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1.
Questing ticks were sampled monthly over a period of 11 months from February, 2011 to December, 2011 at 13 sites in southern Germany using the flagging method. The ticks were identified to species, gender, and stadium. Although both I. ricinus and D. reticulatus were sampled, this study concentrated on I. ricinus, since it was the most abundant tick to be found. Additional weather data (air and soil temperature, relative air humidity, precipitation, sunshine duration) were recorded on each sampling site and the local vegetation described. A total of 14, 394 ticks was collected (7,862 larvae, 5,568 nymphs, 964 adults) and their activity was recorded in order to determine the seasonal activity pattern over different periods of the year. In contrast to the widely accepted pattern of a bimodal seasonal activity in moderate areas with a dominant peak in spring and a minor peak in autumn, a unimodal activity pattern was found for all development stages on six of the 12 sampling sites. Tick abundance was compared to weather variables. Tick host‐seeking activity was found to be significantly dependent on the temperature at ground level, precipitation, and sunshine duration as well as relative air humidity. Adult ticks showed a positive correlation with the duration of sunshine, whereas nymphs were mostly unaffected by this phenomenon. 相似文献
2.
T. G. T. JAENSON L. EISEN P. COMSTEDT H. A. MEJLON E. LINDGREN S. BERGSTRÖM B. OLSEN 《Medical and veterinary entomology》2009,23(3):226-237
The distributional area of the tick Ixodes ricinus (L.), the primary European vector to humans of Lyme borreliosis spirochaetes (Borrelia burgdorferi sensu lato) and tick‐borne encephalitis virus, appears to be increasing in Sweden. It is therefore important to determine which environmental factors are most useful to assess risk of human exposure to this tick and its associated pathogens. The geographical distribution of I. ricinus in Sweden was analysed with respect to vegetation zones and climate. The northern limit of I. ricinus and B. burgdorferi s.l. in Sweden corresponds roughly to the northern limit of the southern boreal vegetation zone, and is characterized climatically by snow cover for a mean duration of 150 days and a vegetation period averaging 170 days. The zoogeographical distribution of I. ricinus in Sweden can be classified as southerly–central, with the centre of the distribution south of the Limes Norrlandicus. Ixodes ricinus nymphs from 13 localities in different parts of Sweden were examined for the presence of B. burgdorferi s.l. and found to be infected with Borrelia afzelii and Borrelia garinii. Tick sampling localities were characterized on the basis of the density of Borrelia‐infected I. ricinus nymphs, presence of specific mammals, dominant vegetation and climate. Densities of I. ricinus nymphs and Borrelia‐infected nymphs were significantly correlated, and nymphal density can thus serve as a general indicator of risk for exposure to Lyme borreliosis spirochaetes. Analysis of data from this and other studies suggests that high densities of Borrelia‐infected nymphs typically occur in coastal, broadleaf vegetation and in mixed deciduous/spruce vegetation in southern Sweden. Ixodes ricinus populations consistently infected with B. burgdorferi s.l. can occur in: (a) biotopes with shrews, rodents, hares and birds; (b) biotopes with shrews, rodents, hares, deer and birds, and (c) island locations where the varying hare (Lepus timidus) is the only mammalian tick host. 相似文献
3.
Joe Prullage;Anthony Pfefferkorn;Martin Knaus;Justin Frost;Elizabeth Mitchell;Eric Tielemans 《Parasite (Paris, France)》2021,28(1)
Esafoxolaner is a purified enantiomer of afoxolaner with insecticidal and acaricidal properties. It is combined with eprinomectin and praziquantel in a novel topical endectoparasiticide formulation for cats. The efficacy of this novel formulation was evaluated in three Ixodes ricinus and two Ixodes scapularis experimental studies,with comparable designs. In each study,cats were randomly allocated,based on a pre-treatment tick infestation and count,to a placebo control group or a group treated with the minimum recommended dose of the novel formulation. Cats were infested two days before treatment and weekly thereafter. Immediate efficacy was evaluated 48h after treatment; persistent efficacy was evaluated 48h after new weekly infestations for at least one month after the treatment (in one of the studies,the first two weeks of persistent efficacy against I. ricinus were not tested). Efficacy was calculated at each timepoint by comparison of arithmetic means of live ticks found in the control and the treated groups. In the three studies targeting I. ricinus ,immediate and persistent efficacies ranged between 91% and 100% for five weeks. In the two studies targeting I. scapularis ,immediate and persistent efficacies ranged between 95% and 100%,and 98% and 100% for one month,respectively. These studies provide robust evidence of efficacy of the novel topical formulation of esafoxolaner,eprinomectin and praziquantel against experimental I. ricinus and I. scapularis infestations for at least one month in cats. 相似文献
4.
