protective efficacy of an oral vaccine to reduce carriage of borrelia burgdorferi (strain n40) in mouse and tick reservoirs.lyme disease is caused by the spirochete borrelia burgdorferi, which is transmitted through the bite of infected ixodes ticks. vaccination of mice with outer surface protein a (ospa) of b. burgdorferi has been shown to both protect mice against b. burgdorferi infection and reduce carriage of the organism in feeding ticks. here we report the development of a murine-targeted ospa vaccine utilizing vaccinia virus to interrupt transmission of disease in the reservoir hosts, thus reducing incidence o ...200616300863
the molecular and biological analysis of ixodid ticks histamine release factors.we previously described a dermacentor varibialis (dv) cdna that encodes a ubiquitously expressed and tick saliva-secreted functional histamine release factor (hrf) homolog. in this study gene specific primers based on dvhrf open reading frame nucleotide sequence were utilized to amplify three orthologs, from the wood tick, d. andersoni (da), the black legged tick, the southern cattle tick, boophilus microplus (bm) and the lone star tick, amblyomma americanum (aa). at nucleotide level, sequence c ...200516323052
orally active acaricidal peptide toxins from spider venom.numerous species of ticks and mites (collectively known as acarines) are serious pests of animals, humans, and crops. there are few commercially available acaricides and major classes of these chemicals continue to be lost from the marketplace due to resistance development or deregistration by regulatory agencies. there is consequently a pressing need to isolate new and safe acaricidal compounds. in this study, we show that two families of peptide neurotoxins isolated from the venom of the austr ...200616330063
ehrlichia under our noses and no one notices.ehrlichia chaffeensis, an obligately intracellular bacterium, resides within a cytoplasmic vacuole in macrophages, establishes persistent infection in natural hosts such as white-tailed deer and canids, and is transmitted transstadially and during feeding by ticks, particularly amblyomma americanum. ehrlichial cell walls contain glycoproteins and a family of divergent 28 kda proteins, but no peptidoglycan or lipopolysaccharide. the dense-cored ultrastructural form preferentially expresses certai ...200516358425
capillary tube feeding system for studying tick-pathogen interactions of dermacentor variabilis (acari: ixodidae) and anaplasma marginale (rickettsiales: anaplasmataceae).a capillary tube feeding (ctf) system was adapted for studying the interaction between dermacentor variabilis (say) and the rickettsial cattle pathogen anaplasma marginale theiler. a. marginale undergoes a complex developmental cycle in ticks that begins in midguts and ends by transmission from salivary glands. in this ctf system, male d. variabilis were fed a. marginale-infected blood or cultured tick cells. ticks that fed on highly rickettsemic calves developed midgut and salivary gland infect ...200516366000
distribution of borreliae among ticks collected from eastern states.lyme disease is the most commonly reported vector-borne disease in the united states and is transmitted by borrelia burgdorferi-infected ixodes species. the disease is typically characterized by an erythema migrans (em) rash at the site of tick feeding. em rashes have also been associated with feeding by amblyomma americanum ticks despite evidence suggesting that they are incompetent vectors for lyme disease. in 1996, a borrelia organism only recently cultivated in the laboratory was described i ...200516417434
theileriosis in a white-tailed deer (odocoileus virginianus) fawn.a white-tailed deer (odocoileus virginianus) fawn was collected in missouri (usa) and submitted for diagnostic evaluation. necropsy and histologic examination revealed severe amblyomma americanum infestation, pronounced icterus, and marked hemosiderin deposition in the liver and spleen. whole blood evaluation revealed a normocytic normochromic anemia and a piroplasm parasitemia of approximately 70%. the piroplasm was identified as theileria cervi by polymerase chain reaction and sequencing of th ...200516456174
white-tailed deer (odocoileus virginianus) develop spirochetemia following experimental infection with borrelia lonestari.borrelia lonestari is considered a putative agent of southern tick-associated rash illness (stari) and is known to occur naturally only in lone star ticks (amblyomma americanum) and white-tailed deer (odocoileus virginianus). we used a low passage isolate of b. lonestari (ls-1) to inoculate white-tailed deer, c3h mice, holstein cattle, and beagles. animals were monitored via examination of giemsa and acridine orange stained blood smears, polymerase chain reaction (pcr), indirect fluorescent anti ...200616459029
novel spotted fever group rickettsiae (sfgr) infecting amblyomma americanum ticks in ohio, usa. 200516481541
overcoming barriers to the transformation of the genus ehrlichia.while bacterial transformation has evolved since the early 20th century to allow for the genetic manipulation of a variety of microbial agents, rickettsial organisms have proved resistant to such advances until only recently. the ehrlichia are small, gram-negative, obligately intracellular bacterial parasites, which belong to the family anaplasmataceae and cause a variety of infections in human and animal hosts. e. chaffeensis is the causative agent of human monocytotropic ehrlichiosis and is tr ...200516481548
comparative genomics of emerging human ehrlichiosis agents.anaplasma (formerly ehrlichia) phagocytophilum, ehrlichia chaffeensis, and neorickettsia (formerly ehrlichia) sennetsu are intracellular vector-borne pathogens that cause human ehrlichiosis, an emerging infectious disease. we present the complete genome sequences of these organisms along with comparisons to other organisms in the rickettsiales order. ehrlichia spp. and anaplasma spp. display a unique large expansion of immunodominant outer membrane proteins facilitating antigenic variation. all ...200616482227
francisella tularensis in the united states.the causative agent of tularemia, francisella tularensis, is a formidable biologic agent that occurs naturally throughout north america. we examined genetic and spatial diversity patterns among 161 us f. tularensis isolates by using a 24-marker multiple-locus variable-number tandem repeat analysis (mlva) system. mlva identified 126 unique genotypes. phylogenetic analyses showed patterns similar to recently reported global-scale analyses. we observed clustering by subspecies, low genetic diversit ...200516485467
bartonella henselae in porpoise blood.we report detection of bartonella henselae dna in blood samples from 2 harbor porpoises (phocoena phocoena). by using real-time polymerase chain reaction, we directly amplified bartonella species dna from blood of a harbor porpoise stranded along the northern north carolina coast and from a pre-enrichment blood culture from a second harbor porpoise. the second porpoise was captured out of habitat (in a low-salinity canal along the northern north carolina coast) and relocated back into the ocean. ...200516485476
