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Haemaphysalis punctata is a three-host tick with a natural life cycle of 1–3 years (Nosek et al. in Bulletin of the World Health Organization, 36:49–59, 1967; Nosek in Zeitschrift fur Parasitenk, 37:198–210, 1971; Liebisch et al. in Berliner und Munchener Tierarztliche Wochenschrift, 89:477–480, 1976; Farkas et al. in Ticks and tick-borne diseases: geographical distribution and control strategies in the Euro-Asian region, CABI, Boston, pp 6–26, 2012).

Rhipicephalus guilhoni is a three-host tick; the life cycle of which takes a year to complete. It has been recorded from a variety of hosts including domestic animals, mostly cattle and sheep, but also dogs and cats, and wild animals including carnivores, insectivores, artiodactyls, perissodactyls, lagomorphs, rodents and non-passerine birds. This species has also been recorded from humans.

The genus Dermacentor is a representative of the Nearctic, Palaearctic, Asian and Afrotropical tick fauna. Around 14 species of the genus are found in the Palaearctic region, but only two are present in the Western Palaearctic. General works on the genus include Filippova and Panova (1986, 1989) and Filippova et al. (1985).

Haemaphysalis Koch, 1844, is a widely distributed genus of ticks with 167 accepted species recognized worldwide (Guglielmone et al. in The hard ticks of the world (Acari: Ixodida: Ixodidae). Springer, Heidelberg, p 738, 2014). The larvae, nymphs and at least one adult stage are described for only 98 (59%) of all the known species. Nevertheless, most parasitic stages of species within the Palaearctic are known (Guglielmone et al. in The hard ticks of the world (Acari: Ixodida: Ixodidae). Springer, Heidelberg, p 738, 2014).

There is some confusion concerning records of Ixodes ventalloi and Ixodes festai (Petney et al. in Appl Parasitol 37:96–98, 1996; Guglielmone et al. in The hard ticks of the world. Springer, Heidelberg, 2014). Because of this diagnostic uncertainty, no references published before Gilot and Perez (1978) will be used here.

Hyalomma aegyptium is a three-host tick (Siroký et al. in Exp Appl Acarol 40:279–90, 2006). Under laboratory conditions, the life cycle is completed within 147 days (Siroký et al. in Exp Appl Acarol 54:277–84, 2011). Although tortoises (Testudinidae, mainly genus Testudo) are the dominant hosts for all of the developmental stages, a wide variety of other hosts are known, including cattle, deer, wild pigs, horses, camels, dogs, hedgehogs, hares, rodents, birds and lizards (Hoogstraal and Kaiser in Ann Entomol Soc Am 53:457–458, 1960; Apanaskevich in Parazitologiia 37:47–59, 2003).

The life cycle of Ixodes trianguliceps may last from 2 to 5 years, depending on the climatic conditions (Balashov in Entomol Rev 76:625–637, 1997).

Ixodes frontalis is an exophilic, three-host tick with a life-cycle of 1 year in its natural environment.

Haemaphysalis concinna is a three-host tick the life cycle of which can be completed within 3 years under natural conditions (Nosek in Z Parasitenkd 36:233–241, 1971).

There are a total of 59 species of ticks in this genus, grouped into about 9 subgenera, that have been reported from the Palaearctic region (Guglielmone et al. 2014).

