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Ticks
Kinds of Ticks Terms modified by Ticks Selected AbstractsSurveys of rodent-borne disease in Thailand with a focus on scrub typhus assessmentINTEGRATIVE ZOOLOGY (ELECTRONIC), Issue 4 2008Kriangkrai Lerdthusnee Abstract The epidemiology of many rodent-borne diseases in South-East Asia remains ill-defined. Scrub typhus and lep-tospirosis are common and medically significant, while other zoonotic diseases, such as spotted fever group Rickettsiae have been identified, but their overall medical significance is unknown. Rodent surveillance was conducted from June 2002 to July 2004 in 18 provinces from Thailand. Traps were set up for one to three nights. Blood and serum samples and animal tissue samples (liver, spleen, kidney and urinary bladder) were collected. Chiggermites, ticks and fleas were removed from captured rodents. A total of 4536 wild-caught rodents from 27 species were captured over two years of animal trapping. Rattus rattus was the dominant species, followed by Rattus exulans and Bandicota indica. Almost 43 000 ectoparasites were removed from the captured animals. Approximately 98% of the ectoparasites were chigger-mites, of which 46% belonged to the genus Leptotrombidium (scrub typhus vector). Other genera included Schoengastia and Blankaartia. Tick and flea specimens together comprised less than 1% of the sample. Among the five species of ticks collected, Haemaphysalis bandicota was the predominant species caught, followed by Ixodes granulatus other Haemaphysalis spp., Rhipicephalus spp. and Dermacentor spp. Only two species of fleas were collected and Xenopsylla cheopis (rat flea) was the predominant species. Using both commercial diagnostic kits and in-house molecular assays, animal tissue samples were examined and screened for zoonotic diseases. Seven zoonotic diseases were detected: scrub typhus, leptospirosis, murine typhus, tick typhus, bartonella, babesiosis and trypanosomiasis. Most samples were positive for scrub typhus. Other zoonotic diseases still under investigation include borrelosis, ehrlichiosis, the plague, and other rickettsial diseases. Using geographic information systems, global positioning systems and remote sensing technology, epidemiological and environmental data were combined to assess the relative risk in different biotopes within highly endemic areas of scrub typhus in Thailand. [source] Development of a consensus microarray method for identification of some highly pathogenic virusesJOURNAL OF MEDICAL VIROLOGY, Issue 11 2009Kang Xiao-Ping Abstract Some highly pathogenic viruses, such as Chikungunya virus, Japanese encephalitis virus, Yellow fever virus, Dengue virus, Hanta virus, SARS-CoV, and H5N1 avian influenza virus can cause severe infectious diseases. However, the consensus method for detecting these viruses has not been well established. A rapid and sensitive microarray approach for detection of these viruses and a panel of specific probes covering nine genera and 16 virus species were designed. 70-mer oligonucleotides were used at the genus level and 50-mer oligonucleotides were at the species level, respectively. To decrease the interference of the host genome in hybridization, the consensus genus primers were designed and used to reverse transcribe only virus genome. The synthesis of the second strand was carried out with a random primer sequence (5,-GTTTCCCAGTAGGTCTCNNNNNNNN-3,). The amplified products were labeled and processed for microarray analyses. This microarray-based method used the highly conserved consensus primers to synthesize specifically the virus cDNA and could identify effectively Chikungunya virus, Japanese encephalitis virus, Yellow fever virus, Dengue virus, Tick borne encephalitis virus, and H5N1 avian influenza virus. Using this method, one unknown virus isolated from pig brain in Shanxi Province, China was identified. This method may have an important potential application for the diagnosis of virus infection. J. Med. Virol. 81:1945,1950, 2009. © 2009 Wiley-Liss, Inc. [source] Pyrosequencing and characterization of immune response genes from the American dog tick, Dermacentor variabilis (L.)INSECT MOLECULAR BIOLOGY, Issue 5 2010D. C. Jaworski Abstract Ticks continue to be a threat to animal and human health, and new and novel control strategies are needed for ticks and tick-borne pathogens. The characterization of the tick,pathogen interface and the tick immune response to microbial infections is fundamental toward the formulation of new control strategies for ticks and the pathogens they transmit. Our overall hypothesis for this research is that the tick immune system manages the maintenance of pathogens. Therefore, discovery of tick immune response genes may provide targets for novel control strategies directed toward reducing vector competency and pathogen transmission. In these studies, 454 pyrosequencing, a high-throughput genomic sequencing method was used to discover tick genes expressed in response to bacterial and fungal infections. Expressed sequence tags (ESTs) were analysed from Dermacentor variabilis ticks that had been injected with bacteria (Escherichia coli, Bacillus subtilis, Micrococcus luteus) or fungi (Saccharomyces cerevisiae and Candida albicans) and ticks that were naturally infected with the intracellular bacterium, Anaplasma marginale. By this approach, ESTs were assembled into 5995 contigs. Contigs fell into the five main functional categories of metabolism, genetic information processing, environmental information processing, cellular processes and human