Tick Abundance Research Articles

Deciphering the microbial communities in ticks of Inner Mongolia: ecological determinants and pathogen profiles

BackgroundTicks are vectors of numerous pathogens, with their bacterial composition, abundance, diversity, and interaction influencing both their growth and disease transmission efficiency. Despite the abundance of ticks in Inner Mongolia, China, comprehensive data on their microbial communities are lacking. This study aims to analyze the microbial communities within ticks from Inner Mongolia to inform innovative control strategies for interrupting pathogen transmission.MethodsTick samples were collected from animals and vegetation in multiple locations across Inner Mongolia and stored at − 80 °C. Ticks were identified using morphological keys and molecular biology methods. Full-length 16S rRNA gene sequencing was performed on collected samples. Bacterial community composition and diversity were mainly analyzed using bioinformatic tools such as QIIME, phyloseq, and DESeq2. Alpha diversity was assessed using Chao1, ACE, and Shannon indices, while beta diversity was evaluated using Bray-Curtis dissimilarity matrices. LEfSe analysis was applied to identify taxa associated with ecological and biological variables.ResultsA total of 5,048,137 high-quality read counts were obtained, forming an average of 789.3 OTUs per sample. Proteobacteria, Firmicutes, and Bacteroidetes were the most dominant phyla. Bacterial community composition varied significantly with geography, with Dermacentor nuttalli showing a higher abundance of Rickettsia in Xilingol League, while other regions had different dominant genera. The microbial community also differed based on the feeding status of ticks. Additionally, the microbiota of engorged ticks showed organ specificity. Pathogen detection efforts revealed the presence of nine pathogens across all three tick species. D. nuttalli was found to carry a significantly higher burden of pathogenic bacteria, making it the most potentially threatening tick species in Inner Mongolia.ConclusionsThe study highlights significant variations in tick microbiomes influenced by geographic location, feeding status, and tick species. It underscores the importance of enhancing tick and tick-borne disease surveillance in Inner Mongolia for early detection and control of emerging pathogens.Graphical

Richness and abundance of ticks associated with domestic animals at different altitudes in Southern Mexico

The objective of this study was to determine the richness, abundance, and altitudinal distribution of ticks collected from domestic animals in five municipalities and sixteen distinct communities along the Pacific coast of southern Mexico in Chiapas. Ticks were sampled from dogs, horses, and cows in each range. A total of 311 hosts were sampled, of which 264 (85 %) were dogs, 26 (8 %) were horses, and 21 (7 %) were cows. Of these, 83 (26 %), 17 (5 %), and 7 (2 %) hosts were infested, respectively. A total of 583 ticks were collected, representing four genera and six species. The most prevalent species was Rhipicephalus linnaei (68.61 %, n = 400), followed by Rhipicephalus microplus (0.51 %, n = 3), Amblyomma ovale (1.71 %, n = 10), Amblyomma mixtum (1.71 %, n = 10), Ixodes ci. boliviensis (2.22 %, n = 13), and Dermacentor dissimilis (25.21 %, n = 147). Of the identified ticks, A. mixtum, A. ovale, R. microplus, and R. linnaei were distributed at elevations between 0 and 1000 m, while at elevations between 1000 and 2000 m, only the species I. ci. boliviensis and D. dissimilis were found. The characteristics of each locality are discussed in order to explain the abundance of ticks and to assess their potential risk as vectors of public health pathogens.

Abundance Trends of Immature Stages of Ticks at Different Distances from Hiking Trails from a Natural Park in North-Western Italy.

Hiking trails may act as hotspots at the wildlife-human interface, posing an acarological risk for people and their pets. Ticks that are maintained in the environment by wild animals may quest on people walking along the trails. Assessing the risk of tick bites for people involved in outdoor activities is a further step in mitigating the risk of tick-borne diseases. This work describes the variation of tick abundance along a gradient of distances from hiking trails, where wildlife passage is favored by higher accessibility. Hiking trails with dense vegetation on the sides were sampled for ticks along a 100 m dragging transect, located in a natural park in North-Western Italy. Additional transects were replicated at 1, 2 and 4 m away from the trail on both sides. After morphological identification, descriptive statistics and modeling were applied to determine the abundance patterns across distances. Larvae were most abundant near the trail, peaking at 1 m and dropping sharply at further distances. Nymphs showed a more gradual and consistent decrease at progressing distance from the trail. Few adults were collected, preventing the identification of a clear trend. With higher tick abundance, the immediate vicinity of hiking trails may represent a source of acarological risk for humans and pets.

