Publications

evidence for the contribution of point mutations to vlse variation and for apparent constraints on the net accumulation of sequence changes in vlse during infection with lyme disease spirochetes.	in the lyme disease spirochetes, both the ospe and vlse gene families have been demonstrated to undergo sequence variation during infection. to further investigate the mechanisms associated with the generation of vls variation, single-nucleotide polymorphism and subsequent dna sequence analyses were performed on the vlse gene and its paralog, bbj51, a related gene with a frameshift mutation. these analyses focused on a series of postinfection clonal populations obtained from mice infected with b ...	2001	11566983
protection against tick-transmitted lyme disease in dogs vaccinated with a multiantigenic vaccine.	in an effort to develop a safe and effective vaccine for the prevention of lyme borreliosis that addresses concerns raised over currently available vaccines, dogs were vaccinated twice with a multiantigenic preparation of borrelia burgdorferi, strain n40, on days 0 and 20 of the experiment. about 70 and 154 days after the first immunization, dogs were challenged by exposing them to field-collected ixodes scapularis ticks harboring b. burgdorferi. vaccinated dogs were completely protected from in ...	2001	11567763
distinct combinations of borrelia burgdorferi sensu lato genospecies found in individual questing ticks from europe.	the genetic diversity of borrelia burgdorferi sensu lato was assessed in individual adult ixodes ricinus ticks from europe by direct pcr amplification of spirochetal dna followed by genospecies-specific hybridization. analysis of mixed infections in the ticks showed that b. garinii and b. valaisiana segregate from b. afzelii. this and previous findings suggest that host complement interacts with spirochetes in the tick, thereby playing an important role in the ecology of lyme borreliosis.	2001	11571205
borrelia burgdorferi sensu lato and ehrlichia spp. in ixodes ticks from southern norway.	we report the results of a study of the prevalence of ehrlichia and borrelia species in 341 questing ixodes ricinus ticks from two locations in southern norway. the prevalences of borrelia burgdorferi sensu lato and ehrlichia spp. were, respectively, 16 and 11.5% at site 1 and 17 and 6% at site 2. prevalence and species composition of borrelia and ehrlichia varied with location and date of collection. the dominant borrelia species at both sites was borrelia afzelii, followed by borrelia burgdorf ...	2001	11574588
antigenic and genetic heterogeneity of borrelia burgdorferi populations transmitted by ticks.	the genome of borrelia burgdorferi encodes a large number of lipoproteins, many of which are expressed only at certain stages of the spirochete's life cycle. in the current study we describe the b. burgdorferi population structure with respect to the production of two lipoproteins [outer surface protein a (ospa) and outer surface protein c (ospc)] during transmission from the tick vector to the mammalian host. before the blood meal, the bacteria in the tick were a homogeneous population that mai ...	2001	11209063
isolation of the etiologic agent of human granulocytic ehrlichiosis from the white-footed mouse (peromyscus leucopus).	we examined white-footed mice (peromyscus leucopus) from minnesota for infection with the etiologic agent of human granulocytic ehrlichiosis (hge). from april to september 1997, we collected p. leucopus from washington county, minnesota, an area enzootic for hge. blood was cultivated in hl60 cells for isolation of the hge agent. of 59 mice examined, only a single mouse was culture positive for the hge agent. the 16s ribosomal dna sequence of the isolate was determined to be identical to that of ...	2001	11136794
effect of immunization with recombinant ospa on serologic tests for lyme borreliosis.	this study evaluated the effects of vaccination with ospa on the use of serologic tests as aids in the diagnosis of lyme borreliosis. sera from control and ospa-immunized mice and from ospa-immunized human volunteers were tested for serologic reactivity to borrelia burgdorferi. testing was performed with samples obtained prior to administration of vaccine and at 30 days following administration of an initial and a second dose of ospa vaccine. the assays used to assess serologic reactivity includ ...	2001	11139199
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
c-terminal invariable domain of vlse may not serve as target for protective immune response against borrelia burgdorferi.	vlse, the variable surface antigen of the lyme disease spirochete, borrelia burgdorferi, contains two invariable domains, at the amino and carboxyl termini, respectively, which collectively account for approximately one-half of the entire molecule's length and remain unchanged during antigenic variation. it is not known if these two invariable domains are exposed at the surface of either the antigen or the spirochete. if they are exposed at the spirochete's surface, they may elicit a protective ...	2001	11179296
effect of tick removal on transmission of borrelia burgdorferi and ehrlichia phagocytophila by ixodes scapularis nymphs.	the effect of feeding duration on pathogen transmission was studied for individual ticks infected with either laboratory or field strains of the lyme disease spirochete borrelia burgdorferi and field strains of ehrlichia phagocytophila, an agent of human granulocytic ehrlichiosis. infected nymphal ixodes scapularis were allowed to feed individually on mice, and equal numbers were removed at 24-h intervals for < or =96 h. mice were assayed for infection by culture, serologic testing, and polymera ...	2001	11181154
tick salivary gland extract inhibits killing of borrelia afzelii spirochetes by mouse macrophages.	salivary gland extract (sge) from ixodes ricinus ticks inhibited the killing of borrelia afzelii spirochetes by murine macrophages. sge also reduced the production of two major defense molecules of phagocytes, superoxide and nitric oxide. it is likely that the suppression of macrophage microbicidal mechanisms contributes to the inhibitory effect of tick saliva on the killing of b. afzelii spirochetes, thus facilitating the transmission of this important pathogen.	2001	11119556
homologous and heterologous borrelia burgdorferi challenge of infection-derived immune rabbits using host-adapted organisms.	we have recently found that strain b31 infection-immune rabbits are completely protected against homologous challenge with large numbers (>10(6)) of host-adapted borrelia burgdorferi (hab) (e. s. shang, c. i. champion, x. wu, j. t. skare, d. b. blanco, j. n. miller, and m. a. lovett, infect. immun. 68:4189-4199, 2000). in this study, we have extended these findings to determine whether b31 strain infection-immune rabbits are also protected against heterologous hab challenge. infection-immune rab ...	2001	11119560