kinetics of borrelia burgdorferi infection in larvae of refractory and competent tick vectors.the acquisition of borrelia burgdorferi by the larvae of competent and refractory ixodid ticks was assessed by quantitative polymerase chain reaction (pcr). larvae were fed on infected mice, and the spirochete loads were determined during feeding and up to 93 d postfeeding. amblyomma americanum (l.) was refractory to b. burgdorferi infection, with almost no detection of spirochete dna during or postfeeding. in contrast, ixodes scapularis say supported high loads of spirochetes (10(3)-10(4) per l ...200616506448
tick infestations of the eastern cottontail rabbit (sylvilagus floridanus) and small rodentia in northwest alabama and implications for disease transmission.studies were conducted over a four-county area of northwest alabama to determine the association of eastern cottontail rabbits with dermacentor variabilis, the eastern united states vector of rocky mountain spotted fever. a secondary objective was to compare infestations of this tick on rabbits with infestations on commonly encountered rodent species as a means of determining the relative importance of each in the disease transmission cycle. these epidemiologic surveys were conducted in response ...200516599149
multiple pruritic papules from lone star tick larvae bites.ticks are the second most common vectors of human infectious diseases in the world. in addition to their role as vectors, ticks and their larvae can also produce primary skin manifestations. infestation by the larvae of ticks is not commonly recognized, with only 3 cases reported in the literature. the presence of multiple lesions and partially burrowed 6-legged tick larvae can present a diagnostic challenge for clinicians.200616618870
climate, deer, rodents, and acorns as determinants of variation in lyme-disease risk.risk of human exposure to vector-borne zoonotic pathogens is a function of the abundance and infection prevalence of vectors. we assessed the determinants of lyme-disease risk (density and borrelia burgdorferi-infection prevalence of nymphal ixodes scapularis ticks) over 13 y on several field plots within eastern deciduous forests in the epicenter of us lyme disease (dutchess county, new york). we used a model comparison approach to simultaneously test the importance of ambient growing-season te ...200616669698
an in vivo rodent model for identifying and characterizing acaricides.evaluation of candidate acaricides in livestock or companion animals is expensive, time-consuming, and usually requires large quantities of test material. to identify promising substances at the earliest possible stage of the development process, robust and predictive surrogate animal models, capable of rapidly characterizing potency with minimal compound requirements, are necessary. the objective of this study was to generate an in vivo surrogate animal bioassay capable of rapidly and accuratel ...200616739411
a novel real-time pcr assay for the speciation of medically important ticks.the identification of ticks using morphological characters is a well-established practice, however specimens that are small or damaged are often difficult to speciate. a novel, rapid real-time pcr assay, which targets the second internal transcribed spacer (its2) region in the nuclear ribosomal dna gene, was developed for identification of four tick species of utmost medical importance in the united states: ixodes scapularis, i. pacificus, dermacentor variabilis, and amblyomma americanum. comput ...200616796512
relative abundance and survival of the tick amblyomma americanum collected from sunlit and shaded habitats.the population density of host-searching nymphal and adult lone star ticks, amblyomma americanum (l.) (acari: ixodidae), was determined at the robinson tract of the kansas ecological reserves and a private farm 5 km north-west of the robinson tract using standard drag cloth methods. nymphs, males and females were counted and collected weekly from shaded habitats and adjacent sunlit habitats from mid-may through late july, 2003. of the 1598 nymphs and 549 males collected by drag sampling, 74.0% a ...200616796613
inferring the population structure and demographic history of the tick, amblyomma americanum linnaeus.a hierarchial population genetic study was conducted on 703 individual amblyomma americanum from nine populations in georgia, u.s.a. populations were sampled from the coastal plain, midland piedmont region, and the upper piedmont region. twenty-nine distinct haplotypes were found. a minimum spanning tree was constructed that indicated these haplotypes comprised two lineages, the root of which was distinctly star-like. the majority of the variation found was among ticks within each population, in ...200616859107
lymph node hemophagocytosis in rickettsial diseases: a pathogenetic role for cd8 t lymphocytes in human monocytic ehrlichiosis (hme)?human monocytic ehrlichiosis (hme) and rocky mountain spotted fever (rmsf) are caused by ehrlichia chaffeensis and rickettsia rickettsii, respectively. the pathogenesis of rmsf relates to rickettsia-mediated vascular injury, but it is unclear in hme.200616859547
efficacy of imidacloprid (8.8% w/w) plus permethrin (44% w/w) spot-on topical solution against amblyomma americanum infesting dogs using a natural tick exposure model.this study evaluated the efficacy of an imidacloprid 8.8% w/w + permethrin 44% w/w spot-on topical solution (k9 advantix, bayer animal health) against amblyomma americanum using a natural field exposure model. sixteen beagles were divided into two groups of eight dogs each. one group of dogs was treated with k9 advantix and the other group served as untreated controls. on day -1 and at 3, 7, 14, 21 and 28 days after treatment, the dogs were walked for 80 minutes in an a. americanum-infested habi ...200616871491
isolation and identification of rickettsia massiliae from rhipicephalus sanguineus ticks collected in arizona.twenty rhipicephalus sanguineus ticks collected in eastern arizona were tested by pcr assay to establish their infection rate with spotted fever group rickettsiae. with a nested pcr assay which detects a fragment of the rickettsia genus-specific 17-kda antigen gene (htra), five ticks (25%) were found to contain rickettsial dna. one rickettsial isolate was obtained from these ticks by inoculating a suspension of a triturated tick into monolayers of vero e6 monkey kidney cells and xtc-2 clawed toa ...200616885311
the emerging diversity of rickettsia.the best-known members of the bacterial genus rickettsia are associates of blood-feeding arthropods that are pathogenic when transmitted to vertebrates. these species include the agents of acute human disease such as typhus and rocky mountain spotted fever. however, many other rickettsia have been uncovered in recent surveys of bacteria associated with arthropods and other invertebrates; the hosts of these bacteria have no relationship with vertebrates. it is therefore perhaps more appropriate t ...200616901827