Extrinsic and intrinsic drivers of prevalence and abundance of hard-bodied ticks (Acari: Ixodidae) in one-humped camel (Camelus dromedarius)

BackgroundTicks are ectoparasites and can be vectors of a wide range of pathogens, posing significant health risks to livestock. In the Sahara Desert of Algeria, particularly among one-humped camels (Camelus dromedarius), there is a need to better understand the factors influencing tick infestation patterns to improve livestock management and health outcomes. ObjectivesThis study aimed to investigate the prevalence, intensity, and abundance of hard-bodied ticks (Acari: Ixodidae) among dromedaries, examining both intrinsic factors (sex, age, coat color) and extrinsic variables (farming systems, vegetation types, climate zones, and elevation) that might influence tick infestation in this region. MethodsTicks were collected from 286 dromedaries across nine sites in the pre-Saharan regions of Algeria, with elevations ranging from 736 m to 980 m. The sampled camels, which ranged in age from 6 days to 21 years, were examined for tick infestations. The ticks were identified through macroscopic and microscopic methods, and their abundance was analyzed in relation to the camels' characteristics and environmental factors. Three breeding systems were recognized: extensive, intensive, and mixed. ResultsA total of 980 ticks were collected, with Hyalomma dromedarii Koch, 1844 being the most abundant species (553 specimens), followed by Hyalomma impeltatum Schulze & Schlottke, 1930 (393 specimens), and Hyalomma excavatum Koch, 1844 (34 specimens). H. dromedarii showed a preference for parasitizing brown-coated dromedaries and exhibited significantly higher infestation levels during spring (p < 0.001). No significant association was observed between tick infestation and the camels' age or sex (p > 0.05). However, the farming system had a significant impact on tick abundance, with extensive and mixed systems showing higher tick burdens compared to intensive systems (p < 0.01). Additionally, the vegetation type, climate zone, and foraging habitat elevation were found to significantly influence tick densities and prevalence. ConclusionThis study provides essential insights into the tick infestation dynamics in dromedaries in drylands of Algeria. It highlights the influence of coat color, seasonality, and farming practices on tick burden, with brown-coated camels being more susceptible during the spring. The findings underline the importance of considering both intrinsic and extrinsic factors when developing effective tick control strategies, especially for camels raised in extensive or mixed farming systems in diverse arid rangelands. Future research should expand the scope to cover other arid regions in North Africa for a comprehensive understanding of tick-host dynamics.

A randomized controlled trial of Tickoff® (Metarhizium anisopliae ICIPE 7) for control of tick infestations and transmission of tick-borne infections in extensively grazed zebu cattle in coastal Kenya

The entomopathogenic fungus Metarhizium anisopliae isolate ICIPE 7 is being developed as an eco-friendly alternative to chemical acaricides in managing natural tick infestation on livestock. Its impact on tick infestation and tick-borne infections in cattle under natural conditions are yet unclear. We conducted a randomized controlled field trial to assess the safety and effects of Tickoff® (a formulation of M. anisopliae isolate ICIPE 7) and the chemical acaricide Triatix® on tick infestation and incidence of Anaplasma marginale and Theileria parva in extensively grazed zebu cattle in coastal Kenya. A total of 217 eligible herds comprising 1459 intent-to-treat zebu cattle were enrolled from 12 villages. The herds were randomly assigned in a 1:1:1 ratio to Tickoff®, Triatix®, or Tickoff® excipients. Tick counts, treatment administrations, and adverse events were registered every two weeks for seven months. The mortality of ticks collected from treated cattle was monitored in vitro. Infections with A. marginale and T. parva were monitored every two months. No adverse events were reported in either treatment group. Tickoff® did not significantly affect tick infestation (p = 0.869) or infection incidence (p > 0.05) compared to excipients. Triatix® significantly reduced tick infestation (p < 0.001) and incidence of T. parva (p = 0.042), but not A. marginale (p = 0.509) compared to the reference Tickoff®. In ticks that were removed from cattle, Tickoff® demonstrated significant pathogenicity in vitro relative to excipients (hazard ratio: 8.50, 95 % CI: 4.67–15.47). Fungus growth and sporulation were also observed on tick cadavers from Tickoff®, but not from excipients. While Tickoff® did not impact tick counts, its delayed, but significant effect on tick mortality may hinder onward pathogen transmission and give rise to indirect (i.e., to untreated animals) epidemiological effects, that were not picked up with this study design. Additionally, adverse environmental conditions resulted in low tick abundance and pathogen circulation towards the end of the study period, reducing the power of the study. This work re-emphasizes the challenges of randomized controlled field trials and the complexity of assessing the impact of vector control products on both direct and indirect impacts on pathogen transmission.

