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Ticks and Tick-borne Diseases Nov 2022The data for human tick encounters in the United States (US) presented in this paper were compiled with the goals of: (i) presenting quantitative data across the full... (Review)
Review
The data for human tick encounters in the United States (US) presented in this paper were compiled with the goals of: (i) presenting quantitative data across the full range of native or recently established human biting ixodid (hard) and argasid (soft) tick species with regards to their frequency of infesting humans, based on published records of ticks collected while biting humans or crawling on clothing or skin; and (ii) providing a guide to publications on human tick encounters. Summary data are presented in table format, and the detailed data these summaries were based on are included in a set of Supplementary Tables. To date, totals of 36 ixodid species (234,722 specimens) and 13 argasid species (230 specimens) have been recorded in the published literature to infest humans in the US. Nationally, the top five ixodid species recorded from humans were the blacklegged tick, Ixodes scapularis (n=158,008 specimens); the lone star tick, Amblyomma americanum (n=36,004); the American dog tick, Dermacentor variabilis (n=26,624); the western blacklegged tick, Ixodes pacificus (n=4,158); and the Rocky Mountain wood tick, Dermacentor andersoni (n=3,518). Additional species with more than 250 ticks recorded from humans included Ixodes cookei (n=2,494); the Pacific Coast tick, Dermacentor occidentalis (n=809); the brown dog tick, Rhipicephalus sanguineus sensu lato (n=714); the winter tick, Dermacentor albipictus (n=465); and the Gulf Coast tick, Amblyomma maculatum (n=335). The spinose ear tick, Otobius megnini (n=69), and the pajaroello tick, Ornithodoros coriaceus (n=55) were the argasid species most commonly recorded from humans. Additional information presented for each of the 49 tick species include a breakdown of life stages recorded from humans, broad geographical distribution in the US, host preference, and associated human pathogens or medical conditions. The paper also provides a history of publications on human tick encounters in the US, with tables outlining publications containing quantitative data on human tick encounters as well as other notable publications on human-tick interactions. Data limitations are discussed. Researchers and public health professionals in possession of unpublished human tick encounter data are strongly encouraged to publish this information in peer-reviewed scientific journals. In future papers, it would be beneficial if data consistently were broken down by tick species and life stage as well as host species and ticks found biting versus crawling on clothing or skin.
Topics: Dogs; Animals; Humans; United States; Dermacentor; Rhipicephalus sanguineus; Ixodes; Ornithodoros; Bites and Stings; Amblyomma; Tick Infestations
PubMed: 35973261
DOI: 10.1016/j.ttbdis.2022.102025 -
Frontiers in Cellular and Infection... 2017Crimean-Congo hemorrhagic fever virus (CCHFV) is transmitted to humans by bite of infected ticks or by direct contact with blood or tissues of viremic patients or... (Review)
Review
Crimean-Congo hemorrhagic fever virus (CCHFV) is transmitted to humans by bite of infected ticks or by direct contact with blood or tissues of viremic patients or animals. It causes to humans a severe disease with fatality up to 30%. The current knowledge about the vector-host-CCHFV interactions is very limited due to the high-level containment required for CCHFV studies. Among ticks, spp. are considered the most competent virus vectors. CCHFV evades the tick immune response, and following its replication in the lining of the tick's midgut, it is disseminated by the hemolymph in the salivary glands and reproductive organs. The introduction of salivary gland secretions into the host cells is the major route via which CCHFV enters the host. Following an initial amplification at the site of inoculation, the virus is spread to the target organs. Apoptosis is induced via both intrinsic and extrinsic pathways. Genetic factors and immune status of the host may affect the release of cytokines which play a major role in disease progression and outcome. It is expected that the use of new technology of metabolomics, transcriptomics and proteomics will lead to improved understanding of CCHFV-host interactions and identify potential targets for blocking the CCHFV transmission.