S. DZIEMIAN J. MICHALIK B. PI ŁACIŃSKA S. BIALIK B. SIKORA R. ZWOLAK 《Medical and veterinary entomology》2014,28(4):465-469
Infestation by the nest‐dwelling Ixodes hexagonus Leach and the exophilic Ixodes ricinus (Linnaeus) (Ixodida: Ixodidae) on the Northern white‐breasted hedgehog, Erinaceus roumanicus (Erinaceomorpha: Erinaceidae), was investigated during a 4‐year study in residential areas of the city of Poznań, west‐central Poland. Of 341 hedgehogs, 303 (88.9%) hosted 10 061 Ixodes spp. ticks encompassing all parasitic life stages (larvae, nymphs, females). Ixodes hexagonus accounted for 73% and I. ricinus for 27% of the collected ticks. Male hedgehogs carried significantly higher tick burdens than females. Analyses of seasonal prevalence and abundance of I. hexagonus revealed relatively stable levels of infestation of all parasitic stages, with a modest summer peak in tick abundance noted only on male hosts. By contrast, I. ricinus females and nymphs peaked in spring and declined steadily thereafter in summer and autumn, whereas the less abundant larvae peaked in summer. This is the first longterm study to evaluate the seasonal dynamics of both tick species on populations of wild hedgehogs inhabiting urban residential areas. 相似文献
5.
Ixodes ricinus (Acari: Ixodidae) L. transmit a wide variety of pathogens to vertebrates including viruses, bacteria and protozoa. Understanding of the epidemiology of tick‐borne infections requires basic knowledge of the regional and local factors influencing tick population dynamics. The present study describes the results of monitoring of a questing I. ricinus population, conducted over 35 years (1977–2011) in the eastern, poorly studied part of its range (Russia, Tula region). We have found that the multiannual average abundance of ticks is small and varies depending on the biotope and degree of urban transformation. Tick abundance for the first 14 years of observations (1977–1990) was at the lower limit of the sensitivity of our methods throughout the study area (0.1–0.9 specimens per 1‐km transect). In the following 21 years (1991–2011), a manifold increase in abundance was observed, which reached 18.1 ± 1.8 individuals per 1‐km transect in moist floodplain terraces, and 4.8 ± 0.9 in xerophylic hill woods. Long‐term growth of tick abundance occurred in spite of a relatively constant abundance of small mammals and only minor fluctuations in the abundance of large wild animals. Climate and anthropogenic changes appear to be the main contributors to increased abundance of the tick. 相似文献
6.
Current concerns over the potential impacts of climate change and the increased movement between countries of people and companion animals on the distribution of ectoparasites, highlight the need for accurate understanding of existing prevalence patterns. Without these future changes will not be detected. Here, the distribution and prevalence of tick infestations of domestic dogs in Great Britain were examined. A total of 173 veterinary practices were recruited to monitor tick attachment to dogs in their local areas between March and October 2009. Practices selected five dogs at random each week from those brought to the surgery and undertook a thorough, standardized examination for ticks. Each veterinary practice participated for 3 months before being replaced. Any ticks identified were collected and a sample sent to the investigators for identification, along with a clinical history of the dog. A total of 3534 dogs were examined; 810 dogs were found to be carrying at least one tick. Ixodes ricinus (Linnaeus) (Acari: Ixodidae) was identified in 72.1% of cases, Ixodes hexagonus Leach in 21.7% and Ixodes canisuga Johnston in 5.6% of cases. Five samples of Dermacentor reticulatus (Fabricius) (Acari: Ixodidae) were also found, adding to the growing evidence that an established population of D. reticulatus now exists in south-eastern England. Almost all the ticks found were adults. Overall, 19.2% of the veterinary practices reported no tick detections, 50% reported that ≥14.9% of the dogs seen were infested and 14.6% reported that >50% of the dogs inspected carried ticks. The estimated incidence of tick attachment was 0.013 per day in March (lowest) and 0.096 per day in June (highest). A number of risk factors affected the likelihood of tick attachment on dogs. Gundog, terrier and pastoral breed groups were more likely to carry ticks, as were non-neutered dogs. Dogs with shorter hair were less likely to have ticks, and dogs were most likely to carry a tick in June. This study is of value because, unusually, it presents the results of a randomized sample of dogs and gives a prevalence which is higher than those previously recorded in Great Britain. 相似文献
7.