identification of ehrlichia spp. and borrelia burgdorferi in ixodes ticks in the baltic regions of russia.	the presence and distribution of ehrlichia spp. and borrelia burgdorferi sensu lato was demonstrated among ixodid ticks collected in the baltic regions of russia, where lyme borreliosis is endemic. a total of 3,426 ixodes ricinus and 1,267 ixodes persulcatus specimens were collected, and dark-field microscopy showed that 265 (11.5%) i. ricinus and 333 (26.3%) i. persulcatus ticks were positive. from these samples, 472 dark-field-positive and 159 dark-field-negative ticks were subjected to pcr an ...	2001	11376063
isolation and characterization of borrelia burgdorferi sensu lato strains in an area of italy where lyme borreliosis is endemic.	between 1993 and 1998, we isolated borrelia burgdorferi sensu lato from 55 of the 119 patients with clinically diagnosed lyme borreliosis who were admitted to "san martino" hospital in belluno, veneto, an adriatic region in northeastern italy where lyme borreliosis is endemic. upon hospitalization, all patients presented erythema migrans. isolates were typed using ribosomal dna pcr-restriction fragment length polymorphism (rflp) analysis of the rrfa-rrlb intergenic spacer. of the 41 isolates typ ...	2001	11376066
characterization of a human granulocytic ehrlichiosis-like agent from ixodes scapularis, ontario, canada.		2001	11384537
inhibition of borrelia burgdorferi-tick interactions in vivo by outer surface protein a antibody.	borrelia burgdorferi outer surface protein (osp) a is preferentially expressed by spirochetes in the ixodes scapularis gut and facilitates pathogen-vector adherence in vitro. here we examined b. burgdorferi-tick interactions in vivo by using abs directed against ospa from each of the three major b. burgdorferi sensu lato genospecies: b. burgdorferi sensu stricto, borrelia afzelii, and borrelia garinii. abs directed against b. burgdorferi sensu stricto (isolate n40) destroy the spirochete and can ...	2001	11390491
interleukin-6 enhances production of anti-ospc immunoglobulin g2b borreliacidal antibody.	protection against infection with borrelia burgdorferi is dependent primarily on induction of complement-dependent antibody that can kill the spirochete. measuring the production of sustained high levels of borreliacidal antibody is thus paramount for determining potential vaccine efficacy. we investigated the borreliacidal antibody response in sera and the amount of antibody produced by cultured lymph node cells of c3h/hej mice vaccinated with outer surface protein c (ospc). we showed that reco ...	2001	11401963
impact of genotypic variation of borrelia burgdorferi sensu stricto on kinetics of dissemination and severity of disease in c3h/hej mice.	various genotypes of borrelia burgdorferi sensu stricto have been previously identified among a large collection of isolates cultured from patients with lyme disease in the united states. furthermore, association of specific genotypes with hematogenous dissemination early in the disease course has been observed. the present study assessed kinetics of spirochete dissemination and disease severity in c3h/hej mice infected with two different genotypes of b. burgdorferi. spirochete load in plasma an ...	2001	11401967
assessing the association between the geographic distribution of deer ticks and seropositivity rates to various tick-transmitted disease organisms in dogs.	to determine whether the geographic distribution of deer ticks (ixodes scapularis) was associated with the distribution of dogs seropositive for various tick-transmitted disease organisms (ie, borrelia burgdorferi, rickettsia rickettsii, the human granulocytic ehrlichiosis [hge] agent, ehrlichia canis, and bartonella vinsonii subsp berkhoffii).	2001	11318358
purification and characterization of borrelia burgdorferi from feeding nymphal ticks (ixodes scapularis).	here we describe a protocol for purifying borrelia burgdorferi from feeding ticks by velocity centrifugation and percoll density gradient centrifugation. the purified spirochetes were motile and 10- to 20-fold purer than the bacteria in crude tick homogenates. the purified bacteria were present in sufficient quantity for protein and gene expression studies. in comparison to culture-grown bacteria, tick-borne spirochetes had several proteins that were upregulated and a few that were downregulated ...	2001	11349010
regulation of ospe-related, ospf-related, and elp lipoproteins of borrelia burgdorferi strain 297 by mammalian host-specific signals.	in previous studies we have characterized the cp32/18 loci in borrelia burgdorferi 297 which encode ospe and ospf orthologs and a third group of lipoproteins which possess ospe/f-like leader peptides (elps). to further these studies, we have comprehensively analyzed their patterns of expression throughout the borrelial enzootic cycle. serial dilution reverse transcription-pcr analysis indicated that although a shift in temperature from 23 to 37 degrees c induced transcription for all nine genes ...	2001	11349022
complement evasion by borrelia burgdorferi: serum-resistant strains promote c3b inactivation.	the most characteristic features of the lyme disease pathogens, the borrelia burgdorferi sensu lato (s.l.) group, are their ability to invade tissues and to circumvent the immune defenses of the host for extended periods of time, despite elevated levels of borrelia-specific antibodies in serum and other body fluids. our aim in the present study was to determine whether b. burgdorferi is able to interfere with complement (c) at the level of c3 by accelerating c3b inactivation and thus to inhibit ...	2001	11349031
gamma interferon is not required for arthritis resistance in the murine lyme disease model.	lyme arthritis is the most common complication following infection of human individuals with borrelia burgdorferi sensu stricto. in mice, b. burgdorferi infection leads to arthritis of the tibiotarsal joints. arthritis severity in mice is under host genetic control, as balb/c mice developed mild arthritis but c3h/he mice developed severe disease following b. burgdorferi infection. to study the role of gamma interferon (ifn-gamma) in arthritogenesis, targeted mutant mice lacking the ifn-gamma rec ...	2001	11349038
immunohistochemical analysis of lyme disease in the skin of naive and infection-immune rabbits following challenge.	in this study, skin histopathology from naive and infection-derived immune rabbits was compared following intradermal challenge using borrelia burgdorferi b31 strain. the presence or absence of spirochetes in relationship to host cellular immune responses was determined from the time of intradermal inoculation to the time of erythema migrans (em) development (approximately 7 days in naive rabbits) and through development of challenge immunity (approximately 5 months in naive rabbits). skin biops ...	2001	11349081
prevention of lyme disease: a review of the evidence.	the healthy people 2010 public health goals targeted a 44% decrease in the incidence of lyme disease, the most commonly reported tick-borne illness in the united states. to review lyme disease prevention, clinical trials, epidemiological and experimental studies, and predictive models were evaluated. geographic distribution of ixodid vectors and local landscape predict lyme disease risk. density of infected ticks correlates with incidence and prevalence of lyme disease, but risk quantitation is ...	2001	11444404