Topics: Animals; Cytokines; Hemorrhagic Fever Virus, Crimean-Congo; Hemorrhagic Fever, Crimean; Host-Pathogen Interactions; Humans; Ixodidae; Metabolomics; Proteomics; Salivary Glands; Symbiosis; Ticks; Virus Replication
PubMed: 28603698
DOI: 10.3389/fcimb.2017.00213 -
Frontiers in Bioscience (Landmark... Jan 2009Many challenges face tick genomics. Ticks have large genomes and their estimated sizes vary from 1.04~7.1 x10(9) bp, about one third to over two times the size of the... (Review)
Review
Many challenges face tick genomics. Ticks have large genomes and their estimated sizes vary from 1.04~7.1 x10(9) bp, about one third to over two times the size of the human genome. Karyotype studies have revealed a range in chromosome number and the sex determining system seems to be primarily driven by a XY or a XO format. Re-association hybridization kinetics indicates that the bulk of the tick genome consists of repetitive sequences and only 30~35% of the genome consists of low copy number sequences. The former remain poorly characterized and most of what we know about the latter has been driven by gene discovery projects via generation of expressed sequence tags (ESTs). However, large scale EST data (>10,000 ESTs) are available for only three tick species. The only whole genome sequencing project for ticks is that on Ixodes scapularis, the primary tick vector of medical importance in the United States. Nevertheless, important advances are being made in developing genomics tools and these will stimulate research in tick and vector biology.
Topics: Animals; Databases, Genetic; Expressed Sequence Tags; Female; Genomics; Male; Ticks
PubMed: 19273226
DOI: 10.2741/3404 -
Parasites & Vectors Sep 2019Ticks are obligate blood-sucking arachnid ectoparasites from the order Acarina, and many are notorious as vectors of a wide variety of zoonotic pathogens. However, the... (Review)
Review
Ticks are obligate blood-sucking arachnid ectoparasites from the order Acarina, and many are notorious as vectors of a wide variety of zoonotic pathogens. However, the systematics of ticks in several genera is still controversial. The mitochondrial genome (mt-genome) has been widely used in arthropod phylogeny, molecular evolution and population genetics. With the development of sequencing technologies, an increasing number of tick mt-genomes have been sequenced and annotated. To date, 63 complete tick mt-genomes are available in the NCBI database, and these genomes have become an increasingly important genetic resource and source of molecular markers in phylogenetic studies of ticks in recent years. The present review summarizes all available complete mt-genomes of ticks in the NCBI database and analyses their characteristics, including structure, base composition and gene arrangement. Furthermore, a phylogenetic tree was constructed using mitochondrial protein-coding genes (PCGs) and ribosomal RNA (rRNA) genes from ticks. The results will provide important clues for deciphering new tick mt-genomes and establish a foundation for subsequent taxonomic research.
Topics: Animals; Base Composition; Gene Order; Genome, Mitochondrial; Mitochondria; Phylogeny; Ticks
PubMed: 31519208
DOI: 10.1186/s13071-019-3705-3 -
Frontiers in Cellular and Infection... 2013Interest in tick-transmitted pathogens has experienced an upsurge in the past few decades. Routine application of tools for the detection of fragments of foreign DNA in... (Review)
Review
Interest in tick-transmitted pathogens has experienced an upsurge in the past few decades. Routine application of tools for the detection of fragments of foreign DNA in ticks, together with a high degree of interest in the quantification of disease risk for humans, has led to a marked increase in the number of reports on the eco-epidemiology of tick-borne diseases. However, procedural errors continue to accumulate in the scientific literature, resulting in misleading information. For example, unreliable identification of ticks and pathogens, erroneous interpretations of short-term field studies, and the hasty acceptance of some tick species as vectors have led to ambiguities regarding the vector role of these arthropods. In this review, we focus on the ecological features driving the life cycle of ticks and the resulting effects on the eco-epidemiology of tick-transmitted pathogens. We review the factors affecting field collections of ticks, and we describe the biologically and ecologically appropriate procedures for describing tick host-seeking activity and its correlation with environmental traits. We detail the climatic variables that have biological importance on ticks and explain how they should be properly measured and analyzed. We also provide evidence to critically reject the use of some environmental traits that are being increasingly reported as the drivers of the behavior of ticks. With the aim of standardization, we propose unambiguous definitions of the status of hosts and ticks regarding their ability to maintain and spread a given pathogen. We also describe laboratory procedures and standards for evaluating the vectorial capacity of a tick or the reservoir role of a host. This approach should provide a coherent framework for the reporting of research findings concerning ticks and tick-borne diseases.
