Diversity and seasonal patterns of ticks parasitizing wild birds in western Portugal

The diversity and abundance of questing ticks and ticks parasitizing birds was assessed during 1?year in two recreational forests in western Portugal, a suburban forest and an enclosed game area. The aim of this study was to assess the distribution and seasonality of tick species and to understand the role of bird species as hosts for ticks. Ixodes ricinus was the most abundant questing tick collected in the enclosed game area, whereas in the suburban forest, only three ticks were collected by blanket dragging. Tick species parasitizing birds included I. ricinus, I. frontalis, I. arboricola, I. acuminatus, Haemaphysalis punctata, Hyalomma marginatum and H. lusitanicum. This is the first record of I. arboricola in Portugal. Tick prevalence and intensity of infestation differed between study areas and was higher in birds from the game area where a large population of deer and wild boar may support tick populations. Ground and shrub dwelling bird species such as Turdus merula, Erithacus rubecula and Sylvia melanocephala were the most heavily parasitized by ticks, but the importance of different bird species as hosts of larvae and nymphs of I. ricinus and I. frontalis differed. Therefore, different bird species may contribute differently for tick population maintenance.     

Borrelia Burgdorferi Sensu Lato in Ixodes Ricinus Ticks and Rodents in a Recreational Park in South-Western Ireland

Ixodes ricinus ticks infected with Borrelia burgdorferi sensu lato were numerous on the edges of paths and roads in a recreational park in south-western Ireland. The abundance of ticks at different sites was related to the presence of deer, but a negative relationship was shown between tick abundance and tick infection rates. This is thought to be due to the deposition of large numbers of uninfected ticks by deer, which are apparently not good reservoir hosts of B. burgdorferi s.l. Blood meal analysis only detected deer DNA in uninfected nymphs. Reservoir competent rodents, Apodemus sylvaticus and Clethrionomys glareolus, were abundant at all sites and a high proportion of captured specimens were infested with larval ticks. However, very few rodents were infected with B. burgdorferi s.l. and none of the unfed infected nymphs analysed for the identity of their larval blood meal had fed on rodents. The spirochaetes detected in I. ricinus in the study area may be poorly adapted to rodents or are not transmitted readily because of the absence of nymphal infestation. The majority of spirochaetes in these ticks were apparently acquired from non-rodent hosts, such as birds.     

Granulocytic Ehrlichia infection in Ixodid ticks and mammals in woodlands and uplands of the U.K.

Abstract .The prevalence of infection with Ehrlichiae of the Ehrlichia phagocytophila genogroup (the granulocytic Ehrlichiae), in questing Ixodes ricinus ticks of U.K. upland and woodland habitats, was investigated by PCR. The prevalence of infection in the three feeding stages of I. ricinus indicated that granulocytic Ehrlichiae are transmitted transstadially with no, or inefficient, transovarial transmission. The presence of infected ticks in both habitats indicates that endemic cycles of granulocytic Ehrlichia (GE) infection are maintained by both domesticated sheep and by wild reservoirs, and coexist with endemic cycles of Borrelia burgdorferi infection. Moreover, demonstration, for the first time, of GE infection in engorged Ixodes trianguliceps ticks and blood collected from wild rodents, suggests that European wild rodents are competent reservoirs. GE infection prevalence in nymphal and adult I. ricinus was significantly greater in uplands than woodlands, which is consistent with ticks of all three feeding stages feeding on reservoir-competent sheep in uplands. In one woodland studied, pheasants are important hosts for nymphal I. ricinus but are incompetent or inefficient reservoirs, so reducing GE infection prevalence in I. ricinus ticks in this habitat. 16S rRNA sequences of GE from ticks of these U.K. habitats, showed a high degree of homology with those of granulocytic Ehrlichiae isolated from humans, but also showed some evidence of genetic diversity of granulocytic ehrlichiae in the U.K. The implications of these findings, for the taxonomy of granulocytic ehrlichiae and the potential for human infections to occur in the U.K., is discussed.     