prophylaxis with single-dose doxycycline for the prevention of lyme disease after an ixodes scapularis tick bite.	it is unclear whether antimicrobial treatment after an ixodes scapularis tick bite will prevent lyme disease.	2001	11450675
transduction by phibb-1, a bacteriophage of borrelia burgdorferi.	we previously described a bacteriophage of the lyme disease agent borrelia burgdorferi designated phibb-1. this phage packages the host complement of the 32-kb circular plasmids (cp32s), a group of homologous molecules found throughout the genus borrelia. to demonstrate the ability of phibb-1 to package and transduce dna, a kanamycin resistance cassette was inserted into a cloned fragment of phage dna, and the resulting construct was transformed into b. burgdorferi ca-11.2a cells. the kan casset ...	2001	11466280
ixodid ticks on white-tailed deer and feral swine in florida.	a state-wide survey was conducted in florida during the 1997-99 hunting seasons to examine white-tailed deer (odocoileus virginianus) and feral swine (sus scrofa) for potential indigenous vectors of the rickettsial agent of heartwater, cowdria ruminantium. a total of 504 white-tailed deer and 166 feral swine was examined from 30 wildlife management areas across the state. amblyomma maculatum, an experimental vector of c. ruminantium, was common on both deer and feral swine throughout the state. ...	2001	11469190
efficacy of an amitraz-impregnated collar in preventing transmission of borrelia burgdorferi by adult ixodes scapularis to dogs.	to determine whether an amitraz-impregnated collar could prevent transmission of borrelia burgdorferi by ixodes scapularis to dogs.	2001	11469572
birds disperse ixodid (acari: ixodidae) and borrelia burgdorferi-infected ticks in canada.	a total of 152 ixodid ticks (acari: ixodidae) consisting of nine species was collected from 82 passerine birds (33 species) in 14 locations in canada from 1996 to 2000. the lyme disease spirochete borrelia burgdorferi johnson, schmidt, hyde, steigerwaldt & brenner was cultured from the nymph of a blacklegged tick, ixodes scapularis say, that had been removed from a common yellowthroat, geothlypis trichas l., from bon portage island, nova scotia. as a result of bird movement, a nymphal i. scapula ...	2001	11476328
different activities and footwear influence exposure to host-seeking nymphs of ixodes scapularis and amblyomma americanum (acari: ixodidae).	the relative potential for a person accidentally acquiring host-seeking nymphs of the blacklegged tick, ixodes scapularis say, and lone star tick, amblyomma americanum (l.), while wearing either of two types of footwear, walking, crawling on hands and knees, and sitting on large fallen logs in deciduous woods, was evaluated. although flag samples indicated substantial populations of i. scapularis nymphs and low to moderate numbers of a. americanum at the study sites, relatively few i. scapularis ...	2001	11476342
developmental profile, isolation, and biochemical characterization of a novel lipoglycoheme-carrier protein from the american dog tick, dermacentor variabilis (acari: ixodidae) and observations on a similar protein in the soft tick, ornithodoros parkeri (acari: argasidae).	a novel lipoglycoheme-carrier protein (cp) in the american dog tick, dermacentor variabilis (say) has been purified and characterized. cp was purified by native-page from partially fed virgin females. cp has a density of 1.25 g/ml with a molecular weight of 200 k by native-page and 340 k by gel filtration chromatography. cp is comprised of two majour subunits, 98 k and 92 k in molecular weight by sds-page. separate amino acid composition of the two subunits indicated high contents of as(x), gl(x ...	2001	11222939
effects of an application of granular carbaryl on nontarget forest floor arthropods.	we evaluated the effects of a single application of granular carbaryl made against nymphal ixodes scapularis say on the diversity and abundance of forest arthropods taken in pitfall traps in oak and mixed oak-pine forest sites for 12 wk after treatment in central new jersey. significant short-term changes in arthropod assemblages were detected immediately posttreatment. effects were not distributed equally across taxa. seasonal changes in numbers and diversity of forest arthropods in the study a ...	2001	11233101
specificities and sensitivities of four monoclonal antibodies for typing of borrelia burgdorferi sensu lato isolates.	borrelia burgdorferi, the agent of lyme borreliosis, is genetically more heterogeneous than previously thought. in europe five genospecies have been described from the original b. burgdorferi sensu lato (sl): b. burgdorferi sensu stricto (ss), b. garinii, b. afzelii, b. lusitaniae, and b. valaisiana. in the united states, b. burgdorferi ss as well as b. bissettii in california and b. andersonii on the east coast were differentiated. in asia, b. japonica has been identified along, with b. garinii ...	2001	11238225
differential adhesion of major surface proteins 1a and 1b of the ehrlichial cattle pathogen anaplasma marginale to bovine erythrocytes and tick cells.	anaplasma marginale is a tick-borne ehrlichial pathogen of cattle for which six major surface proteins (msps) have been described. the msp1 complex, a heterodimer composed of msp1a and msp1b, was shown to induce a protective immune response in cattle and both proteins have been identified as putative adhesins for bovine erythrocytes. in this study the role of msp1a and msp1b as adhesins for bovine erythrocytes and tick cells was defined. msp1alpha and msp1beta1 genes from the oklahoma isolate of ...	2001	11239934
major histocompatibility complex class ii-independent generation of neutralizing antibodies against t-cell-dependent borrelia burgdorferi antigens presented by dendritic cells: regulation by nk and gammadelta t cells.	we previously showed that adoptive transfer of borrelia burgdorferi-pulsed dendritic cells (dcs) into syngeneic mice protects animals from challenge with tick-transmitted spirochetes. here, we demonstrate that the protective immune response is antibody (ab) dependent and does not require the presence of major histocompatibility complex (mhc) class ii molecules on dcs. mice sensitized with b. burgdorferi-pulsed mhc class ii-deficient (mhc class ii(-/-)) dcs mounted a humoral response against prot ...	2001	11254601
borrelia burgdorferi proteins whose expression is similarly affected by culture temperature and ph.	previously, we had demonstrated the upregulation in the expression of several proteins, including the lipoproteins ospc and p35, of borrelia burgdorferi in the stationary growth phase. since the expression of ospc is also known to be affected by culture temperature and ph, we examined the effects of both variables on the expression of the remaining stationary-phase-upregulated proteins. our study revealed that the expression of each of the remaining stationary-phase-upregulated proteins, p35 inc ...	2001	11254645