diseases. We identified more than 30 genes that are likely to encode for proteins involved in tick immune function. We further analysed by reverse transcriptase PCR (RT-PCR) the expression of 22 of these genes in each of our bacterial or fungal treatment groups and found that seven were up-regulated. Up-regulation of these seven genes was confirmed for bacterial, but not fungal treatment by quantitative PCR (qPCR). One of these products was novel, encoding a new tick defensin. Our results clearly demonstrate the complexities of the tick immune system and mark new directions for further study and characterization of proteins that modulate microbial infections in the American dog tick. [source] Transcriptome analysis of the salivary glands of the female tick Amblyomma americanum (Acari: Ixodidae)INSECT MOLECULAR BIOLOGY, Issue 2 2009M. N. Aljamali Abstract Ticks infest a wide range of hosts while bypassing their immune, inflammatory and haemostatic responses during their extended feeding, which may last for more than two weeks. Here, we present a transcriptome analysis of 3868 expressed sequence tags (ESTs) from three cDNA libraries generated from the salivary glands of adult female Ambyomma americanum ticks at different stages of feeding. We applied a normalization step for one library, significantly decreasing the abundance of mitochondrial sequences amongst the 2292 sequences from the normalized library. Our ESTs include homologues that may modulate haemostatic, immune and inflammatory responses of the hosts. Other ESTs probably represent important components of the highly efficient secretory pathways for salivary proteins and concomitantly transmitted pathogens. [source] Ticks have R2 retrotransposons but not the consensus transposon target site of other arthropodsINSECT MOLECULAR BIOLOGY, Issue 5 2005J. Bunikis Abstract Some copies of the large subunit rRNA genes (LSU rDNA) of most arthropods studied to date are inactivated by R-element retrotransposons at a specific target region that is highly conserved in sequence across all kingdoms of organisms. Here we report finding R2 elements in low copy numbers in the LSU rDNA of hard and soft ticks. Although the elements were inserted at the same LSU rDNA location as in insects, there were substitutions in the consensus R2 endonuclease cleavage site in the ticks and some other parasitiform mites. The substituted region comprises a critical contact point with small subunit rRNA, but in vitro structure probing analysis revealed novel, presumably stabilizing base-pairing. [source] Thrombogenic Vasculopathy and Interstitial to Diffuse Dermal Neutrophilic Inflammation as a Histologic Manifestation of Tick Bite ReactionJOURNAL OF CUTANEOUS PATHOLOGY, Issue 1 2005Urvi Pajvani BS Ticks are ectoparasites that cause dermatologic disease both directly through physical trauma to the skin, salivary secretions, or remnant body parts, and indirectly through transmission of disease. Lyme disease, Rocky Mountain spotted fever, tularemia, and babesiosis are known tick-transmitted diseases. The histopathology related to a primary tick bite, similar to other arthropod bites, classically consists of a perivascular infiltrate composed of lymphocytes, neutrophils, histiocytes, plasma cells, and eosinophils in varying amounts. We describe five patients with a novel histologic reaction to embedded tick parts., Each case demonstrates a thrombotic vasculopathy consisting of intraluminal eosinophilic deposits that stain strongly with Periodic acid Schiff stain. The adjacent tissue shows dermal necrosis with surrounding interstitial to diffuse dermal neutrophilic inflammation. We postulate that diffuse dermal nutrophilic infiltrates in association with thrombogenic vasculopathy is an unusual histologic picture of tick bite reactions that may be attributable to remnant tick parts. [source] Ticks and Lyme borreliosis in an alpine area in northeast ItalyMEDICAL AND VETERINARY ENTOMOLOGY, Issue 3 2010F. NAZZI A 2-year study was conducted in a mountainous area of northeast Italy to evaluate the occurrence and distribution of ticks, as well as to assess the prevalence of the spirochaete Borrelia burgdorferi sensu lato. All ticks collected were Ixodes ricinus L. (Parasitiformes: Ixodidae). In general, most nymphs and adult ticks were collected from April to July. Tick density was highly variable among sites; however, two areas with different infestation levels were recognized. Prevalences of B. burgdorferi s.l. in nymphal stages were rather variable between sites; overall the prevalence of infected nymphs in the whole area was slightly higher than 20%. The prevalence of B. burgdorferi s.l. in nymphs does not seem to be correlated with nymph density. The correlation between the incidence of Lyme borreliosis (reported human cases/1000 inhabitants/year) and Borrelia prevalence in nymphs was not significant, although a significant correlation was found between borreliosis incidence and nymph density. [source] Field and laboratory studies in a Neotropical population of the spinose ear tick, Otobius megniniMEDICAL AND VETERINARY ENTOMOLOGY, Issue 1 2009S. NAVA Abstract One ear of each of five cows on a property close to Dean Funes, province of Córdoba, Argentina, was inspected monthly from December 2004 to November 2006 to determine the presence of Otobius megnini (Dugès) and to ascertain its seasonality. Ticks were collected to study the biological parameters of larvae, nymphs and adult ticks. Groups of nymphs were also maintained at three different photoperiods at 25 °C. The abundance of immature stages was