Maps of ticks (Acari: Argasidae,Ixodidae) for Austria and South Tyrol,Italy

A first compilation of georeferenced tick locations in Austria and South Tyrol, Italy, is presented here. This allows the tick fauna to be examined in the various climatic regions of the European Alps. The dataset comprises 424 tick locations of Austria and 48 tick locations of South Tyrol, which were digitized from literature and visualized in the form of geographical maps. The tick fauna of Austria includes two species of Argasidae in the genera Argas and Carios and 15 species of Ixodidae in the genera Dermacentor, Haemaphysalis, and Ixodes, altogether 17 tick species. In addition, two species of Ixodidae in the genera Hyalomma (each spring imported by migratory birds) and Rhipicephalus (occasionally imported by dogs returning from abroad with their owners) are included in the tick atlas. Of these, the georeferenced locations of 18 tick species are depicted in maps. The occurrence of the one remaining tick species, Ixodes inopinatus, is given at the level of the federal states. The first Austrian distribution map of the long-legged bat tick Ixodes vespertilionis, which was reported from 21 caves, deserves special mention. The most common and widespread tick species is Ixodes ricinus, with records in all nine federal states of Austria, followed by Ixodes canisuga, Ixodes hexagonus, and I. vespertilionis in six federal states each. Haemaphysalis concinna and Dermacentor reticulatus are only endemic in the eastern plains, while Dermacentor marginatus only occurs in the west, in the Tyrolean Alpine valleys. Eight tick species were reported from South Tyrol, Italy. There, the most frequently flagged tick from the vegetation is also I. ricinus, while D. marginatus and Haemaphysalis punctata are often collected from sheep. The locations are shown together with those from North and East Tyrol on a separate Tyrol map. The tick atlas in Austria and South Tyrol as well as the underlying digital dataset in the supplement contribute to the closing of data gaps in global distribution maps of ticks and improve the data basis for new species distribution models.

     

Goats,hares, and rabbits as hosts for the New Zealand cattle tick,Haemaphysalis longicornis

Abstract

Feral goats and hares were commonly infested by immature stages of the New Zealand cattle tick, Haemaphysalis longicornis. No explanation could be found for the low prevalence of adult ticks on these hosts. The ears of both host species were almost the exclusive feeding site of the ticks and this may be a consequence of grooming behaviour. Another potential host, the rabbit, was examined but few were found to be infested.

The less restricted range of non-domesticated hosts, together with feeding habits that differ from domestic stock, make them an important additional source of information on the ecology and seasonal pattern of activity of H. longicornis. Also, they are a source of contamination for tick-free pasture, and could possibly maintain the tick population in the absence of sheep and cattle. It is important that their role as alternative hosts be understood and considered in tick-control programmes.     

Mode of action studies of the acaricidal agent,epingaione

Summary

Activity directed isolation studies of the ethanol extract of Bontia daphnoides L (Myoporaceae) leaves and stems led to the isolation of epingaione, a sesquiterpene furan. This compound was previously described by Chinnock et al. (1987) from the same plant. The compound showed growth regulatory activities on gravid adult female Boophilus microplus Canestrini (the southern cattle tick). The dose required for inhibiting the hatching of B. microplus eggs by 50% (Fid₅₀)was 0.4±0.06 mg/g of the tick body weight. The Fid₅₀ dose inhibited the sequestration of protein into eggs oviposited by 80%. These eggs were non-agglutinated and wrinkled. Histological examination of ovarian sections from the treated ticks revealed significant degeneration of funicle cells and reduction in yolk content.     

Adverse effects of extracts of Artocarpus altilis Park,and Azadirachta indica (A. Juss) on the reproductive physiology of the adult female tick,Boophilus microplus (Canest.)

Summary

Adverse effects of extracts from the plants Artocarpus altilis and Azadirachta indica on egg laying and hatching in the tick Boophilus microplus were quantified. A 50% inhibition of egg laying was achieved by a dose of 0.54 and 0.46 μg crude ethanol extract per tick, respectively. These doses also caused a 65% and 80% hatching failure, respectively. Extracts, particularly those of A. indica, inhibit protein and lipid sequestration by ovaries and oocytes. GC-MS analyses revealed reductions in the quantities of four methyl esters sequestered from the ovaries into the oocytes oviposited on the 12th day of engorgement by the treated ticks in the order of (A. indica effects are in parentheses): undecanoic acid 10-methyl-,methyl ester 40% (100%); tetradecanoic acid, methyl ester 100% (100%); tetradecanoic acid, 12-methyl-,methyl ester 100% (100%) and pentadecanoic acid, 14-methyl-,methyl ester 30% (75%).     