L. Gern;Z. Zhu;A. Aeschlimann 《Parasite (Paris, France)》2016,65(2):89-93
The development and modes of transmission of Borrelia burgdorferi during blood feeding of Ixodes ricinus were evaluated. Our results show that during the slow engorgement phase, the Lyme disease spirochete, B. burgdorferi ingested two hours before a blood meal or transmitted transstadially from the nymphs, multiplies in the midgut lumen of I. ricinus females. The deeper parts of the midgut diverticula appeared to be the preferred sites for this spirochete. In some gut-infected ticks, a few spirochetes can penetrate the midgut wall and induce a systemic infection, while the overwhelming majority of spirochetes persist in the midgut. Presence of B. burgdorferi in hemocoel, and in both acini and ducts of the salivary glands, leads us to suppose a salivary transmission of this spirochete by I. ricinus females.https://doi.org/10.1051/parasite/1990652089 相似文献
8.
Theophilus Yaw Alale;Jani J. Sormunen;Eero J. Vesterinen;Tero Klemola;K. Emily Knott;Miguel Baltazar-Soares; 《Ecology and evolution》2024,14(5):e11415
Identifying hybridization between common pathogen vectors is essential due to the major public health implications through risks associated with hybrid's enhanced pathogen transmission potential. The hard-ticks Ixodes ricinus and Ixodes persulcatus are the two most common vectors of tick-borne pathogens that affect human and animal health in Europe. Ixodes ricinus is a known native species in Finland with a well-known distribution, whereas I. persulcatus has expanded in range and abundance over the past 60 years, and currently it appears the most common tick species in certain areas in Finland. Here we used double-digest restriction site-associated DNA (ddRAD) sequencing on 186 ticks (morphologically identified as 92 I. ricinus, and 94 I. persulcatus) collected across Finland to investigate whether RAD generated single nucleotide polymorphisms (SNPs) can discriminate tick species and identify potential hybridization events. Two different clustering methods were used to assign specific species based on how they clustered and identified hybrids among them. We were able to discriminate between the two tick species and identified 11 putative hybrids with admixed genomic proportions ranging from approximately 24 to 76 percent. Four of these hybrids were morphologically identified as I. ricinus while the remaining seven were identified as I. persulcatus. Our results thus indicate that RAD SNPs are robust in identifying both species of the ticks as well as putative hybrids. These results further suggest ongoing hybridization between I. ricinus and I. persulcatus in their natural populations in Finland. The unique ability of RAD markers to discriminate between tick species and hybrids adds a useful aspect to tick evolutionary studies. Our findings align with previous studies and suggest a shared evolutionary history between the species, with instances of individuals possessing a considerable proportion of the other species' genome. This study is a significant step in understanding the formation of hybridization zones due to range expansion potentially associated with climate change. 相似文献
9.
Benjamin Cull Alexander G.C. Vaux Lisa J. Ottowell Emma L. Gillingham Jolyon M. Medlock 《Journal of vector ecology》2017,42(1):74-83
Tick infestations on small mammals were studied from April to November, 2010, in deciduous woodland in southern England in order to determine whether co‐infestations with tick stages occurred on small mammals, a key requirement for endemic transmission of tick‐borne encephalitis virus (TBEV). A total of 217 small mammals was trapped over 1,760 trap nights. Yellow‐necked mice (Apodemus flavicollis) made up the majority (52.5%) of animals, followed by wood mice (A. sylvaticus) 35.5% and bank voles (Myodes glareolus) 12%. A total of 970 ticks was collected from 169 infested animals; 96% of ticks were Ixodes ricinus and 3% I. trianguliceps. Over 98% of ticks were larval stages. Mean infestation intensities of I. ricinus were significantly higher on A. flavicollis (6.53 ± 0.67) than on A. sylvaticus (4.96 ± 0.92) and M. glareolus (3.25 ± 0.53). Infestations with I. ricinus were significantly higher in August than in any other month. Co‐infestations with I. ricinus nymphs and larvae were observed on six (3.6%) infested individuals, and fifteen small mammals (8.9%) supported I. ricinus – I. trianguliceps co‐infestations. This work contributes further to our understanding of European small mammal hosts that maintain tick populations and their associated pathogens, and indicates that co‐infestation of larvae and nymph ticks does occur in lowland UK. The possible implications for transmission of tick‐borne encephalitis virus between UK ticks and small mammals are discussed. 相似文献
10.