This study reports the results of a comparative test of identification of ticks occurring in Western Europe and Northern Africa. A total of 14 laboratories were voluntarily enrolled in the test. Each participant received between 22 and 25 specimens of adult and nymphal ticks of 11 species: Dermacentor marginatus, D. reticulatus, Haemaphysalis punctata, Hyalomma lusitanicum, Hy. marginatum, Ixodes ricinus, I. hexagonus, Rhipicephalus annulatus, R. bursa, R. rossicus, and/or R. sanguineus s.l. Ticks were morphologically identified by three of the co-authors and the identification confirmed by a fourth co-author who used molecular methods based on several genes. Then ticks were randomly selected and blindly distributed among participants, together with a questionnaire. Only specimens collected while questing and, if possible, in the same survey, were circulated. Because of the random nature of the test, a participant could receive several specimens of the same species. Species in the different genera had variable misidentification rates (MR) of 7% (Dermacentor), 14% (Ixodes), 19% (Haemaphysalis), 36% (Hyalomma), and 54% (Rhipicephalus). Within genera, the MR was also variable ranging from 5.4% for I. ricinus or 7.4% for D. marginatus or D. reticulatus to 100% for R. rossicus. The test provided a total misidentification rate of 29.6% of the species of ticks. There are no significant differences in MR according to the sex of the tick. Participants were requested to perform a second round of identifications on the same set of ticks, using only purposely prepared keys (without illustrations), circulated to the enrolled participants, including 2 species of the genus Dermacentor, 8 of Haemaphysalis, 10 of Hyalomma, 23 of Ixodes, and 6 of Rhipicephalus. The average MR in the second round was 28%: 0% (Dermacentor), 33% (Haemaphysalis), 30% (Hyalomma) 18% (Ixodes), and 50% (Rhipicephalus). Species which are not reported in the countries of a participating laboratory had always highest MR, i.e. purely Mediterranean species had highest MR by laboratories in Central and Northern Europe. Participants expressed their concerns about a correct identification for almost 50% of the ticks of the genera Hyalomma and Rhipicephalus. The results revealed less than total confidence in identifying the most prominent species of ticks in the Western Palearctic, and underpin the need for reference libraries for specialists involved in this task. Results also showed that a combination of certain genes may adequately identify the target species of ticks. This study has been carried out under the umbrella of the European COST Action TD1303, “EurNegVec”. info:eu-repo/semantics/publishedVersion

There is currently a discussion as to whether the eastern Palaearctic tick Ixodes redikoverzi Olenev, 1927 is a synonym of Ixodes acuminatus.

This is considered to be a polytypic species containing a number of morphologically definable subspecies: Haemaphysalis erinacei erinacei Pavesi, 1844, Haemaphysalis erinacei taurica Pospelova-Schtom 1940 and Hae. e. turanica Pospelova-Schtom 1940.

To date, almost 900 species of ticks have been described. The three existing families consist of the Argasidae (soft ticks; ca. 191 species), the Ixodidae (hard ticks; ca. 702 species) and the Nuttalliellidae with only one species (Nuttalliella namaqua). They transmit more pathogen species to humans, livestock, companion animals and wildlife than any other blood-sucking arthropod species. However, research focuses predominantly on the most abundant tick species, such as Ixodes ricinus in Europe, Ixodes scapularis in the USA or Rhipicephalus sanguineus s.l. worldwide, and their role in the transmission of diseases. For most other less abundant tick species, information on the biology, ecology and vector capability is rare, as described in the present book. However, tick species that are not a direct threat to humans or animals can still be important for the maintenance of enzootic cycles for different pathogens. Therefore, to understand the eco-epidemiology of various diseases, it is essential to study the interactions between ticks, their hosts, the pathogens and their biotic and abiotic environment. In order to achieve such an understanding, collecting ticks is necessary. The type of collection, as well as the quality of results, depends on the host-seeking behaviour, the life history stages and the natural habitat of the ticks.

To date, there are eight species of the genus Rhipicephalus known from the Western Palaearctic, namely, R. guilhoni Morel and Vassiliades, 1963 (so far only from the Canary Islands, probably introduced); R. camicasi Morel, Mouchet, and Rodhain, 1976 (so far only in Egypt); R. sanguineus s.l.; R. turanicus Pomerantzev, 1940; R. pusillus Gil Collado, 1936; R. rossicus Yakima and Kohl-Yakimova, 1911; and R. bursa Canestrini and Fanzago, 1878. The eighth species is R. annulatus Say, 1821, which was formerly included in the genus Boophilus.

