Hard ticks (Ixodidae) play a critical role in transmitting various tick-borne diseases (TBDs), posing significant global threats to human and animal health. Climatic factors influence the abundance, diversity, and vectorial capacity of tick vectors. It is imperative to have a comprehensive understanding of hard ticks, pathogens, eco-epidemiology, and the impact of climatic changes on the transmission dynamics of TBDs. The distribution and life cycle patterns of hard ticks are influenced by diverse ecological factors that, in turn, can be impacted by changes in climate, leading to the expansion of the tick vector\'s range and geographical distribution. Vector competence, a pivotal aspect of vectorial capacity, involves the tick\'s ability to acquire, maintain, and transmit pathogens. Hard ticks, by efficiently feeding on diverse hosts and manipulating their immunity through their saliva, emerge as competent vectors for various pathogens, such as viruses, parasites and bacteria. This ability significantly influences the success of pathogen transmission. Further exploration of genetic diversity, population structure, and hybrid tick vectors is crucial, as they play a substantial role in influencing vector competence and complicating the dynamics of TBDs. This comprehensive review deals with important TBDs in India and delves into a profound understanding of hard ticks as vectors, their biology, and the factors influencing their vector competence. Given that TBDs continue to pose a substantial threat to global health, the review emphasizes the urgency of investigating tick control strategies and advancing vaccine development. Special attention is given to the pivotal role of population genetics in comprehending the genetic diversity of tick populations and providing essential insights into their adaptability to environmental changes.

The Americas hold the greatest bird diversity worldwide. Likewise, ectoparasite diversity is remarkable, including ticks of the Argasidae and Ixodidae families - commonly associated with birds. Considering that ticks have potential health implications for humans, animals, and ecosystems, we conducted a systematic review to evaluate the effects of bioclimatic, geographic variables, and bird species richness on tick infestation on wild birds across the Americas. We identified 72 articles that met our inclusion criteria and provided data on tick prevalence in wild birds. Using Generalized Additive Models, we assessed the effect of environmental factors, such as habitat type, climatic conditions, bird species richness, and geographic location, on tick infestation. Our findings show that most bird infestation case studies involved immature ticks, such as larvae or nymphs, while adult ticks represented only 13% of case studies. We found birds infested by ticks of the genera Amblyomma (68%), Ixodes (22%), Haemaphysalis (5%), Dermacentor (1%), and Rhipicephalus (0.8%) in twelve countries across the Americas. Our findings revealed that temperature variation and bird species richness were negatively associated with tick infestation, which also varied with geographic location, increasing in mid-latitudes but declining in extreme latitudes. Our results highlight the importance of understanding how environmental and bird community factors influence tick infestation in wild birds across the Americas and the dynamics of tick-borne diseases and their impact on biodiversity.

Ticks are obligate hematophagous ectoparasites of vertebrates and are relevant worldwide due to the number of bacterial and other pathogens they can transmit. To date, the knowledge about the microorganisms that ticks harbor and transmit to their hosts is incipient. In this study, 24 samples of mammals belonging to four taxonomic orders and ticks of the genera Amblyomma and Rhipicephalus from the Orinoco region of Colombia were analyzed to described and compare the bacterial microbiome. Genetic extraction was performed, and the V3-V4 region of the 16S rRNA gene was amplified by PCR. Libraries were created, and those samples with adequate quality indices were sequenced using Illumina MiSeq technology. Bacterial taxonomic assignment analyses were conducted through Amplicon Sequence Variants (ASVs) and Operational Taxonomic Units (OTUs). The results correspond to 16 samples that passed the quality filters, with 3218 OTUs (415 families). Although a considerable number of unknown bacteria was found, Enterobacteriaceae, Beijerinckiaceae, Moraxellaceae, and Burkholderiaceae are the most prevalent families, and the presence of the genera Coxiella, Escherichia-Shigella, Enterobacter, which can harbor pathogenic species was confirmed. In individuals of Amblyomma mixtum found actively feeding on Hydrochoerus hydrochaeris, bacteria of the genera Escherichia-Shigella and Enterobacter were documented. Similarly, Rhipicephalus microplus found actively feeding on Odocoileus virginianus cariacou shared Escherichia-Shigella. Ralstonia was shared among the blood samples of H. hydrochaeris, while Anaplasma and Eubacterium were shared in blood and liver samples of O. v. cariacou. Shared bacteria between A. mixtum and R. microplus included Bacillus, Coxiella, and Escherichia-Shigella. The results highlight the need of additional studies in other natural regions of Colombia and other American countries where tick-borne diseases have been detected. Likewise, the recorded data are the first at the level of bacterial communities in ticks of the family Ixodidae and provide valuable knowledge for the understanding host-tick and pathogen interactions.