Infestation of mammals by Ixodes ricinus ticks (Acari: Ixodidae) in south-central Sweden

Infestation by Ixodes ricinus ticks on rodents, hares and cervids was examined at Bogesund, 10 km north of Stockholm, in south-central Sweden during 1991-1994 and on varying hares (Lepus timidus) at Stora Karlso and Gotska Sandon in the Baltic Sea during 1992-1993. At Bogesund, there were great differences between two consecutive years in the number of I. ricinus larvae infesting bank voles (Clethrionomys glareolus). The seasonal pattern of infestation by I. ricinus larvae and nymphs on bank voles was unimodal in 1991, with peaks in June-July and bimodal in 1992, with peaks in June and August. Male bank voles, compared to females and older voles, compared to young voles, harboured greater numbers of I. ricinus ticks. Apodemus mice, compared to bank voles, harboured greater numbers of I. ricinus ticks. Ixodes ricinus larvae engorged on Apodemus mice were heavier than larvae engorged on bank voles and resulted in larger nymphs. However, there was no difference in the proportions of viable nymphs resulting from larvae engorged on mice or voles. The ranges in the numbers of I. ricinus ticks infesting individual hosts were 1-451 for rodents, 16-2374 for hares and 428-2072 for roe deer (Capreolus capreolus). These ranges of tick numbers are estimated to represent potential blood losses from individual hosts of approximately 0.2-65% for rodents, 0.2-13% for hares and 0.3-9.0% for roe deer. Within the populations of all host species examined, the distributions of all stages of I. ricinus were clumped, with most host individuals harbouring few ticks and only a few individuals harbouring many ticks. The data suggest that, even though a small proportion of tick hosts may be severely affected, the direct effects of feeding by I. ricinus are unlikely to play an important role on mammal population dynamics.     

Effect of host populations on the intensity of ticks and the prevalence of tick-borne pathogens: how to interpret the results of deer exclosure experiments

Deer are important blood hosts for feeding Ixodes ricinus ticks but they do not support transmission of many tick-borne pathogens, so acting as dead-end transmission hosts. Mathematical models show their role as tick amplifiers, but also suggest that they dilute pathogen transmission, thus reducing infection prevalence. Empirical evidence for this is conflicting: experimental plots with deer removal (i.e. deer exclosures) show that the effect depends on the size of the exclosure. Here we present simulations of dynamic models that take into account different tick stages, and several host species (e.g. rodents) that may move to and from deer exclosures; models were calibrated with respect to Ixodes ricinus ticks and tick-borne encephalitis (TBE) in Trentino (northern Italy). Results show that in small exclosures, the density of rodent-feeding ticks may be higher inside than outside, whereas in large exclosures, a reduction of such tick density may be reached. Similarly, TBE prevalence in rodents decreases in large exclosures and may be slightly higher in small exclosures than outside them. The density of infected questing nymphs inside small exclosures can be much higher, in our numerical example almost twice as large as that outside, leading to potential TBE infection risk hotspots.     

Prevalence of the Lyme disease spirochete in populations of white-tailed deer and white-footed mice

The prevalence of the Ixodes dammini spirochete (IDS) in white-tailed deer (Odocoileus virginianus) and white-footed mice (Peromyscus leucopus) was studied on the eastern end of Long Island, New York. Both species commonly occur in a variety of habitats, are preferred hosts of Ixodes dammini, and can harbor the spirochetes in the blood. Each animal was examined for spirochetemia, tick infestation, and IDS infection rates in the ticks that were removed from it. The results obtained suggest that in winter deer can be infected by questing adult I. dammini. Adult ticks apparently are infected through transtadial transmission of spirochetes from subadult ticks which had fed earlier in their life history on infected animals. Deer are important hosts of adult ticks and the IDS in winter and probably are a reservoir host in other seasons. The patterns of spirochete prevalence suggest that deer and mice are reservoirs of the organism and thus are fundamental to the ecology of Lyme disease on Long Island.     