greatest during January,April and August,October in the first and second years of the study, respectively. No larvae successfully moulted. Nymphs weighing < 17 mg also failed to moult, but 89% of heavier nymphs moulted into adults. Nymphs moulting to males weighed less (49.5 ± 16.09 mg) than nymphs moulting to females (98.1 ± 34.08 mg). The pre-moult period was similar for nymphs moulting to either sex and significantly longer (P < 0.01) for female nymphs maintained at 25 °C compared with nymphs kept at 27 °C. No effect of photoperiod on the pre-moult periods of nymphs was detected. Female ticks produced a mean of 7.0 ± 1.94 egg batches after a preoviposition period of 16.4 ± 8.41 days for the first batch. The mean oviposition period was 61 ± 20.8 days and the duration of oviposition for each batch varied from 1 to 6 days. The mean number of eggs per batch was 93.1 ± 87.53. The minimum incubation period for the first egg batch was 13.6 ± 2.77 days. The total number of eggs laid by each female was 651.6 ± 288.90. Parthenogenesis was not observed. The reproductive efficiency index (REI) (number of eggs laid/weight of female in mg) was 5.5 ± 1.26. Pearson's correlations showed a significant direct relationship between the weight of the female and number of eggs laid (P < 0.01) and REI (P < 0.05). Several of the biological values presented above for the tick population from the Neotropical zoogeographic region showed marked differences to equivalent values for O. megnini populations from the U.S.A. (Nearctic) and India (Oriental). Nevertheless, the only two sequences of 16S rDNA deposited in GenBank from ticks originating in Argentina and allegedly in the U.S.A. indicate that they are conspecific (99.8% agreement). We tentatively consider the biological differences among populations of this tick species to represent adaptations for survival at different conditions. [source] Survey of the vectorial competence of ticks in an endemic area of spotted fever group rickettsioses in Fukui Prefecture, JapanMICROBIOLOGY AND IMMUNOLOGY, Issue 6 2008Fubito Ishiguro ABSTRACT The prevalence of SFGR in ixodid ticks in the Mt. Arashima-dake area in the northern part of Fukui Prefecture was surveyed, because of strong suspicions that the first case identified in this Prefecture had become infected with R. helvetica in this region. The ticks identified consisted of three genera and six species; I.ovatus, I. persulcatus, I. monospinosus, H. flava, H. japonica and D. taiwanensis. Of all 222 ticks collected, only I. monospinosus ticks (8 of 32 examined) were positive for SFGR isolates, which were genetically identified as R. helvetica. Ticks (157 of all 222) positive for SFGR-DNA fragments consisted of I. monospinosus (14 of 32), I. persulcatus (11 of 55), I. ovatus (3 of 38), H. flava (5 of 21) and H. japonica (2 of 9). Of these, thirteen I. monospinosus, eight I. persulcatus, three I. ovatus, two H. flava and one H. japonica were identified by nucleotide sequences as positive for R. helvetica. DNA fragments from three H. flava and one H. japonica showed greater homology to R. japonica than to R. helvetica or R. asiatica. The present results indicate that it is most likely that the vector tick of R. helvetica infection in Fukui Prefecture is I. monospinosus. [source] Strategies for development of vaccines for control of ixodid tick speciesPARASITE IMMUNOLOGY, Issue 7 2006J. DE LA FUENTE SUMMARY Ticks are distributed worldwide and impact human and animal health, as well as food animal production. Control of ticks has been primarily by application of acaricides, which has resulted in selection of resistant ticks and environmental pollution. Vaccines have been shown to be a feasible tick control method that offers a cost-effective, environmentally friendly alternative to chemical control. However, identification of tick-protective antigens remains the limiting step in vaccine development. Tick antigens exposed naturally to the host during tick feeding and those concealed have both shown promise as candidate vaccine antigens. Development of vaccines against multiple tick species may be possible using highly conserved tick-protective antigens or by antigens showing immune cross-reaction to different tick species. Vaccines made from a combination of key protective antigens may greatly enhance vaccine efficacy. Preliminary studies have suggested the possibility of vaccine strategies directed toward both tick control and the blocking of pathogen transmission. Characterization of the tick genomes will have a great impact on the discovery of new protective antigens. The future of research directed toward tick vaccine development is exciting because of new and emerging technologies for gene discovery, and vaccine formulation and delivery. [source] Systematics and Biogeography of Hard Ticks, a Total Evidence ApproachCLADISTICS, Issue 1 2000J.S.H. Klompen Systematic relationships among the basal Ixodidae are examined using one morphological and three molecular data sets, 18S and 28S nuclear and 16S mitochondrial rDNA. Although different combinations of partitions are incompatible in a partition homogeneity test, combining them produces similar or better support for most major lineages through both additive and complementary effects. The different data sets are not complete for all taxa, but inclusion or exclusion of taxa with missing data for one or more data sets (8 of 29 ingroup taxa) does not influence overall tree topology and only weakly affects support levels. The only notable effect was based on gap treatment in the 28S data set. Gap treatment