identification of an il-2 binding protein in the saliva of the lyme disease vector tick, ixodes scapularis.	a potent inhibitor of mitogen-stimulated t cell proliferation exists in the saliva of several species of hard ticks, including the lyme disease vector tick, ixodes scapularis. our characterization of this phenomenon has led to the identification of a possible mechanism for the t cell inhibitory activity of i. scapularis saliva. the t cell inhibitor can overcome stimulation of mouse spleen cells with anti-cd3 mab; however, a direct and avid interaction with t cells does not appear to be necessary ...	2001	11254684
ixodes scapularis (acari: ixodidae): abundance and rate of infection with borrelia burgdorferi in four state parks in wisconsin.	four state parks located in lyme disease endemic regions of wisconsin were surveyed for the presence of ixodes scapularis say during may and june of 1998 by drag sampling along hiking trails. nymphal abundance varied between parks, with the average number of nymphs encountered in 1 h ranging from 6.2 +/- 3.8-47.1 +/- 36.3 (mean +/- sd). questing nymphs were tested for the presence of borrelia burgdorferi by culture in bsk medium and 7-12% was found to be infected. the average risk of encounterin ...	2001	11268688
prevalence of infection in ticks submitted to the human tick test kit program of the u.s. army center for health promotion and preventive medicine.	in 1997, ticks removed from humans and received alive by the tick-borne disease laboratory of the u.s. army center for health promotion and preventive medicine (usachppm) were tested for pathogens by polymerase chain reaction (pcr). thirty-three of 222 (15%) amblyomma americanum (l.) dnas produced amplicons of the expected size of ehrlichia chaffeensis anderson, dawson & wilson and 26/222 (12%) produced amplicons indicating borrelia burgdorferi johnson, schmid, hyde, steigalt & brenner. five (2% ...	2001	11268694
contrasts in tick innate immune responses to borrelia burgdorferi challenge: immunotolerance in ixodes scapularis versus immunocompetence in dermacentor variabilis (acari: ixodidae).	the blacklegged tick, ixodes scapularis say, transmits the lyme disease spirochete borrelia burgdorferi, whereas the american dog tick, dermacentor variabilis (say), is unable to transmit the bacterium. we compared the innate immune response of these ticks against spirochetes directly inoculated into the hemocoel cavity of ticks. in i. scapularis, some borrelia were found associated with hemocytes, while numerous other spiral-shaped, intact bacteria remained free in the hemolymph. in contrast, i ...	2001	11268698
resistance to lyme disease in decorin-deficient mice.	microbial adhesion to the host tissue represents an early, critical step in the pathogenesis of most infectious diseases. borrelia: burgdorferi, the causative agent of lyme disease (ld), expresses two surface-exposed decorin-binding adhesins, dbpa and dbpb. a decorin-deficient (dcn(-/-)) mouse was recently developed and found to have a relatively mild phenotype. we have now examined the process of experimental ld in dcn(-/-) mice using both needle inoculation and tick transmission of spirochetes ...	2001	11285303
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
c-terminal invariable domain of vlse is immunodominant but its antigenicity is scarcely conserved among strains of lyme disease spirochetes.	vlse, the variable surface antigen of borrelia burgdorferi, contains two invariable domains located at the amino and carboxyl terminal ends, respectively, and a central variable domain. in this study, both immunogenicity and antigenic conservation of the c-terminal invariable domain were assessed. mouse antiserum to a 51-mer synthetic peptide (ct) which reproduced the entire sequence of the c-terminal invariable domain of vlse from b. burgdorferi strain b31 was reacted on immunoblots with whole- ...	2001	11292744
coinfection with borrelia burgdorferi and the agent of human granulocytic ehrlichiosis alters murine immune responses, pathogen burden, and severity of lyme arthritis.	lyme disease and human granulocytic ehrlichiosis (hge) are tick-borne illnesses caused by borrelia burgdorferi and the agent of hge, respectively. we investigated the influence of dual infection with b. burgdorferi and the hge agent on the course of murine lyme arthritis and granulocytic ehrlichiosis. coinfection resulted in increased levels of both pathogens and more severe lyme arthritis compared with those in mice infected with b. burgdorferi alone. the increase in bacterial burden during dua ...	2001	11292759
infection of ixodes scapularis (acari: ixodidae) with borrelia burgdorferi using a new artificial feeding technique.	to study interactions between ixodes scapularis (say) and borrelia burgdorferi, an artificial feeding system was refined to allow controlled manipulation of single variables. the feeding system uses a mouse skin mounted on a water-jacketed glass membrane feeder. i. scapularis were infected using either bsk-h-cultured b. burgdorferi spirochetes or a b. burgdorferi-infected mouse skin as the source of spirochetes. sixty-six percent of nymphs successfully fed to repletion using the artificial feedi ...	2001	11296818
ticks (acari: ixodidae) and spirochetes (spirochaetaceae: spirochaetales) recovered from birds on a georgia barrier island.	from september 1997 through july 1999, 300 individuals and 46 species of birds were mist-netted and screened for ticks and spirochetes on st. catherine's island, liberty county, ga. seventy-six (25%) of the birds were parasitized by a meal intensity of 4.6 ticks. seasonally, more birds were infested with ticks during the summer (50% in 1998, 34% in 1999) than in spring (15% in 1998, 11% in 1999) or fall (21% in 1997, 20% in 1998), mainly because of severe infestations on some birds by immature s ...	2001	11296828
effects of selected meterological factors on diurnal questing of ixodes scapularis and amblyomma americanum (acari: ixodidade).	the diurnal questing behavior of adult ixodes scapularis say and amblyomma americanum (l.) were monitored in the field to determine whether ticks would be collected with greater frequency during certain times of the day and under certain ambient meteorological conditions. temperature and relative humidity explained a significant amount of the total variation in tick collections. although both species were collected during every period, i. scapularis adults tended to quest earlier and later in th ...	2001	11296842
transcript heterogeneity of the p44 multigene family in a human granulocytic ehrlichiosis agent transmitted by ticks.	human granulocytic ehrlichiosis (hge) is an emerging tick-borne zoonosis caused by a strain of anaplasma phagocytophila called the hge agent, an obligatory intracellular bacterium. the agent expresses immunodominant 44-kda outer membrane proteins (p44s) encoded by a multigene family. the present study established an experimental process for transmission of the hge agent from infected mice (a reservoir model) to nymphal ixodes scapularis ticks (a biological vector) and subsequently to horses (a p ...	2002	11854198
evidence of an assembly pheromone in the black-legged deer tick, ixodes scapularis.	the responses of irodes scapularis (acari: ixodidae) nymphs and adults to extracts of cast larval skins were tested in a petri dish bioassay. assembly was elicited in nymphs and adults in the presence of skins, exudate from ticks, and filter paper exposed to ticks compared to untreated controls. assembly was noted by 1 hr after exposure with little change between 1 and 24 hr. the assembly response increased in the presence of an increased number of skins. similar assembly was elicited in nymphs ...	2002	11868671
