| upscale or downscale: applications of fine scale remotely sensed data to chagas disease in argentina and schistosomiasis in kenya. | depending on the research question or the public health application, the appropriate resolution of the data varies temporally, spatially, and, for satellite data, spectrally and radiometrically. regardless of the scale used to address a research or public health question, the temptation is always there to extrapolate from fine-resolution data or to interpolate from coarse resolution studies. in both cases, the relevance of data and analyses conducted on one spatial level to other levels cannot b ... | 2006 | 17476311 |
| antibiotic treatment of the tick vector amblyomma americanum reduced reproductive fitness. | the lone star tick amblyomma americanum is a common pest and vector of infectious diseases for humans and other mammals in the southern and eastern united states. a coxiella sp. bacterial endosymbiont was highly prevalent in both laboratory-reared and field-collected a. americanum. the coxiella sp. was demonstrated in all stages of tick and in greatest densities in nymphs and adult females, while a rickettsia sp. was less prevalent and in lower densities when present. | 2007 | 17476327 |
| tick-borne flavivirus infection in ixodes scapularis larvae: development of a novel method for synchronous viral infection of ticks. | following a bite from an infected tick, tick-borne flaviviruses cause encephalitis, meningitis and hemorrhagic fever in humans. although these viruses spend most of their time in the tick, little is known regarding the virus-vector interactions. we developed a simple method for synchronously infecting ixodes scapularis larvae with langat virus (lgtv) by immersion in media containing the virus. this technique resulted in approximately 96% of ticks becoming infected. lgtv infection and replication ... | 2007 | 17490700 |
| prevalence of anaplasma phagocytophilum in domestic felines in the united states. | anaplasma phagocytophilum is among the more common tick-borne disease agents in the united states. it is of veterinary and public health significance as dogs, cats, and human beings are known to be susceptible. a. phagocytophilum is transmitted trans-stadially by either nymphs or adults of either the black-legged tick (ixodes scapularis) or the western black-legged tick (ixodes pacificus). little information is available regarding either the prevalence of this agent in cats or the dynamics of ve ... | 2007 | 17493756 |
| purine salvage pathways among borrelia species. | genome sequencing projects on two relapsing fever spirochetes, borrelia hermsii and borrelia turicatae, revealed differences in genes involved in purine metabolism and salvage compared to those in the lyme disease spirochete borrelia burgdorferi. the relapsing fever spirochetes contained six open reading frames that are absent from the b. burgdorferi genome. these genes included those for hypoxanthine-guanine phosphoribosyltransferase (hpt), adenylosuccinate synthase (pura), adenylosuccinate lya ... | 2007 | 17502392 |
| gene expression and the evolution of phenotypic diversity in social wasps. | organisms are capable of developing different phenotypes by altering the genes they express. this phenotypic plasticity provides a means for species to respond effectively to environmental conditions. one of the most dramatic examples of phenotypic plasticity occurs in the highly social hymenopteran insects (ants, social bees, and social wasps), where distinct castes and sexes all arise from the same genes. to elucidate how variation in patterns of gene expression affects phenotypic variation, w ... | 2007 | 17504526 |
| immunity against ixodes scapularis salivary proteins expressed within 24 hours of attachment thwarts tick feeding and impairs borrelia transmission. | in north america, the black-legged tick, ixodes scapularis, an obligate haematophagus arthropod, is a vector of several human pathogens including borrelia burgdorferi, the lyme disease agent. in this report, we show that the tick salivary gland transcriptome and proteome is dynamic and changes during the process of engorgement. we demonstrate, using a guinea pig model of i. scapularis feeding and b. burgdorferi transmission, that immunity directed against salivary proteins expressed in the first ... | 2007 | 17505544 |
| the tick salivary protein, salp15, inhibits the development of experimental asthma. | activation of th2 cd4(+) t cells is necessary and sufficient to elicit allergic airway disease, a mouse model with many features of human allergic asthma. effectively controlling the activities of these cells could be a panacea for asthma therapy. blood-feeding parasites have devised remarkable strategies to effectively evade the immune response. for example, ticks such as ixodes scapularis, which must remain on the host for up to 7 days to feed to repletion, secrete immunosuppressive proteins. ... | 2007 | 17513755 |
| the critical role of the linear plasmid lp36 in the infectious cycle of borrelia burgdorferi. | borrelia burgdorferi, the aetiological agent of lyme disease, follows a life cycle that involves passage between the tick vector and the mammalian host. to investigate the role of the 36 kb linear plasmid, lp36 (also designated the b. burgdorferi k plasmid), in the infectious cycle of b. burgdorferi, we examined a clone lacking this plasmid, but containing all other plasmids known to be required for infectivity. our results indicated that lp36 was not required for spirochete survival in the tick ... | 2007 | 17542926 |
| 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 ... | 2007 | 17550433 |
| the sialotranscriptome of the blood-sucking bug triatoma brasiliensis (hemiptera, triatominae). | triatoma brasiliensis is the most important autochthon vector of trypanosoma cruzi in brazil, where it is widely distributed in the semiarid areas of the northeast. in order to advance the knowledge of the salivary biomolecules of triatominae, a salivary gland cdna library of t. brasiliensis was mass sequenced and analyzed. polypeptides were sequenced by hplc/edman degradation experiments. then 1712 cdna sequences were obtained and grouped in 786 clusters. the housekeeping category had 24.4% and ... | 2007 | 17550826 |
| diversity and distribution of borrelia hermsii. | borrelia hermsii is the most common cause of tickborne relapsing fever in north america. dna sequences of the 16s-23s rdna noncoding intergenic spacer (igs) region were determined for 37 isolates of this spirochete. these sequences distinguished the 2 genomic groups of b. hermsii identified previously with other loci. multiple igs genotypes were identified among isolates from an island, which suggested that birds might play a role in dispersing these spirochetes in nature. in support of this the ... | 2007 | 17552097 |