completely changes the arrangement and support levels for one basal node. The combined analyses show strong support for the Metastriata, a lineage including most endemic Australian Ixodes, and a lineage including the remaining Ixodes, but not for the Prostriata (=Ixodes s.l.). The distribution pattern of endemic Australian taxa (nearly all included in three exclusively Australian basal lineages) suggests that these lineages, and by extension the Ixodidae, originated after the isolation of Australia in the late Cretaceous, much more recently than previously indicated. [source] Guidelines for the diagnosis of tick-borne bacterial diseases in EuropeCLINICAL MICROBIOLOGY AND INFECTION, Issue 12 2004P. Brouqui Abstract Ticks are obligate haematophagous acarines that parasitise every class of vertebrate (including man) and have a worldwide distribution. An increasing awareness of tick-borne diseases among clinicians and scientific researchers has led to the recent description of a number of emerging tick-borne bacterial diseases. Since the identification of Borrelia burgdorferi as the agent of Lyme disease in 1982, 11 tick-borne human bacterial pathogens have been described in Europe. Aetiological diagnosis of tick-transmitted diseases is often difficult and relies on specialised laboratories using very specific tools. Interpretation of laboratory data is very important in order to establish the diagnosis. These guidelines aim to help clinicians and microbiologists in diagnosing infection transmitted by tick bites and to provide the scientific and medical community with a better understanding of these infectious diseases. [source] The significance of feeding for reproduction in a male Metastriata tick, Haemaphysalis longicornis (Acari: Ixodidae)ACTA ZOOLOGICA, Issue 1 2000Tomohide Matsuo In Haemaphysalis longicornis, secretions of the male accessory genital glands were regenerated by re-feeding for 3 or 4 days, although the secretions were almost completely released during the first copulation. It was also shown that spermatogenesis continued during re-feeding, since prospermia (elongated spermatids) were deposited in the seminal vesicle. A potent male seeks a receptive female on the host for copulation. The movement of males to different attachment sites occurred between the third and fourth day of re-feeding, and completely re-fed males (for 4 days) were able to copulate successfully. Spermatogenic cells, ranging from spermatogonia at the anterior end to prospermia at the posterior end, were found in fed males. Degeneration of spermatocytes at the great growth phase and developing spermatids prior to final development of prospermia were seen in virgin males without re-feeding after the first meal. Fully elongated spermatids (prospermia) appeared morphologically normal up to 10 days after the first feeding. Degeneration of spermatocytes and developing spermatids occurred from the second day and was almost complete by the fourth day. The degenerating cells shrank, became electron-dense, and finally died. A reduction in secretions of the four lobes of the accessory glands occurred during the 10 days after feeding. [source] The relationships between habitat topology, critical scales of connectivity and tick abundance Ixodes ricinus in a heterogeneous landscape in northern SpainECOGRAPHY, Issue 5 2003Agustin Estrada-Peña The habitat mosaic was used to quantify connectivity between patches of different tick density of the notorious tick species Ixodes ricinus in an attempt to determine the cause of variations in tick abundance among apparently homogeneous sites in northern Spain. The analysis revealed that patches with high tick abundance are "stepping-stone" territories that, when removed from the landscape, cause large changes in connectivity. Sites with medium tick abundance do not cause such a critical transition in connectivity. Patches with low tick abundance, but optimal abiotic conditions for survival, are located within the minimum cost corridors network joining the patches, while those sites where the tick has been intermittently collected are located at variable distances from this network. Sites where the tick is consistently absent, but where the habitat is predicted to be suitable (old, heterogeneous forests of Quercus spp.) for the tick, are very separated from this main network of connections. These results suggest that tick distribution in a zone is highly affected not only by abiotic variables (vegetation and weather) but also by host movements. Dispersal of the tick is a function of how the hosts perceive the habitat, and the habitat's permeability to host movement. Permanent tick populations seem to be supported by the existence of these critical, high density patches, located at significant places within the habitat network. [source] UNCOORDINATED PHYLOGEOGRAPHY OF BORRELIA BURGDORFERI AND ITS TICK VECTOR, IXODES SCAPULARISEVOLUTION, Issue 9 2010Parris T. Humphrey Vector-borne microbes necessarily co-occur with their hosts and vectors, but the degree to which they share common evolutionary or biogeographic histories remains unexplored. We examine the congruity of the evolutionary and biogeographic histories of the bacterium and vector of the Lyme disease system, the most prevalent vector-borne disease in North America. In the eastern and midwestern US, Ixodes scapularis ticks are the primary vectors of Borrelia burgdorferi, the bacterium that causes Lyme disease. Our phylogeographic and demographic analyses of the 16S mitochondrial rDNA suggest that northern I. scapularis populations originated from very few