single-dose doxycycline prevented lyme disease after an ixodes scapularis tick bite.		2002	11874281
lyme disease and current aspects of immunization.	lyme disease is a tick-borne multisystem disease that affects primarily the skin, nervous system, heart and joints. at least three species of borrelia burgdorferi sensu lato, namely borrelia burgdorferi sensu stricto, borrelia garinii, and borrelia afzelii, can cause the disease. this review will focus mainly on the pathophysiology of lyme arthritis, the long-term outcome of lyme disease, and the recently licensed vaccine against lyme disease.	2002	11879534
pcr detection and serological evidence of granulocytic ehrlichial infection in roe deer (capreolus capreolus) and chamois (rupicapra rupicapra).	the role of wild mammals, such as roe deer (capreolus capreolus) and chamois (rupicapra rupicapra), in the epidemiology of granulocytic ehrlichiae in switzerland was investigated. we tested blood samples for ehrlichia phagocytophila genogroup 16s rrna gene sequences by pcr and for immunoglobulin g antibodies against granulocytic ehrlichiae by indirect fluorescent-antibody assay (ifa). overall means of 60.9% of 133 roe deer serum samples and 28.2% of 39 chamois serum samples were seroreactive by ...	2002	11880411
clonal polymorphism of borrelia burgdorferi strain b31 mi: implications for mutagenesis in an infectious strain background.	a major obstacle to studying the functions of particular gene products in the mouse-tick infectious cycle of borrelia burgdorferi has been an inability to knock out genes in pathogenic strains. here, we investigated conditions for site-directed mutagenesis in b31 mi, the low-passage-number, infectious b. burgdorferi strain whose genome was sequenced. we inactivated several plasmid and chromosomal genes in b31 mi and determined that clones carrying these mutations were not infectious for mice. ho ...	2002	11895980
vector interactions and molecular adaptations of lyme disease and relapsing fever spirochetes associated with transmission by ticks.	pathogenic spirochetes in the genus borrelia are transmitted primarily by two families of ticks. the lyme disease spirochete, borrelia burgdorferi, is transmitted by the slow-feeding ixodid tick ixodes scapularis, whereas the relapsing fever spirochete, b. hermsii, is transmitted by ornithodoros hermsi, a fast-feeding argasid tick. lyme disease spirochetes are generally restricted to the midgut in unfed i. scapularis. when nymphal ticks feed, the bacteria pass through the hemocoel to the salivar ...	2002	11897061
geographic uniformity of the lyme disease spirochete (borrelia burgdorferi) and its shared history with tick vector (ixodes scapularis) in the northeastern united states.	over 80% of reported cases of lyme disease in the united states occur in coastal regions of northeastern and mid-atlantic states. the genetic structure of the lyme disease spirochete (borrelia burgdorferi) and its main tick vector (ixodes scapularis) was studied concurrently and comparatively by sampling natural populations of i. scapularis ticks along the east coast from 1996 to 1998. borrelia is genetically highly diverse at the outer surface protein ospc. since borrelia is highly clonal, the ...	2002	11901105
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
comparative study of early lyme disease: erythema migrans in new york state and northeastern poland.	the objective was to compare the clinical features of early local lyme disease: erythema migrans (em) between two highly endemic areas: new york state and northeastern poland. study was based on self reporting questionnaires, physical examination, and laboratory results.	2002	11782679
genetic diversity of the outer surface protein c gene of southern borrelia isolates and its possible epidemiological, clinical, and pathogenetic implications.	the ospc genes of 20 southern borrelia strains were sequenced. the strains consisted of b. burgdorferi sensu stricto, b. andersonii, b. bissettii, one undescribed genospecies, mi-8, and one probably new borrelia species, txw-1. a high degree of similarity exists between b. burgdorferi sensu stricto and b. bissettii and between b. bissettii and b. andersonii. lateral transfers of the ospc gene probably occurred between b. burgdorferi sensu stricto and b. bissettii and between b. bissettii and b. ...	2002	12089279
ability of the borreliacidal antibody test to confirm lyme disease in clinical practice.	highly specific borreliacidal antibodies are induced by infection with borrelia burgdorferi, and a borreliacidal antibody test (bat) may be an accurate laboratory procedure for confirming lyme disease in clinical practice. to investigate this, 34 lyme disease sera and 34 sera from patients with other illnesses who had presented to a primary-care facility located in an area of borreliosis endemicity were tested by the bat and western blotting (wb). the bat was more sensitive (79% versus 65%; p = ...	2002	12093694
increasing habitat suitability in the united states for the tick that transmits lyme disease: a remote sensing approach.	the warnings about the spread of (italic)ixodes scapularis(/italic), one of the vectors of lyme disease, into the united states are based on reports about regional distribution and increasing local abundance. in a modeling approach, i used the recorded, current distribution of this tick and remotely sensed bioclimatic factors over the united states to establish the changes of habitat for this tick since 1982 and to detect the areas with factors adequate to support tick colonization. results indi ...	2002	12117639
detection, characterization, and prediction of tick-borne disease foci.	tick-borne disease (tbd) transmission foci need to be characterized in space and time, and are often discontinuous on both scales. an active tbd focus is dependent on the fulfillment of three conditions: tick survival, pathogen survival and opportunities for human exposure. the essentials for tick survival include food sources, reproduction, and protection from environmental extremes. the pathogen survival kit includes sufficient densities of ticks and suitable reservoir hosts, and opportunities ...	2002	12141734
simultaneous coexpression of borrelia burgdorferi erp proteins occurs through a specific, erp locus-directed regulatory mechanism.	an individual borrelia burgdorferi bacterium can encode as many as 13 different erp (ospe/f-related) proteins from mono-and bicistronic loci that are carried on up to 10 separate plasmids. we demonstrate through multilabel immunofluorescence analyses that individual bacteria simultaneously coexpress their entire erp protein repertoire. while it has been proposed that b. burgdorferi controls expression of erp and other plasmid-encoded proteins through changes in dna topology, we observed regulate ...	2002	12142424
