Hard ticks
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Ticks and tick-borne pathogens (TBPs) pose a considerable threat to human and animal health in Mongolia; a large and sparsely inhabited country whose economy is largely dependent on animal production. Intensive contact between herdsmen and their livestock, together with the use of pastures without fencing, allows contact between wildlife, domestic animals and humans, thus creating ideal conditions for epizoonoses and zoonoses. Consequently, ticks and TBPs cause significant medical, veterinary, and economical concern. This review summarizes the current state of knowledge about this zoonotic problem in Mongolia, focusing on tick species from the genera Ixodes, Haemaphysalis, Dermacentor, Hyalomma, and Rhipicephalus, which are associated with particular vegetation zones of the country. The most important tick species of medical and veterinary concern are Ixodes persulcatus and Dermacentor nuttalli, which are found in northern boreal forests and central steppes, respectively. These tick species transmit a wide variety of TBPs, including tick-borne encephalitis virus, Borrelia, Anaplasma, and Rickettsia bacteria, and Babesia parasites infecting rodents, wild ungulates, livestock, and humans. Despite basic characteristics of the biology of ticks and TBPs in Mongolia being known, further research is needed to gain more precise and quantitative data on what tick species and TBPs are currently present within Mongolia, and their effects on human health and animal production.
- MeSH
- Ixodidae fyziologie MeSH
- nemoci přenášené klíšťaty přenos virologie MeSH
- rozšíření zvířat * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Geografické názvy
- Mongolsko MeSH
The symbiotic microorganisms of arthropod vectors are highly significant from several points of view, partly due to their possible roles in the transmission of pathogenic causative agents by blood-sucking vectors. Although ticks are well studied because of their significance to human health, novel microbial associations remain to be described. This review summarises several endosymbiotic bacterial species in hard ticks from various parts of the world, including Coxiella-, Francisella-, Rickettsia- and Arsenophonus-like symbionts as well as Candidatus Midichloria mitochondrii and Wolbachia. New methodologies for the isolation and characterization of tick-associated bacteria will, in turn, encourage new strategies of tick control by studying their endosymbionts.
Culture-independent metagenomic methodologies have enabled detection and identification of microorganisms in various biological systems and often revealed complex and unknown microbiomes. In many organisms, the microbiome outnumbers the host cells and greatly affects the host biology and fitness. Ticks are hematophagous ectoparasites with a wide host range. They vector a number of human and animal pathogens and also directly cause major economic losses in livestock. Although several reports on a tick midgut microbiota show a diverse bacterial community, in most cases the size of the bacterial population has not been determined. In this study, the microbiome was quantified in the midgut and ovaries of the ticks Ixodes ricinus and Rhipicephalus microplus before, during, and after blood feeding. Although the size of bacterial community in the midgut fluctuated with blood feeding, it was overall extremely low in comparison to that of other hematophagous arthropods. In addition, the tick ovarian microbiome of both tick species exceeded the midgut 16S rDNA copy numbers by several orders of magnitude. This indicates that the ratio of a tick midgut/ovary microbiome represents an exception to the general biology of other metazoans. In addition to the very low abundance, the tick midgut diversity in I. ricinus was variable and that is in contrast to that found in the tick ovary. The ovary of I. ricinus had a very low bacterial diversity and a very high and stable bacterial abundance with the dominant endosymbiont, Midichloria sp. The elucidation of this aspect of tick biology highlights a unique tissue-specific microbial-invertebrate host interaction.