Following blood meals or questing bouts, hard ticks (Ixodidae) must locate moist off-host microhabitats as refuge. Soil-dwelling fungi, including entomopathogenic Beauveria bassiana (Bb), thrive in moist microhabitats. Working with six species of ixodid ticks in olfactometer bioassays, we tested the hypothesis that ticks avoid Bb. Contrary to our prediction, nearly all ticks sought, rather than avoided, Bb-inoculated substrates. In further bioassays with female black-legged ticks, Ixodes scapularis, ticks oriented towards both harmful Bb and harmless soil-dwelling fungi, implying that fungi-regardless of their pathogenicity-signal habitat suitability to ticks. Only accessible Bb-inoculated substrate appealed to ticks, indicating that they sense Bb or its metabolites by contact chemoreception. Bb-inoculated substrate required ≥24 h of incubation before it appealed to ticks, suggesting that they respond to Bb metabolites rather than to Bb itself. Similarly, ticks responded to Bb-inoculated and incubated cellulose but not to sterile cellulose, indicating that Bb detection by ticks hinges on the Bb metabolism of cellulose. 2-Methylisoborneol-a common fungal metabolite with elevated presence in disturbed soils-strongly deterred ticks. Off-host ticks that avoid disturbed soil may lower their risk of physical injury. Synthetic 2-methylisoborneol could become a commercial tick repellent, provided its repellency extends to ticks in diverse taxa.

BACKGROUND: Amblyomma is the third most diversified genus of Ixodidae that is distributed across the Indomalayan, Afrotropical, Australasian (IAA), Nearctic and Neotropical biogeographic ecoregions, reaching in the Neotropic its highest diversity. There have been hints in previously published phylogenetic trees from mitochondrial genome, nuclear rRNA, from combinations of both and morphology that the Australasian Amblyomma or the Australasian Amblyomma plus the Amblyomma species from the southern cone of South America, might be sister-group to the Amblyomma of the rest of the world. However, a stable phylogenetic framework of Amblyomma for a better understanding of the biogeographic patterns underpinning its diversification is lacking.
METHODS: We used genomic techniques to sequence complete and nearly complete mitochondrial genomes -ca. 15 kbp- as well as the nuclear ribosomal cluster -ca. 8 kbp- for 17 Amblyomma ticks in order to study the phylogeny and biogeographic pattern of the genus Amblyomma, with particular emphasis on the Neotropical region. The new genomic information generated here together with genomic information available on 43 ticks (22 other Amblyomma species and 21 other hard ticks-as outgroup-) were used to perform probabilistic methods of phylogenetic and biogeographic inferences and time-tree estimation using biogeographic dates.
RESULTS: In the present paper, we present the strongest evidence yet that Australasian Amblyomma may indeed be the sister-group to the Amblyomma of the rest of the world (species that occur mainly in the Neotropical and Afrotropical zoogeographic regions). Our results showed that all Amblyomma subgenera (Cernyomma, Anastosiella, Xiphiastor, Adenopleura, Aponomma and Dermiomma) are not monophyletic, except for Walkeriana and Amblyomma. Likewise, our best biogeographic scenario supports the origin of Amblyomma and its posterior diversification in the southern hemisphere at 47.8 and 36.8 Mya, respectively. This diversification could be associated with the end of the connection of Australasia and Neotropical ecoregions by the Antarctic land bridge. Also, the biogeographic analyses let us see the colonization patterns of some neotropical Amblyomma species to the Nearctic.
CONCLUSIONS: We found strong evidence that the main theater of diversification of Amblyomma was the southern hemisphere, potentially driven by the Antarctic Bridge\'s intermittent connection in the late Eocene. In addition, the subgeneric classification of Amblyomma lacks evolutionary support. Future studies using denser taxonomic sampling may lead to new findings on the phylogenetic relationships and biogeographic history of Amblyomma genus.

Forty-five tick species have been recorded in Kazakhstan. However, their genetic diversity and evolutionary relationships, particularly when compared to ticks in neighbouring countries, remain unclear. In the present study, 148 mitochondrial cytochrome c oxidase subunit I (COI) sequence data from our laboratory and NCBI (National Center for Biotechnology Information; https://www.ncbi.nlm.nih.gov/ ) data were used to address this knowledge gap. Phylogenetic analyses showed that i) Hyalomma anatolicum anatolicum (Koch, 1844) ticks from Jambyl Oblast (southeastern Kazakhstan) and Gansu Province (northwestern China) constituted a newly deviated clade; and ii) Dermacentor reticulatus (Fabricius, 1974) ticks from South Kazakhstan Oblast were closer to those in Romania and Turkey. The network diagram of haplotypes showed that i) the H-1 and H-2 haplotypes of Dermacentor marginatus (Sulzer, 1776) ticks from Zhetisu and Almaty were all newly evolved; and ii) the H-3 haplotypes of Haemaphysalis erinacei (Pavesi, 1884) from Almaty Oblast and Xinjiang Uygur Autonomous Region (northwestern China) were evolved from the H-1 haplotype from Italy. In the future, more COI data from different tick species, especially from Kazakhstan and neighbouring countries, should be employed in the field of tick DNA barcoding.