| human babesia microti incidence and ixodes scapularis distribution, rhode island, 1998-2004. | distribution of nymphal ixodes scapularis in rhode island was used as a logistical regressor for predicting presence of human babesiosis. although the incidence of babesiosis is increasing in southern rhode island, large areas of the state are free of babesiosis risk. | 2007 | 17553286 |
| cytokine responses of cd4+ t cells during a plasmodium chabaudi chabaudi (er) blood-stage infection in mice initiated by the natural route of infection. | investigation of host responses to blood stages of plasmodium spp, and the immunopathology associated with this phase of the life cycle are often performed on mice infected directly with infected red blood cells. thus, the effects of mosquito bites and the pre-erythrocytic stages of the parasite, which would be present in natural infection, are ignored in this paper, plasmodium chabaudi chabaudi infections of mice injected directly with infected red blood cells were compared with those of mice i ... | 2007 | 17555592 |
| coordinated expression of borrelia burgdorferi complement regulator-acquiring surface proteins during the lyme disease spirochete's mammal-tick infection cycle. | the lyme disease spirochete, borrelia burgdorferi, is largely resistant to being killed by its hosts' alternative complement activation pathway. one possible resistance mechanism of these bacteria is to coat their surfaces with host complement regulators, such as factor h. five different b. burgdorferi outer surface proteins having affinities for factor h have been identified: complement regulator-acquiring surface protein 1 (bbcrasp-1), encoded by cspa; bbcrasp-2, encoded by cspz; and three clo ... | 2007 | 17562769 |
| lyme disease--united states, 2003-2005. | lyme disease is caused by the spirochete borrelia burgdorferi and is transmitted to humans by the bite of infected blacklegged ticks (ixodes spp.). early manifestations of infection include fever, headache, fatigue, and a characteristic skin rash called erythema migrans. left untreated, late manifestations involving the joints, heart, and nervous system can occur. a healthy people 2010 objective (14-8) is to reduce the annual incidence of lyme disease to 9.7 new cases per 100,000 population in 1 ... | 2007 | 17568368 |
| transposon insertion reveals prm, a plasmid of rickettsia monacensis. | until the recent discovery of prf in rickettsia felis, the obligate intracellular bacteria of the genus rickettsia (rickettsiales: rickettsiaceae) were thought not to possess plasmids. we describe prm, a plasmid from rickettsia monacensis, which was detected by pulsed-field gel electrophoresis and southern blot analyses of dna from two independent r. monacensis populations transformed by transposon-mediated insertion of coupled green fluorescent protein and chloramphenicol acetyltransferase mark ... | 2007 | 17575002 |
| role of outer surface protein d in the borrelia burgdorferi life cycle. | borrelia burgdorferi preferentially induces selected genes in mice or ticks, and studies suggest that ospd is down-regulated in response to host-specific signals. we now directly show that ospd expression is generally elevated within ixodes scapularis compared with mice. we then assessed the importance of ospd throughout the spirochete life cycle by generating ospd-deficient b. burgdorferi and examining the mutant in the murine model of tick-transmitted lyme borreliosis. the lack of ospd did not ... | 2007 | 17620358 |
| tick genomics: the ixodes genome project and beyond. | ticks and mites (subphylum chelicerata; subclass acari) include important pests of animals and plants worldwide. the ixodes scapularis (black-legged tick) genome sequencing project marks the beginning of the genomics era for the field of acarology. this project is the first to sequence the genome of a blood-feeding tick vector of human disease and a member of the subphylum chelicerata. genome projects for other species of acari are forthcoming and their genome sequences will likely feature signi ... | 2007 | 17624352 |
| vertebrate hosts of ixodes pacificus (acari: ixodidae) in california. | the western black-legged tick, ixodes pacificus cooley & kohls, is an important parasite and vector of disease agents that affect human and animal health in the western united states. this paper presents a review of all published california host records for i. pacificus. unpublished data from public health, academic, and vector control agencies and researchers were reviewed as well. host species were identified for each active life stage (larvae, nymph and adult). a total of 108 vertebrate speci ... | 2007 | 17633435 |
| prostaglandin e2 is a major inhibitor of dendritic cell maturation and function in ixodes scapularis saliva. | tick saliva is thought to contain a number of molecules that prevent host immune and inflammatory responses. in this study, the effects of ixodes scapularis saliva on cytokine production by bone marrow-derived dendritic cells (dcs) from c57bl/6 mice stimulated by tlr-2, tlr-4, and tlr-9 ligands were studied. saliva at remarkably diluted concentrations (<1/2000) promotes a dose-dependent inhibition of il-12 and tnf-alpha production induced by all tlr ligands used. using a combination of fractiona ... | 2007 | 17641015 |
| analysis of the rpos regulon in borrelia burgdorferi in response to mammalian host signals provides insight into rpos function during the enzootic cycle. | borrelia burgdorferi (bb) adapts to its arthropod and mammalian hosts by altering its transcriptional and antigenic profiles in response to environmental signals associated with each of these milieus. in studies presented here, we provide evidence to suggest that mammalian host signals are important for modulating and maintaining both the positive and negative aspects of mammalian host adaptation mediated by the alternative sigma factor rpos in bb. although considerable overlap was observed betw ... | 2007 | 17645733 |
| aegyptin, a novel mosquito salivary gland protein, specifically binds to collagen and prevents its interaction with platelet glycoprotein vi, integrin alpha2beta1, and von willebrand factor. | blood-sucking arthropods have evolved a number of inhibitors of platelet aggregation and blood coagulation. in this study we have molecularly and functionally characterized aegyptin, a member of the family of 30-kda salivary allergens from aedes aegypti, whose function remained elusive thus far. aegyptin displays a unique sequence characterized by glycine, glutamic acid, and aspartic acid repeats and was shown to specifically block collagen-induced human platelet aggregation and granule secretio ... | 2007 | 17650501 |