Relating Wildlife Camera Trap Data to Tick Abundance: Testing the Relationship in Different Habitats.

The increase in acarological risk of tick bites is significantly driven by profound changes in landscape, which alter the density and distribution of wildlife that support tick populations. As a result of habitat shifts and land abandonment, which create environments conducive to tick proliferation, the risk of disease transmission to humans and animals is increasing. In this context, it is important to explore tick ecology by applying a comprehensive methodology. In this study, we examined the relationship between wildlife temporal occupancy and tick abundance in two distinct regions: an alpine hunting district and a natural park in the Apennines. For each sampling point, we calculated wildlife temporal occupancy from camera trap pictures and estimated ticks' abundance from dragging transects in the area immediately surrounding camera traps. In modelling the relationship between those two variables, we included abiotic factors such as saturation deficit, normalized difference vegetation index, and altitude. Results show the importance of altitude and wildlife temporal occupancy (itself related to different habitat and land management characteristics) on the ecology of questing ticks. If employed in management decisions for natural environments, such information is useful to modulate the acarological risk and thus the risk of tick-borne pathogens' transmission.

Ticks and Tick-Borne Pathogens in Popular Recreational Areas in Tallinn, Estonia: The Underestimated Risk of Tick-Borne Diseases.

This study reveals a significant presence of ticks and tick-borne pathogens in urban recreational areas of Tallinn, Estonia. During the period of May-June 2018, 815 Ixodes ticks were collected from an area of 11,200 m2 using the flagging method. Tick density reached up to 18.8 ticks per 100 m2, indicating a high concentration of ticks in these urban green spaces. Pathogen analysis demonstrated that 34% of the collected ticks were infected with at least one pathogen. Specifically, Borrelia burgdorferi s.l., the causative agent of Lyme borreliosis, was detected in 17.4% of the ticks; Rickettsia spp. was detected in 13.5%; Neoehrlichia mikurensis was detected in 5.5%; Borrelia miyamotoi was detected in 2.6%; and Anaplasma phagocytophilum and tick-borne encephalitis virus were detected in 0.5% each. These findings indicate that the prevalence and abundance of ticks and tick-borne pathogens in these urban environments are comparable to or even exceed those observed in natural endemic areas. Given the increasing incidence of Lyme borreliosis in Central and Northern Europe, the risk of tick bites and subsequent infection in urban recreational sites should not be underestimated. Public health measures, including enhanced awareness and precautionary information, are essential to mitigate the risk of tick-borne diseases in these urban settings.