unique macrophage and tick cell-specific protein expression from the p28/p30-outer membrane protein multigene locus in ehrlichia chaffeensis and ehrlichia canis.ehrlichia chaffeensis and ehrlichia canis are tick-transmitted rickettsial pathogens that cause human and canine monocytic ehrlichiosis respectively. we tested the hypothesis that these pathogens express unique proteins in response to their growth in vertebrate and tick host cells and that this differential expression is similar in closely related ehrlichia species. evaluation of nine e. chaffeensis isolates and one e. canis isolate demonstrated that protein expression was host cell-dependent. t ...200616922866
confirmation of tick bite by detection of antibody to ixodes calreticulin salivary protein.ticks introduce a variety of pharmacologically active molecules into their host during attachment and feeding in order to obtain a blood meal. people who are repeatedly exposed to ticks may develop an immune response to tick salivary proteins. despite this response, people usually are unaware of having been bitten, especially if they are not repeatedly exposed to ticks. in order to develop a laboratory marker of tick exposure that would be useful in understanding the epidemiology of tick-borne i ...200616928887
tick-borne rickettsial pathogens in ticks and small mammals in order to investigate the prevalence of tick-borne infectious agents among ticks, ticks comprising five species from two genera (hemaphysalis spp. and ixodes spp.) were screened using molecular techniques. ticks (3,135) were collected from small wild-caught mammals or by dragging/flagging in the republic of korea (rok) and were pooled into a total of 1,638 samples (1 to 27 ticks per pool). from the 1,638 tick samples, species-specific fragments of anaplasma phagocytophilum (1 sample), anaplasm ...200616957192
haemaphysalis longicornis: molecular characterization of a homologue of the macrophage migration inhibitory factor from the partially fed ticks.the macrophage migration inhibitory factor (mif) has been identified from some vertebrates and invertebrates. mif is related to inflammation, tumor growth, and angiogenesis in vertebrates. here, we report the molecular characterization of a homologue of mif from partially fed haemaphysalis longicornis. the sequence analysis of the h. longicornis mif (hlmif) indicated that its deduced amino acid sequence has an identity of 77% with the mif of the tick amblyomma americanum. western blot analysis u ...200716987517
serologic evaluation of patients from missouri with erythema migrans-like skin lesions with the c6 lyme test.southern tick-associated rash illness (stari), also known as masters disease, affects people predominantly in the southeast and south central united states. these patients exhibit skin lesions that resemble erythema migrans (em), the characteristic skin lesion in early lyme disease. the etiology of stari remains unknown, and no serologic test is available to aid in its diagnosis. the c6 lyme enzyme-linked immunosorbent assay was used to evaluate coded serum specimens from patients with stari at ...200617028220
evaluation of an imidacloprid (8.8% w/w)--permethrin (44.0% w/w) topical spot-on and a fipronil (9.8% w/w)--(s)-methoprene (8.8% w/w) topical spot-on to repel, prevent attachment, and kill adult ixodes scapularis and amblyomma americanum ticks on dogs.this study evaluated the effectiveness of two topical spot-on formulations -- imidacloprid(8.8% w/w)-permethrin (44.0% w/w) and fipronil (9.8% w/w)-(s)-methoprene (8.8% w/w)--to repel, prevent the attachment of, and kill adult ixodes scapularis and amblyomma americanum on dogs. twelve purpose-bred beagles were distributed into three groups of four dogs each; one group served as untreated controls, and each of the other two groups received one of the test products. dogs were exposed to 25 adult t ...200617039440
differential clearance and immune responses to tick cell-derived versus macrophage culture-derived ehrlichia chaffeensis in mice.human monocytic ehrlichiosis is caused by a tick-transmitted rickettsia, ehrlichia chaffeensis. we recently reported that e. chaffeensis grown in tick cells expresses different proteins than bacteria grown in macrophages. therefore, we tested the hypothesis that immune responses against e. chaffeensis would be different if the mice are challenged with bacteria grown in macrophages or tick cells. we assessed the e. chaffeensis clearance from the peritoneum, spleen, and liver by c57bl/6j mice usin ...200717060466
ehrlichia chaffeensis: a prevalent, life-threatening, emerging pathogen.ehrlichia chaffeensis are small, obligately intracellular, endosomal bacteria with tropism for macrophages. persistent infection in reservoir white-tailed deer is transmitted by lone star ticks. flu-like illness can progress to severe multisystem disease with toxic shock-like syndrome, meningitis, or ards. the case-fatality rate is 2.7%. leukopenia and thrombocytopenia are diagnostically useful. granulomas are associated with control of the infection. ehrlichial proteins and glycoproteins have b ...200417060980
highly prevalent coxiella sp. bacterium in the tick vector amblyomma americanum.laboratory-reared and field-collected amblyomma americanum ticks were hosts of a coxiella sp. and a rickettsia sp. while the coxiella sp. was detected in 50 of 50 field-collected ticks, the rickettsia sp. was absent from 32% of ticks. the coxiella sp. showed evidence of a reduced genome and may be an obligate endosymbiont.200717085709
fecal nirs: detection of tick infestations in cattle and horses.anti-tick treatments are often applied concurrent to routine livestock management practices with little regard to actual infestation levels. prescription treatments against ticks on grazing cattle would be facilitated by non-invasive detection methods. one such method is fecal near infrared spectroscopy (nirs). four studies utilizing cattle (bos spp.) and one with horses (equus caballus) fed varying diets and infested with either amblyomma americanum, a. maculatum, a. cajennense or dermacentor a ...200717097809
infection of ixodes scapularis ticks with rickettsia monacensis expressing green fluorescent protein: a model system.ticks (acari: ixodidae) are ubiquitous hosts of rickettsiae (rickettsiaceae: rickettsia), obligate intracellular bacteria that occur as a continuum from nonpathogenic arthropod endosymbionts to virulent pathogens of both arthropod vectors and vertebrates. visualization of rickettsiae in hosts has traditionally been limited to techniques utilizing fixed tissues. we report epifluorescence microscopy observations of unfixed tick tissues infected with a spotted fever group endosymbiont, rickettsia m ...200717125789
prevalence of ehrlichia, borrelia, and rickettsial agents in amblyomma americanum (acari: ixodidae) collected from nine states.ambyomma americanum (l.) (acari: ixodidae) is an aggressive tick that feeds on humans during all postembryonic life stages. in many regions of the united states, it is the tick most commonly found attached to humans. public health interest has grown recently, due to the recognition of new human pathogens transmitted by a. americanum and the expanding distribution of the tick. a. americanum is a vector of several bacteria pathogenic to humans. ehrlichia chaffeensis and ehrlichia ewingii cause mod ...200617162962