| biochemical and functional characterization of salp20, an ixodes scapularis tick salivary protein that inhibits the complement pathway. | ixodes ticks are vectors of several pathogens including borrelia burgdorferi. tick saliva contains numerous molecules that facilitate blood feeding without host immune recognition and rejection. we have expressed, purified, and characterized ixodes scapularis salivary protein 20 (salp20), a potential inhibitor of the alternative complement pathway that shares homology with the isac protein family. when analysed by sds-page and size exclusion chromatography, salp20 was approximately 48 kda, more ... | 2007 | 17651236 |
| gene organization of a novel defensin of ixodes ricinus: first annotation of an intron/exon structure in a hard tick defensin gene and first evidence of the occurrence of two isoforms of one member of the arthropod defensin family. | antimicrobial peptides (defensins) are effectors of the immune system. herein, we describe a novel ixodes ricinus defensin gene(s), analyse its structure and compare it with other known antimicrobial peptides from different tick species. for the first time, an intron/exon structure is discovered in a hard-tick defensin gene. the intron/exon genomic organization of the gene is similar to the organization in ornithodoros moubata, but not to that of the intronless defensins of dermacentor variabili ... | 2007 | 17651239 |
| tobacco industry lawyers as "disease vectors". | despite their obligation to do so, tobacco companies often failed to conduct product safety research or, when research was conducted, failed to disseminate the results to the medical community and to the public. the tobacco company lawyers' role in these actions was investigated with a focus on their involvement in company scientific research, claims of attorney-client privilege and work-product cover, document concealment, and litigation tactics. | 2007 | 17652236 |
| tick-host-pathogen interactions in lyme borreliosis. | borrelia burgdorferi, the spirochetal agent of lyme borreliosis, is predominantly transmitted by ixodes ticks. spirochetes have developed many strategies to adapt to the different environments that are present in the arthropod vector and the vertebrate host. this review focuses on b. burgdorferi genes that are preferentially expressed in the tick and the vertebrate host, and describes how selected gene products facilitate spirochete survival throughout the enzootic life cycle. interestingly, b. ... | 2007 | 17656156 |
| cdna sequences reveal considerable gene prediction inaccuracy in the plasmodium falciparum genome. | the completion of the plasmodium falciparum genome represents a milestone in malaria research. the genome sequence allows for the development of genome-wide approaches such as microarray and proteomics that will greatly facilitate our understanding of the parasite biology and accelerate new drug and vaccine development. designing and application of these genome-wide assays, however, requires accurate information on gene prediction and genome annotation. unfortunately, the genes in the parasite g ... | 2007 | 17662120 |
| selective cysteine protease inhibition contributes to blood-feeding success of the tick ixodes scapularis. | ixodes scapularis is the main vector of lyme disease in the eastern and central united states. tick salivary secretion has been shown as important for both blood-meal completion and pathogen transmission. here we report a duplication event of cystatin genes in its genome that results in a transcription-regulated boost of saliva inhibitory activity against a conserved and relatively limited number of vertebrate papain-like cysteine proteases during blood feeding. we further show that the polypept ... | 2007 | 17698852 |
| biological activities of chamomile (matricaria chamomile) flowers' extract against the survival and egg laying of the cattle fever tick (acari ixodidae). | in the present work, the potential of acaricidal activity of chamomile flowers' extract was studied against engorged rhipicephalus annulatus tick under laboratory condition. for this purpose, the engorged females of rhipicephalus annulatus were exposed to two-fold serial dilutions of chamomile flowers' extract (0.5%, 1.0%, 2.0%, 4.0% and 8.0%) using "dipping method" in vitro. the engorged ticks were immersed in different plant dilutions (five ticks for each dilution) for 1 min and they were imme ... | 2007 | 17726752 |
| spatial and temporal variability of the glossina palpalis palpalis population in the mbini focus (equatorial guinea). | human african trypanosomiasis is a vector-borne parasitic disease. the geographical distribution of the disease is linked to the spatial distribution of the tsetse fly. as part of a control campaign using traps, the spatial and temporal variability is analysed of the glossina populations present in the mbini sleeping sickness foci (equatorial guinea). | 2007 | 17760953 |
| exploring the midgut transcriptome of phlebotomus papatasi: comparative analysis of expression profiles of sugar-fed, blood-fed and leishmania-major-infected sandflies. | in sandflies, the blood meal is responsible for the induction of several physiologic processes that culminate in egg development and maturation. during blood feeding, infected sandflies are also able to transmit the parasite leishmania to a suitable host. many blood-induced molecules play significant roles during leishmania development in the sandfly midgut, including parasite killing within the endoperitrophic space. in this work, we randomly sequenced transcripts from three distinct high quali ... | 2007 | 17760985 |
| screening dogs in ontario for borrelia burgdorferi and ehrlichia canis should be selective rather than routine. | | 2007 | 17824154 |
| 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. | 2007 | 17824328 |
| isolation and establishment of the raccoon ehrlichia-like agent in tick cell culture. | feral animals are reservoirs of emerging human pathogens, as well as carriers of closely related wildlife diseases. the latter may interfere with epidemiologic studies by inducing cross-reactive antibodies, or by providing false positive signals in pcr based tests. we cultured a novel intracellular bacterium from the blood of two raccoons (procyon lotor): rac413 and rac414. rac413 had been experimentally inoculated with blood from a wild-caught raccoon, and provided the material for a blood pass ... | 2007 | 17867909 |
| feeding by the tick, ixodes scapularis, causes cd4(+) t cells responding to cognate antigen to develop the capacity to express il-4. | effects of tick feeding on an early antigen-specific t cell response were studied by monitoring a clonotypic population of adoptively transferred t cell receptor (tcr) transgenic cd4 cells responding to a tick-associated antigen. when recipient mice were infested with pathogen-free ixodes scapularis nymphs several days prior to t cell transfer and intradermal injection of soluble cognate antigen at the feeding site, the clonotypic cd4 cells gained the ability to express the th2 effector cytokine ... | 2007 | 17883452 |