Estrada-Peña A Martinez JM Sanchez Acedo C Quilez J Del Cacho E 《Medical and veterinary entomology》2004,18(4):387-397
The abundance, seasonal activity patterns and development rates of the tick Ixodes ricinus (L.) (Acari: Ixodidae), as well as microclimate features of the site of study, are described for a 9-year-long study (1994-2002) in north-central Spain. According to drag captures, larvae had a unimodal activity pattern, with a maximum observed around July-August, whereas nymphs displayed a bimodal pattern (May-June and August-September) with strong dominance of spring activity. An inversion of this pattern, with larger autumn peak, was observed in years with humid summers. Adults showed a small spring peak and a large autumn one. In the later years of the study, a small increase in the adult spring peak of activity was noticed, correlated with mild winters. Over the entire period of study, a clear increase in the total tick abundance was detected. Statistically significant differences between years were observed for some climate variables (saturation deficit, winter temperatures and number of days with temperatures above 6 degrees C), but a consistent and constant pattern of change was not observed in any climate variable. Temperature requirements for developing stages showed a sharp decrease in weeks 35-51 (eggs) and 38-50 (larvae and nymphs), a feature attributed to the presence of the morphogenetic diapause, beginning around September. Development rates obtained under quasi-natural conditions were almost twice those reported for other sites, suggesting an adaptation of this local, largely isolated I. ricinus population. According to drag captures and field-obtained development rates, interchange of nymphs between the two cohorts is common in this site, and seems to be influenced by the winter temperature and the date of larval engorgement. 相似文献
11.
Gern L 《Parasite (Paris, France)》2008,15(3):244-247
In Europe, Borrelia burgdorferi sensu lato (sl) the agent of Lyme borreliosis circulates in endemic areas between Ixodes ricinus ticks and a large number of vertebrate hosts upon which ticks feed. Currently, at least 12 different Borrelia species belonging to the complex B. burgdorferi sl have been identified among which seven have been detected in I. ricinus: B. burgdorferi sensu stricto (ss), B. garinii, B. afzelii, B. valaisiana, B. spielmanii and B. bissettii. A few dozens of vertebrate hosts have been identified as reservoirs for these Borrelia species. Specific associations were rather early observed between hosts, ticks and borrelia species, like for example between rodents and B. afzelii and B. burgdorferi ss, and between birds and B. garinii and B. valaisiana. The complement present in the blood of the hosts is the active component in the Borrelia host specificity. Recent studies confirmed trends toward specific association between Borrelia species and particular host, but also suggested that loose associations may be more frequent in transmission cycles in nature than previously thought. 相似文献
12.
The relationship between climate data and tick questing activity is crucial for estimation of the spatial and temporal distribution of the risk of ticks and tick‐borne diseases. This study establishes correlations between selected meteorological variables provided by the Weather Research and Forecasting model (WRF) and the questing activity of Ixodes ricinus nymphs and adults on a regional scale across Lower Silesia, Poland. Application of Generalized Linear Mixed Models (GLMM), built separately for adults and nymphs, showed that solar radiation, air temperature, and saturation deficit appeared to be the meteorological variables of prime importance, whereas the wind speed was less important. However, the effect of meteorological parameters was different for adults and nymphs. The adults are also more influenced by forest cover and the percentage of forest type if compared to nymphs. The WRF model providing meteorological variables separately for each location and day of tick sampling can be useful in studies of questing activity of ticks on a regional scale. 相似文献
13.
J.M. Medlock H. Shuttleworth V. Copley K.M. Hansford S. Leach 《Journal of vector ecology》2012,37(2):307-315
This paper presents preliminary findings towards developing a UK‐specific approach to reducing public exposure to woodland questing Ixodes ricinus tick populations by harnessing existing biodiversity‐enhancing woodland ride (i.e., linear non‐wooded herbaceous habitat either side of track within woodland) management strategies. This preliminary study in an English woodland firstly assesses whether ecological and environmental factors determine presence and density of questing Ixodes ricinus along woodland rides. Secondly, it sets these findings in the context of woodland ride management guidelines in England in order to understand what impact ride management strategies might have on numbers of questing ticks and tick survival. Nymph and adult I. ricinus presence and abundance were modelled in relation to relevant microclimate and ecological parameter variables. Predictor variables for increased questing nymph abundance included ride orientation, mat depth, occurrence of bracken/bramble and animal tracks, ride/path width, and sward height. Ticks thrive in the ecotonal habitat of a woodland ride, therefore we urge woodland managers to consider the impact of their ride management on ticks and human exposure to ticks. Possible recommendations for mitigating questing I. ricinus in line with biodiversity management guidelines rides are discussed in this paper and include seasonal mowing regimes, management of mulch/mat, and bracken/bramble management through use of scalloped ride edges. 相似文献
14.