relative abundance and prevalence of selected borrelia infections in ixodes scapularis and amblyomma americanum (acari: ixodidae) from publicly owned lands in monmouth county, new evaluate their potential importance in the transmission of ixodid tick-borne borrelioses in monmouth county, nj, we collected host-seeking ixodes scapularis say and amblyomma americanum (l.) (acari: ixodidae) adults and nymphs to determine relative encounter frequencies and the infection prevalence of selected borrelia spp. in their respective tick vectors. we also reviewed records of all ticks submitted for identification by the public in monmouth county during 2001-2005. relative abundance ...200617162963
mammal diversity and infection prevalence in the maintenance of enzootic borrelia burgdorferi along the western coastal plains of maryland.the primary vector of borrelia burgdorferi in north america, ixodes scapularis, feeds on various mammalian, avian, and reptilian hosts. several small mammal hosts; peromyscus leucopus, tamias striatus, microtus pennsylvanicus, and blarina spp. can serve as reservoirs in an enzootic cycle of lyme disease. the primary reservoir in the northeast united states is the white-footed mouse, p. leucopus. the infection prevalence of this reservoir as well as the roles of potential secondary reservoirs has ...200617187577
gene silencing of the tick protective antigens, bm86, bm91 and subolesin, in the one-host tick boophilus microplus by rna interference.the use of rna interference (rnai) to assess gene function has been demonstrated in several three-host tick species but adaptation of rnai to the one-host tick, boophilus microplus, has not been reported. we evaluated the application of rnai in b. microplus and the effect of gene silencing on three tick-protective antigens: bm86, bm91 and subolesin. gene-specific double-stranded (dsrna) was injected into two tick stages, freshly molted unfed and engorged females, and specific gene silencing was ...200717196597
association of the bovine leukocyte antigen major histocompatibility complex class ii drb3*4401 allele with host resistance to the lone star tick, amblyomma americanum.the mhc of cattle, known as the bovine leukocyte antigen (bola) complex, plays an integral role in disease and parasite susceptibility, and immune responsiveness of the host. while susceptibility to tick infestation in cattle is believed to be heritable, genes that may be responsible for the manifestation of this phenotype remain elusive. in an effort to analyze the role that genes within the bola complex may play in host resistance to ticks, we have evaluated components of this system within a ...200717208379
infection of a goat with a tick-transmitted ehrlichia from georgia, u.s.a., that is closely related to ehrlichia ruminantium.we detected a novel tick-transmitted ehrlichia in a goat following exposure to lone star ticks (amblyomma americanum) from a park in the metropolitan area of atlanta, ga, u.s.a. nineteen days after infestation with field-collected adult ticks, the goat developed a fever of two days duration, which coincided with mild clinical pathologic changes and the presence of dna from a novel ehrlichia in peripheral blood. the goat transmitted ehrlichiae to uninfected nymphal a. americanum that fed upon the ...200617249337
new tick defensin isoform and antimicrobial gene expression in response to rickettsia montanensis challenge.recent studies aimed at elucidating the rickettsia-tick interaction have discovered that the spotted fever group rickettsia rickettsia montanensis, a relative of r. rickettsii, the etiologic agent of rocky mountain spotted fever, induces differential gene expression patterns in the ovaries of the hard tick dermacentor variabilis. here we describe a new defensin isoform, defensin-2, and the expression patterns of genes for three antimicrobials, defensin-1 (vsna1), defensin-2, and lysozyme, in the ...200717261604
evidence for a population expansion in the west nile virus vector culex tarsalis.population genetic structure of the west nile virus vector culex tarsalis was investigated in 5 states in the western united states using 5 microsatellite loci and a fragment of the mitochondrial reduced form of nicotinamide adenine dinucleotide dehydrogenase 4 (nd4) gene. nd4 sequence analysis revealed a lack of isolation by distance, panmixia across all populations, an excess of rare haplotypes, and a star-like phylogeny. microsatellites revealed moderate genetic differentiation and isolation ...200717339636
transovarial silencing of the subolesin gene in three-host ixodid tick species after injection of replete females with subolesin dsrna.rna interference (rnai) has become the most powerful experimental tool for the study of gene function in ticks. subolesin, initially called 4d8, was found to be protective against tick infestations when used as a vaccine and was shown to be highly conserved among ixodid tick species at the nucleotide and protein levels. rnai caused systemic silencing of subolesin and demonstrated that this protein is involved in regulation of tick feeding, reproduction, and development. recently, these results w ...200717372765
repellency of two terpenoid compounds isolated from callicarpa americana (lamiaceae) against ixodes scapularis and amblyomma americanum ticks.callicarpenal (13, 14, 15, 16-tetranor-3-cleroden-12-al) and intermedeol [(4s,5s,7r,10s)-eudesm-11-en-4-ol], isolated from american beautyberry, callicarpa americana (lamiaceae), were evaluated in laboratory bioassays for repellent activity against host-seeking nymphs of the blacklegged tick, ixodes scapularis, and lone star tick, amblyomma americanum. a strip of organdy cloth treated with test solution was doubly wrapped (treatment on outer layer) around the middle phalanx of a forefinger and t ...200717380408
the molecular basis of the amblyomma americanum tick attachment phase.towards discovery of molecular signaling cascades that trigger and/or facilitate the tick attachment and formation of its feeding lesion, suppressive subtractive hybridization, high throughput sequencing and validation of differential expression by cdna dot blot hybridization were performed on amblyomma americanum ticks that had attained appetence and were exposed to feeding stimuli. this approach allowed for identification of 40 genes that are up regulated before ticks begin to penetrate the ho ...200717406795
virulence potential of ehrlichia chaffeensis strains of distinct genome sequences.human monocytic ehrlichiosis, one of the most frequent life-threatening tick-borne zoonoses, is caused by ehrlichia chaffeensis that lacks endotoxin and peptidoglycan. while sequence polymorphisms in several genes in e. chaffeensis strains have been reported, global genomic divergence and biological differences among strains are unknown. the objectives of the present study were to compare the genome sequences of strains of e. chaffeensis and to examine the virulence potentials of the strains wit ...200717438035