| identification of salp15 homologues in ixodes ricinus ticks. | the 15-kda ixodes scapularis salivary gland protein salp15 protects borrelia burgdorferi sensu stricto from antibody-mediated killing and facilitates infection of the mammalian host. in addition, salp 15 has been shown to inhibit t-cell activation. we determined whether ixodes ricinus, the major vector for lyme borreliosis in western europe, also express salp15-related genes. we show that engorged i. ricinus express salp15 and we have identified three salp15 homologues within these ticks by reve ... | 2007 | 17896872 |
| anaplasma phagocytophilum p44 mrna expression is differentially regulated in mammalian and tick host cells: involvement of the dna binding protein apxr. | the natural life cycle of anaplasma phagocytophilum, an obligatory intracellular bacterium that causes human granulocytic anaplasmosis, consists of alternate infection of two distinct hosts, ticks and mammals, in which bacterial surface proteins are expected to have a critical role. the present study investigated regulation of a. phagocytophilum p44 genes, which encode the p44 major surface proteins. quantitative real-time reverse transcription-pcr analysis revealed that the amount of p44 mrna o ... | 2007 | 17905983 |
| 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 ... | 2007 | 17915502 |
| effects of reduced deer density on the abundance of ixodes scapularis (acari: ixodidae) and lyme disease incidence in a northern new jersey endemic area. | we monitored the abundance of ixodes scapularis say (acari: ixodidae) and the lyme disease incidence rate after the incremental removal of white-tailed deer, odocoileus virginianus zimmermann, within a suburban residential area to determine whether there was a measurable decrease in the abundance of ticks due to deer removal and whether the reduction in ticks resulted in a reduction in the incidence rate within the human population. after three seasons, the estimated deer population was reduced ... | 2007 | 17915504 |
| integrated use of 4-poster passive topical treatment devices for deer, targeted acaricide applications, and maxforce tms bait boxes to rapidly suppress populations of ixodes scapularis (acari: ixodidae) in a residential landscape. | in fall 2003, we began testing an integrated control strategy to rapidly achieve and sustain reduced numbers of ixodes scapularis say (acari: ixodidae) in a residential area. we combined two host-targeted technologies in conjunction with single, barrier acaricide applications to sequentially attack each postembryonic life stage of the tick. granular deltamethrin applied to the lawn-forest interface of participant properties resulted in 100% control of host-seeking nymphs. nymphal and larval tick ... | 2007 | 17915516 |
| seasonal variation in nymphal blacklegged tick abundance in southern new england forests. | in the northeastern united states, risk of human exposure to tick transmitted disease is primarily a function of the abundance of the blacklegged tick, ixodes scapularis say. we assessed seasonal variability in the abundance of nymphal stage i. scapularis over 13 yr, collected from several forested areas throughout rhode island. specifically, we examined intraseasonal differences by using two temporally distinct tick collections made during the peak nymphal tick season. intraseasonal factors sig ... | 2007 | 17915524 |
| genetic basis for retention of a critical virulence plasmid of borrelia burgdorferi. | the genome of borrelia burgdorferi is composed of one linear chromosome and approximately 20 linear and circular plasmids. although some plasmids are required by b. burgdorferi in vivo, most plasmids are dispensable for growth in vitro. however, circular plasmid (cp) 26 is present in all natural isolates and has never been lost during in vitro growth. this plasmid carries ospc, which is critical for mammalian infection. we previously showed that cp26 encodes essential functions, including the te ... | 2007 | 17919281 |
| 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 ... | 2007 | 17923330 |
| global comparative analysis of ests from the southern cattle tick, rhipicephalus (boophilus) microplus. | the southern cattle tick, rhipicephalus (boophilus) microplus, is an economically important parasite of cattle and can transmit several pathogenic microorganisms to its cattle host during the feeding process. understanding the biology and genomics of r. microplus is critical to developing novel methods for controlling these ticks. | 2007 | 17935616 |
| fitness variation of borrelia burgdorferi sensu stricto strains in mice. | lyme borreliosis in north america is caused by the tick-borne spirochete borrelia burgdorferi, a zoonotic bacterium that is able to persistently infect a wide range of vertebrate species. given the pronounced strain structure of b. burgdorferi in the northeastern united states, we asked whether the fitness of the different genotypes varies among susceptible vertebrate hosts. the transmission dynamics of two genetically divergent human isolates of b. burgdorferi, bl206 and b348, were analyzed exp ... | 2008 | 17981941 |
| prior exposure to uninfected mosquitoes enhances mortality in naturally-transmitted west nile virus infection. | the global emergence of west nile virus (wnv) has highlighted the importance of mosquito-borne viruses. these are inoculated in vector saliva into the vertebrate skin and circulatory system. arthropod-borne (arbo)viruses such as wnv are transmitted to vertebrates as an infectious mosquito probes the skin for blood, depositing the virus and saliva into the skin and circulation. growing evidence has demonstrated that arthropod, and recently mosquito, saliva can have a profound effect on pathogen t ... | 2007 | 18000543 |
| lyme arthritis: current concepts and a change in paradigm. | | 2008 | 18003815 |
| a tick antioxidant facilitates the lyme disease agent's successful migration from the mammalian host to the arthropod vector. | the tick ixodes scapularis is an efficient vector for microbes, including the lyme disease agent borrelia burgdorferi. ticks engorging on vertebrates induce recruitment of inflammatory cells to the bite site. for efficient transmission to the vector, pathogens have to traffic through this complex feeding site while avoiding the deleterious effects of immune cells. we show that a tick protein, salp25d, plays a critical role-in the mammalian host-for acquisition of borrelia burgdorferi by the vect ... | 2007 | 18005713 |
