'Omics' technologies have facilitated the identification of hundreds to thousands of tick molecules that mediate tick feeding and play a role in the transmission of tick-borne diseases. Deep sequencing methodologies have played a key role in this knowledge accumulation, profoundly facilitating the study of the biology of disease vectors lacking reference genomes. For example, the nucleotide sequences of the entire set of tick salivary effectors, the so-called tick 'sialome', now contain at least one order of magnitude more transcript sequences compared to similar projects based on Sanger sequencing. Tick feeding is a complex and dynamic process, and while the dynamic 'sialome' is thought to mediate tick feeding success, exactly how transcriptome dynamics relate to tick-host-pathogen interactions is still largely unknown. The identification and, importantly, the functional analysis of the tick 'sialome' is expected to shed light on this 'black box'. This information will be crucial for developing strategies to block pathogen transmission, not only for anti-tick vaccine development but also the discovery and development of new, pharmacologically active compounds for human diseases.
- MeSH
- genom fyziologie MeSH
- interakce hostitele a patogenu MeSH
- klíšťata genetika fyziologie MeSH
- lidé MeSH
- proteomika * MeSH
- slinné žlázy fyziologie MeSH
- transkriptom fyziologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Při registraci biocidního či repelentního přípravku v Evropské Unii a Spojených státech amerických je nutné předložit test účinnosti v souladu s nařízením a metodikou Evropské agentury pro chemické látky a Agentury pro ochranu životního prostředí. Přestože se nymfy a samice klíšťat výrazně liší z behaviorálního i morfologického hlediska, obě výše uvedené instituce ve svých metodikách povolují použít pro laboratorní testy nymfy a (nebo) samice. V tomto článku přinášíme důkaz o rozdílech mezi těmito stádii klíštěte Ixodes ricinus v mobilitě (P < 0,05) a senzitivitě k repelentu DEET (P < 0,0001). Tato studie tedy ukazuje, že výběr stádia pro testování může ovlivnit výsledky testu, přestože budou testy účinnosti provedeny v souladu s doporučenou metodikou.
In the European Union and United States of America, the efficacy of a biocide or repellent coming onto the market has to be evaluated according to the guidelines of the European Chemical Agency and the United States Environmental Protection Agency. Despite the obvious differences in morphology and behaviour, both these guidelines allow the use of nymph or adult female ticks for laboratory testing. Here, we provide evidence that sensitivity of Ixodes ricinus nymphs to diethyltoluamide (DEET) within the in-vitro trial was significantly higher compared to adult females (P < 0.0001). We also observed that feral ticks were less sensitive to the repellent than were laboratory-reared ticks (P < 0.01) and that mobility decreased when the trial was repeated (P < 0.05). This study has shown that the efficacy testing results may vary significantly between the two developmental stages even when the protocol is conducted in accordance with the guidelines.
Vector-borne pathogens establish systemic infections in host tissues to maximize transmission to arthropod vectors. Co-feeding transmission occurs when the pathogen is transferred between infected and naive vectors that feed in close spatiotemporal proximity on a host that has not yet developed a systemic infection. Borrelia afzelii is a tick-borne spirochete bacterium that causes Lyme borreliosis (LB) and is capable of co-feeding transmission. Whether ticks that acquire LB pathogens via co-feeding are actually infectious to vertebrate hosts has never been tested. We created nymphs that had been experimentally infected as larvae with B. afzelii via co-feeding or systemic transmission, and compared their performance over one complete LB life cycle. Co-feeding nymphs had a spirochete load that was 26 times lower than systemic nymphs but both nymphs were highly infectious to mice (i.e., probability of nymph-to-host transmission of B. afzelii was ~100%). The mode of transmission had no effect on the other infection phenotypes of the LB life cycle. Ticks that acquire B. afzelii via co-feeding transmission are highly infectious to rodents, and the resulting rodent infection is highly infectious to larval ticks. This is the first study to show that B. afzelii can use co-feeding transmission to complete its life cycle.
- MeSH
- arachnida jako vektory mikrobiologie fyziologie MeSH
- klíšťata mikrobiologie fyziologie MeSH
- krmivo pro zvířata mikrobiologie MeSH
- lymeská nemoc mikrobiologie přenos MeSH
- myši MeSH
- nymfa mikrobiologie fyziologie MeSH
- stadia vývoje MeSH
- zdroje nemoci mikrobiologie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
Ticks are vectors of pathogens affecting human and animal health worldwide. Nevertheless, the ecological and evolutionary interactions between ticks, hosts, and pathogens are largely unknown. Here, we integrated a framework to evaluate the associations of the tickIxodes ricinuswith its hosts and environmental niches that impact pathogen circulation. The analysis of tick-hosts association suggested that mammals and lizards were the ancestral hosts of this tick species, and that a leap to Aves occurred around 120 M years ago. The signature of the environmental variables over the host's phylogeny revealed the existence of two clades of vertebrates diverging along a temperature and vegetation split. This is a robust proof that the tick probably experienced a colonization of new niches by adapting to a large set of new hosts, Aves. Interestingly, the colonization of Aves as hosts did not increase significantly the ecological niche ofI. ricinus, but remarkably Aves are super-spreaders of pathogens. The disparate contribution of Aves to the tick-host-pathogen networks revealed thatI. ricinusevolved to maximize habitat overlap with some hosts that are super-spreaders of pathogens. These results supported the hypothesis that large host networks are not a requirement of tick survival but pathogen circulation. The biological cost of tick adaptation to non-optimal environmental conditions might be balanced by molecular mechanisms triggered by the pathogens that we have only begun to understand.