antibiotic treatment of the tick vector amblyomma americanum reduced reproductive fitness.the lone star tick amblyomma americanum is a common pest and vector of infectious diseases for humans and other mammals in the southern and eastern united states. a coxiella sp. bacterial endosymbiont was highly prevalent in both laboratory-reared and field-collected a. americanum. the coxiella sp. was demonstrated in all stages of tick and in greatest densities in nymphs and adult females, while a rickettsia sp. was less prevalent and in lower densities when present.200717476327
evolution of the iron-responsive rna hairpin structure referred to as the iron-responsive element (ire) and iron regulatory proteins (irps) are key players in the control of iron metabolism in animal cells. they regulate translation initiation or mrna stability, and the ire is found in a variety of mrnas, such as those encoding ferritin, transferrin receptor (tfr), erythroid aminolevulinic acid synthase (ealas), mitochondrial aconitase (maco), ferroportin, and divalent metal transporter 1 (dmt1). we have studied the evolutio ...200717513696
surface-exposed proteins of ehrlichia chaffeensis.the surface proteins of ehrlichia chaffeensis provide an important interface for pathogen-host interactions. to investigate the surface proteins of e. chaffeensis, membrane-impermeable, cleavable sulfo-nhs-ss-biotin was used to label intact bacteria. the biotinylated bacterial surface proteins were isolated by streptavidin-agarose affinity purification. the affinity-captured proteins were separated by electrophoresis, and five relatively abundant protein bands containing immunoreactive proteins ...200717517859
purification and characterization of two larval glycoproteins from the cattle tick, boophilus annulatus.the present study was conducted to identify new target immunogenic molecules from the larval stage of the cattle tick, boophilus annulatus (acari: ixodidae). two specific larval glycoproteins (glps) were isolated by two-step affinity chromatography. the larval immunogens were first purified with cnbr-sepharose coupled to rabbit anti-larval immunoglobulins, and the glycoproteins were then purified with con-a sepharose. these glycoproteins have molecular weights of approximately 32 and 15 kda with ...200717519572
a call for renewed research on tick-borne francisella tularensis in the arkansas-missouri primary national focus of tularemia in humans.arkansas-missouri has emerged as the primary u.s. focus of tularemia, which is caused by the national institute of allergy and infectious diseases category a priority pathogen francisella tularensis, over the past 30 yr. there are several pieces of indirect evidence suggesting that a key role of ticks in the transmission of f. tularensis to humans in arkansas-missouri is the primary reason why tularemia has remained a prominent disease of humans in this two-state area while fading away from othe ...200717547223
transmission of bacterial agents from lone star ticks to white-tailed deer.amblyomma americanum (l.), the lone star tick, is an aggressive ixodid tick that has been implicated as a vector for several bacteria. among these bacteria are the disease agents ehrlichia chaffeensis and ehrlichia ewingii, and the putative disease agent "borrelia lonestari." the hypothesis in this study was that wild lone star ticks from northeastern georgia are capable of transmitting all three agents to white-tailed deer, odocoileus virginianus, a known reservoir host for e. chaffeensis. in t ...200717547234
tissue and life-stage distribution of a defensin gene in the lone star tick, amblyomma americanum.the transcript sequence of the amblyomma americanum linnaeus (acari: ixodidae) defensin, termed amercin (amn), was ascertained and a 219-bp amn coding region identified. the gene encodes a 72-amino acid prepropeptide with a putative 37-amino acid mature peptide. this gene shows little similarity to either of the defensins from amblyomma hebraeum koch, the only other amblyomma species for which a defensin has been described. sequence comparisons with other tick defensins reveal amn to be shorter ...200717550433
multiplication of tularemia organisms in the lone star tick. 195517648838
transmission of ehrlichia chaffeensis from lone star ticks (amblyomma americanum) to white-tailed deer (odocoileus virginianus).amblyomma americanum is an aggressive ixodid tick that has been implicated as a vector for several bacterial agents. among these is ehrlichia chaffeensis, which causes human monocytic (or monocytotropic) ehrlichiosis. in this study, experimental tick transmission of e. chaffeensis from infected lone star ticks to deer was revisited, and the question of whether it would be possible to re-isolate the organism from deer was asked, because this had not been done previously. here, we were able to tra ...200717699076
localization and visualization of a coxiella-type symbiont within the lone star tick, amblyomma americanum.a coxiella-type microbe occurs at 100% frequency in all amblyomma americanum ticks thus far tested. using laboratory-reared ticks free of other microbes, we identified the amblyomma-associated coxiella microbe in several types of tissue and at various stages of the life cycle of a. americanum by 16s rrna gene sequencing and diagnostic pcr. we visualized amblyomma-associated coxiella through the use of a diagnostic fluorescence in situ hybridization (fish) assay supplemented with pcr-based detect ...200717720830
thyroid hormone receptor orthologues from invertebrate species with emphasis on schistosoma mansoni.thyroid hormone receptors (trs) function as molecular switches in response to thyroid hormone to regulate gene transcription. trs were previously believed to be present only in chordates.200717727708
molecular and expression analysis of a family of the amblyomma americanum tick lospins.serine proteinase inhibitors (serpins) are a family of structurally similar but functionally diverse proteins that regulate several important proteolytic cascades in most branches of life. we have characterized 17 amblyomma americanum serpin cdnas here named as ;lospins' (l; an acronym for lone star tick serpin) that possess three beta-sheets, eight alpha-helices and a reactive center loop consistent with the consensus serpin superfamily secondary structures. visual inspection of deduced amino a ...200717766296
bartonella vinsonii subsp. berkhoffii endocarditis in a dog from saskatchewan.a dog referred for lameness was diagnosed with culture-negative endocarditis. antibodies to bartonella spp. were detected. antibiotic treatment resulted in transient clinical improvement, but the dog developed cardiac failure and was euthanized. bartonella vinsonii subsp. berkhoffii genotype iv was identified within the aortic heart valve lesions by pcr amplification and dna sequencing.200717824328
ecological havoc, the rise of white-tailed deer, and the emergence of amblyomma americanum-associated zoonoses in the united states.two infectious diseases, and one presumably infectious disease, each vectored by or associated with the bite of the lone star tick (amblyomma americanum), were identified and characterized by clinicians and scientists in the united states during the 1980s and 1990s. these three conditions-human monocytic (or monocytotropic) ehrlichiosis (hme), ehrlichia ewingii ehrlichiosis, and southern tick-associated rash illness (stari)-undoubtedly existed in the united states prior to this time. however, th ...200717848069