| conspicuous impacts of inconspicuous hosts on the lyme disease epidemic. | emerging zoonotic pathogens are a constant threat to human health throughout the world. control strategies to protect public health regularly fail, due in part to the tendency to focus on a single host species assumed to be the primary reservoir for a pathogen. here, we present evidence that a diverse set of species can play an important role in determining disease risk to humans using lyme disease as a model. host-targeted public health strategies to control the lyme disease epidemic in north a ... | 2008 | 18029304 |
| ixolaris binding to factor x reveals a precursor state of factor xa heparin-binding exosite. | ixolaris is a two-kunitz tick salivary gland tissue factor pathway inhibitor (tfpi). in contrast to human tfpi, ixolaris specifically binds to factor xa (fxa) heparin-binding exosite (hbe). in addition, ixolaris interacts with zymogen fx. in the present work we characterized the interaction of ixolaris with human fx quantitatively, and identified a precursor state of the heparin-binding exosite (proexosite, hbpe) as the ixolaris-binding site on the zymogen. gel-filtration chromatography demonstr ... | 2008 | 18042685 |
| conformational rearrangement within the soluble domains of the cd4 receptor is ligand-specific. | ligand binding induces shape changes within the four modular ectodomains (d1-d4) of the cd4 receptor, an important receptor in immune signaling. small angle x-ray scattering (saxs) on both a two-domain and a four-domain construct of the soluble cd4 (scd4) is consistent with known crystal structures demonstrating a bilobal and a semi-extended tetralobal z conformation in solution, respectively. detection of conformational changes within scd4 as a result of ligand binding was followed by saxs on s ... | 2008 | 18045872 |
| isolation of cell lines and a rickettsial endosymbiont from the soft tick carios capensis (acari: argasidae: ornithodorinae). | soft ticks are medically important ectoparasites of birds and mammals that are found throughout the world. this report describes isolation and partial characterization of two embryonic cell lines, cce2 and cce3, from the seabird soft tick carios capensis (neumann). sequencing of the mitochondrial 16s rrna gene and karyology confirmed the lines were derived from c. capensis. cce3 cells were diploid with a modal chromosome number of 20. the population doubling time for cell lines cce2 and 3 in pas ... | 2007 | 18047211 |
| passive surveillance in maine, an area emergent for tick-borne diseases. | in 1989, a free-of-charge, statewide tick identification program was initiated in maine, 1 yr after the first ixodes scapularis say (=i. dammini spielman, clifford, piesman & corwin) ticks were reported in the state. this article summarizes data from 18 continuous years of tick submissions during which >24,000 ticks of 14 species were identified. data provided include tick stage, degree of engorgement, seasonal abundance, geographical location, host, and age of the person from whom the tick was ... | 2007 | 18047214 |
| 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 ... | 2008 | 18065613 |
| an insight into the sialome of the soft tick, ornithodorus parkeri. | while hard ticks (ixodidae) take several days to feed on their hosts, soft ticks (argasidae) feed faster, usually taking less than 1h per meal. saliva assists in the feeding process by providing a cocktail of anti-hemostatic, anti-inflammatory and immunomodullatory compounds. saliva of hard ticks has been shown to contain several families of genes each having multiple members, while those of soft ticks are relatively unexplored. analysis of the salivary transcriptome of the soft tick ornithodoru ... | 2008 | 18070662 |
| characterization of anti-hemostatic factors in the argasid, argas monolakensis: implications for the evolution of blood-feeding in the soft tick family. | to date, the only anti-hemostatic factors characterized for softs ticks are for ornithodoros moubata and ornithodoros savignyi, ticks that feeds mainly on mammals. this includes thrombin (ornithodorin and savignin), fxa (tap and fxai) and platelet aggregation (disagegin and savignygrin) inhibitors that belong to the bpti-kunitz protein family. this raises the question on how well anti-hemostatic factors will be conserved in other soft tick genera that feeds on other vertebrates such as birds. we ... | 2008 | 18070663 |
| comparative sialomics between hard and soft ticks: implications for the evolution of blood-feeding behavior. | ticks evolved various mechanisms to modulate their host's hemostatic and immune defenses. differences in the anti-hemostatic repertoires suggest that hard and soft ticks evolved anti-hemostatic mechanisms independently, but raise questions on the conservation of salivary gland proteins in the ancestral tick lineage. to address this issue, the sialome (salivary gland secretory proteome) from the soft tick, argas monolakensis, was determined by proteomic analysis and cdna library construction of s ... | 2008 | 18070664 |
| environmental conditions and puumala virus transmission in belgium. | non-vector-borne zoonoses such as puumala hantavirus (puuv) can be transmitted directly, by physical contact between infected and susceptible hosts, or indirectly, with the environment as an intermediate. the objective of this study is to better understand the causal link between environmental features and puuv prevalence in bank vole population in belgium, and hence with transmission risk to humans. our hypothesis was that environmental conditions controlling the direct and indirect transmissio ... | 2007 | 18078526 |
| the pathogenesis of lyme neuroborreliosis: from infection to inflammation. | this review describes the current knowledge of the pathogenesis of acute lyme neuroborreliosis (lnb), from invasion to inflammation of the central nervous system. borrelia burgdorferi (b.b.) enters the host through a tick bite on the skin and may disseminate from there to secondary organs, including the central nervous system. to achieve this, b.b. first has to evade the hostile immune system. in a second step, the borrelia have to reach the central nervous system and cross the blood-brain barri ... | 2008 | 18097481 |
| borrelia burgdorferi complement regulator-acquiring surface protein 2 (cspz) as a serological marker of human lyme disease. | serological diagnosis of lyme disease may be complicated by antigenic differences between infecting organisms and those used as test references. accordingly, it would be helpful to include antigens whose sequences are well conserved by a broad range of lyme disease spirochetes. in the present study, line blot analyses were performed using recombinant complement regulator-acquiring surface protein 2 (bbcrasp-2) from borrelia burgdorferi sensu stricto strain b31 and serum samples from human lyme d ... | 2008 | 18160620 |