Pathogens detected in ticks (Ixodes ricinus) feeding on red squirrels (Sciurus vulgaris) from city parks in Warsaw

The European red squirrel (Sciurus vulgaris) is a common host for Ixodes ricinus ticks in urban and rural habitats, however, studies on ticks and tick-borne pathogens (TBPs) of squirrels have not been conducted in Poland yet. Thus, the aims of the current study were to assess and compare the prevalence and abundance of ticks on red squirrels trapped at two sites in the Warsaw area (in an urban forest reserve and an urban park) and using molecular tools, to assess the genetic diversity of three pathogens (Borrelia burgdorferi sensu lato, Rickettsia and Babesia spp.) in I. ricinus ticks collected from squirrels. For the detection of Rickettsia spp. a 750 bp long fragment of the citrate synthase gltA gene was amplified; for B. burgdorferi s.l. 132f/905r and 220f/824r primers were used to amplify the bacterial flaB gene fragments (774 and 605 bp, respectively) and for Babesia spp., a 550 bpfragment of 18S rRNA gene was amplified. In total, 91 red squirrels were examined for ticks. There were differences in tick prevalence and mean abundance of infestation in squirrels from the urban forest reserve and urban park. Three species of B. burgdorferi s.l., Rickettsia spp., and Babesia microti were detected in ticks removed from the squirrels. Our results broaden knowledge of S. vulgaris as an important host for immature I. ricinus stages and support the hypothesis that red squirrels act as a reservoir of B. burgdorferi. Moreover, we conclude that red squirrels may also play a role in facilitating the circulation of other pathogens causing serious risk of tick-borne diseases in natural and urban areas.

Features of Consistent Powassan Virus Lineage II Focus in Southern Maine, United States.

Powassan virus lineage II or deer tick virus (DTV) is a rare but increasingly reported human infection in the United States transmitted by Ixodes scapularis ticks. The virus is thought to be maintained in environmental foci that are optimal for tick and vertebrate reservoirs, but details on DTV ecology are poorly understood. We investigated DTV tick infection rates and reservoir host abundance in a focus of consistent DTV activity in Maine, USA. Host and tick abundance, vegetation, and microclimate conditions were measured in three forest sites representing increasing invasive understory infestation. Sites were selected representing native understory, mixed vegetation with some invasive Japanese barberry (Berberis thunbergii), and a highly invasive site dominated by Japanese barberry. Japanese barberry in the mixed vegetation site averaged 1 m in height with space between plants, whereas the highly invasive site had impenetrable Japanese barberry over 1.5 m. The DTV infection rate was greater in the highly invasive site. Density of I. scapularis ticks were significantly lower in the native forest site, and no DTV was found. Another feature of the DTV focus was more stable humid microclimate throughout the year compared with the other sites and a nearby continuous section of forest, consistent with reports from Connecticut, USA. We conclude that invasive Japanese barberry stands provide favorable and consistent microclimate conditions to maintain high DTV infection rates annually among questing I. scapularis ticks. Understanding environmental and landscape features that support high infection rates could lead to the identification of high-risk habitats for contracting DTV.

Monitoring questing winter tick abundance on traditional moose hunting lands

AbstractAn important symbolic and subsistence animal for many Native American Tribes, the moose (Alces alces; mos in Algonquin, Penobscot language) has been under consistent threat in the northeastern United States because of winter tick (Dermacentor albipictus) parasitism over the past several decades, causing declines in moose populations throughout the region. This decline has raised concern for Tribes and agencies that are invested in moose. Given this concern, it is increasingly important to effectively monitor and develop strategies to manage winter ticks to address consistent population declines of moose due to winter ticks. The Penobscot Nation developed a novel strategy to sample questing winter ticks (i.e., ticks that are actively seeking hosts) using a plot‐based sampling protocol that may be suitable for heterogeneous habitats. We deployed this protocol in the northeastern United States in 2022 during the tick questing period (Sep–Dec) on Penobscot Nation sovereign trust lands, the White Mountain National Forest and Umbagog National Wildlife Refuge, and western‐central Massachusetts, USA. We analyzed the data using occupancy and N‐mixture models. Detection probability peaked during mid‐October and tick occupancy and abundance were greatest at sites with intermediate understory vegetation height. The sampling protocol was successful at sampling ticks in Massachusetts, where abundances were expected to be low, indicating that it may be useful for studies planning to monitor winter tick distribution and abundance in areas with sub‐optimal moose habitat and where winter tick abundance is expected to be low. This approach may also benefit managers or researchers intending to monitor many species of hard ticks, and where imperfect detection is expected.