migrants from the southeastern US that expanded rapidly in the Northeast and subsequently in the Midwest after the recession of the Pleistocene ice sheets. Despite this historical gene flow, current tick migration is restricted even between proximal sites within regions. In contrast, B. burgdorferi suffers no barriers to gene flow within the northeastern and midwestern regions but shows clear interregional migration barriers. Despite the intimate association of B. burgdorferi and I. scapularis, the population structure, evolutionary history, and historical biogeography of the pathogen are all contrary to its arthropod vector. In the case of Lyme disease, movements of infected vertebrate hosts may play a larger role in the contemporary expansion and homogenization of the pathogen than the movement of tick vectors whose populations continue to bear the historical signature of climate-induced range shifts. [source] Molecular cloning of the ecdysone receptor and the retinoid X receptor from the scorpion Liocheles australasiaeFEBS JOURNAL, Issue 23 2007Yoshiaki Nakagawa 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 ecdysone receptor-A of the soft tick, Ornithodoros moubata (68%) and to that of the ecdysone receptor-A1 of the lone star tick, Amblyomma americanum (66%), but showed lower similarity to the ecdysone receptors of Orthoptera and Coleoptera (53,57%). The primary sequence of the ligand-binding region of the L. australasiae ecdysone receptor was highly homologous to that of ticks (85,86%). The amino acid sequence of the L. australasiae retinoid X receptor was also homologous to the amino acid sequence of ultraspiracles of ticks (63%) and insects belonging to the orders Orthoptera and Coleoptera (60,64%). The identity of both the L. australasiae ecdysone receptor and the L. australasiae retinoid X receptor to their lepidopteran and dipteran orthologs was less than 50%. The cDNAs of both the L. australasiae ecdysone receptor (L. australasiae ecdysone receptor-A) and the L. australasiae retinoid X receptor were successfully translated in vitro using a rabbit reticulocyte lysate system. An ecdysone analog, ponasterone A, bound to L. australasiae ecdysone receptor-A (KD = 4.2 nm), but not to L. australasiae retinoid X receptor. The L. australasiae retinoid X receptor did not enhance the binding of ponasterone A to L. australasiae ecdysone receptor-A, although L. australasiae retinoid X receptor was necessary for the binding of L. australasiae ecdysone receptor-A to ecdysone response elements. [source] Effect of tick parasitism on the health status of a passerine birdFUNCTIONAL ECOLOGY, Issue 6 2008D. J. A. Heylen Summary 1Little information is available on the ecological interactions between ticks and their hosts under natural conditions, and particularly so for avian hosts. To understand this host,parasite interaction it is necessary to assess the physiological harm ticks can do to their host. 2We combined observational and experimental (field and laboratory) data to examine the effects of a common tick species with major economic importance, the sheep tick (Ixodes ricinus), on the health status of a common passerine bird, the great tit (Parus major). 3In the laboratory experiment a parallel group design was carried out in which the birds of the experimental group were infested with 3,10 nymphs, whereas the birds of the control group were kept free of ticks and received a sham treatment. Both groups were stratified according to age and sex. Health parameters were measured the day before and 3 days after infestation or sham treatment: haematocrit level, erythrocyte sedimentation rate, leucocyte concentration and general body condition (body mass corrected for body size). 4No effects of age were observed on any of the health parameters. The decrease in haematocrit level in the experimental group was significantly greater than in the control group. Moreover, infested males suffered more blood depletion than infested females. The increase in sedimentation rate was greater in the experimental group than in the control group. Surprisingly, no treatment effects were found on leucocyte concentrations, which may indicate immunoregulation by the ticks on components of the birds' cellular immune response. Also no difference in general body condition between the treatment groups was found. None of the infested birds died during infestation. 5Lower haematocrit levels in infested birds, but unaffected leucocyte concentrations and general body condition are confirmed by field data (experimental and observational) of adult birds during breeding season. 6Neither haematocrit level nor general body condition was associated with parasite intensity among infested birds, suggesting that immature Ixodes ricinus are not resource limited at high natural densities. Still, the measurable direct harm caused by sheep tick infestations calls for further study on its importance for the evolutionary ecology of passerine hosts. [source] Impact of a tick size reduction on liquidity: evidence from the Sydney Futures ExchangeACCOUNTING & FINANCE, Issue 1 2009Kiril Alampieski G12 Abstract This paper examines the impact of a reduction in the minimum price increment on liquidity and execution costs in a futures market setting. In 2006, the Sydney Futures Exchange halved the minimum tick in the 3 Year Commonwealth Treasury Bond Futures. Results indicate that bid-ask spreads are significantly reduced after the change. Quoted depth, both at the best quotes and visible in the limit order book, is significantly lower after the tick reduction. Further