Up to 170 tick-borne viruses (TBVs) have been identified to date. However, there is a paucity of information regarding TBVs and their interaction with respective vectors, limiting the development of new effective and urgently needed control methods. To overcome this gap of knowledge, it is essential to reproduce transmission cycles under controlled laboratory conditions. In this study we assessed an artificial feeding system (AFS) and an immersion technique (IT) to infect Ixodes ricinus ticks with tick-borne encephalitis (TBE) and Kemerovo (KEM) virus, both known to be transmitted predominantly by ixodid ticks. Both methods permitted TBEV acquisition by ticks and we further confirmed virus trans-stadial transmission and onward transmission to a vertebrate host. However, only artificial feeding system allowed to demonstrate both acquisition by ticks and trans-stadial transmission for KEMV. Yet we did not observe transmission of KEMV to mice (IFNAR-/- or BALB/c). Artificial infection methods of ticks are important tools to study tick-virus interactions. When optimally used under laboratory settings, they provide important insights into tick-borne virus transmission cycles.
- MeSH
- arachnida jako vektory fyziologie virologie MeSH
- interakce hostitele a patogenu MeSH
- klíště fyziologie virologie MeSH
- klíšťová encefalitida přenos virologie MeSH
- lidé MeSH
- myši inbrední BALB C MeSH
- myši MeSH
- Orbivirus fyziologie MeSH
- reovirové infekce přenos virologie MeSH
- virologie metody MeSH
- viry klíšťové encefalitidy fyziologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem 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.
Quantitative and microscopic tracking of Borrelia afzelii transmission from infected Ixodes ricinus nymphs has shown a transmission cycle different from that of Borrelia burgdorferi and Ixodes scapularisBorrelia afzelii organisms are abundant in the guts of unfed I. ricinus nymphs, and their numbers continuously decrease during feeding. Borrelia afzelii spirochetes are present in murine skin within 1 day of tick attachment. In contrast, spirochetes were not detectable in salivary glands at any stage of tick feeding. Further experiments demonstrated that tick saliva is not essential for B. afzelii infectivity, the most important requirement for successful host colonization being a change in expression of outer surface proteins that occurs in the tick gut during feeding. Spirochetes in vertebrate mode are then able to survive within the host even in the absence of tick saliva. Taken together, our data suggest that the tick gut is the decisive organ that determines the competence of I. ricinus to vector B. afzelii We discuss possible transmission mechanisms of B. afzelii spirochetes that should be further tested in order to design effective preventive and therapeutic strategies against Lyme disease.
- MeSH
- arachnida jako vektory mikrobiologie fyziologie MeSH
- Borrelia burgdorferi komplex fyziologie MeSH
- klíště mikrobiologie fyziologie MeSH
- lidé MeSH
- lymeská nemoc mikrobiologie přenos MeSH
- myši inbrední C3H MeSH
- myši MeSH
- nymfa mikrobiologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Tick-borne encephalitis (TBE) is a serious acute neuroinfection of humans caused by a tick-borne flavivirus. The disease is typically seasonal, linked to the host-seeking activity of Ixodes ricinus (predominantly nymphs), the principal European tick vector species. To address the need for accurate risk predictions of contracting TBE, data on 4,044 TBE cases reported in the Czech Republic during 2001-2006 were compared with questing activity of I. ricinus nymphs monitored weekly at a defined location for the same 6-year period. A time shift of 21 days between infected tick bite and recorded disease onset provided the optimal model for comparing the number of cases of TBE with numbers of questing nymphs. Mean annual distribution of TBE cases and tick counts showed a similar bimodal distribution. Significantly, the ratio of TBE cases to questing nymphs was highest in the summer-autumn period even though the number of questing nymphs peaked in the spring-summer period. However, this pattern changed during a period of extreme meteorological events of flooding and abnormally high temperatures, indicating that changes in climate affect the incidence of TBE. Previous studies failed to link human behavior with changes in incidence of TBE but showed extrinsic temperature impacts arbovirus replication. Hence, we hypothesize the apparent discrepancy between peak nymphal tick activity and greatest risk of contracting TBE is due to the effect of temperature on virus replication in the tick vector. Relative proportions of questing nymphs and the numbers of weeks in which they were found were greater in summer-autumn compared with spring-summer at near-ground temperatures >5°C and at standard day and weekly average temperatures of >15°C. Thus, during the summer-autumn period, the virus dose in infected tick bites is likely greater owing to increased virus replication at higher microclimatic temperatures, consequently increasing the relative risk of contracting TBE per summer-autumn tick bite. The data support the use of weather-based forecasts of tick attack risk (based on daytime ambient temperature) supplemented with weekly average temperature (as a proxy for virus replication) to provide much-needed real-time forecasts of TBE risk.
