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1
de Silva, Aravinda M., Nordin S. Zeidner, Yan Zhang, Marc C. Dolan, Joseph Piesman e Erol Fikrig. "Influence of Outer Surface Protein A Antibody onBorrelia burgdorferi within Feeding Ticks". Infection and Immunity 67, n. 1 (1 gennaio 1999): 30–35. http://dx.doi.org/10.1128/iai.67.1.30-35.1999.
Testo completoAbstract (sommario):
ABSTRACT Borrelia burgdorferi, the spirochetal agent of Lyme disease, is transmitted by Ixodes ticks. When an infected nymphal tick feeds on a host, the bacteria increase in number within the tick, after which they invade the tick’s salivary glands and infect the host. Antibodies directed against outer surface protein A (OspA) of B. burgdorferi kill spirochetes within feeding ticks and block transmission to the host. In the studies presented here, passive antibody transfer experiments were carried out to determine the OspA antibody titer required to block transmission to the rodent host. OspA antibody levels were determined by using a competitive enzyme-linked immunosorbent assay that measured antibody binding to a protective epitope defined by monoclonal antibody C3.78. The C3.78 OspA antibody titer (>213 μg/ml) required to eradicate spirochetes from feeding ticks was considerably higher than the titer (>6 μg/ml) required to block transmission to the host. Although spirochetes were not eradicated from ticks at lower antibody levels, the antibodies reduced the number of spirochetes within the feeding ticks and interfered with the ability of spirochetes to induceospC and invade the salivary glands of the vector. OspA antibodies may directly interfere with the ability of B. burgdorferi to invade the salivary glands of the vector; alternately, OspA antibodies may lower the density of spirochetes within feeding ticks below a critical threshold required for initiating events linked to transmission.
2
Răileanu, Cristian, Cornelia Silaghi, Volker Fingerle, Gabriele Margos, Claudia Thiel, Kurt Pfister e Evelyn Overzier. "Borrelia burgdorferi Sensu Lato in Questing and Engorged Ticks from Different Habitat Types in Southern Germany". Microorganisms 9, n. 6 (10 giugno 2021): 1266. http://dx.doi.org/10.3390/microorganisms9061266.
Testo completoAbstract (sommario):
Borrelia burgdorferi sensu lato (s.l.) causes the most common tick-borne infection in Europe, with Germany being amongst the countries with the highest incidences in humans. This study aimed at (1) comparing infection rates of B. burgdorferi s.l. in questing Ixodes ricinus ticks from different habitat types in Southern Germany, (2) analysing genospecies distribution by habitat type, and (3) testing tissue and ticks from hosts for B. burgdorferi s.l. Questing ticks from urban, pasture, and natural habitats together with feeding ticks from cattle (pasture) and ticks and tissue samples from wild boars and roe deer (natural site) were tested by PCR and RFLP for species differentiation. B. burgdorferi s.l. was found in 29.8% questing adults and 15% nymphs. Prevalence was lower at the urban sites with occurrence of roe deer than where these were absent. Borrelia burgdorferi s.l. DNA was found in 4.8% ticks from roe deer, 6.3% from wild boar, and 7.8% from cattle. Six genospecies were identified in unfed ticks: Borrelia afzelii (48.6%), Borrelia burgdorferi sensu stricto (16%), Borrelia garinii (13.2%), Borrelia valaisiana (7.5%), Borrelia spielmanii (6.2%), and Borrelia bavariensis (0.9%). This study shows high infection levels and a great diversity of Borrelia in questing ticks. The presence of roe deer seems to reduce B. burgdorferi s.l. infection rates in tick populations.
3
Seo, Min-Goo, Byung-Eon Noh, Hak Seon Lee, Tae-Kyu Kim, Bong-Goo Song e Hee Il Lee. "Nationwide Temporal and Geographical Distribution of Tick Populations and Phylogenetic Analysis of Severe Fever with Thrombocytopenia Syndrome Virus in Ticks in Korea, 2020". Microorganisms 9, n. 8 (30 luglio 2021): 1630. http://dx.doi.org/10.3390/microorganisms9081630.
Testo completoAbstract (sommario):
Since 2010, the Korea Disease Control and Prevention Agency has established centers at 16 locations to monitor disease vectors and pathogens. Here, we examined tick populations to understand the geographical and temporal distribution of severe fever with thrombocytopenia syndrome virus (SFTSV) vectors in 2020. From April to November, 63,376 ticks were collected from traps to monitor tick populations, with a trap index of 41.3. Tick incidence varied from April to October, with population peaks observed for nymphs in May, adults in July, and larvae in September. The predominant tick species were Haemaphysalis longicornis, Haemaphysalis spp., H. flava, Ixodes spp., Amblyomma testudinarium, and Ixodes nipponensis. Approximately 50% of the collected ticks were pooled into 2973 groups to detect the rate of SFTSV infection in ticks. The minimum infection rate (MIR) of SFTSV was 0.2%, and Andong had the highest MIR for SFTSV (4.0%). The B3 genotype was the most prevalent (52.2%) followed by B2 (28.6%), B5 (15.9%), B4 (1.6%), and B6 (1.6%). We identified widely distributed tick species and a high degree of diversity in SFTSV strains in ticks from different geographical regions. The results may provide a basis for future epidemiological studies and risk assessments for tick-borne diseases.
4
Hodzic, Emir, Durland Fish, Craig M. Maretzki, Aravinda M. De Silva, Sunlian Feng e Stephen W. Barthold. "Acquisition and Transmission of the Agent of Human Granulocytic Ehrlichiosis by Ixodes scapularis Ticks". Journal of Clinical Microbiology 36, n. 12 (1998): 3574–78. http://dx.doi.org/10.1128/jcm.36.12.3574-3578.1998.
Testo completoAbstract (sommario):
The purpose of the present study was to investigate the transmission of a human isolate of the agent of human granulocytic ehrlichiosis (HGE agent) from infected mice to larval ticks and to examine the population kinetics of the HGE agent in different stages of the tick life cycle. The HGE agent was quantitated by competitive PCR with blood from infected mice and with Ixodes scapularis ticks. The median infectious dose for C3H mice was 104 to 105 organisms when blood from an infected severe combined immunodeficient mouse was used as an inoculum. Uninfected larval ticks began to acquire infection from infected mice within 24 h of attachment, and the number of HGE agent organisms increased in larval ticks during feeding and after detachment of replete ticks. Molted nymphal ticks, infected as larvae, transmitted infection to mice between 40 and 48 h of attachment. Onset of feeding stimulated replication of the HGE agent within nymphal ticks. These studies suggest that replication of the HGE agent during and after feeding in larvae and during feeding in nymphs is a means by which the HGE agent overcomes inefficiencies in acquisition of infection by ticks and in tick-borne transmission to mammalian hosts.
5
Schwan, Tom G., e Sandra J. Raffel. "Transovarial Transmission of Borrelia hermsii by Its Tick Vector and Reservoir Host Ornithodoros hermsi". Microorganisms 9, n. 9 (17 settembre 2021): 1978. http://dx.doi.org/10.3390/microorganisms9091978.