life cycles of seven ixodid tick species (acari: ixodidae) under standardized laboratory conditions.studies of transmission, maintenance, infectivity, virulence, and pathogenicity of tick-borne agents require the use of large numbers of live laboratory-raised ticks. colonies of ixodes scapularis say, ixodes pacificus cooley & kohls, amblyomma americanum (l.), dermacentor occidentalis marx, dermacentor variabilis (say), hemaphysalis leporispalustris (packard), and rhipicephalus sanguineus (latrielle) have been maintained in our laboratory at the centers for disease control and prevention for fi ...200717915502
confirmation of the efficacy of a novel formulation of metaflumizone plus amitraz for the treatment and control of fleas and ticks on dogs.a novel spot-on formulation containing metaflumizone plus amitraz (promeris/promeris duo for dogs, fort dodge animal health, overland park, ks) was evaluated in four laboratory studies to confirm efficacy against fleas and ticks on dogs for 1 month. three different strains of cat flea (ctenocephalides felis felis) and four tick species were used. rhipicephalus sanguineus and dermacentor variabilis were evaluated concurrently in two studies and ixodes scapularis and amblyomma americanum in one st ...200717923330
functional evolution of the vitamin d and pregnane x receptors.the vitamin d receptor (vdr) and pregnane x receptor (pxr) are nuclear hormone receptors of the nr1i subfamily that show contrasting patterns of cross-species variation. vdr and pxr are thought to have arisen from duplication of an ancestral gene, evident now as a single gene in the genome of the chordate invertebrate ciona intestinalis (sea squirt). vdr genes have been detected in a wide range of vertebrates including jawless fish. to date, pxr genes have not been found in cartilaginous fish. i ...200717997857
molecular cloning of the ecdysone receptor and the retinoid x receptor from the scorpion liocheles australasiae.cdnas of the ecdysone receptor and the retinoid x receptor were cloned from the japanese scorpion liocheles australasiae, and the amino acid sequences were deduced. the full-length cdna sequences of the l. australasiae ecdysone receptor and the l. australasiae retinoid x receptor were 2881 and 1977 bp in length, respectively, and the open reading frames encoded proteins of 560 and 414 amino acids. the amino acid sequence of the l. australasiae ecdysone receptor was similar to that of the ecdyson ...200718028192
experimental infection of dairy calves with ehrlichia chaffeensis.human monocytic ehrlichiosis (hme) is a zoonotic emerging tick-borne disease with clinical signs that range from mild symptoms to multiple organ failure and death. ehrlichia chaffeensis, the aetiologic agent of hme, is reported to infect a divergent range of mammals. although cattle are common hosts of the primary vector of this pathogen, the susceptibility of this host to e. chaffeensis has not been reported to date. this study was undertaken to determine if cattle could provide a useful infect ...200718033836
serotonin-like immunoreactivity in the central nervous system of two ixodid tick species.immunocytochemistry was used to describe the distribution of serotonin-like immunoreactive (5ht-ir) neurons and neuronal processes in the central nervous system (cns), the synganglion, of two ixodid tick species; the winter tick, dermacentor albipictus and the lone star tick, amblyomma americanum. 5ht-ir neurons were identified in the synganglion of both tick species. d. albipictus had a significantly higher number of 5ht-ir neurons than a. americanum. the labeling pattern and number of 5ht-ir n ...200718040871
detection of rickettsia amblyommii in association with a tick bite the summer of 2006, an amblyomma americanum tick was removed from a woman in central north carolina, who subsequently developed a rash at the site of tick attachment. when examined by polymerase chain reaction (pcr) for borrelia, anaplasma, ehrlichia, babesia, rickettsia, and bartonella dna, only the rickettsia primers generated an amplicon, which was identified as "r. amblyommii" by sequencing. to our knowledge, this is the first case in which r. amblyommii was temporally associated with a r ...200718052716
plasmids of the prm/prf family occur in diverse rickettsia species.the recent discoveries of the prf and prm plasmids of rickettsia felis and r. monacensis have contravened the long-held dogma that plasmids are not present in the bacterial genus rickettsia (rickettsiales; rickettsiaceae). we report the existence of plasmids in r. helvetica, r. peacockii, r. amblyommii, and r. massiliae isolates from ixodid ticks and in an r. hoogstraalii isolate from an argasid tick. r. peacockii and four isolates of r. amblyommii from widely separated geographic locations cont ...200818065613
an insight into the sialome of the soft tick, ornithodorus parkeri.while hard ticks (ixodidae) take several days to feed on their hosts, soft ticks (argasidae) feed faster, usually taking less than 1h per meal. saliva assists in the feeding process by providing a cocktail of anti-hemostatic, anti-inflammatory and immunomodullatory compounds. saliva of hard ticks has been shown to contain several families of genes each having multiple members, while those of soft ticks are relatively unexplored. analysis of the salivary transcriptome of the soft tick ornithodoru ...200818070662
comparative sialomics between hard and soft ticks: implications for the evolution of blood-feeding behavior.ticks evolved various mechanisms to modulate their host's hemostatic and immune defenses. differences in the anti-hemostatic repertoires suggest that hard and soft ticks evolved anti-hemostatic mechanisms independently, but raise questions on the conservation of salivary gland proteins in the ancestral tick lineage. to address this issue, the sialome (salivary gland secretory proteome) from the soft tick, argas monolakensis, was determined by proteomic analysis and cdna library construction of s ...200818070664
identification of 19 polymorphic major outer membrane protein genes and their immunogenic peptides in ehrlichia ewingii for use in a serodiagnostic assay.ehrlichia ewingii, a tick-transmitted rickettsia previously known only as a canine pathogen, was recently recognized as a human pathogen. e. ewingii has yet to be cultivated, and there is no serologic test available to diagnose e. ewingii infection. previously, a fragment (505 bp) of a single e. ewingii gene homologous to 1 of 22 genes encoding ehrlichia chaffeensis immunodominant major outer membrane proteins 1 (omp-1s)/p28s was identified. the purposes of the present study were to (i) determin ...200818094116
variability and action mechanism of a family of anticomplement proteins in ixodes ricinus.ticks are blood feeding arachnids that characteristically take a long blood meal. they must therefore counteract host defence mechanisms such as hemostasis, inflammation and the immune response. this is achieved by expressing batteries of salivary proteins coded by multigene families.200818167559