analysis reveals that execution costs are significantly reduced after the change. We conclude that a tick size reduction improves liquidity and reduces execution costs in a futures market setting. [source] Pyrosequencing and characterization of immune response genes from the American dog tick, Dermacentor variabilis (L.)INSECT MOLECULAR BIOLOGY, Issue 5 2010D. C. Jaworski Abstract Ticks continue to be a threat to animal and human health, and new and novel control strategies are needed for ticks and tick-borne pathogens. The characterization of the tick,pathogen interface and the tick immune response to microbial infections is fundamental toward the formulation of new control strategies for ticks and the pathogens they transmit. Our overall hypothesis for this research is that the tick immune system manages the maintenance of pathogens. Therefore, discovery of tick immune response genes may provide targets for novel control strategies directed toward reducing vector competency and pathogen transmission. In these studies, 454 pyrosequencing, a high-throughput genomic sequencing method was used to discover tick genes expressed in response to bacterial and fungal infections. Expressed sequence tags (ESTs) were analysed from Dermacentor variabilis ticks that had been injected with bacteria (Escherichia coli, Bacillus subtilis, Micrococcus luteus) or fungi (Saccharomyces cerevisiae and Candida albicans) and ticks that were naturally infected with the intracellular bacterium, Anaplasma marginale. By this approach, ESTs were assembled into 5995 contigs. Contigs fell into the five main functional categories of metabolism, genetic information processing, environmental information processing, cellular processes and human diseases. We identified more than 30 genes that are likely to encode for proteins involved in tick immune function. We further analysed by reverse transcriptase PCR (RT-PCR) the expression of 22 of these genes in each of our bacterial or fungal treatment groups and found that seven were up-regulated. Up-regulation of these seven genes was confirmed for bacterial, but not fungal treatment by quantitative PCR (qPCR). One of these products was novel, encoding a new tick defensin. Our results clearly demonstrate the complexities of the tick immune system and mark new directions for further study and characterization of proteins that modulate microbial infections in the American dog tick. [source] Identification and characterization of antimicrobial peptide, defensin, in the taiga tick, Ixodes persulcatusINSECT MOLECULAR BIOLOGY, Issue 4 2009Y. Saito Abstract Ixodes persulcatus is the primary vector for human tick-borne diseases in Japan. A cDNA library was constructed from whole body homogenates of fed nymphs of I. persulcatus. From this library, one cDNA encoding defensin-like antimicrobial peptide was identified. The amino-acid sequence showed high similarity to those of the defensins of other ticks and arthropods. I. persulcatus defensin mRNA transcripts were detected at all life cycle stages of fed ticks and found to be predominantly expressed in the midguts of adult female ticks, but not in the salivary glands, a finding corroborated by Western blotting analysis. To investigate the function of I. persulcatus defensin, we examined its antibacterial activity by evaluation of growth of several bacterial strains in the presence of the synthetic peptide. The defensin from I. persulcatus markedly inhibited the growth of Gram-positive bacteria including Staphylococcus aureus, Bacillus subtilis and Corynebacterium renale, but not Gram-negative bacteria except Escherichia coli O157. In conclusion, these results suggest that I. persulcatus defensin may be playing a significant role in the defence against microbes from bloodmeals. [source] Microarray analysis of acaricide-inducible gene expression in the southern cattle tick, Rhipicephalus (Boophilus) microplusINSECT MOLECULAR BIOLOGY, Issue 6 2008L. Saldivar Abstract Acaricide-inducible differential gene expression was studied in larvae of Rhipicephalus (Boophilus) microplus using a microarray-based approach. The acaricides used were: coumaphos, permethrin, ivermectin, and amitraz. The microarrays contained over 13 000 probes, having been derived from a previously described R. microplus gene index (BmiGI Version 2; Wang et al., 2007). Relative quantitative reverse transcriptase-PCR, real time PCR, and serial analysis of gene expression data was used to verify microarray data. Among the differentially expressed genes with informative annotation were legumain, glutathione S-transferase, and a putative salivary gland-associated protein. [source] Genome size and organization in the blacklegged tick, Ixodes scapularis and the Southern cattle tick, Boophilus microplusINSECT MOLECULAR BIOLOGY, Issue 2 2005A. J. Ullmann Abstract Genome sizes and the organization of repetitive DNA were determined in the hard ticks Ixodes scapularis and Boophilus microplus using reassociation kinetics. The I. scapularis genome contains ,2.15 pg (2.1 × 103 Mbp) of DNA and consists of no foldback (FB), 27% highly repetitive (HR), 39% moderately repetitive (MR), and 34% unique DNA. The B. microplus genome contains 7.5 pg (7.1 × 103 Mbp) DNA, and consists of 0.82% FB, 31% HR, 38% MR, and 30% unique DNA. In both species, repetitive sequences occur in a mixture of long and short period interspersion but most (65,80%) of the DNA follows a pattern of short period interspersion. Genome size and organization in the three tick species so far examined are distinct from other arthropods in having a greater