Ixodes ricinus, transmitted diseases and reservoirs

The tick Ixodes ricinus has been recorded in most Italian regions especially in thermo-mesophilous woods and shrubby habitats where the relative humidity allow the tick to complete its 3 year developmental cycle, as predicted for the European climatic ranges. This tick acts both as vector and reservoir for a series of wildlife zoonotic pathogens, especially the agents of Lyme diseases, Tick borne encephalitis and Human Granulocytic Ehrlichiosis, which are emerging in most of Europe. To assess the spatial distribution of these pathogens and the infection risk for humans and animals within the territory of the Province of Trento, we carried out a long term study using a combination of eco-epidemiological surveys and mathematical modelling. An extensive tick collection with a GIS based habitat suitability analysis allowed us to identify the areas where tick occurs at various density. To identify the areas with higher infection risk, we estimated the values of R0 for Borrelia burgdorferi s.l., TBE virus and Anaplasma phagocytophila under different ecological conditions. We assessed the infection prevalence in the vector and in the wildlife reservoir species that play a central role in the persistence of these infections, ie the small mammals A. flavicollis and C. glareolus. We also considered the double effect of roe deer (Capreolus capreolus) which act as reservoir for A. phagocytophila but is an incompetent host for B. burgdorferi and TBE virus, thus reducing the infection prevalence in ticks of these last two pathogens. Infection prevalence with B. burgdorferi and A. phagocytophila in the vector was assessed by PCR screening 1212 I. ricinus nymphs collected by dragging in six main study areas during 2002. The mean infection prevalence recorded was 1.32% for B. burgdorferi s.l. and 9.84% for A. phagocytophila. Infection prevalence in nymphs with TBE virus, as assessed in a previous study was 0.03%. Infection prevalence in rodents was assessed by screening (with ELISA and PCR) tissues and blood samples collected from 367 rodent individuals trapped extensively during 2002 within 6 main study areas. A. flavicollis (N=238) was found to be infected with all three pathogens investigated, with infection prevalence ranging from 3.3% for TBE virus to 11.7% for A. phagocytophila, and 16.6% with B. burgdorferi s.l. C. glareolus (N=108) showed an infection prevalence of 6.5% with A. phagocytophila and 12.7% with B. burgdorferi s.l., while no individuals were infected with TBE virus. We also screened 98 spleen samples collected from roe deer with PCR, resulting in a mean prevalence of infection with A. phagocytophila of 19.8%. Using a deterministic model we explored the condition for diseases persistence under different rodent and roe deer densities. R0 values resulted largely above 1 for B. burgdorferi s.l. in the vast majority of the areas classified as suitable for I. ricinus occurrence in Trentino, while the condition for TBE persistence appeared to be more restricted by a combination of climatic condition and host densities.     

Do the level of energy reserves, hydration status and Borrelia infection influence walking by Ixodes ricinus (Acari: Ixodidae) ticks?

Ixodes ricinus horizontal movement within a humidity gradient and the influence of infection by Borrelia burgdorferi sensu lato (s.l.) on tick walking were investigated. Nymphs were placed within an arena containing a humidity gradient ranging from 45 to 95% relative humidity (RH). After 1 h of acclimation at 70% RH ticks were released so that they could either stay, or walk towards either the wet or the dry end. Their position was recorded 2 h post-release. Fat content was quantified and Borrelia infection was detected using real-time PCR and PCR followed by Reverse Line Blotting. Among the 1500 ticks tested, 29·85% were infected. More low-fat nymphs walked inside the arena than high-fat individuals. When nymphs walked, more low-fat ticks walked towards wetter than drier air, whereas more high-fat individuals walked towards drier than wetter air. Among high-fat nymphs, a lower proportion of Borrelia-infected ticks walked inside the arena compared to uninfected individuals, as though spirochetes manipulated their arthropod vector to stay. However, Borrelia infection had no effect on walking direction towards the dry or the wet end. Hence, it appears that I. ricinus nymphs walk horizontally over short distances within a humidity gradient depending on both energy resources and Borrelia infection.     

Ehrlichiosis in a moose calf in Norway

A case of granulocytic ehrlichiosis in a moose calf (Alces alces) in Norway is described. The animal was heavily infested with ticks (Ixodes ricinus), and died from a Klebsiella pneumoniae septicemia. Examination of blood smears from the calf revealed cytoplasmic inclusions (morulae) typical of infection with Ehrlichia phagocytophila in the granulocytes. Ehrlichia sp. was detected by polymerase chain reaction (PCR) in blood from the calf, and in the ticks. Sequence determination identified it as E. phagocytophila. This is the first report of ehrlichiosis in moose.     