rickettsia amblyommii infecting amblyomma americanum larvae.polymerase chain reaction analysis of amblyomma americanum adults, nymphs, and larvae from aberdeen proving ground, md (apg), revealed a very high prevalence of a spotted fever group (sfg) rickettsia. restriction fragment length polymorphism (rflp) and sequence analysis identified "rickettsia amblyommii." this organism is not yet described or well studied, and its pathogenicity is unknown; however, investigations of the organism are warranted because of its high prevalence in a. americanum. this ...200818171102
identity and transfer of male reproductive gland proteins of the dengue vector mosquito, aedes aegypti: potential tools for control of female feeding and reproduction.male reproductive gland proteins (mrgps) impact the physiology and/or behavior of mated females in a broad range of organisms. we sought to identify mrgps of the yellow fever mosquito, aedes aegypti, the primary vector of dengue and yellow fever viruses. earlier studies with ae. aegypti demonstrated that "matrone" (a partially purified male reproductive accessory gland substance) or male accessory gland fluid injected into virgin female ae. aegypti affect female sexual refractoriness, blood feed ...200818207079
use of drosophila s2 cells as a model for studying ehrlichia chaffeensis infections.ehrlichia chaffeensis is an obligate intracellular bacterium and the causative agent of human monocytic ehrlichiosis. although this pathogen grows in several mammalian cell lines, no general model for eukaryotic cellular requirements for bacteria replication has yet been proposed. we found that drosophila s2 cells are permissive for the growth of e. chaffeensis. we saw morulae (aggregates of bacteria) by microscopy, detected the e. chaffeensis 16s rrna gene by reverse transcriptase pcr, and used ...200818245255
detection of two bartonella tamiae-like sequences in amblyomma americanum (acari: ixodidae) using 16s-23s intergenic spacer region-specific primers.four hundred and sixty-six questing amblyomma americanum (l.) (acari: ixodidae) from carolina county, va, and 98 questing a. americanum from chatham county, nc, were screened by polymerase chain reaction (pcr) for the bartonella 16s-23s intergenic spacer region. two amplicons, approximately 270-280 bp, were detected in two ticks from virginia. based upon pcr and sequencing, an adult male and adult female tick harbored dna sequences closely related to bartonella tamiae (dq395180). bartonella dna ...200818283962
ehrlichia chaffeensis in child, venezuela. 200818325283
two usa ehrlichia spp. cause febrile illness in goats.ehrlichia spp. are not currently recognized as a cause of illness in goats in the usa, but three ehrlichia are enzootic in lone star ticks (amblyomma americanum) in the eastern usa, and related bacteria in other countries cause illness in goats. we exposed naïve goats to ehrlichia-infected amblyomma and demonstrated that infection and clinical illness can be caused by two usa species, e. ewingii and the recently discovered panola mountain ehrlichia sp. clinical features in all five goats are des ...200818328644
a critical analysis of disease-associated dna polymorphisms in the genes of cattle, goat, sheep, and pig.genetic variations through their effects on gene expression and protein function underlie disease susceptibility in farm animal species. the variations are in the form of single nucleotide polymorphisms, deletions/insertions of nucleotides or whole genes, gene or whole chromosomal rearrangements, gene duplications, and copy number polymorphisms or variants. they exert varying degrees of effects on gene action, such as substitution of an amino acid for another, shift in reading frame and prematur ...200818350334
expression and porin activity of p28 and omp-1f during intracellular ehrlichia chaffeensis development.ehrlichia chaffeensis, an obligatory intracellular gram-negative bacterium, must take up various nutrients and metabolic compounds because it lacks many genes involved in metabolism. nutrient uptake by a gram-negative bacterium occurs primarily through pores or channels in the bacterial outer membrane. here we demonstrate that isolated e. chaffeensis outer membranes have porin activities, as determined by a proteoliposome swelling assay. the activity was partially blocked by an antibody that rec ...200818359808
rnai-mediated gene silencing in tick synganglia: a proof of concept study.progress in generating comprehensive est libraries and genome sequencing is setting the stage for reverse genetic approaches to gene function studies in the blacklegged tick (ixodes scapularis). however, proving that rnai can work in nervous tissue has been problematic. developing an ability to manipulate gene expression in the tick synganglia likely would accelerate understanding of tick neurobiology. here, we assess gene silencing by rna interference in the adult female black-legged tick synga ...200818366768
evolution of pharmacologic specificity in the pregnane x receptor.the pregnane x receptor (pxr) shows the highest degree of cross-species sequence diversity of any of the vertebrate nuclear hormone receptors. in this study, we determined the pharmacophores for activation of human, mouse, rat, rabbit, chicken, and zebrafish pxrs, using a common set of sixteen ligands. in addition, we compared in detail the selectivity of human and zebrafish pxrs for steroidal compounds and xenobiotics. the ligand activation properties of the western clawed frog (xenopus tropica ...200818384689
a possible canine tick-bite reaction to ixodes airedale terrier became acutely ill following attachment of an ixodes muris tick. clinical signs waned within hours of tick removal, similar to a pattern previously documented in animals harboring i. muris. this supports the theory that i. muris can induce a noninfectious, severe inflammatory reaction in domestic animals.200818390101
ligand specificity and evolution of liver x receptors.liver x receptors (lxrs) are key regulators of lipid and cholesterol metabolism in mammals. little is known, however, about the function and evolution of lxrs in non-mammalian species. the present study reports the cloning of lxrs from african clawed frog (xenopus laevis), western clawed frog (xenopus tropicalis), and zebrafish (danio rerio), and their functional characterization and comparison with human and mouse lxrs. additionally, an ortholog of lxr in the chordate invertebrate ciona intesti ...200818395439
characterization of rickettsial infection in amblyomma americanum (acari: ixodidae) by quantitative real-time polymerase chain reaction.several species of the spotted fever group rickettsia (sfgr), with considerable variation in vertebrate host pathogenicity, are present in ticks in the united states. in this study, quantitative real-time pcr (qpcr) was used to characterize the growth and the distribution of rickettsia amblyommii in selected tissues (salivary glands, gut, and ovaries) of naturally infected amblyomma americanum (l.) (acari: ixodidae), during bloodmeal acquisition and throughout vertical transmission to eggs and p ...200818402143