proportion of MR, a lower proportion of unique and HR DNA of very low sequence complexity. [source] Apis mellifera ultraspiracle: cDNA sequence and rapid up-regulation by juvenile hormoneINSECT MOLECULAR BIOLOGY, Issue 5 2004A. R. Barchuk Abstract Two hormones, 20-hydroxyecdysone (20E) and juvenile hormone (JH) are key regulators of insect development including the differentiation of the alternative caste phenotypes of social insects. In addition, JH plays a different role in adult honey bees, acting as a ,behavioural pacemaker'. The functional receptor for 20E is a heterodimer consisting of the ecdysone receptor and ultraspiracle (USP) whereas the identity of the JH receptor remains unknown. We have cloned and sequenced a cDNA encoding Apis mellifera ultraspiracle (AMUSP) and examined its responses to JH. A rapid, but transient up-regulation of the AMUSP messenger is observed in the fat bodies of both queens and workers. AMusp appears to be a single copy gene that produces two transcripts (,4 and ,5 kb) that are differentially expressed in the animal's body. The predicted AMUSP protein shows greater sequence similarity to its orthologues from the vertebrate,crab,tick,locust group than to the dipteran,lepidopteran group. These characteristics and the rapid up-regulation by JH suggest that some of the USP functions in the honey bee may depend on ligand binding. [source] RNA interference in ticks: a study using histamine binding protein dsRNA in the female tick Amblyomma americanumINSECT MOLECULAR BIOLOGY, Issue 3 2003M. N. Aljamali Abstract RNA interference (RNAi), a gene silencing process, has been recently exploited to determine gene function by degrading specific mRNAs in several eukaryotic organisms. We constructed a double stranded RNA (dsRNA) from a previously cloned putative Amblyomma americanum histamine binding protein (HBP) to test the significance of using this methodology in the assessment of the function and importance of gene products in ectoparasitic ticks. The female salivary glands incubated in vitro with HBP dsRNA had a significantly lower histamine binding ability. In addition, the injection of HBP dsRNA into the unfed females led both to a reduced histamine binding ability in the isolated salivary glands and to an aberrant tick feeding pattern or host response. Molecular data demonstrated less expression of the HBP mRNA in the RNAi group. Taken together, these results suggest that RNAi might be an important tool for assessing the significance of tick salivary gland secreted proteins modulating responses at the tick,host interface. [source] A preliminary linkage map of the hard tick, Ixodes scapularisINSECT MOLECULAR BIOLOGY, Issue 2 2003A. J. Ullmann Abstract A linkage map of the Ixodes scapularis genome was constructed, based upon segregation amongst 127 loci. These included 84 random amplified polymorphic DNA (RAPD) markers, 32 Sequence- Tagged RAPD (STAR) markers, 5 cDNAs, and 5 microsatellites in 232 F1 intercross progeny from a single, field-collected P1 female. A preliminary linkage map of 616 cM was generated across 14 linkage groups with one marker every 10.8 cM. Assuming a genome size of , 109 bp, the relationship of physical to genetic distance was found to be , 300 kb/cM in the I. scapularis genome. [source] Molecular characterization of a peroxiredoxin from the hard tick Haemaphysalis longicornisINSECT MOLECULAR BIOLOGY, Issue 2 2001N. Tsuji Abstract Antioxidant enzymes in eukaryotes play an important role in protection against the oxygen radicals generated during aerobic metabolism. Here we report the cloning and characterization of a cDNA encoding the antioxidant enzyme peroxiredoxin from the hard tick Haemaphysalis longicornis (HlPrx). HlPrx is 939 bp long and contains a 101 bp non-translated sequence at the 5, end and a polyadenylation singnal followed by a poly(A) tail at the 3, end. HlPrx encodes a full-length protein with a predicted molecular mass of 26 kDa that possesses one cysteine residue at amino acid 49 that is conserved among Prx proteins of various species. GenBankÔ analysis showed that the deduced amino acid sequence had significant similarity to mammalian and plant Prxs at the amino acid level. A DNA-nicking assay revealed that Escherichia coli,expressed recombinant HlPrx (rHlPrx) inhibited oxidative-nicking of supercoiled plasmid DNA. Two-dimensional immunoblot analysis with mouse antirHlPrx serum showed reaction with a major constituent protein spot in extracts of adult ticks. In addition, immunoblot analysis showed that rHlPrx was immunoreacted with serum from rabbits repeatedly infested with H. longicornis. Localization analysis using mouse antirHlPrx serum revealed that native HlPrx was highly expressed in the salivary gland of the tick. Moreover, Northern blot analysis showed that the level of HlPrx transcripts was increased during blood sucking. The present results indicate that HlPrx may be an important detoxifying enzyme during the normal life span as well as during blood sucking in ticks. [source] Cloning and transcriptional expression of a leucokinin-like peptide receptor from the Southern cattle tick, Boophilus microplus (Acari: Ixodidae)INSECT MOLECULAR BIOLOGY, Issue 5 2000S. P. Holmes Abstract Leucokinins are invertebrate neuropeptides that exhibit myotropic and diuretic activity. Only one leucokinin-like peptide receptor is known, the lymnokinin receptor from the mollusc Lymnaeastagnalis. A cDNA encoding a leucokinin-like peptide receptor was cloned from the Southern cattle tick, Boophilus microplus, a pest of cattle world-wide. This is the first