The abundance of Ixodes ricinus ticks depends on tree species composition and shrub cover

SUMMARY The mainstream forestry policy in many European countries is to convert coniferous plantations into (semi-natural) deciduous woodlands. However, woodlands are the main habitat for Ixodes ricinus ticks. Therefore, assessing to what extent tick abundance and infection with Borrelia spirochetes are affected by forest composition and structure is a prerequisite for effective prevention of Lyme borreliosis. We selected a total of 25 pine and oak stands, both with and without an abundant shrub layer, in northern Belgium and estimated tick abundance between April and October 2008-2010. Additionally, the presence of deer beds was used as an indicator of relative deer habitat use. Borrelia infections in questing nymphs were determined by polymerase chain reactions. The abundance of larvae, nymphs, and adults was higher in oak stands compared to pine stands and increased with increasing shrub cover, most likely due to differences in habitat use by the ticks' main hosts. Whereas tick abundance was markedly higher in structure-rich oak stands compared to homogeneous pine stands, the Borrelia infection rates in nymphs did not differ significantly. Our results indicate that conversion towards structure-rich deciduous forests might create more suitable tick habitats, but we were unable to detect an effect on the infection rate.     

Molecular cloning and characterization of a cDNA encoding cellobiose dehydrogenase from the wood-rotting fungus Grifola frondosa

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.     

Tick-borne encephalitis virus in northern Italy: molecular analysis, relationships with density and seasonal dynamics of Ixodes ricinus

Ixodes ricinus ticks were collected from dragging vegetation and from shot roe deer in the province of Trento and Belluno in northern Italy. Ticks were pooled for analyses and from 1060 pools of ticks collected in the province of Belluno and 12390 tick samples collected in Trentino, four proved positive by immunofluorescence microscopy using a tick-borne encephalitis (TBE)-specific antiserum. The identity of the virus isolates was determined by RT-PCR cycle sequencing and they were all found to be closely similar (> 98% nucleotide identity) to typical western European TBE complex viruses as found in Austria. The isolates from Trentino differed from the Neudorfl strain of western European TBE virus at eight nucleotide positions but as these nucleotide substitutions were all synonymous, there were no amino acid changes. These results imply that the virus isolates in Trentino have changed slightly from the typical European strains isolated in nearby Austria. The abundance of questing ticks and ticks feeding on roe deer was greater in TBE positive hunting districts than in hunting districts where TBE complex viruses were only probable or believed to be absent. In TBE positive and probable districts synchrony in the seasonal dynamics of larvae and nymphs of L. ricinus was observed. This study provides evidence to suggest that roe deer may have an important role to play in the maintenance of tick density and in the persistence of TBE virus.     

Density of Ixodes scapularis ticks on Monhegan Island after complete deer removal: A question of avian importation?

Questing adult blacklegged tick (Ixodes scapularis Say) abundance declined markedly three years after the 1999 removal of white‐tailed deer (Odocoileus virginianus Zimmermann) from Monhegan Island, ME. Since 2000, subadult ticks have not been found on Norway rats (Rattus norvegicus Berkenhout); questing nymphs have not been found since 2002. This suggested I. scapularis was reintroduced annually via bird importation of subadult ticks, but unable to complete its two‐year life cycle on the island due to lack of deer. To investigate this, we used uncertainty analysis to estimate 1) questing adult ticks/ha that would result from avian importation of nymphs, and 2) questing adult ticks/ha on Monhegan Island, using bird capture and tick burden data from Appledore Island, ME, flagged tick data from Monhegan Island, and ten uncertain parameters. During the deer‐fed period (1990–2001), estimated tick density on Monhegan Island was 18 times greater than that of imported ticks. During the post‐deer‐fed period (2002–2008), Monhegan Island tick density was equivalent to imported tick density. This supported the premise that all I. scapularis ticks on Monhegan Island have been bird‐derived since 2002.     