Tick tubes reduce blacklegged tick burdens on white-footed mice in Pennsylvania,USA

Lyme disease cases are increasing in the United States. The vector of the pathogen that causes Lyme disease is the blacklegged tick (Ixodes scapularis Say) (Acari:Ixodidae). While there are several tick control options, many are expensive or involve large-scale or ecological interventions such as landscape acaricide spraying or wildlife baiting. Tick control tubes, cardboard tubes with acaricide-treated cotton that can be used as nesting material by tick hosts, offer an alternative to more invasive tick control by treating tick hosts with an acaricide. In this study, tick tubes with cotton treated with two formulations of acaricide and water as a control were evaluated for wildlife use and for tick burden reductions on Peromyscus spp. an important reservoir host for the Lyme disease pathogen. Tick tubes were deployed for four weeks. Ticks parasitizing Peromyscus spp. and cotton use by wildlife were evaluated pre-deployment and post-deployment. Cotton from both treatments was used similarly, and permethrin-treated cotton was used more frequently than the control. In addition, I. scapularis were eliminated from hosts captured in treatment plots post-tick tube deployment. Tick tubes show promise as a tool for tick control on Peromyscus spp., especially as part of an integrated pest management plan.     

蜱传脑炎病毒跨过血脑屏障的体外实验

【目的】构建蜱传脑炎病毒(Tick-borne encephalitis virus,TBEV)跨血脑屏障研究的体外细胞模型,研究2种不同细胞的TBEV培养物在病毒跨过血脑屏障中的主要差异,从而为进一步TBEV跨血脑屏障的分子机制研究奠定基础。【方法】利用人脑微血管内皮细胞(Human brain microvascular endothelial cells,hCMEC/D3)构建体外血脑屏障的细胞模型。用BHK-21细胞中培养的蜱传脑炎病毒感染人脑微血管内皮细胞,检测TBEV在hCMEC/D3中的复制增殖情况;将TBEV加入体外血脑屏障模型的上层微孔中,用实时荧光定量PCR和噬斑测定的方法检测跨过血脑屏障的病毒量;将感染TBEV的人单核细胞加入血脑屏障模型的上层微孔中,观察渗漏进下层孔中的淋巴细胞,并用实时荧光定量PCR和噬斑测定的方法检测跨过血脑屏障的病毒量。利用伊文思蓝标记的白蛋白确定血脑屏障细胞的渗透率变化。【结果】实时荧光定量PCR和病毒滴度测定结果表明,TBEV不能在hCMEC/D3细胞中复制增殖,也不能直接跨过血脑屏障;然而,人单核细胞THP-1感染TBEV后,尽管单核细胞不能直接携带TBEV跨过血脑屏障,但THP-1中产生的病毒却能跨过血脑屏障模型进入下层孔中,并引起血脑屏障渗透率的增高。【结论】单核细胞有助于TBEV跨过血脑屏障。     

Comparison of closely related,uncultivated Coxiella tick endosymbiont population genomes reveals clues about the mechanisms of symbiosis

Understanding the symbiotic interaction between Coxiella‐like endosymbionts (CLE) and their tick hosts is challenging due to lack of isolates and difficulties in tick functional assays. Here we sequenced the metagenome of a CLE population from wild Rhipicephalus sanguineus ticks (CRs) and compared it to the previously published genome of its close relative, CLE of R. turanicus (CRt). The tick hosts are closely related sympatric species, and their two endosymbiont genomes are highly similar with only minor differences in gene content. Both genomes encode numerous pseudogenes, consistent with an ongoing genome reduction process. In silico flux balance metabolic analysis (FBA) revealed the excess production of L‐proline for both genomes, indicating a possible proline transport from Coxiella to the tick. Additionally, both CR genomes encode multiple copies of the proline/betaine transporter, proP gene. Modelling additional Coxiellaceae members including other tick CLE, did not identify proline as an excreted metabolite. Although both CRs and CRt genomes encode intact B vitamin synthesis pathway genes, which are presumed to underlay the mechanism of CLE‐tick symbiosis, the FBA analysis indicated no changes for their products. Therefore, this study provides new testable hypotheses for the symbiosis mechanism and a better understanding of CLE genome evolution and diversity.     