Topics: Animals; Arachnid Vectors; Ecology; Entomology; Host-Pathogen Interactions; Humans; Microbiological Techniques; Parasitology; Tick-Borne Diseases; Ticks; Virology
PubMed: 23964348
DOI: 10.3389/fcimb.2013.00029 -
Parasites & Vectors Jan 2018The tick microbiome comprises communities of microorganisms, including viruses, bacteria and eukaryotes, and is being elucidated through modern molecular techniques. The... (Review)
Review
The tick microbiome comprises communities of microorganisms, including viruses, bacteria and eukaryotes, and is being elucidated through modern molecular techniques. The advent of next-generation sequencing (NGS) technologies has enabled the genes and genomes within these microbial communities to be explored in a rapid and cost-effective manner. The advantages of using NGS to investigate microbiomes surpass the traditional non-molecular methods that are limited in their sensitivity, and conventional molecular approaches that are limited in their scalability. In recent years the number of studies using NGS to investigate the microbial diversity and composition of ticks has expanded. Here, we provide a review of NGS strategies for tick microbiome studies and discuss the recent findings from tick NGS investigations, including the bacterial diversity and composition, influential factors, and implications of the tick microbiome.
Topics: Animals; High-Throughput Nucleotide Sequencing; Metagenomics; Microbiota; Ticks
PubMed: 29301588
DOI: 10.1186/s13071-017-2550-5 -
Frontiers in Cellular and Infection... 2017Ticks are obligate hematophagous arthropods of significant importance to human and veterinary medicine. They transmit a vast array of pathogens, including bacteria,... (Review)
Review
Ticks are obligate hematophagous arthropods of significant importance to human and veterinary medicine. They transmit a vast array of pathogens, including bacteria, viruses, protozoa, and helminths. Most epidemiological data on ticks and tick-borne pathogens (TBPs) in the West Indies are limited to common livestock pathogens such as spp. (i.e., and ), and , and less information is available on companion animal pathogens. Of note, human tick-borne diseases (TBDs) remain almost completely uncharacterized in the West Indies. Information on TBP presence in wildlife is also missing. Herein, we provide a comprehensive review of the ticks and TBPs affecting human and animal health in the Caribbean, and introduce the challenges associated with understanding TBD epidemiology and implementing successful TBD management in this region. In particular, we stress the need for innovative and versatile surveillance tools using high-throughput pathogen detection (e.g., high-throughput real-time microfluidic PCR). The use of such tools in large epidemiological surveys will likely improve TBD prevention and control programs in the Caribbean.
Topics: Anaplasma marginale; Animal Diseases; Animals; Animals, Wild; Babesia; Caribbean Region; Ehrlichia ruminantium; Epidemiological Monitoring; High-Throughput Screening Assays; Humans; Insect Vectors; Tick-Borne Diseases; Ticks; West Indies
PubMed: 29238699
DOI: 10.3389/fcimb.2017.00490 -
Virus Research Jan 2023Ticks transmit diverse human and animal pathogens, leading to an increasing number of public health concerns. In the forest area of northeast China, the spread of...
Ticks transmit diverse human and animal pathogens, leading to an increasing number of public health concerns. In the forest area of northeast China, the spread of tick-borne diseases (TBDs) is severe; however, little is known about the tick virome composition and evolution. Herein, we investigate the geographical distribution of tick species and related viruses in Heilongjiang and Jilin Provinces in Northeast China. To reveal the diversity of tick-borne viruses in parts of Heilongjiang and Jilin, ticks were collected at 9 collection points in these provinces in 2018. Morphology and molecular biology were used to identify tick species, and 1411 ticks from nine sampling sites were collected and analysed by next-generation sequencing (NGS). Four Ixodidae were identified, including Ixodes persulcatus, Haemaphysalis japonica, Dermacentor silvarum, and Haemaphysalis concinna. After removal of host genome sequences, 13,003 high-quality NGS reads were obtained and annotated as viruses. Further phylogenetic analysis based on amplicons revealed that these viral sequences belong to Beiji nairovirus, Alongshan virus, bovine parvovirus-2, and tick-associated circovirus; some distinct sequences are closely related to Songling virus, Changping tick virus, Norway luteo-like virus 2, and Norway partiti-like virus 1. In summary, this study describes the prevalence of local ticks and variety of tick-borne viruses in northeastern China, providing a basis for further research on tick-borne viruses in the future.
Topics: Animals; Humans; Phylogeny; Virome; Ixodes; Ixodidae; Viruses; China
PubMed: 36414189
DOI: 10.1016/j.virusres.2022.199006 -
Parasites & Vectors Mar 2022In Ethiopia, ixodid ticks and associated tick-borne pathogens (TBPs) are of great importance from both a veterinary and public health point of view. This review aimed at... (Review)
Review
BACKGROUND
In Ethiopia, ixodid ticks and associated tick-borne pathogens (TBPs) are of great importance from both a veterinary and public health point of view. This review aimed at compiling available published data on the distribution of ixodid tick species and TBPs in the country.