Argas polonicus is a parasite of rock pigeons (Columba livia). It was first found in Krakow, Poland, where trumpeters of St. Mary’s Church were frequently bitten by this tick when their hosts were driven from their resting places. Molecular and biochemical tests based on cuticular hydrocarbon composition supported the early morphological observations reporting this tick as a new species.

Only limited information is available on this species. Other than some records used in its original description, only a few data on its distribution are available. It is an argasid which has some peculiar morphological features, as described by Hoogstraal (1957). The larva has peritremes, a kind of elongated structure on the lateral and ventral sides of the idiosome, which are related to air exchange. These are most similar to those found in predatory and free-living mesostigmatid mites. This unusual feature, plus others found in the adult stage, provided enough background to create the subgenus Secretargas.

Hoogstraal (1958) and Filippova (1966) provide detailed descriptions of the morphology of the different stages of A. vespertilionis.

Hyalomma dromedarii has been recorded as a one-, two- or three-host species, although the two-host life cycle is thought to be the most common with attached larvae detaching as engorged nymphs.

The crucial steps in biological invasions, related to the shaping of genetic architecture and the current evolution of adaptations to a novel environment, usually occur in small populations during the phases of introduction and establishment. However, these processes are difficult to track in nature due to invasion lag, large geographic and temporal scales compared with human observation capabilities, the frequent depletion of genetic variance, admixture and other phenomena. In this study, we compared genetic and historical evidence related to the invasion of the West European hedgehog to New Zealand to infer details about the introduction and establishment. Historical information indicates that the species was initially established on the South Island. A molecular assay of populations from Great Britain and New Zealand using mitochondrial sequences and nuclear microsatellite loci was performed based on a set of analyses including approximate Bayesian computation, a powerful approach for disentangling complex population demographies. According to these analyses, the population of the North Island was most similar to that of the native area and showed greatest reduction in genetic variation caused by founder demography and/or drift. This evidence indicated the location of the establishment phase. The hypothesis was corroborated by data on climate and urbanization. We discuss the contrasting results obtained by the molecular and historical approaches in the light of their different explanatory power and the possible biases influencing the description of particular aspects of invasions, and we advocate the integration of the two types of approaches in invasion biology.

We aim to produce a review of the most important literature references necessary for the identification of ticks of the families Ixodidae and Argasidae in Europe and northern Africa (i.e. the Western Palaearctic region). The purpose of this paper is to pinpoint a set of critically selected papers that contain reliable information on morphology, taxonomic keys, and comparative discussions which are critical for the identification of the ticks reported in the target region. When necessary, comments are provided on the systematic position of a species, or on suitable papers already addressing the issue. This review includes a list of 216 references which cover all Ixodoidea species reported as permanent residents of the Western Palaearctic, namely 28 species of the genus Ixodes, two Dermacentor, seven Haemaphysalis, nine Hyalomma, eight Rhipicephalus, five Argas and about seven species of Ornithodoros.

In order to determine whether European hedgehogs ( Erinaceus europaeus and E. roumanicus ) play a role in the epidemiological cycle of Borrelia burgdorferi sensu lato in Central Europe and Great Britain, tissue samples of hedgehogs from Germany ( n = 211), Austria ( n = 4), the Czech Republic ( n = 22), and the UK ( n = 32) were tested for the presence of these tick-borne pathogens. PCR for amplification of the B. burgdorferi s.l.-specific 5S-23S intergenic spacer region as well as the outer surface protein A ( ospA ) gene were used. B. burgdorferi s.l. DNA was detected in 35 of the 259 E. europaeus and in 2 of 10 E. roumanicus . B. burgdorferi prevalences in E. europaeus ranged from 0% (UK) to 37.5% (Czech Republic), for E. roumanicus from 0% (Czech Republic) to 50.0% (Austria). Sequencing revealed the occurrence of 3 different B. burgdorferi genospecies in E. europaeus : B. afzelii was the dominant genospecies, followed by B. bavariensis (previously B. garinii OspA serotype 4) and B. spielmanii , the latter was detected for the first time in Hamburg (Germany). B. afzelii and B. bavariensis were also found in E. roumanicus. Our results suggest that hedgehogs modulate the epidemiology of certain species of the B. burgdorferi s.l. complex, potentially affecting the distribution and abundance of individual B. burgdorferi s.l. genospecies in various habitats. We hypothesise that juvenile or individuals with low immune competence in particular, have a high reservoir potential for the 3 genospecies identified here.