- MeSH
- arachnida jako vektory fyziologie virologie MeSH
- incidence MeSH
- klíště fyziologie virologie MeSH
- klíšťová encefalitida epidemiologie přenos virologie MeSH
- lidé MeSH
- počasí MeSH
- roční období MeSH
- teplota MeSH
- viry klíšťové encefalitidy genetika izolace a purifikace fyziologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
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
Dermacentor reticulatus is a hard tick species with extraordinary biological features. It has a high reproduction rate, a rapid developmental cycle, and is also able to overcome years of unfavourable conditions. Dermacentor reticulatus can survive under water for several months and is cold-hardy even compared to other tick species. It has a wide host range: over 60 different wild and domesticated hosts are known for the three active developmental stages. Its high adaptiveness gives an edge to this tick species as shown by new data on the emergence and establishment of D. reticulatus populations throughout Europe. The tick has been the research focus of a growing number of scientists, physicians and veterinarians. Within the Web of Science database, more than a fifth of the over 700 items published on this species between 1897 and 2015 appeared in the last three years (2013-2015). Here we attempt to synthesize current knowledge on the systematics, ecology, geographical distribution and recent spread of the species and to highlight the great spectrum of possible veterinary and public health threats it poses. Canine babesiosis caused by Babesia canis is a severe leading canine vector-borne disease in many endemic areas. Although less frequently than Ixodes ricinus, D. reticulatus adults bite humans and transmit several Rickettsia spp., Omsk haemorrhagic fever virus or Tick-borne encephalitis virus. We have not solely collected and reviewed the latest and fundamental scientific papers available in primary databases but also widened our scope to books, theses, conference papers and specialists colleagues' experience where needed. Besides the dominant literature available in English, we also tried to access scientific literature in German, Russian and eastern European languages as well. We hope to inspire future research projects that are necessary to understand the basic life-cycle and ecology of this vector in order to understand and prevent disease threats. We conclude that although great strides have been made in our knowledge of the eco-epidemiology of this species, several gaps still need to be filled with basic research, targeting possible reservoir and vector roles and the key factors resulting in the observed geographical spread of D. reticulatus.
- MeSH
- arachnida jako vektory klasifikace mikrobiologie parazitologie fyziologie MeSH
- Babesia izolace a purifikace MeSH
- babezióza epidemiologie přenos MeSH
- demografie MeSH
- Dermacentor klasifikace mikrobiologie parazitologie fyziologie MeSH
- ekologie MeSH
- hostitelská specificita MeSH
- infestace klíšťaty epidemiologie parazitologie MeSH
- klasifikace MeSH
- lidé MeSH
- nemoci přenášené klíšťaty epidemiologie mikrobiologie parazitologie přenos MeSH
- nemoci psů epidemiologie mikrobiologie parazitologie přenos MeSH
- omská hemoragická horečka epidemiologie přenos virologie MeSH
- psi MeSH
- stadia vývoje MeSH
- veřejné zdravotnictví MeSH
- viry klíšťové encefalitidy izolace a purifikace MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- psi MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Geografické názvy
- Asie epidemiologie MeSH
- Evropa epidemiologie MeSH
Host-seeking Dermacentor reticulatus ticks were detected by flagging method at 46 localities at south-east part of the Czech Republic, in the basins of rivers Morava and Dyje. Exact north-west distribution limits of D. reticulatus were defined in this area for the first time. Detailed prediction map of probabilities of D. reticulatus occurrence was obtained using GIS analysis. Spatial model delimited a south-north gradient in probability across the studied area, with highest probabilities above 0.8 in its southernmost part. Abundance of D. reticulatus varied markedly between localities in interval 0.33-222 of ticks per flag per hour. The highest abundances were in flooded areas at lower streams, towards upper streams abundance and density of these ticks decreased. Females prevailed in samples with population sex ratio of 0.413, significantly deviating from parity. Larvae and nymphs of this species were not detected by flagging. Although D. reticulatus range expansion probably did not reach such a degree as reported in other countries, these ticks became very abundant in some parts of studied area. Since spreading of vector-borne diseases became a problem in Europe, the knowledge of their exact recent geographic ranges is important for future modelling of their shift predictability.