M. Brossard;V. Papatheodorou 《Parasite (Paris, France)》2016,65(1):32-36
Rabbits have been infested 3 times with 10 females and 10 males Ixodes ricinus . Immunity which is acquired when ticks feed on naive rabbits (first infestation) perturbs tick feeding on reinfested animals (third infestation). Then ticks ingest less blood (p < 0.001). Blood meal digestion in also altered. It was estimated by measuring haemoglobin concentration in ixodid midgut during 20 days after their drop off. After the first infestation this concentration decreases linearly with time (r 1 2 p < 0.001). After 3 infestations it is no longer correlated with time, indicating an impaired digestive process (r 2 3 p > 0.05).This observation was corroborated by an analysis of multiple regression. Haemoglobin concentration of tick midgut only correlates with time after a first infestation (r 2 1 r 2 3
15.
A. Paulauskas E. Galdikaitė‐Brazienė J. Radzijevskaja A. Aleksandravičienė M. Galdikas 《Journal of vector ecology》2016,41(2):244-253
Ixodes ricinus (Linnaeus 1758) and Ixodes persulcatus (Schulze 1930) ticks are involved in the transmission of a wide variety of pathogens with considerable impact on human and animal health. The co‐distribution zone of these two tick species is situated in the Baltic countries, which provides a special setting for the population studies. In the present study, genetic variability of I. ricinus ticks collected in allopatric and sympatric locations in the Baltic countries has been investigated using a sequence analysis of the mitochondrial DNA control region, 16S rRNA and cytb genes. There were 32 haplotypes (Hd: 0.8551) and 27 haplotypes (Hd:0.8213) of control region sequences from ticks in allopatric and sympatric zones detected, respectively. Out of 47 16S rRNA gene haplotypes, 32 haplotypes (Hd: 0.7213) were found in the allopatric zone and 27 (Hd:0.9572) in the sympatric zone. The Cytb gene was very conserved and monomorphic in ticks from the allopatric zone, whereas three unique haplotypes were observed in the sympatric zone. The higher number of unique haplotypes of the control region was detected in the allopatric zone. Median joining network and Fst analysis did not reveal a clear separation between ticks from the two zones. 相似文献
16.
A total of 305 Ixodes ricinus ticks (243 nymphs and 62 adults) were collected from three different regions of Thuringia in Middle Germany which are known to be endemic for Borrelia burgdorferi. Our aim was to investigate the carrier rate of ticks for granulocytic Ehrlichia species. The presence of ehrlichial 16S ribosomal DNA was investigated by polymerase chain reaction. Using primers specific for the Ehrlichia phagocytophila group PCR fragments of 151 bp and 943 bp, respectively, were produced in positive samples. Adult ticks showed a significantly higher infection rate (4/62; 6.5%) compared to nymphs (3/243; 1.2%). Prevalence rates varied between 0 and 3.8% regarding the different areas under investigation. The nucleotide sequences showed high similarity (between 97.5% and 99% identity) to the known sequences of the three E. phagocytophila group members HGE agent, E. phagocytophila and Ehrlichia equi. The sequence data did not allow a final classification to a particular member of this group. 相似文献
17.
Five calves were given an intraruminal bolus orally, designed to release ivermectin for 120 days at the rate of 8 mg/day. This is equivalent to a dose of 40 micrograms/kg/day for a calf expected to weigh 200 kg at the end of the delivery period. Five control calves were given a placebo bolus. On days 7 and 36 after treatment ten nymphs and ten adult female Ixodes ricinus (Linnaeus 1758) were placed in ear bags on the calves. The engorgement rates were monitored for 10 days and subsequent egg production and hatching percentages determined. There were no significant differences between treatment groups for female mortality. However, ivermectin treatment significantly reduced the numbers and weights of engorged females, females laying eggs, and the number of larvae produced on the treated calves was reduced to 3% of that of the control group. The effects on nymphs, although similar, were less consistent than on adults. 相似文献
18.