Identification and prevalence of ticks infesting small ruminants of Fort Munro region in South Punjab, Pakistan

Fort Munro is a hill station in Southern Punjab the residents of whom are heavily dependent upon livestock for their living but ticks are a big treat for the livestock. The purpose of this study was to ascertain the tick infestation among the small ruminants of Fort Munro. Ticks (N = 273) were collected from 333 animals (165 goats and 168 sheep) during August and September 2022. Two tick genera Hyalomma and Rhipicephalus were identified. Rhipicephalus was most abundant tick genera (78.02%) followed by Hyalomma (21.98%).Tick distribution significantly varied with the host: Rhipicephalus ticks were more frequently infesting goats while Hyalomma were more common on sheep. For both hosts, tick infestation varied with the sampling sites and male animals were significantly more infested than females. Five tick species were infesting goats with the following relative abundance: Rhipicephalus (R.) senegalensis (39.20%) > R. sanguineus (36.8%) > R. appendiculatus (10.40%) > R. turanicus (8%) > R. guilhoni (5.6%). Rhipicephalus senegalensis (41.22%) was also the most common tick species infesting sheep followed by Hyalomma (H.) marginatum (29.73%), R. guilhoni (18.24%), H. dromedarii (5.41%) and H. impeltatum (5.41%). Male ticks very more abundantly on both goats and sheep than female. Distribution of Hyalomma species also varied between the sampling sites. In conclusion, we are reporting the infestation of 3 Hyalomma and 5 Rhipicephalus in small ruminants of Fort Munro. The data generated through this study will help in developing appropriate tick control in the study area and will add to the existing knowledge regarding tick species that are infesting the small ruminants of Pakistan.

Fauna and abundance of ixodids (Parasitiformes, Ixodidae) on Askold island (Primorsky krai): uniqueness, infection with pathogens

Collecting of hard ticks by a flag from vegetation in Askold Island (Primorsky Territory) in May 17, 2023 has revealed the following 3 species: Haemaphysalis longicornis Neumann, 1901 (809 specimens), Haemaphysalis japonica douglasi Nuttall et Warburton, 1915 (223), Ixodes persulcatus Schulze, 1930 (4). A total of 1036 tick specimens were collected. The territory of the western part of the island was surveyed: a broad-leaved maple forest (925 ticks were collected) and a large-grass meadow (111). Identification of tick species was carried out according to morphological characters. The hard tick fauna of Askold Island is characterized by: 1) the dominance of H. longicornis, which is absent on neighboring islands; 2) a high proportion of nymphs in May among representatives of the genus Haemaphysalis (H. longicornis 96.0%, H. japonica 25.1%), the peak abundance of which is common in July–August; 3) a high abundance of ticks (more than 90.0 individuals per flag-hour; 4) absence of males in H. longicornis (32 females were collected). PCR did not detect infection of 160 nymphs (pools of 20 individuals) H. longicornis with markers of nucleic acids of tick-borne encephalitis virus, borrelia, anaplasma, ehrlichia and West Nile fever. However, since representatives of the genus Haemaphysalis are known as carriers of many other pathogens, the high abundance of hard ticks and the incompleteness of data on their infection rate do not allow us to classify the territory of Askold Island as an epidemiologically low-risk territory.

Tick abundance and infection with three zoonotic bacteria are heterogeneous in a Belgian peri-urban forest.

Ixodes ricinus is a vector of several pathogens of public health interest. While forests are the primary habitat for I. ricinus, its abundance and infection prevalence are expected to vary within forest stands. This study assesses the spatio-temporal variations in tick abundance and infection prevalence with three pathogens in and around a peri-urban forest where human exposure is high. Ticks were sampled multiple times in 2016 and 2018 in multiple locations with a diversity of undergrowth, using the consecutive drags method. Three zoonotic pathogens were screened for, Borrelia burgdorferi s.l., Coxiella burnetii, and Francisella tularensis. The influence of season, type of site and micro-environmental factors on tick abundance were assessed with negative binomial generalized linear mixed-effects models. We collected 1642 nymphs and 181 adult ticks. Ticks were most abundant in the spring, in warmer temperatures, and where undergrowth was higher. Sites with vegetation unaffected by human presence had higher abundance of ticks. Forest undergrowth type and height were significant predictors of the level of tick abundance in a forest. The consecutive drags method is expected to provide more precise estimates of tick abundance, presumably through more varied contacts with foliage. Borrelia burgdorferi s.l. prevalence was estimated from pooled ticks at 5.33%, C. burnetii was detected in six pools and F. tularensis was not detected. Borrelia afzelii was the dominant B. burgdorferi genospecies. Tick abundance and B. burgdorferi s.l. infection prevalence were lower than other estimates in Belgian forests.