During an examination of the acanthocephalan fauna of the European hedgehog, Erinaceus europaeus Linneaus, from Auckland, New Zealand a single late stage acanthella of a putative species of Polymorphus (Polymorphidae) was found. The proboscis armature of the species differed from all congeners thus far described. The infection appeared to be an occasional infection of the hedgehog by a polymorphid whose normal definitive host has yet to be determined, but may be a native New Zealand bird.

The palaeacanthocephalan Plagiorhynchus cylindraceus is a common intestinal parasite of passerine birds, which can also occur parenterally or in the intestinal tract of mammals, often as an invading species in many countries worldwide. In this survey, introduced hedgehogs (Erinaceus europaeus, n = 183) killed in New Zealand during a biocontrol campaign and conspecifics (n = 174) that had died in hedgehog rehabilitation centers in Germany and Britain were examined for this parasite. In New Zealand, P. cylindraceus is recorded for the first time here, in the vicinity of Auckland. In Europe, prevalences ranged from 4.2% up to 47.6%, while in New Zealand, only 1.6% (Auckland 7.9%). Most of the worms occurred inside the peritoneal cavity where they had partly degenerated. Since hedgehogs are seldom preyed upon in continental Europe but often become traffic victims, we hypothesize that the worms inside them, whether extra- or intraperitoneally, contribute to the abundance and persistence of the parasite by being ingested by scavenging birds. Accordingly, we consider P. cylindraceus as a "modern parasite" taking advantage of two aspects of global change: anthropogenic promoted transmission (road kills) and the transcontinental spread of infected intermediate and/or final hosts caused by humans.

Dermacentor reticulatus is widespread throughout Europe and is expanding its range in several European countries. It is associated with a number of different pathogens. Its role in the transmission of disease to humans is currently small; however, it might play an important role in the maintenance of pathogens in enzootic cycles. The ecology of D. reticulatus, especially of the immatures, is not well known. In this study, ticks from small mammals, caught in a capture-mark-release study between May 2012 and October 2014 in a unique woodland area close to Karlsruhe, Germany, were collected. The main host species trapped were the yellow-necked mouse (Apodemus flavicollis) and the bank vole (Myodes glareolus). Small mammal populations showed high variability in their density between the study years, which is probably due to harsh winter conditions in 2012/2013 and missing mast leading to high winter mortality. Larvae and nymphs of D. reticulatus were predominantly found in July and August, respectively, and the infestation rates among the different small mammal species suggest a host preference of D. reticulatus for M. glareolus.