Testo completoAbstract (sommario):
Transovarial passage of relapsing fever spirochetes (Borrelia species) by infected female argasid ticks to their progeny is a widespread phenomenon. Yet this form of vertical inheritance has been considered rare for the North American tick Ornithodoros hermsi infected with Borrelia hermsii. A laboratory colony of O. hermsi was established from a single infected female and two infected males that produced a population of ticks with a high prevalence of transovarial transmission based on infection assays of single and pooled ticks feeding on mice and immunofluorescence microscopy of eggs and larvae. Thirty-eight of forty-five (84.4%) larval cohorts (groups of larvae originating from the same egg clutch) transmitted B. hermsii to mice over four and a half years, and one hundred and three single and one hundred and fifty-three pooled nymphal and adult ticks transmitted spirochetes during two hundred and fourteen of two hundred and fifty-six (83.6%) feedings on mice over seven and a half years. The perpetuation of B. hermsii for many years by infected ticks only (without acquisition of spirochetes from vertebrate hosts) demonstrates the reservoir competence of O. hermsi. B. hermsii produced the variable tick protein in eggs and unfed larvae infected by transovarial transmission, leading to speculation of the possible steps in the evolution of borreliae from a tick-borne symbiont to a tick-transmitted parasite of vertebrates.
6
Peter, Trevor F., Anthony F. Barbet, Arthur R. Alleman, Bigboy H. Simbi, Michael J. Burridge e Suman M. Mahan. "Detection of the Agent of Heartwater, Cowdria ruminantium, in Amblyomma Ticks by PCR: Validation and Application of the Assay to Field Ticks". Journal of Clinical Microbiology 38, n. 4 (2000): 1539–44. http://dx.doi.org/10.1128/jcm.38.4.1539-1544.2000.
Testo completoAbstract (sommario):
We have previously reported that the pCS20 PCR detection assay forCowdria ruminantium, the causative agent of heartwater disease of ruminants, is more sensitive than xenodiagnosis and the pCS20 DNA probe for the detection of infection in the vectorAmblyomma ticks. Here, we further assessed the reliability of the PCR assay and applied it to field ticks. The assay detected DNA of 37 isolates of C. ruminantium originating from sites throughout the distribution of heartwater and had a specificity of 98% when infected ticks were processed concurrently with uninfected ticks. The assay did not detect DNA of Ehrlichia chaffeensis, which is closely related to C. ruminantium. PCR sensitivity varied with tick infection intensity and was high (97 to 88%) with ticks bearing 107 to 104 organisms but dropped to 61 and 28%, respectively, with ticks bearing 103 and 102 organisms. The assay also detected C. ruminantium in collections of Amblyomma hebraeum andAmblyomma variegatum field ticks from 17 heartwater-endemic sites in four southern African countries. Attempts at tick transmission of infection to small ruminants failed with four of these collections. The pCS20 PCR assay is presently the most characterized and reliable test for C. ruminantium in ticks and thus is highly useful for field and laboratory epidemiological investigations of heartwater.
7
Ogata, Shohei, Wessam Mohamed Ahmed Mohamed, Kodai Kusakisako, May June Thu, Yongjin Qiu, Mohamed Abdallah Mohamed Moustafa, Keita Matsuno, Ken Katakura, Nariaki Nonaka e Ryo Nakao. "Spiroplasma Infection among Ixodid Ticks Exhibits Species Dependence and Suggests a Vertical Pattern of Transmission". Microorganisms 9, n. 2 (8 febbraio 2021): 333. http://dx.doi.org/10.3390/microorganisms9020333.
Testo completoAbstract (sommario):
Members of the genus Spiroplasma are Gram-positive bacteria without cell walls. Some Spiroplasma species can cause disease in arthropods such as bees, whereas others provide their host with resistance to pathogens. Ticks also harbour Spiroplasma, but their role has not been elucidated yet. Here, the infection status and genetic diversity of Spiroplasma in ticks were investigated using samples collected from different geographic regions in Japan. A total of 712 ticks were tested for Spiroplasma infection by PCR targeting 16S rDNA, and Spiroplasma species were genetically characterized based on 16S rDNA, ITS, dnaA, and rpoB gene sequences. A total of 109 samples originating from eight tick species were positive for Spiroplasma infection, with infection rates ranging from 0% to 84% depending on the species. A linear mixed model indicated that tick species was the primary factor associated with Spiroplasma infection. Moreover, certain Spiroplasma alleles that are highly adapted to specific tick species may explain the high infection rates in Ixodes ovatus and Haemaphysalis kitaokai. A comparison of the alleles obtained suggests that horizontal transmission between tick species may not be a frequent event. These findings provide clues to understand the transmission cycle of Spiroplasma species in wild tick populations and their roles in host ticks.
8
Tirosh-Levy, Sharon, Asael Roth, Binyamin Leibovich, Ludmila Fleiderovitz, Ohad Frid, Daniel Yasur-Landau, Ricardo Wolkomirskyi e Monica L. Mazuz. "Establishing Babesia bovis-Free Tick Colony Following Treatment of the Host with Diminazene Aceturate (Berenil)". Pathogens 10, n. 5 (3 maggio 2021): 554. http://dx.doi.org/10.3390/pathogens10050554.
Testo completoAbstract (sommario):
Babesia bovis is a widely-spread tick-borne hemoparasite of cattle with major economic and animal welfare consequences. Rhipicephalus (Boophilus) annulatus is a one-host tick which transmits bovine babesiosis in the Middle East and Africa. Laboratory rearing of ixodid ticks is essential for the investigation on ticks or tick-borne diseases. Establishing a tick colony in the laboratory usually originates from ticks harvested in the field, which may be naturally infected with various pathogens. This especially applies to carriage of B. bovis as it is highly prevalent in endemic areas and is transmitted transovarially in ticks. Here, we describe the use of diminazene aceturate (Berenil) in order to establish laboratory colonies of Babesia-free R. annulatus, from ticks collected in the field. Ticks collected in the field were kept until oviposition and hatched larvae were introduced to naïve calves, which led to infection of the calves with B. bovis. Calves were then treated with diminazene aceturate several times until the engorged ticks dropped. The eggs and larvae collected from these ticks were parasite-free, as demonstrated both by infection of splenectomized calves and by PCR. This suggested protocol is a useful tool to create parasite-free tick colony and may, theoretically, also be beneficial to reduce parasite circulation in the field, although not recommended, as resistance to diamenizene aceturate might develop.
9
Gilmore, Robert D., e Joseph Piesman. "Inhibition of Borrelia burgdorferi Migration from the Midgut to the Salivary Glands following Feeding by Ticks on OspC-Immunized Mice". Infection and Immunity 68, n. 1 (1 gennaio 2000): 411–14. http://dx.doi.org/10.1128/iai.68.1.411-414.2000.