METHODS
A standard review approach was employed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Published peer-reviewed articles and theses/dissertations reporting on ixodid ticks and TBPs in Ethiopia were searched using different keywords in many electronic databases including PubMed, Scopus, Web of Science, Google Scholar, African Journals OnLine, and institutional repositories. Articles were screened based on inclusion and exclusion criteria using the PRISMA flowchart. Data were retrieved from eligible articles and recorded in a preformed data record sheet. Descriptive statistics were employed to present data using graphs. QGIS (Quantum GIS) software version 3.4.5 was used to show the distribution of ixodid tick species and TBPs.
RESULTS
Overall, 35 articles that met the inclusion criteria were included in this review. Of these, 24 articles report only on ixodid ticks of domestic animals, six articles report only on TBPs in livestock or ticks, and five articles report on both ticks and TBPs in either animals or ticks. Of these studies, 54% were in the Oromia region, while only 3% of studies were in the Benishangul-Gumuz region. The Gambela region lacked studies on ticks and TBPs. At least 19 ixodid tick species have been recorded from different domestic animals including cattle, small ruminants, donkeys, horses, camels, dogs, and cats. Morphological characterization appears to be the sole method of tick species identification in the country. The distribution and abundance of specific tick species depend on geographical locations and agroecological factors. Sixteen molecularly confirmed TBPs have been identified in animal and tick tissue using molecular methods from only four administrative regions, despite the wide distribution of ticks. Among TBPs, five Anaplasma, two Ehrlichia, two Rickettsia, five Theileria, two Babesia, and one Coxiella species are the major pathogens in both livestock and humans.
CONCLUSIONS
Many ixodid ticks circulate in a wide geographical zone of Ethiopia. However, the limited reports on TBPs at the country level in general, and the absence of either tick or TBP reports around the border region with neighboring countries in particular, highlights the need for further study.
Topics: Animals; Animals, Domestic; Ethiopia; Ixodidae; Tick-Borne Diseases; Ticks
PubMed: 35346354
DOI: 10.1186/s13071-022-05221-x -
Parasites & Vectors Jan 2022A number of tick-borne pathogens circulate in the Belgian tick population in addition to the causative agent of Lyme borreliosis. However, so far, only a few patients...
BACKGROUND
A number of tick-borne pathogens circulate in the Belgian tick population in addition to the causative agent of Lyme borreliosis. However, so far, only a few patients with tick-borne diseases other than Lyme borreliosis have been reported in Belgium. The aim of this study was to investigate the occurrence of other human tick-borne infections in Belgium and their possible clinical manifestation.
METHODS
Patients with fever (> 37.5 °C) after a tick bite or those with erythema migrans (EM) were included in the study. EDTA-blood samples were screened for the presence of DNA from Borrelia burgdorferi sensu lato, Borrelia miyamotoi, Anaplasma phagocytophilum, Neoehrlichia mikurensis, spotted fever group rickettsiae (genus Rickettsia), Babesia spp., Bartonella spp., Spiroplasma ixodetis and tick-borne encephalitis virus, using multiplex PCR methods. A questionnaire on, among others, demographics and clinical symptoms, was also filled in.
RESULTS
Over a period of 3 years, 119 patients with EM and 14 patients with fever after a recent tick bite were enrolled in the study. Three samples initially tested positive for N. mikurensis by quantitative PCR (qPCR), but the results could not be confirmed by other PCR methods, and repetition of the DNA extraction procedure and qPCR test was not successful. The qPCR test results for the other tick-borne pathogens were negative.
CONCLUSIONS
In general, only a few patients with fever after a tick bite could be identified. Although no tick-borne pathogens were detected, their occurrence cannot be excluded based on the limited number of patients and the limitations inherent to current methodologies. This study underscores the possibility of false-positive PCR results and the necessity for the development of multiple independent tools for the sensitive and specific detection of emerging tick-borne pathogens.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Animals; Babesia; Belgium; Borrelia; Erythema; Female; Fever; Humans; Male; Middle Aged; Rickettsia; Tick Bites; Tick-Borne Diseases; Ticks; Young Adult
PubMed: 35057826
DOI: 10.1186/s13071-021-05139-w