ticks, dermacentor andersoni, as a member of the genus francisella.	a microorganism (dermacantor andersoni symbiont [das]) infecting rocky mountain wood ticks (d. andersoni) collected in the bitterroot mountains of western montana was characterized as an endosymbiont belonging to the genus francisella. previously described as wolbachia like, the organism's dna was amplified from both naturally infected tick ovarial tissues and vero cell cultures by pcr assay with primer sets derived from eubacterial 16s ribosomal dna (rdna) and francisella membrane protein genes ...	1997	9327558
detection of colorado tick fever virus by using reverse transcriptase pcr and application of the technique in laboratory diagnosis.	colorado tick fever (ctf) virus elicits an acute illness in humans, producing nonspecific flu-like symptoms and a biphasic fever in approximately 50% of patients. the disease is transmitted by the adult rocky mountain wood tick (dermacentor andersoni), and therefore incidence is limited by the habitat and life cycle of that vector. the early symptoms of infection are difficult to distinguish from those of several other agents, especially rickettsia rickettsii. serologic testing is usually unable ...	1997	9114408
developmental studies of anaplasma marginale (rickettsiales:anaplasmataceae) in male dermacentor andersoni (acari:ixodidae) infected as adults by using nonradioactive in situ hybridization and microscopy.	the development of anaplasma marginale theiler was studied in ticks using a nonradioactive in situ hybridization method developed in our laboratory. male rocky mountain wood ticks, dermacentor andersoni stiles, were infected intrastadially by allowing them to feed for 7 d on an infected calf (acquisition feeding). the ticks were then removed and held in a humidity chamber for 5 d before being fed on a 2nd susceptible call for 10 d (transmission feeding). two groups of 10 ticks were collected dai ...	1996	8961639
antibody against an anaplasma marginale msp5 epitope common to tick and erythrocyte stages identifies persistently infected cattle.	a protein epitope of major surface protein 5 (msp5), defined by monoclonal antibody (mab) anaf16c1, is conserved among anaplasma species (e. s. visser, t. c. mcguire, g. h. palmer, w. c. davis, v. shkap, e. pipano, and d. p. knowles, jr., infect. immun. 60:5139-5144, 1992) and is expressed in the salivary glands of infected ticks. a competitive inhibition elisa (celisa) for the detection of bovine anti-msp5 antibodies was developed by using purified recombinant msp5 fusion protein and mab anaf16 ...	1996	8862589
preliminary studies on the effect of anaplasma marginale antibodies ingested by dermacentor andersoni ticks (acari:ixodidae) with their blood meal on infections in salivary glands.	the effect of anaplasma marginale antibodies ingested with the tick blood meal was tested on infected male ticks that were allowed to feed on cattle immunized with the erythrocytic stage of a. marginale. the experiments were done in two trials. trial 1 was done using splenectomized calves (two calves per treated and control groups) while ticks in trial 2 were fed on intact yearling cattle (four cattle per treated and control groups). the cattle were immunized with purified outer membrane protein ...	1996	8674360
tick paralysis in two llamas.	an 18-month-old sexually intact male llama and a 7-month-old female llama were examined because of weakness, lethargy, and recumbency. both had signs of ascending motor paralysis with minimal or no afferent sensory loss. tick paralysis was diagnosed on the basis of complete clinical recovery following removal of a single, attached and engorged female tick (dermacentor andersoni) from each llama. the male llama recovered within a few hours after removal of the tick, but recovery in the female lla ...	1995	7591950
dermacentor andersoni: salivary gland proteins suppressing t-lymphocyte responses to concanavalin a in vitro.	salivary glands obtained from feeding adult female dermacentor andersoni (acari:ixodidae) were fractionated using differential centrifugation, detergents, centrifugal concentrators incorporating filter membranes with various molecular weight cutoffs, and preparative sds-page. a lymphocyte proliferation assay was used to evaluate the effects of salivary gland fractions on cona-induced blastogenesis of normal murine splenocytes. lipid, soluble, and detergent-soluble fractions were found to signifi ...	1995	7498423
evidence of common and genus-specific epitopes on ornithodoros spp. tick (acari: argasidae) salivary proteins.	new zealand white rabbits were repeatedly infested with ornithodoros turicata (duges), ornithodoros talaje (guérin-méneville), and ornithodoros coriaceus (koch) at 2-wk intervals. blood samples were taken from each animal 10 d after each infestation and the titer of anti-tick antibody was determined by enzyme-linked immunosorbent assay. subsequent cross-reactivity studies demonstrated that the antitick antisera nonspecifically bound to salivary gland extract proteins prepared from several other ...	1995	7544412
