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The Ixodidae include the most common tick species encountered in Europe. The ticks transmit a variety of bacterial and protozoan agents of medical and veterinary significance. The aim of the current work was to investigate distribution of Ixodes ricinus and Dermacentor reticulatus ticks in Kyiv, the largest and most densely populated megapolis of Ukraine. Ticks were collected at various recreational areas by flagging during May, the month that showed the highest tick abundance in the past. Sex distribution among I. ricinus ticks was relatively equal, whereas females were collected in higher numbers for D. reticulatus . As opposed to western and central Europe where nymphal ticks had been more abundant, the nymph:adult ratio for I. ricinus was reversed. Also, this report documents detection of Rhipicephalus sanguineus sensu lato (s.l.) in Kyiv region, well outside of its historically documented distribution area. Previously thought to be restricted to the southern Ukraine, a single male specimen of R. sanguineus s.l. was collected just outside the city limits. Data on tick diversity over the past 30 years, however, indicates that this finding may only be incidental. [ABSTRACT FROM AUTHOR]

Cattle fever ticks, Rhipicephalus microplus and R. annulatus have been eradicated from the United States and inspectors from the U.S. Department of Agriculture (USDA), Animal Plant Health Inspection Service (APHIS), Cattle Fever Tick Eradication Program (CFTEP) monitor the quarantine zone along the Texas border to prevent the introduction of livestock carrying cattle fever ticks from Mexico. Stray livestock apprehended by CFTEP in the zone are checked for ticks and tested for infectious disease-causing pathogens but are not evaluated for evidence of infection with tick-borne pathogens. We tested blood samples collected from stray cattle by CFTEP inspectors for evidence of infection with tick-borne pathogens. As a comparison group representing U.S. resident cattle, we tested blood samples that had been sent to the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) for unrelated testing. Both sets of blood samples were evaluated using the same specific and broad-spectrum PCR assays. For the border cattle the overall prevalence of infection with one or more tick-borne pathogen was 58.5 % (79/135) with many co-infections, including 30 cattle positive for Babesia bovis and/or Babesia bigemina (22.2 %) and 77 cattle positive for Anaplasma marginale (57 %), three of these animals were also positive for Borrelia theileri. No resident cattle represented by the TVMDL samples were infected with either of the Babesia spp., or with Borrelia theileri , but three were positive for Theileria orientalis and 7.3 % (7/96) were positive for A. marginale. These data show that cattle originating in Mexico have a higher prevalence of infection with tick-borne pathogens relative to resident U.S. cattle and specifically, a proportion are infected with bovine Babesia , which is absent from U.S. cattle populations. Consequently, these stray cattle may be a reservoir of tick-borne pathogens and if populations of Boophilus ticks become reestablished in areas where they had previously been eradicated, could pose a significant risk to the U.S. Cattle industry. [ABSTRACT FROM AUTHOR]

For most organisms, iron is an essential nutrient due to its role in fundamental cellular processes. Insufficient iron causes sub-optimal metabolism with potential effects on viability, while high levels of iron are toxic due to the formation of oxidative radicals, which damage cellular components. Many molecules and processes employed in iron uptake, storage, transport and metabolism are conserved, however significant knowledge gaps remain regarding these processes in ticks due to their unique physiology. In this study, we first identified and sequenced 13 genes likely to be involved in iron metabolism in Dermacentor andersoni cells. We then developed a method to reduce iron levels in D. andersoni cells using the iron chelator 2,2′-bipyridyl and measured the transcriptional response of these genes to iron reduction. The genes include a putative transferrin receptor , divalent metal transporter 1, duodenal cytochrome b, zinc/iron transporters zip7 , zip13 , zip14 , mitoferrin , ferrochelatase, iron regulatory protein 1, ferritin1, ferritin2 , transferrin and poly r(C)-binding protein. Overall, the transcriptional response of the target genes to iron reduction was modest. The most marked changes were a decrease in ferritin2 , which transports iron through the tick hemolymph, the mitochondrial iron transporter mitoferrin , and the mitochondrial enzyme ferrochelatase. Iron regulatory protein1 was the only gene with an overall increase in transcript in response to reduced iron levels. This work lays the foundation for an improved understanding of iron metabolism in ticks which may provide molecular targets for the development of novel tick control methods and aid in the understanding of tick-pathogen interactions. [ABSTRACT FROM AUTHOR]

Infiltration and proliferation of Theileria parva infected lymphocytes in bovine host lymphoid organs is one of the hallmarks of T. parva infection. The relative abundance of parasites within infected host tissues, both lymphoid and non-lymphoid is however unknown. Using quantitative PCR, we have shown that significantly higher concentrations of T. parva DNA are detected in the spleens of cattle undergoing severe disease compared to other organs. [ABSTRACT FROM AUTHOR]