Testo completoAbstract (sommario):
ABSTRACT Borrelia burgdorferi-infected ticks were fed on either OspC-immunized mice or normal, nonimmunized mice. After 72 h, the ticks were detached, followed by dissection and subsequent culturing in Barbour-Stoenner-Kelley II medium of the salivary glands from each tick to determine the presence of borreliae. Forty percent (10 of 25) of salivary glands from ticks that had fed on nonimmunized mice were culture positive, while only 7.4% (2 of 27) of salivary glands from ticks that had fed on OspC-immunized mice were culture positive, thus indicating a much reduced borrelial migration from the midgut when the bloodmeal contained anti-OspC antibodies. Fluorescent antibody staining of the corresponding midguts from ticks that had fed on the OspC-immunized mice showed that borreliae were present but did not produce OspC. In contrast, borreliae in midguts from ticks that had fed on normal mice demonstrated substantial ospC expression. This study provides evidence that, during tick feeding on an OspC-immunized host, transmission of borreliae from the tick is prevented; it also suggests that OspC functions in a tick-to-host transmission mechanism.
10
Richter, Dania, Andrew Spielman e Franz-Rainer Matuschka. "Effect of Prior Exposure to Noninfected Ticks on Susceptibility of Mice to Lyme Disease Spirochetes". Applied and Environmental Microbiology 64, n. 11 (1 novembre 1998): 4596–99. http://dx.doi.org/10.1128/aem.64.11.4596-4599.1998.
Testo completoAbstract (sommario):
ABSTRACT To determine whether prior exposure to Nearctic Ixodesvector ticks protects native reservoir mice from tick-borne infection by Lyme disease spirochetes, we compared their infectivities for white-footed mice and laboratory mice that had been repeatedly infested by noninfected deer ticks. Nymphal ticks readily engorged on tick-exposed laboratory mice, but their feeding success on white-footed mice progressively declined. Tick-borne spirochetes readily infected previously tick-infested mice. Thus, prior infestation by Nearctic ticks does not protect sympatric reservoir mice or Palearctic laboratory mice from infection by sympatric tick-borne spirochetes.
11
Kobayashi, Toshiya, Elisha Chatanga, Yongjin Qiu, Martin Simuunza, Masahiro Kajihara, Bernard Mudenda Hang’ombe, Yoshiki Eto et al. "Molecular Detection and Genotyping of Coxiella-Like Endosymbionts in Ticks Collected from Animals and Vegetation in Zambia". Pathogens 10, n. 6 (21 giugno 2021): 779. http://dx.doi.org/10.3390/pathogens10060779.
Testo completoAbstract (sommario):
Ticks are obligate ectoparasites as they require to feed on their host blood during some or all stages of their life cycle. In addition to the pathogens that ticks harbor and transmit to vertebrate hosts, they also harbor other seemingly nonpathogenic microorganisms including nutritional mutualistic symbionts. Tick nutritional mutualistic symbionts play important roles in the physiology of the host ticks as they are involved in tick reproduction and growth through the supply of B vitamins as well as in pathogen maintenance and propagation. Coxiella-like endosymbionts (CLEs) are the most widespread endosymbionts exclusively reported in ticks. Although CLEs have been investigated in ticks in other parts of the world, there is no report of their investigation in ticks in Zambia. To investigate the occurrence of CLEs, their maintenance, and association with host ticks in Zambia, 175 ticks belonging to six genera, namely Amblyomma, Argas, Haemaphysalis, Hyalomma, Ornithodoros, and Rhipicephalus, were screened for CLEs, followed by characterization of CLEs by multi-locus sequence typing of the five Coxiella housekeeping genes (dnaK, groEL, rpoB, 16S rRNA, and 23S rRNA). The results showed that 45.7% (n = 80) were positive for CLEs. The comparison of the tick 16S rDNA phylogenetic tree with that of the CLEs concatenated sequences showed that there was a strong correlation between the topology of the trees. The results suggest that most of the CLEs have evolved within tick species, supporting the vertical transmission phenomenon. However, the negative results for CLE in some ticks warrants further investigations of other endosymbionts that the ticks in Zambia may also harbor.
12
Tveten, Ann-Kristin, Andreas Riborg e Hanne Tjelle Vadseth. "DGGE Identification of Microorganisms Associated withBorrelia burgdorferiSensu Lato- orAnaplasma phagocytophilum-InfectedIxodes ricinusTicks from Northwest Norway". International Journal of Microbiology 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/805456.
Testo completoAbstract (sommario):
Ticks acquire a wide range of microorganisms as a natural part of their lifecycle. Bacteria, viruses, and protozoa can be transmitted to ticks during feeding and free-living phases. DGGE profiling is a molecular method to describe the microbial population associated with ticks and demonstrate some of the complexity and variety of tick-borne microorganisms. The present study profiled a total of 120I. ricinusticks, which were divided into three equally sized groups. We found thatB. burgdorferis.l.-infected ticks presented a pattern consisting of bacterialPseudomonasspp. (67.5%),Bacillusspp. (50%), andSphingomonasspp. (77.5%), whileA. phagocytophilum-infected ticks were associated withPseudomonasspp. (82.5%) andSphingomonasspp. (57.5%). All profiles had one or morePseudomonasspecies present, and the intramitochondrial endosymbiont CandidatusMidichloria mitochondriiwas present in more than 25% of the samples. Statistical analysis demonstrated that the microbial communities were not significantly different between the groups and that the groups could not be characterised by a specific microbial population.
13
Strother, Keith O., e Aravinda de Silva. "Role of Borrelia burgdorferi Linear Plasmid 25 in Infection of Ixodes scapularis Ticks". Journal of Bacteriology 187, n. 16 (15 agosto 2005): 5776–81. http://dx.doi.org/10.1128/jb.187.16.5776-5781.2005.
Testo completoAbstract (sommario):
ABSTRACT The tick-borne bacterium Borrelia burgdorferi has over 20 different circular and linear plasmids. Some B. burgdorferi plasmids are readily lost during in vitro culture or genetic manipulation. Linear plasmid 25, which is often lost in laboratory strains, is required for the infection of mice. Strains missing linear plasmid 25 (lp25−) are able to infect mice if the BBE22 gene on lp25 is provided on a shuttle vector. In this study, we examined the role of lp25 and BBE22 in tick infections. We tested the hypothesis that complementation with BBE22 in spirochetes lacking lp25 would restore the ability of spirochetes to infect ticks. A natural tick infection cycle was performed by feeding larvae on mice injected with the parental, lp25−, or lp25− BBE22-complemented spirochete strains. In addition, larvae and nymphs were artificially infected with different strains to study tick infections independent of mouse infections. B. burgdorferi missing lp25 was significantly impaired in its ability to infect larval and nymphal ticks. When an lp25− strain was complemented with BBE22, the ability to infect ticks was partially restored. Complementation with BBE22 allowed spirochetes lacking lp25 to establish short-term infections in ticks, but in most cases the infection prevalence was lower than that of the wild-type strain. In addition, the number of infected ticks decreased over time, suggesting that another gene(s) on lp25 is required for long-term persistence in ticks and completion of a natural infection cycle.