Savicalin,a lipocalin from hemocytes of the soft tick, <Emphasis Type="Italic">Ornithodoros savignyi</Emphasis>

Savicalin, is a lipocalin found in the hemocytes of the soft tick, Ornithodoros savignyi. It could be assigned to the tick lipocalin family based on BLAST analysis. Savicalin is the first non-salivary gland lipocalin described in ticks. The mature sequence is composed of 188 amino acids with a molecular mass of 21481.9 Da. A homolog for savicalin was found in a whole body EST-library from a related soft tick O. porcinus, while other tick salivary gland derived lipocalins retrieved from the non-redundant sequence database are more distantly related. Homology modeling supports the inclusion of savicalin into the lipocalin family. The model as well as multiple alignments suggests the presence of five disulphide bonds. Two conserved disulphide bonds are found in hard and soft tick lipocalins. A third disulphide bond is shared with the TSGP4-clade of leukotriene C4 binding soft tick lipocalins and a fourth is shared with a lipocalin from the hard tick Ixodes scapularis. The fifth disulphide bond is unique and links strands D-E. Phylogenetic analysis showed that savicalin is a distant relative of salivary gland derived lipocalins, but groups within a clade that is possibly non-salivary gland derived. It lacks the biogenic amine-binding motif associated with tick histamine and serotonin binding proteins. Expression profiles indicate that savicalin is found in hemocytes, midgut and ovaries, but not in the salivary glands. Up-regulation occurs in hemocytes after bacterial challenge and in midguts and ovaries after feeding. Given its tissue distribution and up-regulation of expression, it is possible that this lipocalin functions in tick development after feeding or in an anti-microbial capacity.     

The geographic distribution and ecological preferences of the American dog tick,Dermacentor variabilis (Say), in the U.S.A.

Equine piroplasmosis (EP), caused by two parasitic organisms, Theileria equi and Babesia caballi, is a tick‐borne disease of recent concern in horses in the U.S.A. Outbreaks of EP have been detected in Florida, Missouri, Kansas and Texas. In 2009, EP transmission in Texas occurred through the adults of two tick species, Amblyomma mixtum [formerly known as Amblyomma cajennense (Fabricius, 1787)] Koch (Ixodida: Ixodidae) and Dermacentor variabilis (Say) (Ixodida: Ixodidae), the American dog tick (ADT). In this study, we developed a continent‐scale map for the distribution of the EP vector species D. variabilis, using a presence‐only modelling approach to assess the habitat preferences of this tick. We used identification records from our tick geodatabase of locations in which the presence of the ADT had been noted. The potential distribution of the ADT in the U.S.A. was estimated from environmental factors using the maximum entropy approach based on localities in which there is a high probability of occurrence according to habitat suitability. Elevation and temperature were found to be biologically significant environmental variables influencing the presence of this tick species. Properly designed and constructed probability surfaces using maximum entropy offer one useful approach to the mapping of distribution ranges of tick species based on suitable habitat in the U.S.A.     

Molecular Detection of Tick-Borne Pathogens in Humans with Tick Bites and Erythema Migrans,in the Netherlands

BackgroundTick-borne diseases are the most prevalent vector-borne diseases in Europe. Knowledge on the incidence and clinical presentation of other tick-borne diseases than Lyme borreliosis and tick-borne encephalitis is minimal, despite the high human exposure to these pathogens through tick bites. Using molecular detection techniques, the frequency of tick-borne infections after exposure through tick bites was estimated.MethodsTicks, blood samples and questionnaires on health status were collected from patients that visited their general practitioner with a tick bite or erythema migrans in 2007 and 2008. The presence of several tick-borne pathogens in 314 ticks and 626 blood samples of this cohort were analyzed using PCR-based methods. Using multivariate logistic regression, associations were explored between pathogens detected in blood and self-reported symptoms at enrolment and during a three-month follow-up period.ResultsHalf of the ticks removed from humans tested positive for Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Candidatus Neoehrlichia mikurensis, Rickettsia helvetica, Rickettsia monacensis, Borrelia miyamotoi and several Babesia species. Among 92 Borrelia burgdorferi s. l. positive ticks, 33% carried another pathogen from a different genus. In blood of sixteen out of 626 persons with tick bites or erythema migrans, DNA was detected from Candidatus Neoehrlichia mikurensis (n = 7), Anaplasma phagocytophilum (n = 5), Babesia divergens (n = 3), Borrelia miyamotoi (n = 1) and Borrelia burgdorferi s. l. (n = 1). None of these sixteen individuals reported any overt symptoms that would indicate a corresponding illness during the three-month follow-up period. No associations were found between the presence of pathogen DNA in blood and; self-reported symptoms, with pathogen DNA in the corresponding ticks (n = 8), reported tick attachment duration, tick engorgement, or antibiotic treatment at enrolment.ConclusionsBased on molecular detection techniques, the probability of infection with a tick-borne pathogen other than Lyme spirochetes after a tick bite is roughly 2.4%, in the Netherlands. Similarly, among patients with erythema migrans, the probability of a co-infection with another tick-borne pathogen is approximately 2.7%. How often these infections cause disease symptoms or to what extend co-infections affect the course of Lyme borreliosis needs further investigations.     