Background The study describes the estimation of the spatial distribution of questing nymphal tick densities by investigating Ixodes ricinus in Southwest Germany as an example. The production of high-resolution maps of questing tick densities is an important key to quantify the risk of tick-borne diseases. Previous I. ricinus maps were based on quantitative as well as semi-quantitative categorisations of the tick density observed at study sites with different vegetation types or indices, all compiled on local scales. Here, a quantitative approach on the landscape scale is introduced. Methods During 2 years, 2013 and 2014, host-seeking ticks were collected each month at 25 sampling sites by flagging an area of 100 square meters. All tick stages were identified to species level to select nymphal ticks of I. ricinus, which were used to develop and calibrate Poisson regression models. The environmental variables height above sea level, temperature, relative humidity, saturation deficit and land cover classification were used as explanatory variables. Results The number of flagged nymphal tick densities range from zero (mountain site) to more than 1,000 nymphs/100 m2. Calibrating the Poisson regression models with these nymphal densities results in an explained variance of 72 % and a prediction error of 110 nymphs/100 m2 in 2013. Generally, nymphal densities (maximum 374 nymphs/100 m2), explained variance (46 %) and prediction error (61 nymphs/100 m2) were lower in 2014. The models were used to compile high-resolution maps with 0.5 km2 grid size for the study region of the German federal state Baden-Württemberg. The accuracy of the mapped tick densities was investigated by leave-one-out cross-validation resulting in root-mean-square-errors of 227 nymphs/100 m2 for 2013 and 104 nymphs/100 m2 for 2014. Conclusions The methodology introduced here may be applied to further tick species or extended to other study regions. Finally, the study is a first step towards the spatial estimation of tick-borne diseases in Central Europe. Electronic supplementary material The online version of this article (doi:10.1186/s12942-015-0015-7) contains supplementary material, which is available to authorized users.

Zecken und von Zecken ubertragene Krankheitserreger sind von groser Bedeutung fur die Gesundheit von Mensch und Tier. Uber die Faktoren, die die Verbreitung und Dynamik von Zecken beeinflussen, ist allerdings nur wenig bekannt. In einem vom Ministerium fur Umwelt, Klima und Energiewirtschaft Baden-Wurttemberg im Rahmen des Forderprogrammes BWPLUS finanzierten Projektes arbeiten daher Spezialisten aus verschiedenen Fachbereichen zusammen, um den Einfluss von Wetter, (Mikro-)Klima, Habitat, Landnutzung, menschlichen Eingriffen und der Populationsdynamik der Wirtstiere auf die Verbreitung und Dynamik von Zecken und den von ihnen ubertragenen Krankheitserregern in Baden-Wurttemberg zu untersuchen. Das Projekt ist in 4 Module unterteilt, die sich mit dem grosraumigen Verbreitungsmuster von Zecken in Baden-Wurttemberg (Modul 1), mit Detailstudien zu Zecken-Wirt-Pathogen-Interaktionen im Zusammenhang mit dem Bestandesklima (Modul 2) und mit dem Auftreten wichtiger, durch Zecken ubertragener Pathogene befassen (Modul 3). Das vierte Modul beinhaltet eine ubergreifende Analyse und Synthese aller Daten, um die relative Bedeutung der untersuchten Faktoren zu bestimmen und um damit ein Risikomodell zu entwickeln. Daruber hinaus wurden in den letzten Jahren intensive Versuche mit verschiedenen entomopathogenen Pilzen, Nematoden sowie mit einer parasitoiden Erzwespe durchgefuhrt. Ziel dieser Versuche war und ist es zu uberprufen, ob diese naturlichen Antagonisten eingesetzt werden konnen, um die Anzahl der Zecken im Freiland wirksam zu reduzieren.

Anaplasma phagocytophilum is a Gram-negative obligate intracellular bacterium that replicates in neutrophils. It is transmitted via tick-bite and causes febrile disease in humans and animals. Human granulocytic anaplasmosis is regarded as an emerging infectious disease in North America, Europe and Asia. However, although increasingly detected, it is still rare in Europe. Clinically apparent A. phagocytophilum infections in animals are mainly found in horses, dogs, cats, sheep and cattle. Evidence from cross-infection experiments that A. phagocytophilum isolates of distinct host origin are not uniformly infectious for heterologous hosts has led to several approaches of molecular strain characterization. Unfortunately, the results of these studies are not always easily comparable, because different gene regions and fragment lengths were investigated. Multilocus sequence typing is a widely accepted method for molecular characterization of bacteria. We here provide for the first time a universal typing method that is easily transferable between different laboratories. We validated our approach on an unprecedented large data set of almost 400 A. phagocytophilum strains from humans and animals mostly from Europe. The typability was 74% (284/383). One major clonal complex containing 177 strains was detected. However, 54% (49/90) of the sequence types were not part of a clonal complex indicating that the population structure of A. phagocytophilum is probably semiclonal. All strains from humans, dogs and horses from Europe belonged to the same clonal complex. As canine and equine granulocytic anaplasmosis occurs frequently in Europe, human granulocytic anaplasmosis is likely to be underdiagnosed in Europe. Further, wild boars and hedgehogs may serve as reservoir hosts of the disease in humans and domestic animals in Europe, because their strains belonged to the same clonal complex. In contrast, as they were only distantly related, roe deer, voles and shrews are unlikely to harbor A. phagocytophilum strains infectious for humans, domestic or farm animals.