mosquito sensitivity to a scorpion neurotoxin expressed using an infectious sindbis virus vector.	the scorpion, androctonus australis hector, produces an insect-specific toxin (aahit) encoded by the scotox gene. to assess the toxicity of aahit for mosquitoes, we have taken a novel approach to express the scotox gene in vivo. we have engineered a double subgenomic sindbis (dssin) virus that contains the scotox gene in the viral genome and intrathoracically inoculated the virus (te/3'2j/scotox) into mosquitoes (aedes aegypti, ae. triseriatus and culex pipiens), houseflies (musca domestica) and ...	1995	7551198
effects of dermacentor andersoni (acari: ixodidae) salivary gland extracts on bos indicus and b. taurus lymphocytes and macrophages: in vitro cytokine elaboration and lymphocyte blastogenesis.	cattle and laboratory animal species-acquired resistance to tick infestation has an immunological basis involving antigen presenting cells, b-lymphocytes, t-lymphocytes, and cytokines. tick infestation has been shown to impair guinea pig antibody responses to a thymic-dependent antigen and in vitro responsiveness of lymphocytes to t-cell mitogens. tick salivary gland extracts inhibited in vitro proliferative responses of normal murine lymphocytes to the t-cell mitogen concanavalin a (con a) and ...	1995	7616525
dna typing of rickettsiae in naturally infected ticks using a polymerase chain reaction/restriction fragment length polymorphism system.	we used the polymerase chain reaction/restriction fragment length polymorphism (pcr/rflp) rickettsial typing system of regnery and others to rapidly identify rickettsiae in naturally infected ticks. unlike previously described methods, our pcr assays type rickettsiae directly from tick tissues without first isolating the organisms. we collected 226 adult dermacentor andersoni ticks in the bitterroot mountains of western montana and analyzed them for possible rickettsial infection by hemolymph te ...	1994	7906924
molecular and biological characterization of a newly isolated anaplasma marginale strain.	anaplasma marginale, a rickettsial hemoparasite of cattle and other ruminants, results in significant economic losses worldwide. distinct strains of a. marginale have been identified based on differences in tick transmissibility, molecular size of surface proteins and dna restriction fragments, and reactivity to a panel of monoclonal antibodies. these different strains vary considerably in their virulence, antigenic composition, and ability to protect against heterologous challenge. in this pape ...	1994	7858023
persistence of tick-derived anaplasma marginale in cultured bovine turbinate and endothelial cells.	anaplasma marginale from salivary glands of dermacentor andersoni was used to inoculate monolayers of bovine turbinate and endothelial cells. monolayers were passaged at 2 or 4 week intervals and monitored with light and electron microscopy and with an a. marginale-specific dna probe. intracellular inclusions were observed in turbinate cells after 2-4 weeks. the number of inclusion-bearing cells increased over 1-2 weeks and gradually disappeared. a radiolabeled fragment from within the msp1 beta ...	1993	8134656
detection of anaplasma marginale (rickettsiales: anaplasmataceae) in hemolymph of dermacentor andersoni (acari: ixodidae) with the polymerase chain reaction.	the polymerase chain reaction (pcr) was used to detect anaplasma marginale in hemolymph collected from live dermacentor andersoni stiles ticks. hemolymph was collected from severed legs of male and female ticks exposed to a. marginale as either nymphs or adults. heat treatment was found to be the optimum method of hemolymph preparation for pcr. hemolymph samples were collected and pooled from adult ticks exposed as nymphs on days 0-10 of feeding on a susceptible calf. for male and female ticks e ...	1993	8360902
acquired resistance of guinea pigs to dermacentor andersoni mediated by humoral factors.	humoral and cell-mediated immune resistance to tick infestation has been documented in many host-parasite relationships. this study examines passive transfer of resistance to dermacentor andersoni expressed by recipients of serum pools derived from guinea pigs that had acquired resistance through experimental infestation. recipients of sera from high titer adult-infested animals expressed resistance evidenced by reduced engorgement weights, histological changes at tick attachment sites, and tick ...	1993	8277384
impact of persistent anaplasma marginale rickettsemia on tick infection and transmission.	anaplasma marginale, an intraerythrocytic rickettsia of cattle, is transmitted biologically by ticks. because of the brevity of acute a. marginale infection, transmission may rely on the tick's ability to acquire the organism from persistently infected cattle with low rickettsemia levels. by using a nucleic acid probe to quantitate low-level infection, we found that rickettsemia levels in persistently infected cattle fluctuated at approximately 5-week intervals during a 24-week period, from < 10 ...	1993	8370734
development of anaplasma marginale in salivary glands of male dermacentor andersoni.	development of the rickettsia, anaplasma marginale, in salivary glands of male dermacentor andersoni exposed as nymphs or adult ticks, was studied indirectly by inoculation of susceptible calves with homogenates and directly by examination, using light microscopy and a dna probe; some unfed ticks were incubated before tissues were collected. salivary gland homogenates made from ticks in every treatment group caused anaplasmosis when injected into susceptible calves; prepatent periods decreased a ...	1993	8427453