Population genetic studies provide insights into the basic biology of arthropod disease vectors by estimating dispersal patterns and their potential to spread pathogens. In wingless vectors, such as ticks, gene flow will be defined in large part by the mobility of their hosts. However, tick behaviors and life cycle strategies can limit their dispersal even on highly mobile hosts and lead to an increase in genetic structure. In this review we synthesize the published literature from three decades of tick population genetic studies. Based on studies from 22 tick species (including representatives from Amblyomma , Bothriocroton , Dermacentor , Ixodes , Ornithodoros , and Rhipicephalus ), observed levels of population genetic structure in ticks varied from no structure to very high levels. In about half of the species (including representatives from Amblyomma , Bothriocroton , Dermacentor , and Ornithodoros ), tick genetic structure appeared to be determined primarily by the movement capacity of hosts, with low gene flow observed in ticks that use smaller bodied less mobile hosts and high gene flow in ticks using highly mobile hosts. In a number of other species (primarily from Ixodes , Ornithodoros , and Rhipicephalus ), behavioral limitations to gene flow appeared to result in greater genetic structure than expected based upon host movement capability alone. We also discuss the strengths and limitations of genetic markers and their applicability to ticks and suggest possible analyses when planning population genetic studies for ticks. [ABSTRACT FROM AUTHOR]

Abstract: Differences in protein expression in midgut tissue of uninfected and Babesia bovis-infected southern cattle ticks, Rhipicephalus (Boophilus) microplus, were investigated in an effort to establish a proteome database containing proteins involved in successful pathogen transmission. The electrophoretic separation of midgut membrane proteins was greatly improved by using liquid-phase isoelectric focusing combined with one-dimensional or two-dimensional (2-D) gel electrophoresis. A selection of differentially expressed proteins were subjected to analysis by capillary-HPLC-electrospray tandem mass spectrometry (HPLC-ESI-MS/MS). Among the identified Babesia-affected tick midgut proteins were six proteins that are implicated in signaling processes, including three Ca2+-binding proteins, a guanine nucleotide-binding protein, a protein with signal peptide activity and a translocon-associated receptor protein. Up-regulation of five metabolic enzymes indicated parasite-induced changes in electron and proton transport, protein processing and retinoic acid metabolism. Among the down-regulated proteins were a molecular chaperone, a cytoskeletal protein and a multifunctional protein of the prohibitin family. Identification of these proteins may provide new insights into the molecular interactions between B. bovis and its tick vector, and could lead to identification of anti-tick and transmission-blocking vaccine candidates. [Copyright &y& Elsevier]

Abstract: We used gel electrophoresis and mass spectrometry to investigate differences in protein expression in ovarian tissues from Babesia bovis-infected and uninfected southern cattle tick, Rhipicephalus (Boophilus) microplus. Soluble and membrane proteins were extracted from ovaries of adult female ticks, and analyzed by isoelectric focusing (IEF) and one-dimensional or two-dimensional (2-D) gel electrophoresis. Protein patterns were analyzed for differences in expression between infected and uninfected ticks. 2-D separation of proteins revealed a number of proteins that appeared to be up- or down-regulated in response to infection with Babesia, in particular membrane/membrane-associated proteins and proteins in a low molecular mass range between 6 and 36kDa. A selection of differentially expressed proteins was subjected to analysis by capillary-HPLC-electrospray tandem mass spectrometry (HPLC-ESI-MS/MS). Among the ovarian proteins that were up-regulated in infected ticks were calreticulin, two myosin subunits, an endoplasmic reticulum protein, a peptidyl-prolyl cis–trans isomerase (PPIase), a cytochrome c oxidase subunit, a glutamine synthetase, and a family of Kunitz-type serine protease inhibitors. Among the down-regulated ovarian proteins were another PPIase, a hemoglobin subunit, and a lysozyme. This study is part of an ongoing effort to establish a proteome database that can be utilized to investigate specific proteins involved in successful pathogen transmission. [Copyright &y& Elsevier]