enhanced spatial models for predicting the geographic distributions of tick-borne pathogens.disease maps are used increasingly in the health sciences, with applications ranging from the diagnosis of individual cases to regional and global assessments of public health. however, data on the distributions of emerging infectious diseases are often available from only a limited number of samples. we compared several spatial modelling approaches for predicting the geographic distributions of two tick-borne pathogens: ehrlichia chaffeensis, the causative agent of human monocytotropic ehrlichi ...200818412972
experimental and field studies on the suitability of raccoons (procyon lotor) as hosts for tick-borne pathogens.we investigated the experimental susceptibility and natural exposure of raccoons (procyon lotor) to five tick-borne pathogens of human and veterinary importance, ehrlichia canis, e. chaffeensis, e. ewingii, anaplasma phagocytophilum (apvariant 1 and ap-ha hge-1 strains), and borrelia lonestari. infections were assessed by polymerase chain reaction (pcr), indirect fluorescent antibody (ifa) testing, and/or culture isolation methods for at least 30 days postinoculation (dpi). two e. chaffeensis-in ...200818429696
geographic distribution and genetic diversity of the ehrlichia sp. from panola mountain in amblyomma americanum.a novel ehrlichia, closely related to ehrlichia ruminantium, was recently discovered from panola mountain state park, ga, usa. we conducted a study to determine if this agent was recently introduced into the united states.200818433500
natural and experimental infection of white-tailed deer (odocoileus virginianus) from the united states with an ehrlichia sp. closely related to ehrlichia ehrlichia sp. (panola mountain [pm] ehrlichia sp.) closely related to ehrlichia ruminantium was recently detected in a domestic goat experimentally infested with lone star ticks (lsts, amblyomma americanum) collected from georgia, usa. the infected goat exhibited pyrexia and mild clinical pathologic abnormalities consistent with ehrlichiosis. at least two other ehrlichia species (ehrlichia chaffeensis and ehrlichia ewingii) are maintained in nature by a cycle involving lsts as the primary vec ...200818436670
tick-borne diseases in north carolina: is "rickettsia amblyommii" a possible cause of rickettsiosis reported as rocky mountain spotted fever?cases of rocky mountain spotted fever (rmsf) in north carolina have escalated markedly since 2000. in 2005, we identified a county in the piedmont region with high case numbers of rmsf. we collected ticks and examined them for bacterial pathogens using molecular methods to determine if a novel tick vector or spotted fever group rickettsiae (sfgr) might be emerging. amblyomma americanum, the lone star tick, comprised 99.6% of 6,502 specimens collected in suburban landscapes. in contrast, dermacen ...200818447622
the first report of human illness associated with the panola mountain ehrlichia species: a case report.two species of ehrlichia are known to cause human illness. several other species have been discovered in ticks and animals, and recent reports suggest that some of these ehrlichia species might be human pathogens. we report here the first association of a recently discovered pathogen, the panola mountain ehrlichia species, with a case of human illness.200818447934
stari, or masters disease: lone star tick-vectored lyme-like illness.lyme-like illness (also known as southern tick-associated rash illness [stari] or masters disease) is vectored by the lone star tick (amblyomma americanum). lyme-like illness lesions, which are similar to the erythema migrans rash of lyme disease, tend to have lymphocytic dermal infiltrates. with the exception of borrelia lonestari, the possible causative agent or agents of lyme-like illness have not been cultured. more research is needed to fully understand this newly recognized zoonosis. clini ...200818452807
insight into the sialome of the castor bean tick, ixodes recent years, there have been several sialome projects revealing transcripts expressed in the salivary glands of ticks, which are important vectors of several human diseases. here, we focused on the sialome of the european vector of lyme disease, ixodes ricinus.200818489795
neuropeptide discovery in ixodoidea: an in silico investigation using publicly accessible expressed sequence tags.the ixodoidea (ticks) are important vectors in the transmission of many human diseases; for example, the blacklegged tick ixodes scapularis is the major vector in the transmission of lyme disease, the most frequently reported vector-borne illness in the united states. the development of expressed sequence tags (ests) for ixodoidean cdna libraries, and their public deposition, has generated a rich resource for protein discovery in members of this taxon, thereby providing an opportunity for better ...200818495123
failure by engorged stages of the lone star tick, amblyomma americanum, to react to assembly pheromone, guanine and uric acid.response to tick-exposed filter paper discs (tick excreta) by fed and non-fed stages of the lone star tick amblyomma americanum (l.) (acari: ixodidae) was examined from larva to adult. by contrast with engorged stages, each non-fed stage exhibited a classic arrestment response to assembly pheromone, characterized by lack of movement, retraction of legs and formation of small groups; this response was seen in approximately 75% of ticks that made contact with pheromone-treated surfaces. less prono ...200818498612
twelve-hour duration testing of cream formulations of three repellents against amblyomma americanum.the repellent efficacies of the u.s. military repellent 33% n,n-diethyl-3-methylbenzamide (deet), 10% and 20% (1s, 2's) 2-methylpiperidinyl-3-cyclohexene-1-carboxamide (ss220) and 10% and 20% 1-methyl-propyl-2-(hydroxyethyl)-1-piperidinecarboxylate (bayrepel) cream formulations on human volunteers against the lone star tick amblyomma americanum (l.) were evaluated in a simulated forest floor environment over a 12-h testing period. at 2-h intervals, volunteers, with repellent applied in a 5-cm-wi ...200818498614
conjunctival attachment of a tick: clinicopathologic report of a case.attachment by ticks to ocular surfaces is uncommon, but has been reported. the objective of this article is to describe a case of conjunctival tick attachment and a method for removal by conjunctival excision. a 39-year-old man presented to the emergency department with a complaint of foreign-body sensation in his right eye. he was found to have a live tick embedded in his conjunctiva. the tick was removed en bloc with surrounding conjunctiva by an ophthalmologist. the arthropod was identified a ...201118514466
a leishmania ortholog of macrophage migration inhibitory factor modulates host macrophage responses.parasitic organisms have evolved specialized strategies to evade immune defense mechanisms. we describe herein an ortholog of the cytokine, macrophage migration inhibitory factor (mif), which is produced by the obligate intracellular parasite, leishmania major. the leishmania mif protein, lm1740mif, shows significant structural homology with human mif as revealed by a high-resolution x-ray crystal structure (1.03 a). differences between the two proteins in the n-terminal tautomerization site are ...200818523291
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