| the ixodes scapularis salivary protein, salp15, prevents the association of hiv-1 gp120 and cd4. | ixodes scapularis salivary protein, salp15, inhibits cd4(+) t cell activation by binding to the most-extracellular domains of the cd4 molecule, potentially overlapping with the gp120-binding region. we now show that salp15 inhibits the interaction of gp120 and cd4. furthermore, salp15 prevents syncytia formation between hl2/3 (a stable hela cell line expressing the envelope protein) and cd4-expressing cells. salp15 prevented gp120-cd4 interaction at least partially through its direct interaction ... | 2008 | 18162176 |
| borrelia burgdorferi complement regulator-acquiring surface proteins (bbcrasps): expression patterns during the mammal-tick infection cycle. | host complement is widely distributed throughout mammalian body fluids and can be activated immediately as part of the first line of defense against invading pathogens. the agent of lyme disease, borrelia burgdorferi sensu lato (s.l.), is naturally resistant to that innate immune defense system of its hosts. one resistance mechanism appears to involve binding fluid-phase regulators of complement to distinct borrelial outer surface molecules known as crasps (complement regulator acquiring surface ... | 2008 | 18165150 |
| borrelia burgdorferi basic membrane proteins a and b participate in the genesis of lyme arthritis. | lyme arthritis results from colonization of joints by borrelia burgdorferi and the ensuing host response. using gene array-based differential analysis of b. burgdorferi gene expression and quantitative reverse trancription-polymerase chain reaction, we identified two paralogous spirochete genes, bmpa and bmpb, that are preferentially up-regulated in mouse joints compared with other organs. transfer of affinity-purified antibodies against either bmpa or bmpb into b. burgdorferi-infected mice sele ... | 2008 | 18166585 |
| variability and action mechanism of a family of anticomplement proteins in ixodes ricinus. | ticks are blood feeding arachnids that characteristically take a long blood meal. they must therefore counteract host defence mechanisms such as hemostasis, inflammation and the immune response. this is achieved by expressing batteries of salivary proteins coded by multigene families. | 2008 | 18167559 |
| the midgut transcriptome of lutzomyia longipalpis: comparative analysis of cdna libraries from sugar-fed, blood-fed, post-digested and leishmania infantum chagasi-infected sand flies. | in the life cycle of leishmania within the alimentary canal of sand flies the parasites have to survive the hostile environment of blood meal digestion, escape the blood bolus and attach to the midgut epithelium before differentiating into the infective metacyclic stages. the molecular interactions between the leishmania parasites and the gut of the sand fly are poorly understood. in the present work we sequenced five cdna libraries constructed from midgut tissue from the sand fly lutzomyia long ... | 2008 | 18194529 |
| complement evasion by human pathogens. | the human immune system has developed an elaborate network of cascades for dealing with microbial intruders. owing to its ability to rapidly recognize and eliminate microorganisms, the complement system is an essential and efficient component of this machinery. however, many pathogenic organisms have found ways to escape the attack of complement through a range of different mechanisms. recent discoveries in this field have provided important insights into these processes on a molecular level. th ... | 2008 | 18197169 |
| effect of electronic laboratory reporting on the burden of lyme disease surveillance--new jersey, 2001-2006. | lyme disease (ld) is a vector-borne illness caused by the spirochete borrelia burgdorferi and transmitted in the united states by blacklegged ticks (ixodes spp.). ld is most commonly found in the northeastern, mid-atlantic, and north-central regions of the united states. in 2005, new jersey reported 38.6 ld cases per 100,000 population, the third-highest incidence in the united states after delaware and connecticut. since 1980, new jersey has mandated that health-care providers and clinical labo ... | 2008 | 18199968 |
| zoonotic pathogens in ixodes scapularis, michigan. | | 2007 | 18214207 |
| lyme disease in urban areas, chicago. | | 2007 | 18217578 |
| competitive exclusion between piroplasmosis and anaplasmosis agents within cattle. | | 2008 | 18225951 |
| role of migratory birds in introduction and range expansion of ixodes scapularis ticks and of borrelia burgdorferi and anaplasma phagocytophilum in canada. | during the spring in 2005 and 2006, 39,095 northward-migrating land birds were captured at 12 bird observatories in eastern canada to investigate the role of migratory birds in northward range expansion of lyme borreliosis, human granulocytic anaplasmosis, and their tick vector, ixodes scapularis. the prevalence of birds carrying i. scapularis ticks (mostly nymphs) was 0.35% (95% confidence interval [ci] = 0.30 to 0.42), but a nested study by experienced observers suggested a more realistic infe ... | 2008 | 18245258 |
| clustering of genetically defined allele classes in the caenorhabditis elegans daf-2 insulin/igf-1 receptor. | the daf-2 insulin/igf-1 receptor regulates development, metabolism, and aging in the nematode caenorhabditis elegans. however, complex differences among daf-2 alleles complicate analysis of this gene. we have employed epistasis analysis, transcript profile analysis, mutant sequence analysis, and homology modeling of mutant receptors to understand this complexity. we define an allelic series of nonconditional daf-2 mutants, including nonsense and deletion alleles, and a putative null allele, m65. ... | 2008 | 18245374 |
| lyme borreliosis spirochete erp proteins, their known host ligands, and potential roles in mammalian infection. | lyme borreliae naturally maintain numerous distinct dna elements of the cp32 family, each of which carries a mono- or bicistronic erp locus. the encoded erp proteins are surface-exposed outer membrane lipoproteins that are produced at high levels during mammalian infection but largely repressed during colonization of vector ticks. recent studies have revealed that some erp proteins can serve as bacterial adhesins, binding host proteins such as the complement regulator factor h and the extracellu ... | 2008 | 18248770 |
| evolution of insect proteomes: insights into synapse organization and synaptic vesicle life cycle. | the molecular components in synapses that are essential to the life cycle of synaptic vesicles are well characterized. nonetheless, many aspects of synaptic processes, in particular how they relate to complex behaviour, remain elusive. the genomes of flies, mosquitoes, the honeybee and the beetle are now fully sequenced and span an evolutionary breadth of about 350 million years; this provides a unique opportunity to conduct a comparative genomics study of the synapse. | 2008 | 18257909 |