14
Getange, Dennis, Joel L. Bargul, Esther Kanduma, Marisol Collins, Boku Bodha, Diba Denge, Tatenda Chiuya et al. "Ticks and Tick-Borne Pathogens Associated with Dromedary Camels (Camelus dromedarius) in Northern Kenya". Microorganisms 9, n. 7 (30 giugno 2021): 1414. http://dx.doi.org/10.3390/microorganisms9071414.
Testo completoAbstract (sommario):
Ticks and tick-borne pathogens (TBPs) are major constraints to camel health and production, yet epidemiological data on their diversity and impact on dromedary camels remain limited. We surveyed the diversity of ticks and TBPs associated with camels and co-grazing sheep at 12 sites in Marsabit County, northern Kenya. We screened blood and ticks (858 pools) from 296 camels and 77 sheep for bacterial and protozoan TBPs by high-resolution melting analysis and sequencing of PCR products. Hyalomma (75.7%), Amblyomma (17.6%) and Rhipicephalus (6.7%) spp. ticks were morphologically identified and confirmed by molecular analyses. We detected TBP DNA in 80.1% of blood samples from 296 healthy camels. “Candidatus Anaplasma camelii”, “Candidatus Ehrlichia regneryi” and Coxiella burnetii were detected in both camels and associated ticks, and Ehrlichia chaffeensis, Rickettsia africae, Rickettsia aeschlimannii and Coxiella endosymbionts were detected in camel ticks. We also detected Ehrlichia ruminantium, which is responsible for heartwater disease in ruminants, in Amblyomma ticks infesting camels and sheep and in sheep blood, indicating its endemicity in Marsabit. Our findings also suggest that camels and/or the ticks infesting them are disease reservoirs of zoonotic Q fever (C. burnetii), ehrlichiosis (E. chaffeensis) and rickettsiosis (R. africae), which pose public health threats to pastoralist communities.
15
Truong, A.-Tai, Jinhyeong Noh, Yeojin Park, Hyun-Ji Seo, Keun-Ho Kim, Subin Min, Jiyeon Lim et al. "Molecular Detection and Phylogeny of Tick-Borne Pathogens in Ticks Collected from Dogs in the Republic of Korea". Pathogens 10, n. 5 (17 maggio 2021): 613. http://dx.doi.org/10.3390/pathogens10050613.
Testo completoAbstract (sommario):
Ticks are important vectors of various pathogens that result in clinical illnesses in humans and domestic and wild animals. Information regarding tick infestations and pathogens transmitted by ticks is important for the identification and prevention of disease. This study was a large-scale investigation of ticks collected from dogs and their associated environments in the Republic of Korea (ROK). It included detecting six prevalent tick-borne pathogens (Anaplasma spp., A. platys, Borrelia spp., Babesia gibsoni, Ehrlichia canis, and E. chaffeensis). A total of 2293 ticks (1110 pools) were collected. Haemaphysalis longicornis (98.60%) was the most frequently collected tick species, followed by Ixodes nipponensis (0.96%) and H. flava (0.44%). Anaplasma spp. (24/1110 tick pools; 2.16%) and Borrelia spp. (4/1110 tick pools; 0.36%) were detected. The phylogenetic analyses using 16S rRNA genes revealed that the Anaplasma spp. detected in this study were closely associated with A. phagocytophilum reported in humans and rodents in the ROK. Borrelia spp. showed phylogenetic relationships with B. theileri and B. miyamotoi in ticks and humans in Mali and Russia. These results demonstrate the importance of tick-borne disease surveillance and control in dogs in the ROK.
16
KIEWRA, DOROTA, GRZEGORZ ZALEŚNY e ALEKSANDRA CZUŁOWSKA. "The prevalence of Anaplasma phagocytophilum in questing Ixodes ricinus Ticks in SW Poland". Polish Journal of Microbiology 63, n. 1 (2014): 89–93. http://dx.doi.org/10.33073/pjm-2014-013.
Testo completoAbstract (sommario):
Ticks constitute important vectors of human and animal pathogens. Besides the Lyme borreliosis and tick-borne encephalitis, other pathogens such as Babesia spp., Rickettsia spp., and Anaplasma phagocytophilum, are of increasing public health interest. In Poland, as in other European countries, Ixodes ricinus, the most prevalent tick species responsible for the majority of tick bites in humans, is the main vector of A. phagocytophilum. The aim of the study was to estimate the infection level of I. ricinus with A. phagocytophilum in selected districts, not previously surveyed for the presence of this agent. Sampling of questing ticks was performed in 12 forested sites, located in four districts (Legnica, Milicz, Lubań, and Oława) in SW Poland. Altogether, 792 ticks (151 females, 101 males, and 540 nymphs) representing I. ricinus were checked for the presence of A. phagocytophilum. The average infection level was 4.3%, with higher rate reported for adult ticks. The highest percentage of infected adults was observed in Milicz (17.4%) and the lowest in Oława (6.8%). The abundance of questing I. ricinus in all examined sites as well as the infection with A. phagocytophilum indicate for the first time the risk for HGA transmission in SW Poland.
17
Hodzic, Emir, Sunlian Feng, Kimberly J. Freet, Dori L. Borjesson e Stephen W. Barthold. "Borrelia burgdorferi Population Kinetics and Selected Gene Expression at the Host-Vector Interface". Infection and Immunity 70, n. 7 (luglio 2002): 3382–88. http://dx.doi.org/10.1128/iai.70.7.3382-3388.2002.
Testo completoAbstract (sommario):
ABSTRACT By using real-time quantitative PCR, the population dynamics and gene transcription of Borrelia burgdorferi were examined in ticks and skin of mice during acquisition of the infection from mice by ticks and during transmission of the infection from ticks to mice. Population dynamics were determined by using a flaB DNA target. A quantitative analysis of flaB, ospA, ospC, dbpA, and arp transcription was also performed. The results revealed that both uninfected larval and nymphal Ixodes scapularis ticks acquired B. burgdorferi as early as 1 day after attachment and that the sizes of spirochete populations within ticks increased during feeding. In addition, all gene targets revealed that there was RNA transcription during feeding. Similar events occurred within infected nymphal ticks feeding on uninfected hosts. Transmission from infected nymphal ticks to mice could be detected within 1 day after attachment. Analysis of skin during the first 3 days after attachment of infected ticks revealed rising numbers of spirochetes but minimal gene transcription. In contrast, the skin of mice with established infections revealed static populations of spirochetes and active but stable transcription of flaB, ospC, dbpA, and arp. There were consistent reductions in the number of spirochetes in the skin at the tick attachment sites compared to the number of spirochetes in the skin at nontick sites, but there were no differences in gene expression between tick and nontick skin sites. Evidence of ospA transcription in skin could be found 1 day after tick attachment but not thereafter.
18
Onyiche, ThankGod E., Cristian Răileanu, Susanne Fischer e Cornelia Silaghi. "Global Distribution of Babesia Species in Questing Ticks: A Systematic Review and Meta-Analysis Based on Published Literature". Pathogens 10, n. 2 (19 febbraio 2021): 230. http://dx.doi.org/10.3390/pathogens10020230.