A. M. PALOMAR A. PORTILLO P. SANTIBÁÑEZ D. MAZUELAS L. RONCERO L. GARCÍA‐ÁLVAREZ S. SANTIBÁÑEZ Ó. GUTIÉRREZ J. A. OTEO 《Medical and veterinary entomology》2015,29(3):349-353
The genus Anaplasma (Rickettsiales: Anaplasmataceae) includes species of medical and veterinary importance. The presence of Anaplasma spp. in ticks from birds, as well as in Haemaphysalis punctata (Ixodida: Ixodidae) specimens collected from cattle and vegetation in northern Spain was investigated. A total of 336 ticks from birds [174 Ixodes frontalis (Ixodida: Ixodidae), 108 H. punctata, 34 Hyalomma marginatum (Ixodida: Ixodidae), 17 Ixodes ricinus (Ixodida: Ixodidae) and three Ixodes spp.], and 181 H. punctata specimens collected from cattle (n = 71) and vegetation (n = 110) were analysed. Anaplasma bovis was detected in five H. punctata, including two from birds (1.9%) and three from vegetation (2.7%). Four I. frontalis (2.3%) (one co‐infected with ‘Candidatus Midichloria mitochondrii’) and one I. ricinus (5.9%) removed from birds, as well as four H. punctata (5.6%) collected from cattle showed Anaplasma phagocytophilum infection. In addition, Anaplasma centrale was found in two H. punctata, one from a cow (1.4%) and the other from vegetation (0.9%). This study represents the first evidence of the presence of A. bovis in European ticks, and reports the first detection of A. bovis and A. centrale in H. punctata, and the first finding of A. phagocytophilum and ‘Ca. Midichloria mitochondrii’ in I. frontalis. 相似文献
19.
The spatial aggregation of ticks feeding on vertebrate hosts has been recognized for some time but, for hosts supporting more than one stage of the tick, observations of interstadial variation in the site of attachment have not previously been quantified. This study showed that all three parasitic stages of Ixodes ricinus ticks feeding on sheep attach most commonly to the hair-covered areas of the head and limbs while few ticks attach to the fleeced region of the body. However, significant differences were observed in the site of attachment of the three feeding stages of the tick. Larvae attached to distal limbs and rostral areas of the head and adult females attached to the proximal areas of the limbs and around the neck and ears, while nymphs attached in locations between the larvae and adults. The importance of the spatial aggregation of the ticks and interstadial variation in their distribution on the host, for the transmission of tick-borne pathogens and the epidemiology of the diseases they cause, is discussed. © Rapid Science Ltd. 1998 相似文献
20.
Ogden NH Cripps P Davison CC Owen G Parry JM Timms BJ Forbes AB 《Medical and veterinary entomology》2000,14(3):332-338
The species of ixodid ticks, attached to dogs and cats presented to veterinary practices in Great Britain and Ireland were identified. Most host animals carried only one tick species with Ixodes ricinus Linné (Acari: Ixodidae) being the most common, identified on 52% of animals, Ixodes hexagonus Leach (Acari: Ixodidae) the second most common (on 39%) and Ixodes canisuga Johnston (Acari: Ixodidae) the third most common (on 11%). A significantly higher proportion of dogs than cats carried I. ricinus, while I. hexagonus was more frequently carried by cats. One animal carried a single specimen of Haemaphysalis punctata Canestrini & Fanzago (Acari: Ixodidae), one carried a Dermacentor reticulatus Fabricius (Acari: Ixodidae) but none carried Rhipicephalus sanguineus Latreille (Acari: Ixodidae). This indicates that the latter two species, vectors of 'exotic' tick-borne diseases, remain at low densities in Great Britain and Ireland. Retrospective information on exposure of the animals to different habitats and geographic regions was collected by questionnaire and subject to contingency table and logistic regression analysis. Woodlands and moorlands were habitats significantly associated with I. ricinus attachment. Exposure to urban parks was significantly associated with I. hexagonus attachment and exposure to boarding kennels and catteries was significantly associated with I. canisuga attachment. Ixodes hexagonus, rather than I. ricinus, was the ixodid tick species most likely to be encountered by urban populations of dogs and cats and, by inference, possibly also humans. The implications of these findings, for the transmission of tick-borne pathogens to dogs, cats and humans are discussed. 相似文献