- MeSH
- biologická adaptace MeSH
- druhová specificita MeSH
- ekologie metody MeSH
- interakce hostitele a patogenu MeSH
- ještěři parazitologie MeSH
- klíšťata mikrobiologie parazitologie fyziologie MeSH
- klíště klasifikace parazitologie fyziologie MeSH
- lidé MeSH
- nemoci přenášené klíšťaty parazitologie přenos MeSH
- obratlovci klasifikace parazitologie MeSH
- ptáci klasifikace parazitologie MeSH
- savci klasifikace parazitologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Ticks and the pathogens they transmit constitute a growing burden for human and animal health worldwide. Vector competence is a component of vectorial capacity and depends on genetic determinants affecting the ability of a vector to transmit a pathogen. These determinants affect traits such as tick-host-pathogen and susceptibility to pathogen infection. Therefore, the elucidation of the mechanisms involved in tick-pathogen interactions that affect vector competence is essential for the identification of molecular drivers for tick-borne diseases. In this review, we provide a comprehensive overview of tick-pathogen molecular interactions for bacteria, viruses, and protozoa affecting human and animal health. Additionally, the impact of tick microbiome on these interactions was considered. Results show that different pathogens evolved similar strategies such as manipulation of the immune response to infect vectors and facilitate multiplication and transmission. Furthermore, some of these strategies may be used by pathogens to infect both tick and mammalian hosts. Identification of interactions that promote tick survival, spread, and pathogen transmission provides the opportunity to disrupt these interactions and lead to a reduction in tick burden and the prevalence of tick-borne diseases. Targeting some of the similar mechanisms used by the pathogens for infection and transmission by ticks may assist in development of preventative strategies against multiple tick-borne diseases.
- MeSH
- arachnida jako vektory mikrobiologie parazitologie virologie MeSH
- interakce hostitele a patogenu * MeSH
- klíšťata mikrobiologie parazitologie fyziologie virologie MeSH
- lidé MeSH
- nemoci přenášené klíšťaty epidemiologie MeSH
- přenos infekční nemoci * MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Haem and iron homeostasis in most eukaryotic cells is based on a balanced flux between haem biosynthesis and haem oxygenase-mediated degradation. Unlike most eukaryotes, ticks possess an incomplete haem biosynthetic pathway and, together with other (non-haematophagous) mites, lack a gene encoding haem oxygenase. We demonstrated, by membrane feeding, that ticks do not acquire bioavailable iron from haemoglobin-derived haem. However, ticks require dietary haemoglobin as an exogenous source of haem since, feeding with haemoglobin-depleted serum led to aborted embryogenesis. Supplementation of serum with haemoglobin fully restored egg fertility. Surprisingly, haemoglobin could be completely substituted by serum proteins for the provision of amino-acids in vitellogenesis. Acquired haem is distributed by haemolymph carrier protein(s) and sequestered by vitellins in the developing oocytes. This work extends, substantially, current knowledge of haem auxotrophy in ticks and underscores the importance of haem and iron metabolism as rational targets for anti-tick interventions.
- MeSH
- fertilita MeSH
- hem metabolismus MeSH
- klíšťata metabolismus fyziologie MeSH
- rozmnožování MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- klíšťata * fyziologie MeSH
- lidé MeSH
- myši MeSH
- serpiny chemie imunologie MeSH
- sliny * chemie imunologie mikrobiologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- biografie MeSH
- O autorovi
- Chmelař, Jindřich Autorita
Blood-protein digestion is a key physiological process providing essential nutrients for ticks and is a prerequisite for the transmission of tick-borne pathogens. Recently, substantial progress has been made in determining the proteolytic machinery in tick gut tissue, which is based on a dynamic multienzyme network capable of processing a vast amount of host blood. In this article we summarize our current knowledge of the molecular mechanisms of tick hematophagy and their similarities to those of Platyhelminthes, nematodes, and Plasmodium. Future research perspectives, including the potential for rational control of ticks and transmitted diseases, are also discussed.
- MeSH
- gastrointestinální trakt enzymologie MeSH
- klíšťata fyziologie MeSH
- krevní proteiny metabolismus MeSH
- trávení fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