- MeSH
- Ixodidae * MeSH
- klíště * MeSH
- lidé MeSH
- mikrobiota * MeSH
- ovarium MeSH
- Rhipicephalus * MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
In Romania, data regarding hard-tick diversity and tick-host associations in wild carnivores are scarce. We aimed to identify tick species in wild carnivores and to establish reliable data on tick-host associations. The study was conducted in various Romanian localities from all five ecoregions found in the country. Fourteen species of wild carnivores were examined. Immature and adult ticks were collected and identified using the morphological keys. The frequency and mean intensity of tick infestation, overall and differentiated by species, developmental stage and host were calculated. Of 202 wild carnivores, 68 were parasitized by seven tick species (predominantly Ixodes ricinus, I. hexagonus and Dermacentor reticulatus). The mean intensity of tick infestation was similar in males (6.97, BCa 95% CI 5.15-9.88) and females (5.76, BCa 95% CI 4.15-9.17). The highest prevalence of infested animals was recorded in the pannonian and steppic ecoregions, 66.7 and 52.7%, respectively. In the continental ecoregion the prevalence was 26.7%, whereas in the pontic ecoregion it was 28%. The lowest value, 16.7% was recorded in the alpine ecoregion. In total 430 ticks were collected, and 24.8% (n = 50) of the animals were infested with more than one tick species. Fourteen new tick-host associations were recorded. Our results suggest that anthropogenic changes of the environment lead to the diminishing of the boundaries, between wild and domestic animals, increasing the exposure for both animals and humans, to infective agents, including tick-borne pathogens.
- MeSH
- Carnivora * MeSH
- divoká zvířata MeSH
- infestace klíšťaty epidemiologie parazitologie veterinární MeSH
- Ixodidae růst a vývoj fyziologie MeSH
- larva fyziologie MeSH
- nymfa fyziologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Rumunsko epidemiologie MeSH
Borrelia turcica comprises the third major group of arthropod-transmitted borreliae and is phylogenetically divergent from other Borrelia groups. The novel group of Borrelia was initially isolated from Hyalomma aegyptium ticks in Turkey and it was recently found in blood and multiple organs of tortoises exported from Jordan to Japan. However, the ecology of these spirochetes and their development in ticks or the vertebrate hosts were not investigated in detail; our aims were to isolate the pathogen and to evaluate the possibility of transstadial transmission of Borrelia turcica by H. aegyptium ticks. Ticks were collected from Testudo graeca tortoises during the summer of 2013 from southeastern Romania. Engorged nymphs were successfully molted to the adult stage. Alive B. turcica was isolated from molted ticks by using Barbour-Stoenner-Kelly (BSK) II medium. Four pure cultures of spirochetes were obtained and analyzed by PCR and sequencing. Sequence analysis of glpQ, gyrB and flaB revealed 98%-100% similarities with B. turcica. H. aegyptium ticks collected from T. graeca tortoises were able to pass the infection with B. turcica via transstadial route, suggesting its vectorial capacity.
The aim of this study was to document the presence of Rickettsia spp. in ticks parasitizing wild birds in Costa Rica. Birds were trapped at seven locations in Costa Rica during 2004, 2009, and 2010; then visually examined for the presence of ticks. Ticks were identified, and part of them was tested individually for the presence of Rickettsia spp. by polymerase chain reaction (PCR) using primers targeting fragments of the rickettsial genes gltA and ompA. PCR products were DNA-sequenced and analyzed in BLAST to determine similarities with previously reported rickettsial agents. A total of 1878 birds were examined, from which 163 birds (9%) were infested with 388 ticks of the genera Amblyomma and Ixodes. The following Amblyomma (in decreasing order of abundance) were found in immature stages (larvae and nymphs): Amblyomma longirostre, Amblyomma calcaratum, Amblyomma coelebs, Amblyomma sabanerae, Amblyomma varium, Amblyomma maculatum, and Amblyomma ovale. Ixodes ticks were represented by Ixodes minor and two unclassified species, designated here as Ixodes sp. genotype I, and Ixodes sp. genotype II. Twelve of 24 tested A. longirostre ticks were found to be infected with 'Candidatus Rickettsia amblyommii', and 2 of 4 A. sabanerae were found to be infected with Rickettsia bellii. Eight of 10 larval Ixodes minor were infected with an endosymbiont (a novel Rickettsia sp. agent) genetically related to the Ixodes scapularis endosymbiont. No rickettsial DNA was found in A. calcaratum, A. coelebs, A. maculatum, A. ovale, A. varium, Ixodes sp. I, and Ixodes sp. II. We report the occurrence of I. minor in Costa Rica for the first time and a number of new bird host-tick associations. Moreover, 'Candidatus R. amblyommii' and R. bellii were found in A. longirostre and A. sabanerae, respectively, in Costa Rica for the first time.