Autochthonous and migratory birds as a dispersion source for Ixodes ricinus in southern Italy

The present study was carried out in a protected wooded area, which is part of the Parco Regionale Gallipoli Cognato Piccole Dolomiti Lucane, one of the most important ecological reserves in southern Italy. From April 2010 to April 2011, 212 birds, comprising 22 species from 12 families, were captured and examined for ticks. A total of 75 (35.4?%) birds were found infested by ticks, with 451 ticks being collected. All ticks were identified as Ixodes ricinus, of which 241 (53.4?%) were larvae and 210 nymphs (46.6?%). The highest intensity of infestation was found in April 2010, when 117 ticks were retrieved on 25 birds. No ticks were found on birds (n?=?5) netted in December 2010. High infestation rates were recorded on blackbirds (Turdus merula) (90 %; 29 birds examined) and on mistle thrushes (Turdus viscivorus) (100?%; 2 birds examined). The highest intensity of infestation by larvae was found on wrens (5.6 larvae/bird) and by nymphs on mistle thrushes (11.5 nymphs/bird). Temperature and number of hours of light showed to influence the activity of larvae and nymphs. These data support the notion that birds may be responsible for the heterogeneous distribution of I. ricinus in Europe, thus playing a role in the epidemiology of certain tick-borne pathogens.     

Effects of deer density on tick infestation of rodents and the hazard of tick-borne encephalitis. I: empirical assessment

Tick borne encephalitis (TBE) is endemic to eastern and central Europe with broad temporal and spatial variation in infection risk. Although many studies have focused on understanding the environmental and socio-economic factors affecting exposure of humans to TBE, comparatively little research has been devoted to assessing the underlying ecological mechanisms of TBE occurrence in enzootic cycles, and therefore TBE hazard. The aim of this study was to evaluate the effect of the main ungulate tick hosts on the pattern of tick infestation in rodents and TBE occurrence in rodents and questing adult ticks. In this empirical study, we considered three areas where endemic human TBE occurs and three control sites having no reported human TBE cases. In these six sites located in Italy and Slovakia, we assessed deer density using the pellet group count-plot sampling technique, collected questing ticks, live-trapped rodents (primarily Apodemus flavicollis and Myodes glareolus) and counted ticks feeding on rodents. Both rodents and questing ticks were screened for TBE infection. TBE infection in ticks and rodents was positively associated with the number of co-feeding ticks on rodents and negatively correlated with deer density. We hypothesise that the negative relationship between deer density and TBE occurrence on a local scale (defined by the minimum overlapping area of host species) could be attributed to deer (incompetent hosts) diverting questing ticks from rodents (competent hosts), know as the 'dilution effect hypothesis'. We observed that, after an initial increase, the number of ticks feeding on rodents reached a peak for an intermediate value of estimated deer density and then decreased. Therefore, while at a regional scale, tick host availability has already been shown to be directly correlated with TBE distribution, our results suggest that the interactions between deer, rodents and ticks are much more complex on a local scale, supporting the possibility of a dilution effect for TBE.     

An empirical quantitative framework for the seasonal population dynamics of the tick Ixodes ricinus

The wide geographic and climatic range of the tick Ixodes ricinus, and the consequent marked variation in its seasonal population dynamics, have a direct impact on the transmission dynamics of the many pathogens vectored by this tick species. We use long-term observations on the seasonal abundance and fat contents (a marker of physiological ageing) of ticks, and contemporaneous microclimate at three field sites in the UK, to establish a simple quantitative framework for the phenology (i.e. seasonal cycle of development) of I. ricinus as a foundation for a generic population model. An hour-degree tick inter-stadial development model, driven by soil temperature and including diapause, predicts the recruitment (i.e. emergence from the previous stage) of a single cohort of each stage of ticks each year in the autumn. The timing of predicted emergence coincides exactly with the new appearance of high-fat nymphs and adults in the autumn. Thereafter, fat contents declined steadily until unfed ticks with very low energy reserves disappeared from the questing population within about 1 year from their recruitment. Very few newly emerged ticks were counted on the vegetation in the autumn, but they appeared in increasing numbers through the following spring. Larger ticks became active and subsequently left the questing population before smaller ones. Questing tick population dynamics are determined by seasonal patterns of tick behaviour, host-contact rates and mortality rates, superimposed on a basal phenology that is much less complex than has hitherto been portrayed.     