Testo completoAbstract (sommario):
Babesiosis caused by the Babesia species is a parasitic tick-borne disease. It threatens many mammalian species and is transmitted through infected ixodid ticks. To date, the global occurrence and distribution are poorly understood in questing ticks. Therefore, we performed a meta-analysis to estimate the distribution of the pathogen. A deep search for four electronic databases of the published literature investigating the prevalence of Babesia spp. in questing ticks was undertaken and obtained data analyzed. Our results indicate that in 104 eligible studies dating from 1985 to 2020, altogether 137,364 ticks were screened with 3069 positives with an estimated global pooled prevalence estimates (PPE) of 2.10%. In total, 19 different Babesia species of both human and veterinary importance were detected in 23 tick species, with Babesia microti and Ixodesricinus being the most widely reported Babesia and tick species, respectively. Regardless of species, adult ticks with 2.60% had the highest infection rates, while larvae had the least with 0.60%. Similarly, female ticks with 4.90% were infected compared to males with 3.80%. Nested-polymerase chain reaction (PCR) 2.80% had the highest prevalence among the molecular techniques employed. In conclusion, results obtained indicate that Babesia species are present in diverse questing tick species at a low prevalence, of which some are competent vectors.
19
Cao, Wu-Chun, Qiu-Min Zhao, Pan-He Zhang, J. Stephen Dumler, Xi-Tan Zhang, Li-Qun Fang e Hong Yang. "Granulocytic Ehrlichiae in Ixodes persulcatus Ticks from an Area in China Where Lyme Disease Is Endemic". Journal of Clinical Microbiology 38, n. 11 (2000): 4208–10. http://dx.doi.org/10.1128/jcm.38.11.4208-4210.2000.
Testo completoAbstract (sommario):
A total of 372 adult Ixodes persulcatus ticks were collected from vegetation in a forest area of Heilongjiang Province in northeastern China, where Lyme disease is known to be endemic. The ticks were examined for the presence of granulocytic ehrlichiae by heminested PCR with primers derived from the 16S rRNA gene. Of 310 ticks obtained from the Dahe forestry farm, two pools (each containing 5 ticks) were found positive, with a minimum infection rate of 0.6%. Ehrlichial DNA was also detected in one female (1.6%) of 62 ticks collected from the Yulin forestry farm. The overall minimum infection rate of the 372 I. persulcatus adults was 0.8%. The nucleotide sequences of 919-bp PCR products from the three positive tick specimens were identical to each other and very closely related to the members of the Ehrlichia phagocytophila genogroup. This is the first identification of granulocytic ehrlichiae in ticks in Asia and the first report of infection in I. persulcatusanywhere.
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Reye, Anna L., Judith M. Hübschen, Aurélie Sausy e Claude P. Muller. "Prevalence and Seasonality of Tick-Borne Pathogens in Questing Ixodes ricinus Ticks from Luxembourg". Applied and Environmental Microbiology 76, n. 9 (12 marzo 2010): 2923–31. http://dx.doi.org/10.1128/aem.03061-09.
Testo completoAbstract (sommario):
ABSTRACT In Europe, ixodid ticks are important arthropod vectors of human and animal pathogens, but comprehensive studies of the prevalence of all relevant pathogens in Central Europe are scarce. As a result of ecological changes, the incidences of tick-borne infections are expected to increase. In this study, 1,394 nymphal and adult Ixodes ricinus ticks sampled monthly during the active season from 33 ecologically distinct collection sites throughout Luxembourg were screened for all human tick-borne pathogens relevant in Central Europe. Species were identified by sequence analysis of detection PCR amplicons. Mean infection rates of ticks were 11.3% for Borrelia burgdorferi sensu lato, 5.1% for Rickettsia sp., 2.7% for Babesia sp., and 1.9% for Anaplasma phagocytophilum. No tick was found to be infected with Coxiella sp., Francisella tularensis subsp., or Tick-borne encephalitis virus (TBEV). A total of 3.2% of ticks were infected with more than one pathogen species, including mixed Borrelia infections (1.5%). Seasonal variations of tick infection rates were observed for Borrelia, Babesia, and Anaplasma, possibly reflecting a behavioral adaptation strategy of questing ticks. A positive correlation between the grade of urbanization and Borrelia infection rate of ticks was observed, suggesting an established urban zoonotic cycle. We also found Hepatozoon canis (0.1%) and Bartonella henselae (0.3%), which so far have not been found in questing Ixodes ricinus ticks in Central Europe.
21
Dietrich, Florian, Thomas Schmidgen, Ricardo G. Maggi, Dania Richter, Franz-Rainer Matuschka, Reinhard Vonthein, Edward B. Breitschwerdt e Volkhard A. J. Kempf. "Prevalence of Bartonella henselae and Borrelia burgdorferi Sensu Lato DNA in Ixodes ricinus Ticks in Europe". Applied and Environmental Microbiology 76, n. 5 (8 gennaio 2010): 1395–98. http://dx.doi.org/10.1128/aem.02788-09.
Testo completoAbstract (sommario):
ABSTRACT Bartonella spp. can cause persistent bloodstream infections in humans and animals. To determine whether Bartonella henselae is present in questing Ixodes ricinus ticks, we analyzed the prevalence of B. henselae DNA among tick stages compared to the prevalence of DNA from Borrelia burgdorferi sensu lato, the pathogen most frequently transmitted by ticks. B. henselae DNA was present with a prevalence of up to ∼40% in tick populations sampled in four European sites (Eberdingen, Germany; Klasdorf, Germany; Lembach, France; and Madeira, Portugal). The odds of detecting B. henselae DNA in nymphal ticks was ∼14-fold higher than in adult ticks. No tick was found to be coinfected with B. henselae and B. burgdorferi sensu lato. Taken together, our data indicate that ticks might serve as a vector for the transmission of B. henselae to humans.
22
Löhr, Christiane V., Fred R. Rurangirwa, Terry F. McElwain, David Stiller e Guy H. Palmer. "Specific Expression of Anaplasma marginale Major Surface Protein 2 Salivary Gland Variants Occurs in the Midgut and Is an Early Event during Tick Transmission". Infection and Immunity 70, n. 1 (gennaio 2002): 114–20. http://dx.doi.org/10.1128/iai.70.1.114-120.2002.