Tick species establishment in Oklahoma County,Oklahoma, U.S.A., identified by seasonal sampling in residential and non‐residential sites

In recent years, human tick‐borne disease occurrence has risen in Oklahoma, U.S.A., but year‐round data on tick presence in frequently used recreational areas is not widely available. In this study, ticks were collected monthly for one year at residential and non‐residential sites in a suburban area of Oklahoma County, OK, U.S.A. At each trapping site, dry ice traps were used in both woodland and grassland areas and fabric tick drags were used in grassland areas. Four species were collected from each park: Amblyomma americanum, Amblyomma maculatum, Dermacentor variabilis, and Ixodes scapularis. Prior to this study, A. americanum was the only species with an established population in Oklahoma County. Consistent with this, A. americanum was collected in all months of the year and accounted for over 90% of ticks collected at each site. Based on our tick survey, we report that A. maculatum, D. variabilis, and I. scapularis, which were each collected in numbers greater than six within a single sampling occasion, are now each confirmed as established populations in Oklahoma County.     

Borrelia burgdorferi genes,bb0639‐0642, encode a putative putrescine/spermidine transport system,PotABCD, that is spermidine specific and essential for cell survival

Polyamines are an essential class of metabolites found throughout all kingdoms in life. Borrelia burgdorferi harbors no enzymes to synthesize or degrade polyamines yet does contain a polyamine uptake system, potABCD. In this report, we describe the initial characterization of this putative transport system. After several unsuccessful attempts to inactivate potABCD, we placed the operon under the control of an inducible LacI promoter expression system. Analyses of this construct confirmed that potABCD was required for in vitro survival. Additionally, we demonstrated that the potABCD operon were upregulated in vitro by low osmolarity. Previously, we had shown that low osmolarity triggers the activation of the Rrp2/RpoN/RpoS regulatory cascade, which regulates genes essential for the transmission of spirochetes from ticks to mammalian hosts. Interestingly, induction of the pot operon was only affected in an rpoS mutant but not in a rpoN mutant, suggesting that the genes were RpoS dependent and RpoN independent. Furthermore, potABCD was upregulated during tick feeding concomitant with the initiation of spirochete replication. Finally, uptake experiments determined the specificity of B. burgdorferi's PotABCD for spermidine.     

Relationship between habitat type,fire frequency,and Amblyomma americanum populations in east‐central Alabama

Ticks were collected from 20 sites in the Calhoun, Cherokee, and Cleburne Counties in east‐central Alabama areas to determine the relationship between plant physiognomy, environmental variables, and tick populations. Sites investigated included various burning regimes, wildland‐urban–interface (WUI), a college campus, and an unmanaged area. Amblyomma americanum (L.) (Acari: Ixodidae) dominated the tick population while Ixodes scapularis Say was not encountered. There were complex differences in tick populations among site conditions. After prescribed burning, the tick population size was small but was larger in subsequent 2‐ and 5‐year post‐burn sites. An increase in Odocoileus virginianus foraging in recently burned sites is likely responsible for this phenomenon. WUI areas had the largest tick populations likely due to Odocoileus virginianus activity in an area that provides cover, forage, and a connection to a wildlife refuge. It is possible that the likelihood of humans coming in contact with ticks and tick‐borne diseases is greater in WUI areas than in unbroken contiguous forest. A. americanum showed a positive correlation with percent cover of grass and leaf litter mass and a negative relationship with pine sapling density. Variables expected to be strongly correlated with A. americanum populations such as soil moisture, canopy closure, and tree density were found to have weak correlations.     

Hyalomma ticks on northward migrating birds in southern Spain: Implications for the risk of entry of Crimean‐Congo haemorrhagic fever virus to Great Britain

Crimean‐Congo haemorrhagic fever virus (CCHFV) is a zoonotic virus transmitted by Hyalomma ticks, the immature stages of which may be carried by migratory birds. In this study, a total of 12 Hyalomma ticks were recovered from five of 228 migratory birds trapped in Spring, 2012 in southern Spain along the East Atlantic flyway. All collected ticks tested negative for CCHFV. While most birds had zero Hyalomma ticks, two individuals had four and five ticks each and the statistical distribution of Hyalomma tick counts per bird is over‐dispersed compared to the Poisson distribution, demonstrating the need for intensive sampling studies to avoid underestimating the total number of ticks. Rates of tick exchange on migratory birds during their northwards migration will affect the probability that a Hyalomma tick entering Great Britain is positive for CCHFV. Drawing on published data, evidence is presented that the latitude of a European country affects the probability of entry of Hyalomma ticks on wild birds. Further data on Hyalomma infestation rates and tick exchange rates are required along the East Atlantic flyway to further our understanding of the origin of Hyalomma ticks (i.e., Africa or southern Europe) and hence the probability of entry of CCHFV into GB.     