neuropeptide receptor known from the Acari and the second known in the subfamily of leucokinin-like peptide G-protein-coupled receptors. The deduced amino acid sequence exhibits 40% identity to the lymnokinin receptor. The receptor transcript is present in all tick life stages as determined by semiquantitative reverse transcription polymerase chain reaction. We also propose that the sequence AAF50775.1 from the Drosophila melanogaster genome (CG10626) encodes the first identified insect leucokinin receptor. [source] Red cell exchange transfusion for babesiosis in Rhode IslandJOURNAL OF CLINICAL APHERESIS, Issue 3 2009Joshua Spaete Abstract We report four cases of clinically severe tick borne babesiosis treated with chemotherapy and adjunctive red cell exchange (RCE) at two Rhode Island hospitals from 2004 to 2007. All RCE procedures were performed using a Cobe Spectra device and were well tolerated without complications. The volume of allogeneic red cells used in the exchange was determined using the algorithm in the apheresis device with the input variables of preprocedure hematocrit, weight, height, an assumed allogeneic red cell hematocrit of 55 and a desired post procedure hematocrit of 27. The preprocedure level of parasitemia varied between 2.4% and 24% and the postprocedure level of parasitemia between 0.4 and 5.5% with an average overall percent reduction in parasitemia of 74%. Retrospectively, application of a new formula to calculate red cell mass appeared to correlate better with the percent reduction in parasitemia. Previous reports of RCE in babesiosis were reviewed. The reported reduction in parasitemia varied from 50% to >90%. Although a preprocedure level of parasitemia of 10% is sometimes used as a threshold for RCE in clinically severe babesiosis, this threshold does not have a firm empirical basis. No postprocedure desired level of parasitemia is indicated nor the mass of allogeneic red cells needed to achieve such a level. We conclude that current estimates of the dose of allogeneic red cells used in RCE are probably inaccurate, advocate a new formula to estimate this dose and suggest that a 90% reduction in parasitemia should be the minimally desired target of RCE in babesiosis. J. Clin. Apheresis, 2009. © 2009 Wiley-Liss, Inc. [source] Prevalence of tick-borne encephalitis virus in Ixodes Ricinus from a novel endemic area of North Eastern ItalyJOURNAL OF MEDICAL VIROLOGY, Issue 2 2009P. D'Agaro Abstract In Alpine area of extreme North Eastern Italy the first autochthonous case of TBE was reported in 1998 and was followed by 45 cases during the period 2001,2007, thus defining this area as definitely endemic. An ecological survey evaluated the tick density and the Tick-borne encephalitis virus (TBEV) infection prevalence in tick collected in selected sites. In addition, TBE strains were characterized by sequencing and phylogenetic analysis. Overall, 2,361 ticks (2,198 nymphs and 163 adults) of the Ixodes ricinus L. species collected during 2005 and 2006 were examined. Five samples were positive for TBEV, corresponding to an overall prevalence rate of 0.21%. When analyzed by place, TBEV was discovered in three sites where the highest tick density was found. The difference of prevalence between high and low density areas tested to be statistically significant (P,=,0.028). Phylogenetic analysis showed that four sequences clustered with the Neudoerfl prototype, while the other clustered with the Isosaari 17 strain and with a number of Slovenian isolates. In addition, a sequence detected in archival samples from one human case segregated with another variant, namely the Swedish Torö strain. J. Med. Virol. 81:309,316, 2009. © 2008 Wiley-Liss, Inc. [source] Characterization of tick-borne encephalitis virus from latvia: Evidence for co-circulation of three distinct subtypesJOURNAL OF MEDICAL VIROLOGY, Issue 4 2001Åke Lundkvist Abstract Viruses of the tick-borne encephalitis (TBE) antigenic complex within the family Flaviviridae cause a variety of diseases, including uncomplicated febrile illness, meningoencephalitis, and hemorrhagic fever. Different domesticated animals or wildlife species often act as reservoir hosts and ixodid ticks serve as vectors. Although TBE is a serious problem in Latvia, the knowledge concerning TBE virus (TBEV) strains circulating in the country is most limited. Only two strains (Latvia-1-96 isolated from a TBE patient, and RK1424 originating from an Ixodes persulcatus tick), which belonged to the Siberian and the Far Eastern subtypes of TBEV, respectively, have previously been characterized. In the present study, we concentrated on the western and central regions of Latvia, with predominantly Ixodes ricinus ticks. Five virus strains were isolated from serum samples of patients with clinical symptoms of an acute TBE infection. Nucleotide sequences encoding the envelope (E) protein of TBEV, which were recovered from the five TBEV isolates, showed the highest level of identity to the corresponding sequences of the prototype strain Neudoerfl and other European strains of the Western TBEV subtype characterized previously. Accordingly, phylogenetic analysis placed the new Latvian isolates within the Western genetic lineage of TBEV. Taken together with earlier observations, the results proved that all three TBEV subtypes are co-circulating in Latvia and indicated that the genetic diversity of TBEV within certain geographical areas is much more complex than previously believed. J. Med. Virol. 65:730,735, 2001. © 2001 Wiley-Liss, Inc. 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