The European hedgehog (Erinaceus europaeus) is a common wild mammal in Central Europe that shares habitats with humans in urban, peri-urban, and rural areas. Thus, this species may play a role in human contact with zoonotic diseases. Here we report the presence of the pathogen Anaplasma phagocytophilum in hedgehogs and their ticks in Germany.

Zoonotic diseases are major causes of infection related morbidity and mortality worldwide. Of the various arthropods capable of transmitting pathogens that cause such diseases to humans, ticks, which are vectors of more kinds of pathogens than any other group of invertebrate, have become an increasing focus of attention. This is particularly the case in the temperate northern hemisphere where they are a significant vector of human disease. Here, we provide an overview of the complex ecological systems defining the various epidemiological cycles of tick-borne diseases. We highlight the abiotic and biotic factors influencing the establishment and persistence of tick populations and their associated pathogens. Furthermore, we emphasize the dynamic nature of such systems, especially when they are under the influence of both small and large-scale anthropogenic changes to the environment. Although a great deal of work has been done on ticks and the diseases which they transmit, the very dynamism of the system means that new factors are continually arising which shift the epidemiological pattern within specific areas. We therefore consider that more detailed, long-term (i.e. at least 10 years), multidisciplinary studies need to be carried out to define why and how these pattern shifts take place and to determine their public health significance.

The role of wild mammals in the dissemination and maintenance of Rickettsia in nature is still under investigation. European hedgehogs (Erinaceus europaeus) are often heavily infested by tick and flea species that are known to harbor and transmit different Rickettsia spp. We investigated ixodid ticks sampled from European hedgehogs for the presence of Rickettsia. A total of 471 Ixodes ricinus and 755 I. hexagonus were collected from 26 German and 7 British European hedgehogs. These were tested by a genus-specific real-time PCR assay targeting the citrate synthase gene (gltA). The rickettsia minimum infection rate was 11.7% with an increase detected with each parasitic tick stage. No significant difference in Rickettsia prevalence in the 2 Ixodes species was detected. Using sequencing of partial ompB, Rickettsia helvetica was the only species identified. More than half of the hedgehogs carried Rickettsia-positive ticks. In addition, tissue samples from 2/5 hedgehogs (where tissue DNA was available) were PCR-positive. These results show that European hedgehogs are exposed to R. helvetica via infected ticks and might be involved in the natural transmission cycle of this Rickettsia species.

Ticks (Ixodida: Argasidae, Ixodidae) are the main arthropod vectors of disease in Central Europe, including Germany. One species, Ixodes ricinus , dominates the tick fauna throughout this area and, as such, is justifiably the most common species studied. However, this concentration on a single species has led to the neglect of a variety of other species, also often common on their wild hosts, and also involved in the natural, zoonotic cycles of disease. In this contribution we provide a checklist of the species currently known to occur in Germany. The information summarized under the endemic species includes general distribution, hosts, and basic ecology, as well as each species’ medical and veterinary significance. Our aim is to bring the diversity of species present to the attention of the research community in the hope that the more neglected species will also be integrated into epidemiological models of the tick-borne diseases present.