| blood coagulation, inflammation, and malaria. | malaria remains a highly prevalent disease in more than 90 countries and accounts for at least 1 million deaths every year. plasmodium falciparum infection is often associated with a procoagulant tonus characterized by thrombocytopenia and activation of the coagulation cascade and fibrinolytic system; however, bleeding and hemorrhage are uncommon events, suggesting that a compensated state of blood coagulation activation occurs in malaria. this article (i) reviews the literature related to blood ... | 2008 | 18260002 |
| co-circulating microorganisms in questing ixodes scapularis nymphs in maryland. | ixodes scapularis can be infected with borrelia burgdorferi, anaplasma phagocytophilum, bartonella spp., babesia microti, and rickettsia spp., including spotted-fever group rickettsia. as all of these microorganisms have been reported in maryland, the potential for these ticks to have concurrent infections exists in this region. to assess the frequency of these complex infections, 348 i. scapularis nymphs collected in 2003 were screened for these microorganisms by pcr with positives being confir ... | 2007 | 18260514 |
| host-seeking behavior of ixodes pacificus (acari: ixodidae) nymphs in relation to environmental parameters in dense-woodland and woodland-grass habitats. | in the far-western united states, the bacteria that cause lyme disease (borrelia burgdorferi, bb) and human granulocytic anaplasmosis (anaplasma phagocytophilum, ap) are transmitted by the western black-legged tick (ixodes pacificus). in a dense woodland, human behaviors involving contact with wood were recently found to pose greater risk for encountering i. pacificus nymphs than behaviors entailing exclusive exposure to leaf litter. a four-year follow-up study was undertaken in the same woodlan ... | 2007 | 18260527 |
| genomic resources for invertebrate vectors of human pathogens, and the role of vectorbase. | high-throughput genome sequencing techniques have now reached vector biology with an emphasis on those species that are vectors of human pathogens. the first mosquito to be sequenced was anopheles gambiae, the vector for plasmodium parasites that cause malaria. further mosquitoes have followed: aedes aegypti (yellow fever and dengue fever vector) and culex pipiens (lymphatic filariasis and west nile fever). species that are currently in sequencing include the body louse pediculus humanus (typhus ... | 2009 | 18262474 |
| salp15 binding to dc-sign inhibits cytokine expression by impairing both nucleosome remodeling and mrna stabilization. | ixodes ticks are major vectors for human pathogens, such as borrelia burgdorferi, the causative agent of lyme disease. tick saliva contains immunosuppressive molecules that facilitate tick feeding and b. burgdorferi infection. we here demonstrate, to our knowledge for the first time, that the ixodes scapularis salivary protein salp15 inhibits adaptive immune responses by suppressing human dendritic cell (dc) functions. salp15 inhibits both toll-like receptor- and b. burgdorferi-induced productio ... | 2008 | 18282094 |
| anaplasma phagocytophilum msp2(p44)-18 predominates and is modified into multiple isoforms in human myeloid cells. | anaplasma phagocytophilum is the etiologic agent of human granulocytic anaplasmosis. msp2(p44), the bacterium's major surface protein, is encoded by a paralogous gene family and has been implicated in a variety of pathobiological processes, including antigenic variation, host adaptation, adhesion, porin activity, and structural integrity. the consensus among several studies performed at the dna and rna levels is that a heterogeneous mix of a limited number of msp2(p44) transcripts is expressed b ... | 2008 | 18285495 |
| isolation, cloning and structural characterisation of boophilin, a multifunctional kunitz-type proteinase inhibitor from the cattle tick. | inhibitors of coagulation factors from blood-feeding animals display a wide variety of structural motifs and inhibition mechanisms. we have isolated a novel inhibitor from the cattle tick boophilus microplus, one of the most widespread parasites of farm animals. the inhibitor, which we have termed boophilin, has been cloned and overexpressed in escherichia coli. mature boophilin is composed of two canonical kunitz-type domains, and inhibits not only the major procoagulant enzyme, thrombin, but i ... | 2008 | 18286181 |
| persistence of borrelia burgdorferi following antibiotic treatment in mice. | the effectiveness of antibiotic treatment was examined in a mouse model of lyme borreliosis. mice were treated with ceftriaxone or saline solution for 1 month, commencing during the early (3 weeks) or chronic (4 months) stages of infection with borrelia burgdorferi. tissues from mice were tested for infection by culture, pcr, xenodiagnosis, and transplantation of allografts at 1 and 3 months after completion of treatment. in addition, tissues were examined for the presence of spirochetes by immu ... | 2008 | 18316520 |
| a novel mechanism of complement inhibition unmasked by a tick salivary protein that binds to properdin. | ixodes scapularis salivary protein 20 (salp20) is a member of the ixodes scapularis anti-complement protein-like family of tick salivary proteins that inhibit the alternative complement pathway. in this study, we demonstrate that the target of salp20 is properdin. properdin is a natural, positive regulator of the alternative pathway that binds to the c3 convertase, stabilizing the molecule. salp20 directly bound to and displaced properdin from the c3 convertase. displacement of properdin acceler ... | 2008 | 18322205 |
| a tightly regulated surface protein of borrelia burgdorferi is not essential to the mouse-tick infectious cycle. | borrelia burgdorferi synthesizes a variety of differentially regulated outer surface lipoproteins in the tick vector and in vertebrate hosts. among these is ospd, a protein that is highly induced in vitro by conditions that mimic the tick environment. using genetically engineered strains in which ospd is deleted, we demonstrate that this protein is not required for b. burgdorferi survival and infectivity in either the mouse or the tick. however, examination of both transcript levels and protein ... | 2008 | 18332210 |
| profiling of proteolytic enzymes in the gut of the tick ixodes ricinus reveals an evolutionarily conserved network of aspartic and cysteine peptidases. | abstract: | 2008 | 18348719 |
| 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 ... | 2008 | 18359808 |