lyme disease knowledge, beliefs, and practices of new hampshire primary care physicians.	lyme disease is the most commonly reported vectorborne illness in the united states and is endemic in many counties in the northeast, including counties in new hampshire. previous studies conducted elsewhere on lyme disease have indicated substantial differences between physician practices and published consensus guidelines for diagnosis and treatment.	2002	12150460
borrelia burgdorferi-specific monoclonal antibodies derived from mice primed with lyme disease spirochete-infected ixodes scapularis ticks.	we have generated a panel of igg monoclonal antibodies (mabs) directed against borrelia burgdorferi strain b31 antigens, using a method whereby mice were primed with organisms naturally inoculated by ixodes scapularis nymphal ticks. western blot analysis showed that these mabs recognized several b. burgdorferi b31 antigens, including the complement inhibitor factor h-binding proteins erpa/i/n and erpc. two other mabs were specific for the reva protein, and have enabled characterization of that p ...	2002	12165143
exploring the sialome of the tick ixodes scapularis.	to attempt description of the set of mrna and protein (sialome) expressed in the salivary glands of the tick ixodes scapularis, we randomly sequenced 735 clones of a full-length salivary gland cdna library of this arthropod and performed edman degradation of protein bands from salivary gland homogenates (sgh) and saliva separated by sds-page. the sequences were grouped into 410 clusters, of which 383 are not associated with known i. scapularis sequences. 15- and 17-protein bands from page yielde ...	2002	12177149
cellular immunity, but not gamma interferon, is essential for resolution of babesia microti infection in balb/c mice.	a new strain of babesia microti (kr-1) was isolated from a connecticut resident with babesiosis by hamster inoculation and adapted to c3h/hej and balb/c mice. to examine the relative importance of humoral and cellular immunity for the control of b. microti infection, we compared the course of disease in wild-type balb/c mice with that in balb/c scid mice, jhd-null (b-cell-deficient) mice, and t-cell receptor alphabeta (tcrbeta(-/-)) or gamma interferon (ifn-gamma) (ifn-gamma(-/-)) knockout mice ...	2002	12183588
spatial analysis of human granulocytic ehrlichiosis near lyme, connecticut.	geographic information systems combined with methods of spatial analysis provide powerful new tools for understanding the epidemiology of diseases and for improving disease prevention and control. in this study, the spatial distribution of a newly recognized tick-borne disease, human granulocytic ehrlichiosis (hge), was investigated for nonrandom patterns and clusters in an area known to be endemic for tick-borne diseases. analysis of confirmed cases of hge identified in 1997-2000 in a 12-town a ...	2002	12194771
disease severity in a murine model of lyme borreliosis is associated with the genotype of the infecting borrelia burgdorferi sensu stricto strain.	the pathogenicity of borrelia burgdorferi sensu stricto clinical isolates representing 2 distinct ribosomal dna spacer restriction fragment-length polymorphism genotypes (rsts) was assessed in a murine model of lyme disease. b. burgdorferi was recovered from 71.5% and 26.6% of specimens from mice infected with rst1 and rst3 isolates, respectively (p<.0001). the average ankle diameter and histologic scores for carditis and arthritis were significantly higher after 2 weeks of infection among mice ...	2002	12198612
predicting the risk of lyme disease: habitat suitability for ixodes scapularis in the north central united states.	the distribution and abundance of ixodes scapularis were studied in wisconsin, northern illinois, and portions of the upper peninsula of michigan by inspecting small mammals for ticks and by collecting questing ticks at 138 locations in state parks and natural areas. environmental data were gathered at a local level (i.e., micro and meso levels), and a geographic information system (gis) was used with several digitized coverages of environmental data to create a habitat profile for each site and ...	2002	11927027
prevalence of the agent of human granulocytic ehrlichiosis in ixodes scapularis (acari: ixodidae) in the coastal southeastern united states.	human granulocytic ehrlichiosis (hge) is an emerging tick-borne disease recently recognized in the united states. the blacklegged tick, ixodes scapularis say, is the principle vector in the eastern united states. the disease has been commonly reported in the northeastern and upper midwestern states; however, suitable vectors and reservoir hosts exist in the southeast. to assay the prevalence of the hge agent in vector ticks, we screened 818 individual i. scapularis from 15 locations in south car ...	2002	11931023
glass capillary tube feeding: a method for infecting nymphal ixodes scapularis (acari: ixodidae) with the lyme disease spirochete borrelia burgdorferi.	we evaluated an artificial capillary feeding method to infect nymphal ixodes scapularis (say) ticks with borrelia burgdoeferi, the causative agent of lyme disease. thirty to 70% of the nymphs were infected after feeding for 2.5 h from glass capillary tubes filled with a solution of spirochetes. capillary infection was stable and persisted in the nymphs for at least 10 d after feeding. capillary feeding also maintained natural vector competence patterns because i. scapularis ticks acquired infect ...	2002	11931028
ticks parasitizing dogs in northwestern georgia.	from january 1998 through september 1999, 324 dogs in three northwestern georgia counties were examined for ticks. six species of ticks were recovered. the three most commonly collected ticks were the american dog tick, dermacentor variabilis (say) (310 male male, 352 female female; prevalence, 97%; mean intensity 2.1); the brown dog tick, rhipicephalus sanguineus (latreille) (118 male male, 119 female female, 38 nymphs; prevalence, 22%; mean intensity, 3.8); and the lone star tick, amblyomma am ...	2002	11931241
the prevalence of borrelia burgdorfieri (spirochaetales: spirochaetaceae) and the agent of human granulocytic ehrlichiosis (rickettsiaceae: ehrlichieae) in ixodes scapularis (acari:ixodidae) collected during 1998 and 1999 from minnesota.	we tested 103 adult ixodes scapularis say from 12 counties in minnesota for the presence of borrelia burgdorferi and the causative agent of human granulocytic ehrlichiosis (hge), using polymerase chain reaction (pcr). a total of 17 ticks (16.5%) was positive for b. burgdoiferi using nested pcr for the flagellin gene. or both pcr for the ospa gene and nested pcr for the flagellin gene. a total of four ticks (3.8%) was positive for the agent of hge using nested pcr for 16s rdna. counties in minnes ...	2002	11931260
a survey for nymphs of host-seeking ixodes scapularis and amblyomma americanum (acari: ixodidae) on tree trunks in deciduous forests.	trunks of 83 trees in a mixed deciduous forests in maryland were sampled for the presence of nymphs of the blacklegged tick, ixodes scapularis say, and the lone star tick, amblyomma americanum (l.). although one or more nymphs of either i. scapularis or a. americanum was found in leaf litter and substrate < or = 1 m from the bases of 47% of the trees sampled, a total of 6 i. scapularis nymphs was found on the trunks of only five trees. no nymphs were found on the trunks of 12 dead trees. no a. a ...	2002	11931264