Infections and coinfections of questing Ixodes ricinus ticks by emerging zoonotic pathogens in Western Switzerland

In Europe, Ixodes ricinus is the vector of many pathogens of medical and veterinary relevance, among them Borrelia burgdorferi sensu lato and tick-borne encephalitis virus, which have been the subject of numerous investigations. Less is known about the occurrence of emerging tick-borne pathogens like Rickettsia spp., Babesia spp., "Candidatus Neoehrlichia mikurensis," and Anaplasma phagocytophilum in questing ticks. In this study, questing nymph and adult I. ricinus ticks were collected at 11 sites located in Western Switzerland. A total of 1,476 ticks were analyzed individually for the simultaneous presence of B. burgdorferi sensu lato, Rickettsia spp., Babesia spp., "Candidatus Neoehrlichia mikurensis," and A. phagocytophilum. B. burgdorferi sensu lato, Rickettsia spp., and "Candidatus Neoehrlichia mikurensis" were detected in ticks at all sites with global prevalences of 22.5%, 10.2%, and 6.4%, respectively. Babesia- and A. phagocytophilum-infected ticks showed a more restricted geographic distribution, and their prevalences were lower (1.9% and 1.5%, respectively). Species rarely reported in Switzerland, like Borrelia spielmanii, Borrelia lusitaniae, and Rickettsia monacensis, were identified. Infections with more than one pathogenic species, involving mostly Borrelia spp. and Rickettsia helvetica, were detected in 19.6% of infected ticks. Globally, 34.2% of ticks were infected with at least one pathogen. The diversity of tick-borne pathogens detected in I. ricinus in this study and the frequency of coinfections underline the need to take them seriously into consideration when evaluating the risks of infection following a tick bite.     

Ticks in the ecotone: the impact of agri-environment field margins on the presence and intensity of Ixodes ricinus ticks (Acari: Ixodidae) in farmland in southern England

The present study aimed to assess whether agri-environment field margins provide a habitat for the sheep/deer tick Ixodes ricinus. Field studies were conducted in arable farmland in southern England in both extant and newly constructed field margins. The presence and intensity (i.e. the mean number of nymphs per transect, excluding zeros) of questing nymphs and adult I. ricinus were compared between field margins with three adjacent habitats: woodland, hedgerow and arable land. The presence and intensity of ticks within a field margin was also compared between three ecozones: the ecotone, the margin and the crop. It was found that field margins do support I. ricinus, although the intensity of ticks was associated with field margins with adjacent woodland, with a higher tick intensity along the ecotonal ecozone, compared with the rest of the margin or the crop edge. The presence of a hedge also increased the likelihood of finding questing nymphs in a field margin compared with a margin adjacent to arable land. This effect, however, was less pronounced than in field margins with adjacent woodland. The provision of footpaths within the margin (at least 1–2 m from the ecotone), or on the edge of the crop where paths run next to woodland known to be an important tick habitat, could be promoted to minimize tick exposure. In addition, based on the results of the present study, raising awareness that walking alongside woodlands also constitutes a tick risk could be promoted.     

Factors driving the abundance of ixodes ricinus ticks and the prevalence of zoonotic I. ricinus-borne pathogens in natural foci

Environmental factors may drive tick ecology and therefore tick-borne pathogen (TBP) epidemiology, which determines the risk to animals and humans of becoming infected by TBPs. For this reason, the aim of this study was to analyze the influence of environmental factors on the abundance of immature-stage Ixodes ricinus ticks and on the prevalence of two zoonotic I. ricinus-borne pathogens in natural foci of endemicity. I. ricinus abundance was measured at nine sites in the northern Iberian Peninsula by dragging the vegetation with a cotton flannelette, and ungulate abundance was measured by means of dung counts. In addition to ungulate abundance, data on variables related to spatial location, climate, and soil were gathered from the study sites. I. ricinus adults, nymphs, and larvae were collected from the vegetation, and a representative subsample of I. ricinus nymphs from each study site was analyzed by PCR for the detection of Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum DNA. Mean prevalences of these pathogens were 4.0% ± 1.8% and 20.5% ± 3.7%, respectively. Statistical analyses confirmed the influence of spatial factors, climate, and ungulate abundance on I. ricinus larva abundance, while nymph abundance was related only to climate. Interestingly, cattle abundance rather than deer abundance was the main driver of B. burgdorferi sensu lato and A. phagocytophilum prevalence in I. ricinus nymphs in the study sites, where both domestic and wild ungulates coexist. The increasing abundance of cattle seems to increase the risk of other hosts becoming infected by A. phagocytophilum, while reducing the risk of being infected by B. burgdorferi sensu lato. Controlling ticks in cattle in areas where they coexist with wild ungulates would be more effective for TBP control than reducing ungulate abundance.