Testo completoAbstract (sommario):
ABSTRACT Infectivity of Anaplasma spp. develops when infected ticks feed on a mammalian host (transmission feed). Specific Anaplasma marginale major surface protein 2 (MSP2) variants are selected for within the tick and are expressed within the salivary glands. The aims of this study were to determine when and where MSP2 variant selection occurs in the tick, how MSP2 expression is regulated in salivary glands of transmission-feeding ticks, and whether the number of A. marginale organisms per salivary gland is significantly increased during transmission feeding. The South Idaho strain of A. marginale was used, as MSP2 expression is restricted to two variants, SGV1 and SGV2, in Dermacentor andersoni. Using Western blot, real-time PCR, and DNA sequencing analyses it was shown that restriction and expression of MSP2 occurs early in the midgut within the first 48 h of the blood meal, when ticks acquire infection. A. marginale is present in the tick salivary glands before transmission feeding is initiated, but the msp2 mRNA and MSP2 protein levels per A. marginale organism increase only minimally and transiently in salivary glands of transmission-feeding ticks compared to that of unfed ticks. A. marginale numbers per tick increase gradually in salivary glands of both transmission-fed and unfed ticks. It is concluded that MSP2 variant selection is an early event in the tick and that MSP2 variants SGV1 and SGV2 are expressed both in the midgut and salivary glands. While MSP2 may be required for infectivity, there is no strict temporal correlation between MSP2 expression and the development of infectivity.
23
Franke, Jan, Julia Fritzsch, Herbert Tomaso, Eberhard Straube, Wolfram Dorn e Anke Hildebrandt. "Coexistence of Pathogens in Host-Seeking and Feeding Ticks within a Single Natural Habitat in Central Germany". Applied and Environmental Microbiology 76, n. 20 (20 agosto 2010): 6829–36. http://dx.doi.org/10.1128/aem.01630-10.
Testo completoAbstract (sommario):
ABSTRACT The importance of established and emerging tick-borne pathogens in Central and Northern Europe is steadily increasing. In 2007, we collected Ixodes ricinus ticks feeding on birds (n = 211) and rodents (n = 273), as well as host-seeking stages (n = 196), in a habitat in central Germany. In order to find out more about their natural transmission cycles, the ticks were tested for the presence of Lyme disease borreliae, Anaplasma phagocytophilum, spotted fever group (SFG) rickettsiae, Francisella tularensis, and babesiae. Altogether, 20.1% of the 680 ticks examined carried at least one pathogen. Bird-feeding ticks were more frequently infected with Borrelia spp. (15.2%) and A. phagocytophilum (3.2%) than rodent-feeding ticks (2.6%; 1.1%) or questing ticks (5.1%; 0%). Babesia spp. showed higher prevalence rates in ticks parasitizing birds (13.2%) and host-seeking ticks (10.7%), whereas ticks from small mammals were less frequently infected (6.6%). SFG rickettsiae and F. tularensis were also found in ticks collected off birds (2.1%; 1.2%), rodents (1.8%; 1.5%), and vegetation (4.1%; 1.6%). Various combinations of coinfections occurred in 10.9% of all positive ticks, indicating interaction of transmission cycles. Our results suggest that birds not only are important reservoirs for several pathogens but also act as vehicles for infected ticks and might therefore play a key role in the dispersal of tick-borne diseases.
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Boularias, Ghania, Naouelle Azzag, Clemence Galon, Ladislav Šimo, Henri-Jean Boulouis e Sara Moutailler. "High-Throughput Microfluidic Real-Time PCR for the Detection of Multiple Microorganisms in Ixodid Cattle Ticks in Northeast Algeria". Pathogens 10, n. 3 (18 marzo 2021): 362. http://dx.doi.org/10.3390/pathogens10030362.
Testo completoAbstract (sommario):
Ixodid ticks are hematophagous arthropods considered to be prominent ectoparasite vectors that have a negative impact on cattle, either through direct injury or via the transmission of several pathogens. In this study, we investigated the molecular infection rates of numerous tick-borne pathogens in ticks sampled on cattle from the Kabylia region, northeastern Algeria, using a high-throughput microfluidic real-time PCR system. A total of 235 ticks belonging to seven species of the genera Rhipicephalus, Hyalomma, and Ixodes were sampled on cattle and then screened for the presence of 36 different species of bacteria and protozoans. The most prevalent tick-borne microorganisms were Rickettsia spp. at 79.1%, followed by Francisella-like endosymbionts (62.9%), Theileria spp. (17.8%), Anaplasma spp. (14.4%), Bartonella spp. (6.8%), Borrelia spp. (6.8%), and Babesia spp. (2.5%). Among the 80.4% of ticks bearing microorganisms, 20%, 36.6%, 21.7%, and 2.1% were positive for one, two, three, and four different microorganisms, respectively. Rickettsia aeschlimannii was detected in Hyalomma marginatum, Hyalomma detritum, and Rhipicephalus bursa ticks. Rickettsia massiliae was found in Rhipicephalus sanguineus, and Rickettsiamonacensis and Rickettsia helvetica were detected in Ixodesricinus. Anaplasma marginale was found in all identified tick genera, but Anaplasma centrale was detected exclusively in Rhipicephalus spp. ticks. The DNA of Borrelia spp. and Bartonella spp. was identified in several tick species. Theileria orientalis was found in R. bursa, R. sanguineus, H. detritum, H. marginatum, and I. ricinus and Babesia bigemina was found in Rhipicephalus annulatus and R. sanguineus. Our study highlights the importance of tick-borne pathogens in cattle in Algeria.
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Ledger, Kimberly J., Lorenza Beati e Samantha M. Wisely. "Survey of Ticks and Tick-Borne Rickettsial and Protozoan Pathogens in Eswatini". Pathogens 10, n. 8 (17 agosto 2021): 1043. http://dx.doi.org/10.3390/pathogens10081043.
Testo completoAbstract (sommario):
Ticks are widespread parasites of vertebrates and major vectors of pathogens to humans, domestic animals, and wildlife. In southern Africa, numerous tick species transmit diseases of economic and health importance. This study aimed to describe the occurrence of ticks and tick-borne pathogens in multiple land-use types and the possible role of ticks in the transmission of pathogen species. Using molecular techniques, we screened 1716 ticks for infection by rickettsial bacteria and protozoans. To characterize pathogen identity, we sequenced multiple loci from positive samples and analyzed sequences within a phylogenetic framework. Across the seven tick species collected as nymphs or adults, we detected Rickettsia, Anaplasma, Ehrlichia, Babesia, Hepatozoon, and Theileira species. We found that some tick species and tick-borne pathogens differed according to land use. For example, we found a higher density of Haemaphysalis elliptica and higher prevalence of Rickettsia in H. elliptica collected from savanna grasses used for livestock grazing near human settlements than savanna grasses in conservation areas. These findings highlight the importance of comprehensive surveillance to achieve a full understanding of the diversity and ecology of the tick-borne pathogens that can infect humans, domestic animals, and wildlife.
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Boretti, Felicitas S., Andrea Perreten, Marina L. Meli, Valentino Cattori, Barbara Willi, Nicole Wengi, S�ndor Hornok et al. "Molecular Investigations of Rickettsia helvetica Infection in Dogs, Foxes, Humans, and Ixodes Ticks". Applied and Environmental Microbiology 75, n. 10 (27 marzo 2009): 3230–37. http://dx.doi.org/10.1128/aem.00220-09.