disease-specific diagnosis of coinfecting tickborne zoonoses: babesiosis, human granulocytic ehrlichiosis, and lyme disease.	to determine whether a unique group of clinical and laboratory manifestations characterize certain major deer tick-transmitted human pathogens in north america, we compared the symptoms, short-term complications, and laboratory test results of new england residents who became ill due to > or =1 of these pathogens. patients completed a uniformly structured questionnaire and submitted blood samples for serologic and polymerase chain reaction (pcr) testing after developing symptoms of lyme disease, ...	2002	11941544
outcomes of treated human granulocytic ehrlichiosis cases.	we conducted a case-control study in wisconsin to determine whether some patients have long-term adverse health outcomes after antibiotic treatment for human granulocytic ehrlichiosis (hge). a standardized health status questionnaire was administered to patients and controls matched by age group and sex. consenting patients provided blood samples for serologic testing. among the 85 previously treated patients, the median interval since onset of illness was 24 months. compared with 102 controls, ...	2002	11971774
ixolaris, a novel recombinant tissue factor pathway inhibitor (tfpi) from the salivary gland of the tick, ixodes scapularis: identification of factor x and factor xa as scaffolds for the inhibition of factor viia/tissue factor complex.	saliva of the hard tick and lyme disease vector, ixodes scapularis, has a repertoire of compounds that counteract host defenses. following sequencing of an i scapularis salivary gland complementary dna (cdna) library, a clone with sequence homology to tissue factor pathway inhibitor (tfpi) was identified. this cdna codes for a mature protein, herein called ixolaris, with 140 amino acids containing 10 cysteines and 2 kunitz-like domains. recombinant ixolaris was expressed in insect cells and show ...	2002	11986214
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
genetic variants of ehrlichia phagocytophila, rhode island and connecticut.	primers were used to amplify a 561-bp region of the 16s rrna gene of ehrlichia phagocytophila from ixodes scapularis ticks and small mammals collected in rhode island and connecticut. dna sequences for all 50 e. phagocytophila-positive samples collected from 1996 through 1998 in southwestern connecticut were identical to the sequence reported for e. phagocytophila dna from confirmed human cases. in contrast, the sequences from 92 of 123 e. phagocytophila-positive rhode island samples collected f ...	2002	11996680
examination of the borrelia burgdorferi transcriptome in ixodes scapularis during feeding.	borrelia burgdorferi gene expression within the guts of engorging ixodes scapularis ticks was examined by use of differential immunoscreening and differential expression with a customized amplified library. fourteen chromosomal genes involved in energy metabolism, substrate transport, and signal transduction and 10 (4 chromosomal and 6 plasmid) genes encoding putative lipoproteins and periplasmic proteins were preferentially expressed in engorging ticks. these data demonstrate a new approach to ...	2002	12003955
modulation of borrelia burgdorferi stringent response and gene expression during extracellular growth with tick cells.	borrelia burgdorferi n40 multiplied extracellularly when it was cocultured with tick cells in l15bs medium, a medium which by itself did not support b. burgdorferi n40 growth. growth of b. burgdorferi n40 in the presence of tick cells was associated with decreased production of (p)ppgpp, the stringent response global regulator, a fourfold decrease in rela/spot mrna, an eightfold net decrease in bmpd mrna, and a fourfold increase in rpsl-bmpd mrna compared to growth of b. burgdorferi in bsk-h med ...	2002	12010998
reassessment of a midwestern lyme disease focus for borrelia burgdorferi and the human granulocytic ehrlichiosis agent.	previous studies from the late 1980s defined the risk of human lyme disease by determining the prevalence of borrelia burgdorferi infection in ixodes scapularis ticks and peromyscus sp. mice captured from areas around la crosse, wis. high percentages of b. burgdorferi-infected i. scapularis ticks and p. leucopus mice were common in areas located north of interstate 90 but were not detected in areas south of this major east-west thoroughfare. in this study, we reevaluated the extent of b. burgdor ...	2002	12037066
protection against lyme disease spirochete transmission provided by prompt removal of nymphal ixodes scapularis (acari: ixodidae).	public health recommendations for lyme disease prevention generally include daily tick checks and prompt removal of attached ticks as a means of decreasing the risk of acquiring lyme disease in highly endemic regions. in the current study, we determined whether crushing nymphal ticks during removal with forceps increased the risk of b. burgdorferi transmission, what degree of protection from transmission of b. burgdorferi was provided by removal of nymphal ixodes scapularis say at specific inter ...	2002	12061448
a preliminary linkage map of the tick, ixodes scapularis.	a linkage map of the ixodes scapularis genome was constructed based upon segregation amongst 127 loci. these included 84 random amplified polymorphic dna (rapd) markers, 32 sequence-tagged rapd (star) markers, 5 cdnas, and 5 microsatellites in 232 f1 intercross progeny from a single, field-collected p1 female. a preliminary linkage map of 616 cm was generated across 14 linkage groups with one marker every 10.8 cm. assuming a genome size of approximately 10(9) bp, the relationship of physical to ...	2002	14570121
how specific are host-produced kairomones to host-seeking ixodid ticks?	ixodid ticks respond to host-produced substances (kairomones) that influence the ticks' host-finding behavior. in the laboratory adult blacklegged ticks, ixodes scapularis say, lone star ticks, amblyomma americanum l., and american dog ticks, dermacentor variabilis (say) became akinetic on residues rubbed from their principal hosts (deer for the former two species and dogs for the latter). however, arrestment also occurred when adults of these species were tested using the same method bioassay, ...	2002	14570126
photoperiodic control of developmental diapause in nymphs of prostriate ixodid ticks (acari: ixodidae).	extrinsic control of developmental diapause in nymphs of prostriate ticks of the subgenus ixodes sensu stricto (ixodes ricinus and ixodes persulcatus from eurasia and ixodes scapularis from north america) appears to be based on a complex two-step photoperiodic reaction of a short-day/long-day type. diapause control in the subgenus afrixodes (the south african tick ixodes rubicundus) appears to be based on a simple long-day reaction. the option between non-diapause development and diapausing arre ...	2002	14570127