- MeSH
- arachnida jako vektory fyziologie MeSH
- demografie MeSH
- Dermacentor fyziologie MeSH
- hustota populace MeSH
- infestace klíšťaty epidemiologie parazitologie MeSH
- poměr pohlaví 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
Borrelia burgdorferi sensu lato (s.l.) complex is a diverse group of worldwide distributed bacteria that includes 18 named spirochete species and a still not named group proposed as genomospecies 2. Descriptions of new species and variants continue to be recognized, so the current number of described species is probably not final. Most of known spirochete species are considered to have a limited distribution. Eleven species from the B. burgdorferi s.l. complex were identified in and strictly associated with Eurasia (B. afzelii, B. bavariensis, B. garinii, B. japonica, B. lusitaniae, B. sinica, B. spielmanii, B. tanukii, B. turdi, B. valaisiana, and B. yangtze), while another 5 (B. americana, B. andersonii, B. californiensis, B. carolinensis, and B. kurtenbachii) were previously believed to be restricted to the USA only. B. burgdorferi sensu stricto (s.s.), B. bissettii, and B. carolinensis share the distinction of being present in both the Old and the New World. Out of the 18 genospecies, 3 commonly and 4 occasionally infect humans, causing Lyme borreliosis (LB) - a multisystem disease that is often referred to as the 'great imitator' due to diversity of its clinical manifestations. Among the genospecies that commonly infect people, i.e. B. burgdorferi s.s., B. afzelii, and B. garinii, only B. burgdorferi s.s. causes LB both in the USA and in Europe, with a wide spectrum of clinical conditions ranging from minor cutaneous erythema migrans (EM) to severe arthritis or neurological manifestations. The epidemiological data from many European countries and the USA show a dramatic increase of the diagnosed cases of LB due to the development of new progressive diagnostic methods during the last decades (Hubálek, 2009). Recently, the definition of the disease has also changed. What was not considered Lyme borreliosis before might be now.
- MeSH
- arachnida jako vektory mikrobiologie fyziologie MeSH
- Borrelia burgdorferi klasifikace genetika izolace a purifikace patogenita MeSH
- DNA bakterií genetika MeSH
- druhová specificita MeSH
- fylogeneze MeSH
- fylogeografie MeSH
- genetická variace MeSH
- hlodavci MeSH
- klíšťata mikrobiologie fyziologie MeSH
- lidé MeSH
- lymeská nemoc diagnóza epidemiologie mikrobiologie přenos MeSH
- polymerázová řetězová reakce MeSH
- ptáci MeSH
- techniky typizace bakterií metody MeSH
- veřejné zdravotnictví MeSH
- zdroje nemoci MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Research Support, N.I.H., Extramural MeSH
- Research Support, U.S. Gov't, P.H.S. MeSH
- Geografické názvy
- Asie MeSH
- Evropa MeSH
- Spojené státy americké MeSH
A comparison of the behavioural peculiarities of Ixodes persulcatus Schulze, 1930 (north-western population, Russia) and Ixodes ricinus (L., 1758) from western Russia and Denmark was determined by using two methods. Method 1 involved a sojourn of ticks on vertical plastic sticks and showed that the questing behaviour of I. ricinus nymphs was dependent on temperature and relative humidity (RH). A significantly greater number of nymphs quested at 22 degrees C and 100% RH than at 18 degrees C. When the humidity was reduced to 30% all of the nymphs departed. In the second method, the activity of ticks on an inclined "ticksdrome" was estimated. The activity of I. ricinus adults from the Danish population was 1.2 times greater than that of ticks from Russia. Females of the species studied and specimens from all study areas were more active than all other stages of development. The locomotor activity of both adult and immature I. ricinus that were infected with Borrelia burgdorferi sensu lato was suppressed when compared with uninfected specimens. The locomotor activity of I. persulcatus females infected by borreliae with exoskeleton anomalies was 1.3 times greater (P<0.05) than that of infected ticks without anomalies. Our data showed that infected females with exoskeleton anomalies could crawl faster on a human and reach uncovered parts of the body that are vulnerable for attachment and feeding. A study of locomotor activity and questing behaviour may be useful for comparing the risk for different tick species and populations to transmit tick-borne pathogens.
- MeSH
- arachnida jako vektory parazitologie fyziologie MeSH
- Borrelia burgdorferi komplex fyziologie MeSH
- klíště růst a vývoj mikrobiologie fyziologie MeSH
- larva fyziologie MeSH
- lymeská nemoc mikrobiologie přenos MeSH
- nymfa fyziologie MeSH
- pohybová aktivita fyziologie MeSH
- stromy MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- Geografické názvy
- Dánsko MeSH
- Sibiř MeSH