Ixodid ticks are the most important vectors of human pathogens and are significant vectors of animal pathogens in Europe. Evidence is accumulating that several tick species have extended their distributions, related at least in part to climate and habitat changes. With increasing anthropogenic modification of the environment, these distributional modifications are likely to continue, with the likelihood that tick-borne diseases will spread to new areas. We discuss those factors which are involved in the changing distributions of ixodid ticks and provide a list of possible invading species given potential changes in tick habitat.

During observation of an ambiguous Necker cube, our percept changes spontaneously although the external stimulus does not. An EEG paradigm allowing time-resolved EEG measurement during endogenous perceptual reversals recently revealed a chain of ERP correlates beginning with an early occipital positivity at around 130 ms (Reversal Positivity, "RP"). In order to better understand the functional role of this RP, we investigated its relation to the P100, which is spatiotemporally close, typically occurring 100 ms after onset of a visual stimulus at occipital electrodes. We compared the relation of the ERP amplitudes to varying sizes of ambiguous Necker cubes. The main results are: (1) The P100 amplitude increases monotonically with stimulus size but is independent of the participants' percept. (2) The RP, in contrast, is percept-related and largely unaffected by stimulus size. (3) A similar pattern to RP was found for reaction times: They depend on the percept but not on stimulus size. We speculate that the P100 reflects processing of elementary visual features, while the RP is related to a processing conflict during 3D interpretation that precedes a reversal. The present results indicate that low-level visual processing (related to stimulus size) and (relative) high-level processing (related to perceptual reversal) occur in close spatial and temporal vicinity.

The European hedgehog (Erinaceus europaeus) is a common insectivore in most parts of Europe and is frequently infested by the ticks Ixodes ricinus and I. hexagonus. I. ricinus ticks have been found infected with Anaplasma phagocytophilum, an obligate intracellular bacterium, but little is known about the potential of the hedgehog as a reservoir host. In this study, the infection with A. phagocytophilum and the genetic variants involved were investigated in a captive hedgehog population which was kept in a fenced, natural grass and bush garden habitat, and also in its ticks. Additionally hedgehogs from hedgehog caretaking stations were investigated. EDTA blood and ticks were collected from the captive hedgehog population once a month from March to October 2007 and in March and April 2008. All 3 developmental stages of I. ricinus and I. hexagonus occurred on the hedgehogs. After DNA extraction, the samples were screened for A. phagocytophilum with a real-time PCR, and selected samples were further investigated with a nested PCR targeting the partial 16S rRNA gene, followed by sequencing. One hundred thirty-six out of 220 hedgehog blood samples (61.8%) from altogether 48 individuals, 413 out of 563 I. ricinus samples and 90 out of 338 I. hexagonus samples were PCR-positive. Thirty-two hedgehogs were positive more than once, most frequently twice or 3 times, but also up to 9 times. Sequencing of the partial 16S rRNA gene resulted in 6 variants, but one variant ('A') was the most frequent which appeared in 93.8% of the positive hedgehogs. This variant (equaling Frankonia II, GenBank AF136712) has recently been reported from human, equine, and canine granulocytic anaplasmosis cases and thus, its specific association with hedgehogs is an important finding in the epidemiology of A. phagocytophilum in Europe. The high infection rate of both hedgehogs and ticks with A. phagocytophilum and the simultaneous infestation with 2 tick species of all developmental stages suggest that the hedgehog may be a suitable reservoir for at least some variants of A. phagocytophilum.