Ixodid ticks are distributed across all countries of the Western Balkans, with a high diversity of species. Many of these species serve as vectors of pathogens of veterinary and medical importance. Given the scattered data from Western Balkan countries, we have conducted a comprehensive review of available literature, including some historical data, with the aim to compile information about all recorded tick species and associated zoonotic pathogens in this region. Based on the collected data, the tick fauna of the Western Balkans encompasses 32 tick species belonging to five genera: Ixodes, Haemaphysalis, Dermacentor, Rhipicephalus and Hyalomma. A range of pathogens responsible for human diseases has also been documented, including viruses, bacteria and parasites. In this review, we emphasize the necessity for integrated surveillance and reporting, urging authorities to foster research by providing financial support. Additionally, international and interdisciplinary collaborations should be encouraged that include the exchange of expertise, experiences and resources. The present collaborative effort can effectively address gaps in our knowledge of ticks and tick-borne diseases.

Ticks pose significant threats to hosts by transmitting Borrelia spp., which are grouped into Lyme borreliae, relapsing fever borreliae (RF), and reptiles- and monotremes-associated borreliae. The RF borreliae encompass a group of Borrelia species predominantly transmitted by soft ticks, but some of its members can also be transmitted by hard ticks. Information on the detection and genetic characterization of tick-borne RF borreliae, including Borrelia theileri, is notably rare in Asia, particularly in Pakistan. Herein, we employed molecular techniques to detect borreliae in hard ticks collected from domestic animals in Khyber Pakhtunkhwa, Pakistan. Ticks were subjected to morphological analysis, followed by DNA extraction and PCR amplification of partial fragments of borrelial 16S rRNA and flaB genes. A total of 729 ticks were collected from 264 hosts, with Haemaphysalis cornupunctata (12.9%; 94/729) being the most prevalent, followed by Hyalomma anatolicum (11.7%; 85/729), Rhipicephalus microplus (10.0%; 73/729), Haemaphysalis kashmirensis (9.1%; 66/729), Haemaphysalis bispinosa (8.5%; 62/729), Rhipicephalus sanguineus (8%; 58/729), Haemaphysalis montgomeryi (6.2%; 45/729), Rhipicephalus turanicus (5.5%; 40/729), Hyalomma dromedarii and Ixodes kashmirensis (4.4%; 32/729 each), Rhipicephalus haemaphysaloides (4.1%; 30/729), Haemaphysalis sulcata and Hyalomma scupense (3.8%; 28/729 each), Haemaphysalis danieli (2.9%; 21/729), Hyalomma kumari (2.6%; 19/729), and Hyalomma isaaci (2.2%; 16/729). Based on 16S rRNA detection of Borrelia spp., only R. turanicus yielded positive results, resulting in an overall infection rate of 0.3% (2/160), while using flaB-based detection, four tick species including R. microplus, R. turanicus, Ha. sulcata, and Ha. cornupunctata showed positive results, yielding an overall infection rate of 6.9% (11/160). The amplified DNA fragments of borrelial 16S rRNA and flaB in R. turanicus from goats shared maximum identities of 100 and 99.40% with Borrelia theileri, respectively. Amplified borrelial flaB fragments in R. microplus from cows and sheep displayed 100% identity with B. theileri, while flaB fragments in Ha. cornupunctata and Ha. sulcata from goats revealed identities of 99.32 and 99.75% with undetermined RF Borrelia spp., respectively. Phylogenetic analysis revealed clustering of B. theileri from R. microplus and R. turanicus with the same species, while Borrelia spp. from Ha. cornupunctata and Ha. sulcata with undetermined RF Borrelia spp. Notably, this research marks the first documentation of B. theileri in R. turanicus and the identification of RF Borrelia spp. in Ha. cornupunctata and Ha. sulcata.

The present study aimed to molecularly identify and characterize the hard ticks infesting camels from the northern region (Ha\'il province) of Saudi Arabia using the mitochondrial barcoding gene cytochrome oxidase subunit I (COI). The sequences of tick samples from camels in three regions of Ha\'il were aligned with those previously reported from different geographic regions, revealing nine haplotypes, of which six were newly described in this study for the first time. These haplotypes were used to determine their phylogenetic relationships using the maximum likelihood method, displaying two distinct clades corresponding to Hyalomma dromedarii and H. impeltatum. Moreover, the haplotypes showing the highest homology with those deposited in NCBI-GenBank from different geographic regions, including Saudi Arabia, were obtained and combined to determine their phylogenetic relationships among them. The results showed that the haplotypes belonging to two clades were grouped with those previously determined as H. dromedarii and H. impeltatum. Moreover, the presence of H. scupense (syn. H. detritum) together with H. impeltatum suggests possible asymmetrical hybridization and mitochondrial introgression between these species. H. scupense infesting different mammal species apart from camels were also clustered in a different clade, indicating the presence of different lineages of this species that show different host specificities.

Hard ticks are mainly responsible for more \"tick-borne\" diseases in humans when compared to soft ticks. Tick infestation of ocular and periocular tissues is rare. We report the case of a 61-year-old male with left upper eyelid edema with erythema and live parasite on the lid margin.