phylogenetic analysis of spotted fever group rickettsiae isolated from ticks in japan.	eight spotted fever group (sfg) rickettsiae isolated from ticks in japan were classified by phylogenetic analysis based on the nucleotide sequences of both the citrate synthase-encoding gene (glta) and 190-kda antigen-encoding gene (rompa). in the phylogenetic tree of glta, strains dt-1 and fla-1 isolated from the dermacentor taiwanensis and haemaphysalis frava ticks, respectively, were placed as rickettsia japonica, and strains io-1, io-2, io-25, im-1 and ip-2 from genus ixodes ticks were place ...	2002	12061626
analysis of weather effects on variability in lyme disease incidence in the northeastern united states.	in this study, variability in reported lyme disease incidence between 1993 and 2001 was analyzed in seven states in the northeastern part of the usa. positive significant correlations at p < 0.05 were found in all states between early summer disease incidence and the june moisture index in the region two years prior. these correlations may reflect an enhanced nymphal ixodes scapularis survival under wetter conditions. in some states, significant correlations were observed related to warmer winte ...	2002	14570138
effect of tetracycline on development of anaplasma marginale in cultured ixodes scapularis cells.	infections of the tick-borne ehrlichial pathogen, anaplasma marginale, in cattle have been controlled, in part, by administration of low doses of tetracycline. recently, a cell culture system was developed for a. marginale using a tick cell line derived from embryonic ixodes scapularis. this study was designed to determine the effect of tetracycline on a. marginale propagated in a tick cell culture assay. various concentrations of tetracycline (0, 0.01, 0.10, 1.0, 5, 10, 20 or 100 microg/ml) wer ...	2002	12072219
salp15, an ixodes scapularis salivary protein, inhibits cd4(+) t cell activation.	tick saliva has pleiotropic properties that facilitate persistence of the arthropod upon the host. we now describe a feeding-inducible protein in ixodes scapularis saliva, salp15, that inhibits cd4(+) t cell activation. the mechanism involves the repression of calcium fluxes triggered by tcr ligation and results in lower production of interleukin-2. salp15 also inhibits the development of cd4(+) t cell-mediated immune responses in vivo, demonstrating the functional importance of this protein. sa ...	2002	12121666
transmission studies of babesia microti in ixodes ricinus ticks and gerbils.	in order to investigate the possible role of ixodes ricinus as a vector of zoonotic babesia microti infection in europe, a european rodent isolate (hk) and a zoonotic american isolate (gi) were studied in transmission experiments. pcr detected b. microti in the blood and spleens of infected gerbils (meriones unguiculatus) and also in laboratory-induced infections of i. ricinus ticks. b. microti dna was detected by pcr in all pooled samples of nymphs and the majority of adults that had fed as lar ...	2002	11923342
investigations on the mode and dynamics of transmission and infectivity of borrelia burgdorferi sensu stricto and borrelia afzelii in ixodes ricinus ticks.	borrelia burgdorferi sensu lato (sl), the agent of lyme disease, is transmitted to the host during the blood meal of ixodes ticks. in most unfed ticks, spirochetes are present in the midgut and migrate during blood feeding to the salivary glands, from which they are transmitted to the host via saliva. in the present study, the efficiency of ixodes ricinus ticks to transmit b. afzelii and b. burgdorferi sensu stricto (ss) and their infectivity for mice were examined in relation to the duration of ...	2002	12656125
applications of a cell culture system for studying the interaction of anaplasma marginale with tick cells.	a cell culture system for the tick-borne rickettsia anaplasma marginale offers new opportunities for research on this economically important pathogen of cattle. a. marginale multiplies in membrane-bound inclusions in host cells. whereas erythrocytes appear to be the only site of infection in cattle, a. marginale undergoes a complex developmental cycle in ticks and transmission occurs via the salivary glands during feeding. we recently developed a cell culture system for a. marginale using a cell ...	2002	12665106
comparison of the reservoir competence of medium-sized mammals and peromyscus leucopus for anaplasma phagocytophilum in connecticut.	in the northeastern united states, anaplasma phagocytophilum, the agent of human granulocytic ehrlichiosis (hge), is transmitted by the tick vector ixodes scapularis. the white-footed mouse peromyscus leucopus is a competent reservoir for this agent, but the reservoir competence of non-peromyscus hosts of i. scapularis has not been studied. here, we report data confirming reservoir competence of medium-sized mammals for a. phagocytophilum. raccoons, virginia opossums, gray squirrels, and striped ...	2002	12737542
kinetics of ingested host immunoglobulin g in hemolymph and whole body homogenates during nymphal development of dermacentor variabilis and ixodes scapularis ticks (acari: ixodidae).	patterns in the utilization of host immunoglobulin g (igg) during nymphal development differed between dermacentor varibilis (say) and ixodes scapularis say ticks. in unfed nymphs of d. variabilis, host igg was readily detectable in both hemolymph and whole body homogenates. in unfed nymphs of i. scapularis, host igg was absent in hemolymph and at very low concentrations in whole body homogenates. host igg in unfed nymphs was undoubtedly the remnants of igg acquired during the larval bloodmeal t ...	2002	12797408
diagnosis of human granulocytic ehrlichiosis: state of the art.	human granulocytic ehrlichiosis is an emerging zoonosis caused by anaplasma phagocytophilum and transmitted through the bite of infected ixodes scapularis. it is prevalent in the midwest and northeast united states and also in europe, and it presents as a nonspecific febrile illness a few days after a tick bite usually between late spring and fall. most cases present in adult patients with a mild form of the disease, although it can be severe with multiorgan failure, particularly in the elderly ...	2002	12804164
epidemiology and impact of coinfections acquired from ixodes ticks.	ixodes scapularis and other ticks in the ixodes ricinus complex may transmit multiple pathogens, but research on coinfections has been limited. coinfections occur with varying frequency in ticks, but single infections are more common than dual infections. the proportion of i. scapularis or i. ricinus ticks coinfected with both borrelia burgdorferi sensu lato and anaplasma phagocytophila is generally low, ranging from < 1% to 6% in six geographic areas. a higher prevalence of tick coinfection (26 ...	2002	12804168
a ten-year study of tick biting in mississippi: implications for human disease transmission.	to determine exactly which tick species bit people in mississippi, information was gathered on ticks involved in human biting cases for the ten-year period, january 1, 1990-december 31, 1999. specimens were identified by the author and, in most cases, confirmed by personnel at the institute of arthropodology and parasitology, georgia southern university. a total of 119 ticks were recovered from 73 humans during the study period. seven tick species were represented; most common included the lone ...	2002	12853269
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