Testo completoAbstract (sommario):
ABSTRACT Rickettsia helvetica, a tick-borne member of the spotted-fever-group rickettsiae, is a suspected pathogen in humans; however, its role in animals is unknown. The aims of this study were to establish a R. helvetica-specific real-time TaqMan PCR assay and apply it to the analysis of tick vectors (to determine potential exposure risk) and blood samples from Canidae and humans (to determine prevalence of infection). The newly designed 23S rRNA gene assay for R. helvetica was more sensitive than a published citrate synthase gene (gltA) assay for several rickettsiae. Blood samples from 884 dogs, 58 foxes, and 214 human patients and 2,073 ticks (Ixodes spp.) collected from either vegetation or animals were analyzed. Although the maximal likelihood estimate of prevalence was 12% in unfed ticks and 36% in ticks collected from animals, none of the 1,156 blood samples tested PCR positive. Ticks from cats were more frequently PCR positive than ticks from dogs. Sequencing of the 23S rRNA and/or the gltA gene of 17 tick pools confirmed the presence of R. helvetica. Additionally, Rickettsia monacensis, which has not been previously found in Switzerland, was identified. In conclusion, R. helvetica was frequently detected in the tick population but not in blood samples. Nevertheless, due to the broad host range of Ixodes ticks and the high rate of infestation with this agent (i.e., R. helvetica was 13 times more frequent in unfed ticks than the tick-borne encephalitis virus), many mammals may be exposed to R. helvetica. The PCR assay described here represents an important tool for studying this topic.
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Gassner, Fedor, Patrick Verbaarschot, Renate C. Smallegange, Jeroen Spitzen, Sipke E. Van Wieren e Willem Takken. "Variations in Ixodes ricinus Density and Borrelia Infections Associated with Cattle Introduced into a Woodland in The Netherlands". Applied and Environmental Microbiology 74, n. 23 (3 ottobre 2008): 7138–44. http://dx.doi.org/10.1128/aem.00310-08.
Testo completoAbstract (sommario):
ABSTRACT The effect of introduced large herbivores on the abundance of Ixodes ricinus ticks and their Borrelia infections was studied in a natural woodland in The Netherlands. Oak and pine plots, either ungrazed or grazed by cattle, were selected. Ticks were collected weekly by blanket dragging. Borrelia infections were determined by PCR and restriction fragment length polymorphism. Rodent densities were estimated using mark-release-recapture methods. On occasion, the cattle were inspected for tick infestations. Meteorological data were recorded for each habitat. Significantly more ticks were collected in the ungrazed woodland than in the grazed woodland. The ungrazed oak habitat had higher tick densities than the pine habitat, while in the grazed habitats, tick densities were similar. Borrelia infection rates ranged from zero in larvae to 26% in nymphs to 33% in adult ticks, and B. afzelii, B. burgdorferi sensu stricto, B. garinii, and B. valaisiana were the species involved. Coinfections were found in five ticks. There was no effect of the presence of cattle on Borrelia infections in the ticks. In the ungrazed area, Borrelia infections in nymphs were significantly higher in the oak habitat than in the pine habitat. More mice were captured in the ungrazed area, and these had a significantly higher tick burden than mice from the grazed area. Tick burden on cattle was low. The results suggest that grazing has a negative effect on small rodents as well as on ticks but not on Borrelia infections. Implications of these results for management of woodland reserves and risk of Lyme disease are discussed.
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Tilly, Kit, Aaron Bestor e Patricia A. Rosa. "Functional Equivalence of OspA and OspB, but Not OspC, in Tick Colonization by Borrelia burgdorferi". Infection and Immunity 84, n. 5 (7 marzo 2016): 1565–73. http://dx.doi.org/10.1128/iai.00063-16.
Testo completoAbstract (sommario):
Borrelia burgdorferi, a Lyme disease agent, makes different major outer surface lipoproteins at different stages of its mouse–tick infectious cycle. Outer surface protein A (OspA) coats the spirochetes from the time they enter ticks until they are transmitted to a mammal. OspA is required for normal tick colonization and has been shown to bind a tick midgut protein, indicating that OspA may serve as a tick midgut adhesin. Tick colonization by spirochetes lacking OspA is increased when the infecting blood meal is derived from mice that do not produce antibody, indicating that OspA may protect the spirochetes from host antibody, which will not recognize tick-specific proteins such as OspA. To further study the importance of OspA during tick colonization, we constructed a form ofB. burgdorferiin which theospAopen reading frame, on lp54, was replaced with theospCgene or theospBgene, encoding a mammal-specific or tick-specific lipoprotein, respectively. These fusions yielded a strain that produces OspC within a tick (from the fusion gene) and during early mammalian infection (from the normalospClocus) and a strain that produces OspB in place of OspA within ticks. Here we show that the related, tick-specific protein OspB can fully substitute for OspA, whereas the unrelated, mammal-specific protein OspC cannot. These data were derived from three different methods of infecting ticks, and they confirm and extend previous studies indicating that OspA both protects spirochetes within ticks from mammalian antibody and serves an additional role during tick colonization.
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Lommano, Elena, Luce Bertaiola, Christèle Dupasquier e Lise Gern. "Infections and Coinfections of Questing Ixodes ricinus Ticks by Emerging Zoonotic Pathogens in Western Switzerland". Applied and Environmental Microbiology 78, n. 13 (20 aprile 2012): 4606–12. http://dx.doi.org/10.1128/aem.07961-11.
Testo completoAbstract (sommario):
ABSTRACTIn Europe,Ixodes ricinusis the vector of many pathogens of medical and veterinary relevance, among themBorrelia burgdorferisensu lato and tick-borne encephalitis virus, which have been the subject of numerous investigations. Less is known about the occurrence of emerging tick-borne pathogens likeRickettsiaspp.,Babesiaspp., “CandidatusNeoehrlichia mikurensis,” andAnaplasma phagocytophilumin questing ticks. In this study, questing nymph and adultI. ricinusticks were collected at 11 sites located in Western Switzerland. A total of 1,476 ticks were analyzed individually for the simultaneous presence ofB. burgdorferisensu lato,Rickettsiaspp.,Babesiaspp., “CandidatusNeoehrlichia mikurensis,” andA. phagocytophilum. B. burgdorferisensu lato,Rickettsiaspp., and “CandidatusNeoehrlichia mikurensis” were detected in ticks at all sites with global prevalences of 22.5%, 10.2%, and 6.4%, respectively.Babesia- andA. phagocytophilum-infected ticks showed a more restricted geographic distribution, and their prevalences were lower (1.9% and 1.5%, respectively). Species rarely reported in Switzerland, likeBorrelia spielmanii,Borrelia lusitaniae, andRickettsia monacensis, were identified. Infections with more than one pathogenic species, involving mostlyBorreliaspp. andRickettsia helvetica, were detected in 19.6% of infected ticks. Globally, 34.2% of ticks were infected with at least one pathogen. The diversity of tick-borne pathogens detected inI. ricinusin this study and the frequency of coinfections underline the need to take them seriously into consideration when evaluating the risks of infection following a tick bite.