Although the population dynamics of the tick Ixodes ricinus are relatively well studied, those of other Western European tick species are largely unknown. Moreover, there is very little information related to the interactions between I. ricinus and other ticks. Such knowledge, however, is of special interest in respect to the epidemiology of tick-borne pathogens such as Borrelia spp. We compared the dynamics of the generalist I. ricinus with the nest-dwelling hedgehog specialist, I. hexagonus. Both species were collected from hedgehogs from a naturally infested experimental population between 2006 and 2008. Ticks were collected once a month from March to October from each hedgehog counted and the life history stage and species determined. All hedgehogs harboured both tick species. Nymphs, females and males of I. ricinus showed clear bimodal seasonal distributions with peaks in spring and autumn, while larvae peaked only in summer. The density of I. hexagonus life stages was low during the whole investigation period and seasonal fluctuations of population density were much weaker compared to I. ricinus. Nymphs and larvae showed comparatively little change in population size and no consistent period of peak density. Females showed a single peak in summer and males were found only occasionally on hedgehogs. We suggest density-dependent mechanisms regulating the population density of the specialist I. hexagonus but not of the generalist I. ricinus.

SUMMARYAlthough there is an increasing understanding of the role of parasites in their host dynamics, accurate, quantitative estimates of parasite caused morbidity in wild animals are rare. Here, we examine the possible impact of 2 tick species (Ixodes ricinus, I. hexagonus) on the condition of the European hedgehog (Erinaceus europaeus). For this, we tested for correlations between blood parameters of 36 adult hedgehogs from an experimental population enclosed in a natural habitat and their tick infestation over a period of 8 months (March–October 2007). We found correlations between the tick infestation and the concentration of red blood cells, haemoglobin, haematocrit, MCH, MCHC, thrombocytes, lymphocytes and neutrophils. These results indicate that ticks can induce anaemia in the hedgehog. The peripheral blood characteristics and the erythrocyte indices characterize this anaemia as haemorrhagic and regenerative. During the course of our study the hedgehogs of our population showed below normal mortality but morbidity was found to be high resulting from the blood loss caused by the feeding activity of the ticks.

A healthy ecosystem is sustainable, meaning that it has the ability to maintain its structure and functions over time. Past definitions concerning the health of an ecosystem included, among others, both the diversity and complexity of the system, meaning that a healthy ecosystem is a diverse one. In the last decade, researchers have started to focus more on the importance of biodiversity for the distribution and maintenance of diseases in ecosystems, and therefore the ecosystems' role for human health. Based on a vector-borne model of Lyme disease, it was claimed that with a higher biodiversity of non-reservoir hosts for a pathogen, transmission events and infection risk would become reduced, called the dilution effect. This was further adapted for other vector-borne and nonvector-borne diseases, providing evidence for both the absence and the presence of the dilution effect in the wild. Until now, there is still a large lack of knowledge about the mechanisms driving disease transmission in the wild. The aim of this review is to provide insight into disease systems that were studied in relation to biodiversity and disease transmission risk. Furthermore, we discuss methods and strategies which are necessary to improve our understanding of the impact of biodiversity on disease systems and to help fill the existing gaps in our current knowledge.

Since the publication of “An annotated checklist of the ticks of Germany” in 2012, the list now includes two additional ixodid species. Ixodes acuminatus is endemic in several countries bordering Germany. Sufficient specimens have now been found in southwestern Germany to show that this species is also native there. The other species, Ixodes inopinatus, has its main area of distribution in the western Mediterranean, and it is not yet clear whether the two females and one male found in Rhineland-Palatinate were accidental introductions or are part of a viable population.

A number of bird species are known to be involved in the transmission cycles of at least two Borrelia species in Europe. Recent evidence suggests that the European blackbird (Turdus merula) and song thrush (T. philomelos) are the dominant hosts in these cycles. Examination of a suburban garden used as a winter roosting site for the European starling, Sturnus vulgaris, revealed an extremely high density of Ixodes ricinus nymphs and adults of up to ca. 50 ticks/m2, suggesting that this common, flocking avian species could also be of major epidemiological significance. Sampling of microhabitats showed that the ticks had not accumulated under the bamboo roosting site but had moved predominantly to open grassy areas. Both adults and nymphs were found to be infected with Borrelia valaisiana and/or Borrelia garinii.