Characterization and Seasonal Dynamics of Tick Populations in Dairy Cattle Production Systems of Northwestern Colombian Amazon.

Cattle ticks are a significant health concern in tropical livestock production due to their hematophagous behavior and potential as vectors for human and animal pathogens. In this study, we investigated the tick population present in dairy cattle production, calves, and grazing areas of livestock systems in the northwestern Colombian Amazon. Identification was based on taxonomic keys and molecular markers. Phylogenetic relationships were established using mitochondrial COX1 and 16S genes. Population structure analysis was performed considering age, racial type (B. indicus vs. B. taurus), and the influence of environmental factors and the geomorphological landscape on tick population dynamics. Our findings revealed the presence of a single tick species, with a unique haplotype identified for each mitochondrial gene assessed. Phylogenetic analysis classified the found species within Clade A of the Rhipicephalus microplus complex. Ticks were more prevalent during periods of low rainfall and high temperature, and B. taurus cows exhibited the highest tick abundance. Thus, these results provide insights into the population characteristics and distribution of the tick species present in dairy cattle production systems in the northwestern part of the Colombian Amazon. This information is fundamental for developing targeted strategies based on seasonal variation and host characteristics to mitigate tick infestation severity in the region.

Occurrence of Coxiella burnetii in wild lagomorphs and their ticks in Spanish Mediterranean ecosystems.

Coxiella burnetii, the causative agent of Q fever, is a zoonotic multi-host vector-borne pathogen of major public health importance. Although the European Food Safety Authority has recently made the monitoring of this bacterium in wildlife a priority, the role of wild lagomorphs in the transmission and maintenance of C. burnetii is poorly understood. The aims of this study were to determine the prevalence and risk factors associated with C. burnetii circulation in European wild rabbits (Oryctolagus cuniculus) and Iberian hares (Lepus granatensis) and to assess the presence of this pathogen in ticks that feed on them in Mediterranean ecosystems in Spain, the country with the highest number of reported cases of Q fever in Europe. A total of 574 spleen samples were collected from 453 wild rabbits and 121 Iberian hares, and 513 ticks (processed in 120 pools) between the 2017/2018 and 2021/2022 hunting seasons. C. burnetii DNA was detected in 103 (17.9%; 95% CI: 14.8-21.1) of the 574 wild lagomorphs tested. By species, prevalence was 16.3% (74/453; 95% CI: 12.9-19.7) in the European wild rabbit and 24.0% (29/121; 95% CI: 16.4-31.6) in the Iberian hare. At least one positive lagomorph was found on 47.9% of the 96 hunting estates sampled and in every hunting season since 2018/2019. Two risk factors associated with C. burnetii infection were as follows: outbreak of myxomatosis on the hunting estate in the month prior to sampling and high tick abundance observed by gamekeepers on the hunting estate. C. burnetii DNA was also found in 33 of the 120 (27.5%; 95% CI: 19.5-35.5) tick pools tested. The pathogen was detected in 66.7% (4/6), 29.2% (26/89) and 21.4% (3/14) of Haemaphysalis hispanica, Rhipicephalus pusillus and Hyalomma lusitanicum pools respectively. This study provides new epidemiological data on C. burnetii in European wild rabbits and is the first survey on this zoonotic pathogen performed in Iberian hares. Our results indicate widespread endemic circulation of C. burnetii and highlight the importance of both wild lagomorph species as natural reservoirs of this zoonotic bacterium in Mediterranean ecosystems in southern Spain, which may be of public and animal health concern. The high prevalence and wide diversity of positive tick species suggest the possible role of ticks in the epidemiological cycle of C. burnetii, with the potential risk of transmission to sympatric species, including humans.