A novel apicomplexan parasite was serendipitously discovered in horses at the United States – Mexico border. Phylogenetic analysis based on 18S rDNA showed the erythrocyte-infective parasite to be related to, but distinct from, Theileria spp. in Africa, the most similar taxa being Theileria spp . from waterbuck and mountain zebra. The degree of sequence variability observed at the 18S rDNA locus also suggests the likely existence of additional cryptic species. Among described species, the genome of this novel equid Theileria parasite is most similar to that of Theileria equi , also a pathogen of horses. The estimated divergence time between the new Theileria sp. and T. equi , based on genomic sequence data, is greater than 33 million years. Average protein sequence divergence between them, at 23%, is greater than that of Theileria parva and Theileria annulata proteins, which is 18%. The latter two represent highly virulent Theileria spp. of domestic cattle, as well as of African and Asian wild buffalo, respectively, which differ markedly in pathology, host cell tropism, tick vector and geographical distribution. The extent of genome-wide sequence divergence, as well as significant morphological differences, relative to T. equi justify the classification of Theileria sp. as a new taxon. Despite the overall genomic divergence, the nine member equi merozoite antigen (EMA) superfamily, previously found as a multigene family only in T. equi , is also present in the novel parasite. Practically, significant sequence divergence in antigenic loci resulted in this undescribed Theileria sp. not being detectable using currently available diagnostic tests. Discovery of this novel species infective to equids highlights exceptional diversity within the genus Theileria , a finding with serious implications for apicomplexan parasite surveillance. [ABSTRACT FROM AUTHOR]

Rhipicephalus microplus is an important biological vector of Anaplasma marginale , the etiological agent of bovine anaplasmosis. The knowledge of tick immune responses to control bacterial infections remains limited. In this study, we demonstrate that transcription factor Relish from the IMD signaling pathway has an important role in the control of A. marginale infection in ticks. We found that RNA-mediated silencing of Relish caused a significant increase in the number of A. marginale in the midgut and salivary glands of R. microplus . In addition, the IMD pathway regulates the expression of the gene that encodes the antimicrobial peptide (AMP) microplusin. Moreover, microplusin expression was up-regulated in the midgut (2×) and salivary glands (8×) of A. marginale infected R. microplus. Therefore, it is plausible to hypothesize that microplusin may be involved in the A. marginale control. This study provides the first evidence of IMD signaling pathway participation on the A. marginale control in R. microplus . [ABSTRACT FROM AUTHOR]

Dermacentor andersoni , known as the Rocky Mountain wood tick, is found in the western United States and transmits pathogens that cause diseases of veterinary and public health importance including Rocky Mountain spotted fever, tularemia, Colorado tick fever and bovine anaplasmosis. Tick saliva is known to modulate both innate and acquired immune responses, enabling ticks to feed for several days without detection. During feeding ticks subvert host defences such as hemostasis and inflammation, which would otherwise result in coagulation, wound repair and rejection of the tick. Molecular characterization of the proteins and pharmacological molecules secreted in tick saliva offers an opportunity to develop tick vaccines as an alternative to the use of acaricides, as well as new anti-inflammatory drugs. We performed proteomics informed by transcriptomics to identify D. andersoni saliva proteins that are secreted during feeding. The transcript data generated a database of 21,797 consensus sequences, which we used to identify 677 proteins secreted in the saliva of D. andersoni ticks fed for 2 and 5 days, following proteomic investigations of whole saliva using mass spectrometry. Salivary gland transcript levels of unfed ticks were compared with 2 and 5 day fed ticks to identify genes upregulated early during tick feeding. We cross-referenced the proteomic data with the transcriptomic data to identify 157 proteins of interest for immunomodulation and blood feeding. Proteins of unknown function as well as known immunomodulators were identified. [ABSTRACT FROM AUTHOR]

Highlights: [•] AmStM-GFP is a marked, culture derived, live vaccine candidate for anaplasmosis. [•] AmStM-GFP and A. centrale result in similar levels of bacteremia and anemia. [•] AmStM-GFP provides protection against disease following homologous challenge. [Copyright &y& Elsevier]

Abstract: Reassociation kinetics and flow cytometry data indicate that ixodid tick genomes are large, relative to most arthropods, containing ≥109 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 tissues in four species of ixodid ticks, namely R. appendiculatus, B. (R.) microplus, Amblyomma variegatum and also the more distantly related Ixodes scapularis. Secondary structure predictions indicated that Ruka could adopt a tRNA structure that was, atypically, most similar to a serine tRNA. By extrapolation the frequency of occurrence in the randomly selected BAC clone sequences is consistent with approximately 65,000 copies of Ruka in the R. appendiculatus genome. Real time PCR analyses on genomic DNA indicate copy numbers for specific Ruka subsets between 5800 and 38,000. Several putative conserved Ruka insertion sites were identified in EST sequences of three ixodid tick species based on the flanking sequences associated with the SINEs, indicating that some Ruka transpositions probably occurred prior to speciation within the metastriate division of the Ixodidae. The data strongly suggest that Class I transposable elements form a significant component of tick genomes and may partially account for the large genome sizes observed. [Copyright &y& Elsevier]