- MeSH
- divoká zvířata parazitologie MeSH
- infestace klíšťaty parazitologie veterinární MeSH
- Ixodidae klasifikace genetika růst a vývoj mikrobiologie MeSH
- larva klasifikace genetika růst a vývoj mikrobiologie MeSH
- nemoci ptáků parazitologie MeSH
- ptáci MeSH
- Rickettsia klasifikace genetika izolace a purifikace MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Kostarika MeSH
Despite the importance of ticks as vectors of disease very little is known about their immune system. Antimicrobial peptides, including defensins (phylogenetically ancient antibacterial peptides) are major components of innate immunity in ticks that have been shown to provide protection against gram-negative and gram-positive bacteria, fungi, viruses and protozoan parasites. With the aim of studying the evolution of the genes involved in tick defense, we identified the preprodefensin genes from four Ornithodoros tick species (O. papillipes: isoforms A, B, and D; O. tartakovskyi and O. puertoricensis: isoforms A and B; O. rostratus: isoform A) and from two Dermacentor tick species (D. reticulatus and D. marginatus: one isoform) not previously described. Phylogenetic analyses revealed that Ornithodoros defensin isoforms (A, B, C, and D) form 4 separate clades, while hard tick defensins are divided into several branches based on particular tick species.
Ticks are important vectors of various pathogens that cause infectious diseases in humans. Endosymbiotic bacteria have been explored as targets for tick and tick-borne disease control. However, the tick bacterial community on Hainan Island, which is the largest tropical island in China and has an environment favourable to ticks, has not yet been studied. In this study, we surveyed the bacterial community of ticks collected from grass in one village in Haikou. A total of 20 ticks were morphologically and molecularly identified as Haemaphysalis spp. The tick bacterial 16S rRNA hypervariable region amplicon libraries were sequenced on an Illumina MiSeq platform. A total of 10 possible bacterial genera were detected, indicating a low-diversity bacterial community profile. The dominant bacterial genus, Massilia, accounted for 97.85% of the population. Some other bacterial genera, including Arsenophonus and Pseudomonas, have been reported to play a role in tick development and tick-borne pathogen transmission in other tick species. Overall, the study highlights the first descriptive understanding of the tick bacterial community on Hainan Island and provides a basis for deciphering the interactions between the tick microbiome and tick-borne pathogens.
- MeSH
- Bacteria genetika MeSH
- Ixodidae * mikrobiologie MeSH
- klíšťata * MeSH
- lidé MeSH
- RNA ribozomální 16S genetika MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Čína MeSH
The aim of the present study is to compare the prevalence of Borrelia burgdorferi sensu lato (s.l.) and Anaplasma phagocytophilum in questing ticks by using molecular methods from spring to autumn 2007. A total of 526 Ixodes ricinus ticks were collected from vegetation in three different sampling sites, representing an urban area (city park), a suburban area (village) and a natural montane habitat. The prevalence of B. burgdorferi s.l. was 17.3% (7.5% in males, 18.7% in females and 20.2% in nymphs), while 4.4% of ticks (13.1% of males, 3.7% of females and 1.6% of nymphs) tested positive for A. phagocytophilum. We found higher rates of Anaplasma infection in ticks from the urban area (8.6%) than from the suburban (0.8%) and natural (1.6%) habitats in the spring months. The prevalence of Borrelia infection in the urban park increased significantly from spring (14% in March) to autumn (50% in October). The Anaplasma positivity in the urban area in the autumn months (2.2%) was significantly lower than in the spring and summer months (9.6%). The prevalence of A. phagocytophilum was significantly higher in male ticks than in females and nymphs. For B. burgdorferi s.l., the inverse was true. We conclude that infection risks associated with the presence of Anaplasma and Borrelia in ticks in cities may be comparable to those in natural ecosystems or may be even higher. Our results indicate the need for the surveillance of tick-borne pathogens in urban areas.
- MeSH
- Anaplasma phagocytophilum izolace a purifikace MeSH
- Borrelia burgdorferi komplex izolace a purifikace MeSH
- ekosystém MeSH
- Ixodidae růst a vývoj mikrobiologie MeSH
- nymfa růst a vývoj mikrobiologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