Effect of environmental variables on the abundance of Amblyomma ticks, potential vectors of Rickettsia parkeri in central Brazil.

Amblyomma ticks are vectors of both Rickettsia rickettsii and R. parkeri in the Americas, where capybaras (Hydrochoerus hydrochaeris) are the main hosts in urban areas, thus contributing to the transmission of spotted fever. Herein, we studied: (i) the seasonal dynamics and abundance of ticks in areas where capybaras live, (ii) the effect of environmental variables on tick abundance, and (iii) the presence of Rickettsia-infected ticks. Between September 2021 and September 2022, we sampled ticks using cloth-dragging at 194 sites on the shore of Lake Paranoá in Brasília, Brazil. We measured environmental data (season, vegetation type, canopy density, temperature, humidity, and presence or vestige of capybara) at each site. Nymphs and adults were morphologically identified to the species level, and a selected tick sample including larvae was subjected to genotypic identification. We investigated Rickettsia-infected ticks by PCR (gltA, htrA, ompB, and ompA genes) and associations between tick abundance and environmental variables using Generalized Linear Models. A total of 30,334 ticks (96% larvae) were captured. Ticks were identified as Amblyomma, with A. sculptum comprising 97% of the adult/nymphs. Genotype identification of a larval sample confirmed that 95% belonged to A. dubitatum. Seasonal variables showed significant effects on tick abundance. Most larvae and nymphs were captured during the early dry season, while the adults were more abundant during the wet season. Vegetation variables and the presence of capybaras showed no association with tick abundance. Rickettsia parkeri group and R. bellii were identified in A. dubitatum, while A. sculptum presented R. bellii. We conclude that: (i) Amblyomma ticks are widely distributed in Lake Paranoá throughout the year, especially larvae at the dry season, (ii) the abundance of Amblyomma ticks is explained more by climatic factors than by vegetation or presence of capybaras, and (iii) A. dubitatum ticks are potential vectors of R. parkeri in Brasília.

Aggressive interactions among white-tailed deer (Artiodactyla: Cervidae) at 4-poster devices for host-targeted tick control.

White-tailed deer, Odocoileus virginianus Zimmermann (Artiodactyla: Cervidae), are the primary wildlife host for adult stages of blacklegged ticks (Acari: Ixodidae: Ixodes scapularis Say) and an important host for lone star ticks (Acari: Ixodidae: Amblyomma americanum Linnaeus), both of which are vectors of numerous tick-borne pathogens. The 4-poster passive deer treatment device is a topical, host-targeted method to control free-living tick populations and has been proven to successfully reduce tick abundance in several states. Aggressive behavior of white-tailed deer at concentrated feeding stations is hypothesized to interfere with the effective use of 4-poster devices and deer contact with acaricide applicators. We analyzed images collected by camera traps at 4-poster feeding stations deployed at 3 sites in Maryland and found a negative relationship between some aggressive interactions and contact with applicators. Our results emphasize the need for further investigation into whether deer social dynamics can impact 4-poster efficacy for tick control. This study serves as a reminder that intraspecific interactions are important to consider when using host-targeted acaricide approaches.

A First Look at the Relationship Between Large Herbivore-Induced Landscape Modifications and Ixodes ricinus Tick Abundance in Rewilding Sites.