| characterization and growth of polymorphic rickettsia felis in a tick cell line. | morphological differentiation in some arthropod-borne bacteria is correlated with increased bacterial virulence, transmission potential, and/or as a response to environmental stress. in the current study, we utilized an in vitro model to examine rickettsia felis morphology and growth under various culture conditions and bacterial densities to identify potential factors that contribute to polymorphism in rickettsiae. we utilized microscopy (electron microscopy and immunofluorescence), genomic (pc ... | 2008 | 18359823 |
| 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 ... | 2008 | 18366768 |
| a possible canine tick-bite reaction to ixodes muris. | an airedale terrier became acutely ill following attachment of an ixodes muris tick. clinical signs waned within hours of tick removal, similar to a pattern previously documented in animals harboring i. muris. this supports the theory that i. muris can induce a noninfectious, severe inflammatory reaction in domestic animals. | 2008 | 18390101 |
| phlebotomine salivas inhibit immune inflammation-induced neutrophil migration via an autocrine dc-derived pge2/il-10 sequential pathway. | in the present study, we investigated whether saliva from phlebotomus papatasi and phlebotomus duboscqi inhibited antigen-induced neutrophil migration and the mechanisms involved in these effects. the pretreatment of immunized mice with salivary gland extracts (sge) of both phlebotomines inhibited ova challenge-induced neutrophil migration and release of the neutrophil chemotactic mediators, mip-1alpha, tnf-alpha, and leukotriene b4 (ltb4). furthermore, sge treatment enhanced the production of a ... | 2008 | 18390928 |
| herbivore benefits from vectoring plant virus through reduction of period of vulnerability to predation. | herbivores can profit from vectoring plant pathogens because the induced defence of plants against pathogens sometimes interferes with the induced defence of plants against herbivores. plants can also defend themselves indirectly by the action of the natural enemies of the herbivores. it is unknown whether the defence against pathogens induced in the plant also interferes with the indirect defence against herbivores mediated via the third trophic level. we previously showed that infection of pla ... | 2008 | 18392858 |
| a novel sine family occurs frequently in both genomic dna and transcribed sequences in ixodid ticks of the arthropod sub-phylum chelicerata. | reassociation kinetics and flow cytometry data indicate that ixodid tick genomes are large, relative to most arthropods, containing>or=10(9) base pairs. the molecular basis for this is unknown. we have identified a novel small interspersed element with features of a trna-derived sine, designated ruka, in genomic sequences of rhipicephalus appendiculatus and boophilus (rhipicephalus) microplus ticks. the sine was also identified in expressed sequence tag (est) databases derived from several tissu ... | 2008 | 18394826 |
| presence of multiple variants of borrelia burgdorferi in the natural reservoir peromyscus leucopus throughout a transmission season. | white-footed mice (peromyscus leucopus) serve as the principal reservoir for borrelia burgdorferi and have been shown to remain infected for life. complex infections with multiple genetic variants of b. burgdorferi occur in mice through multiple exposures to infected ticks or through exposure to ticks infected with multiple variants of b. burgdorferi. using a combination of cloning and single strand conformation polymorphism (sscp), b. burgdorferi ospc variation was assessed in serial samples co ... | 2008 | 18399776 |
| identification of rickettsia felis in the salivary glands of cat fleas. | rickettsia felis, a flea-associated rickettsial pathogen, has been identified in many tissues, including the digestive and reproductive tissues, within the cat flea, ctenocephalides felis. we utilized transmission electron microscopy and polymerase chain reaction to identify r. felis in the salivary glands of fed fleas and further define the distribution of r. felis within the arthropod host. we identified rickettsia-like organisms in salivary glands using electron microscopy. sequence analysis ... | 2008 | 18399779 |
| infection and co-infection rates of anaplasma phagocytophilum variants, babesia spp., borrelia burgdorferi, and the rickettsial endosymbiont in ixodes scapularis (acari: ixodidae) from sites in indiana, maine, pennsylvania, and wisconsin. | in total, 394 questing adult blacklegged ticks, ixodes scapularis say (acari: ixodidae), collected at four sites were analyzed by polymerase chain reaction (pcr) for five microbial species: anaplasma phagocytophilum, babesia microti, babesia odocoilei, borrelia burgdorferi, and the rickettsial i. scapularis endosymbiont. identities of genetic variants of a. phagocytophilum were determined by sequencing a portion of the 16s dna. in 55% of infected ticks (193/351), a single agent was detected. in ... | 2008 | 18402145 |
| emerging pathogens: challenges and successes of molecular diagnostics. | more than 50 emerging and reemerging pathogens have been identified during the last 40 years. until 1992 when the institute of medicine issued a report that defined emerging infectious diseases, medicine had been complacent about such infectious diseases despite the alarm bells of infections with human immunodeficiency virus. molecular tools have proven useful in discovering and characterizing emerging viruses and bacteria such as sin nombre virus (hantaviral pulmonary syndrome), hepatitis c vir ... | 2008 | 18403608 |
| cellular and molecular characterization of an embryonic cell line (bme26) from the tick rhipicephalus (boophilus) microplus. | the cellular and molecular characteristics of a cell line (bme26) derived from embryos of the cattle tick rhipicephalus (boophilus) microplus were studied. the cells contained glycogen inclusions, numerous mitochondria, and vesicles with heterogeneous electron densities dispersed throughout the cytoplasm. vesicles contained lipids and sequestered palladium meso-porphyrin (pd-mp) and rhodamine-hemoglobin, suggesting their involvement in the autophagic and endocytic pathways. the cells phagocytose ... | 2008 | 18405834 |
| genome-wide screen for temperature-regulated genes of the obligate intracellular bacterium, rickettsia typhi. | the ability of rickettsiae to survive in multiple eukaryotic host environments provides a good model for studying pathogen-host molecular interactions. rickettsia typhi, the etiologic agent of murine typhus, is a strictly intracellular gram negative alpha-proteobacterium, which is transmitted to humans by its arthropod vector, the oriental rat flea, xenopsylla cheopis. thus, r. typhi must cycle between mammalian and flea hosts, two drastically different environments. we hypothesize that temperat ... | 2008 | 18412961 |
| 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 ... | 2008 | 18412972 |