Differences in the Transmissibility of Two Anaplasma phagocytophilum Strains by the North American Tick Vector Species, Ixodes Pacificus and Ixodes Scapularis (Acari: Ixodidae)

The etiologic agent of granulocytic anaplasmosis, Anaplasma phagocytophilum, has a circum-global distribution within the northern hemisphere and shows a host species predilection that varies by the geographic region in which the disease is found. Adaptation by the bacterium to a host species potentially contributes to the variation found worldwide but this is confounded by the bacterium's relationship with its tick vectors, all of which belong to the Ixodes ricinus group. We tested the hypothesis that tick vector species collected from geographic regions sympatric with particular A. phagocytophilum strains will show evidence of a higher degree of vector competence than will tick species and allopatric A. phagocytophilum strains. A reciprocal cross-transmission experiment was performed using an eastern and a western North American strain of A. phagocytophilum (Webster and MRK, respectively) and the two tick species, I. scapularis and I. pacificus, most commonly associated with human and animal transmission of the bacteria in the United States. The western tick, I. pacificus, showed a significantly higher vector competence for A. phagocytophilum than I. scapularis and the eastern isolate, Webster, was more transmissible than its western counterpart, MRK. These results indicate that geographic variation in host susceptibility to A. phagocytophilum strains may play a more important role in the epidemiology of granulocytic anaplasmosis than does the competence of its tick vectors to transmit the pathogen.     

The effect of rainfall on tick challenge at Kyle Recreational Park,Zimbabwe

The effect of rainfall pattern on tick challenge was investigated at Kyle Recreational Park, Zimbabwe, from 1991 to 1992 using drag and removal plot methods to sample environmental tick density. The abundance of adults and nymphs of the brown ear-tick Rhipicephalus appendiculatus and larvae of the bont tick Amblyomma hebraeum was positively correlated with monthly rainfall, whereas no relationship with rainfall was revealed for larval R. appendiculatus, adults of the red-legged tick R. evertsi, or larvae of the blue tick Boophilus decoloratus. A comparison between 1991 (490 mm rainfall) and the drought year of 1992 (161 mm) revealed significant differences in the abundance of R. appendiculatus, A. hebraeum, and B. decoloratus. During the wet season, R. appendiculatus adults were 2–3 time more numerous in the environment during the higher rainfall year of 1991. A. hebraeum larval abundance exhibited a similar pattern to that of R. appendiculatus adults, but B. decoloratus larvae were more abundant in the drought year of 1992 during both the wet and dry seasons. Comparable tick abundance data collected at Kyle during the above-average rainfall years of 1975–1977 (mean = 1029 mm) were compared with tick challenge during the below-average rainfall years of 1991–1992 (mean = 326 mm). In grassland sand habitat and all habitats combined R. appendiculatus adults, nymphs, and larvae were much more abundant during the high rainfall years. In contrast, larvae of B. decoloratus were more numerous during the drier years. A. hebraeum larvae were also more abundant during the drier years. The strong positive correlation of adult R. appendiculatus abundance with rainfall and the coincidence of increased adult tick challenge with increased rainfall indicates that adult R. appendiculatus tick burden on hosts would be heaviest during the wet season and high rainfall years.     

The Argasidae, Ixodidae and Nuttalliellidae (Acari: Ixodida): A World List of Valid Tick Names

The world's argasid tick fauna comprises 183 species in four genera, namely Argas, Carios, Ornithodoros and Otobius in the family Argasidae. The ixodid tick fauna consists of 241 species in the genus Ixodes and 442 species in the genera Amblyomma, Anomalohimalaya, Bothriocroton, Cosmiomma, Dermacentor, Haemaphysalis, Hyalomma, Margaropus, Nosomma, Rhipicentor and Rhipicephalus in the family Ixodidae, with the genus Boophilus becoming a subgenus of the genus Rhipicephalus. The family Nuttalliellidae is represented by the monospecific genus Nuttalliella. The species names of these ticks, based on seven previous complete or partial listings, as well as those of recently described new species, are presented in tabular format. This revised version was published online in July 2006 with corrections to the Cover Date.