Background: While the influence of landscape and microclimatic conditions on tick populations is well-documented, there remains a gap in more specific data regarding their relationship to rewilding efforts with large herbivore activity. Objective: This pilot study, spanning from 2019 to 2021, explores the effects of naturalistic grazing by large semi-wild ungulates on tick abundance in the Milovice Reserve, Czechia. Methods: Tick collection was observed using flagging techniques at two distinct sites of rewilding area: one grazed, actively utilized by animals involved in the rewilding project, and one ungrazed, left fallow in neighboring areas utilized only by wild animals. Transects, each measuring 150 m in length and 5 m in width (750 m2), were established at these two sampling locations from March to September between 2019 and 2021. To minimize potential bias resulting from tick movement, a 300 m buffer zone separated the two sites. Data analysis employed a generalized estimating equations (GEE) model with negative binomial regression. The study assessed potential variations in tick abundance between selected transects, considering factors such as plant cover seasonality, temperature, and humidity. Results: During the collection periods, we gathered 586 live ticks, with 20% found in grazed areas and 80% in ungrazed areas. Notably, tick abundance was significantly higher in ungrazed areas. Peaks in tick abundance occurred in both grazed and ungrazed areas during spring, particularly in April. However, tick numbers declined more rapidly in grazed areas. Microclimatic variables like temperature and humidity did not significantly impact tick abundance compared to landscape management and seasonal factors. Conclusion: Rewilding efforts, particularly natural grazing by large ungulates, influence tick abundance and distribution. This study provides empirical data on tick ecology in rewilded areas, highlighting the importance of landscape management and environmental factors in tick management and conservation. Trophic rewilding plays a crucial role in shaping ecosystems and tick population dynamics in transformed landscapes.

Variation in prevalence and intensity of macroparasites in moose and their interactions with winter tick load in eastern Canada

Wild animals are infected with a large diversity and abundance of parasites that can affect their behavior, growth, body condition, and ultimately their survival. Although the adverse effects of parasites and the mechanisms involved in the interactions between a host and its parasites are generally well studied, much less is known about the additive or synergistic effects of multiple parasite species on a host. Moose populations in eastern Canada are infected by several species of endoparasites. In the last decades, the intensity of infestations by winter ticks, an ectoparasite, on moose have increased as a result of increased moose densities and favorable weather conditions that benefit winter tick survival. We aimed to document the diversity, intensity, prevalence, and distribution of different parasite species of moose in southern Quebec, Canada. We then evaluated the potential interaction between winter tick and endoparasites of moose, and we evaluated the effect of the simultaneous presence of ticks and endoparasites on moose body condition. To do so, we collected organs to identify and count endoparasite species, estimate winter tick abundance, and measure subcutaneous fat thickness from 174 hunted moose in fall 2019 in 8 regions of Quebec. Our results showed that the prevalence and intensity of winter tick and gastrointestinal parasites differed among regions, as well as the prevalence of the heart parasite Taenia krabbei and the intensity of lung parasite Echinoccocus granulosus. Moose body condition, however, was not influenced by the simultaneous presence of winter tick and endoparasites. The documentation of the interactive effects of multiple parasite species on a host is fundamental given that future environmental conditions in temperate climate will favor the reproduction, development, and survival of several parasite species, which could affect parasite diversity and abundance in the environment and modify host–parasite dynamics.

Parasite infestation patterns differ between ticks and chigger mites on two rodent host species in Taiwan.

Parasites are typically concentrated on a few host individuals, and identifying the mechanisms underlying aggregated distribution can facilitate a more targeted control of parasites. We investigated the infestation patterns of hard ticks and chigger mites on two rodent species, the striped field mouse, Apodemus agrarius, and the lesser ricefield rat, Rattus losea, in Taiwan. We also explored abiotic and biotic factors that were important in explaining variation in the abundance of ticks and chiggers on rodent hosts. Ticks were more aggregated than chiggers on both rodent species. Factors important for the variation in parasitic loads, especially biotic factors, largely differed between ticks and chiggers. Variation partitioning analyses revealed that a larger proportion of variation in chiggers than in ticks can be explained, especially by abiotic factors. If, as proposed, the higher number of parasites in males is due to a larger range area or immunity being suppressed by testosterone, when A. agrarius males host more ticks, they are expected to also host more chiggers, given that chiggers adopt a similar host finding approach to that of ticks. Instead, the similar abundance of chiggers in male and female A. agrarius implies that a large home range or suppressed immunity does not predispose males to inevitably host more parasites. More variations were explained by abiotic than biotic factors, suggesting that controlling practices are more likely to be successful by focusing on factors related to the environment instead of host traits. Our study indicated that the extent of parasitism is rarely determined by a sole factor, but is an outcome of complex interactions among animal physiology, animal behavior, characteristics of parasites, and the environments.