30
Wang, Guiqing, Dionysios Liveris, Brandon Brei, Hongyan Wu, Richard C. Falco, Durland Fish e Ira Schwartz. "Real-Time PCR for Simultaneous Detection and Quantification of Borrelia burgdorferi in Field-Collected Ixodes scapularis Ticks from the Northeastern United States". Applied and Environmental Microbiology 69, n. 8 (agosto 2003): 4561–65. http://dx.doi.org/10.1128/aem.69.8.4561-4565.2003.
Testo completoAbstract (sommario):
ABSTRACT The density of spirochetes in field-collected or experimentally infected ticks is estimated mainly by assays based on microscopy. In this study, a real-time quantitative PCR (qPCR) protocol targeting the Borrelia burgdorferi-specific recA gene was adapted for use with a Lightcycler for rapid detection and quantification of the Lyme disease spirochete, B. burgdorferi, in field-collected Ixodes scapularis ticks. The sensitivity of qPCR for detection of B. burgdorferi DNA in infected ticks was comparable to that of a well-established nested PCR targeting the 16S-23S rRNA spacer. Of the 498 I. scapularis ticks collected from four northeastern states (Rhode Island, Connecticut, New York, and New Jersey), 91 of 438 (20.7%) nymphal ticks and 15 of 60 (25.0%) adult ticks were positive by qPCR assay. The number of spirochetes in individual ticks varied from 25 to 197,200 with a mean of 1,964 spirochetes per nymphal tick and a mean of 5,351 spirochetes per adult tick. No significant differences were found in the mean numbers of spirochetes counted either in nymphal ticks collected at different locations in these four states (P = 0.23 by one-way analysis of variance test) or in ticks infected with the three distinct ribosomal spacer restriction fragment length polymorphism types of B. burgdorferi (P = 0.39). A high degree of spirochete aggregation among infected ticks (variance-to-mean ratio of 24,877; moment estimate of k = 0.279) was observed. From the frequency distribution data and previously published transmission studies, we estimated that a minimum of 300 organisms may be required in a host-seeking nymphal tick to be able to transmit infection to mice while feeding on mice. These data indicate that real-time qPCR is a reliable approach for simultaneous detection and quantification of B. burgdorferi infection in field-collected ticks and can be used for ecological and epidemiological surveillance of Lyme disease spirochetes.
31
Gipson, Clay L., e Aravinda M. de Silva. "Interactions of OspA Monoclonal Antibody C3.78 with Borrelia burgdorferi within Ticks". Infection and Immunity 73, n. 3 (marzo 2005): 1644–47. http://dx.doi.org/10.1128/iai.73.3.1644-1647.2005.
Testo completoAbstract (sommario):
ABSTRACT The Borrelia burgdorferi outer surface protein A (OspA) vaccine induces antibodies that prevent transmission from the tick to the host. Here we describe studies with an OspA monoclonal antibody (C3.78) to understand the mechanism by which antibodies entering the tick block Borrelia transmission. Host complement in the tick's blood meal did not contribute to protection because the antibody was equally effective whether infected ticks fed on normal or complement-deficient mice. Antibody-mediated cross-linking of bacteria or cross-linking of OspA molecules was not required for protection because C3.78 Fab′ fragments were as effective as whole antibody molecules. At low C3.78 concentrations, transmission was blocked despite the presence of many live spirochetes within the tick, confirming that clearance of Borrelia organisms was not required to block transmission. We propose that OspA antibody binding to the surface of spirochetes blocks transmission by a mechanism that does not require bacterial killing.
32
Perveen, Nighat, Sabir Bin Muzaffar e Mohammad Ali Al-Deeb. "Four Tick-Borne Microorganisms and Their Prevalence in Hyalomma Ticks Collected from Livestock in United Arab Emirates". Pathogens 10, n. 8 (9 agosto 2021): 1005. http://dx.doi.org/10.3390/pathogens10081005.
Testo completoAbstract (sommario):
Ticks and associated tick-borne diseases in livestock remain a major threat to the health of animals and people worldwide. However, in the United Arab Emirates (UAE), very few studies have been conducted on tick-borne microorganisms thus far. The purpose of this cross-sectional DNA-based study was to assess the presence and prevalence of tick-borne Francisella sp., Rickettsia sp., and piroplasmids in ticks infesting livestock, and to estimate their infection rates. A total of 562 tick samples were collected from camels, cows, sheep, and goats in the Emirates of Abu Dhabi, Dubai, and Sharjah from 24 locations. DNA was extracted from ticks and PCR was conducted. We found that Hyalomma dromedarii ticks collected from camels had Francisella sp. (5.81%) and SFG Rickettsia (1.36%), which was 99% similar to Candidatus Rickettsia andeanae and uncultured Rickettsia sp. In addition, Hyalomma anatolicum ticks collected from cows were found to be positive for Theileria annulata (4.55%), whereas H. anatolicum collected from goats were positive for Theileria ovis (10%). The widespread abundance of Francisella of unknown pathogenicity and the presence of Rickettsia are a matter of concern. The discovery of T. ovis from relatively few samples from goats indicates the overall need for more surveillance. Increasing sampling efforts over a wider geographical range within the UAE could reveal the true extent of tick-borne diseases in livestock. Moreover, achieving successful tick-borne disease control requires more research and targeted studies evaluating the pathogenicity and infection rates of many microbial species.
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Bestor, Aaron, Ryan O. M. Rego, Kit Tilly e Patricia A. Rosa. "Competitive Advantage of Borrelia burgdorferi with Outer Surface Protein BBA03 during Tick-Mediated Infection of the Mammalian Host". Infection and Immunity 80, n. 10 (30 luglio 2012): 3501–11. http://dx.doi.org/10.1128/iai.00521-12.
Testo completoAbstract (sommario):
ABSTRACTLinear plasmid lp54 is one of the most highly conserved and differentially expressed elements of the segmented genome of the Lyme disease spirocheteBorrelia burgdorferi. We previously reported that deletion of a 4.1-kb region of lp54 (bba01tobba07[bba01-bba07]) led to a slight attenuation of tick-transmitted infection in mice following challenge with a large number of infected ticks. In the current study, we reduced the number of ticks in the challenge to more closely mimic the natural dose and found a profound defect in tick-transmitted infection of thebba01-bba07mutant relative to wild-typeB. burgdorferi. We next focused on deletion ofbba03as the most likely cause of this mutant phenotype, as previous studies have shown that expression ofbba03is increased by culture conditions that simulate tick feeding. Consistent with this hypothesis, we demonstrated increased expression ofbba03by spirochetes in fed relative to unfed ticks. We also observed that abba03deletion mutant, although fully competent by itself, did not efficiently infect mice when transmitted by ticks that were simultaneously coinfected with wild-typeB. burgdorferi. These results suggest that BBA03 provides a competitive advantage to spirochetes carrying this protein during tick transmission to a mammalian host in the natural infectious cycle.
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OKŁA, HUBERT, MALWINA SOSNOWSKA, KRZYSZTOF P. JASIK, JAN SŁODKI e ROBERT D. WOJTYCZKA. "Nonspecific Bacterial Flora Isolated from the Body Surface and Inside Ixodes ricinus Ticks". Polish Journal of Microbiology 61, n. 3 (2012): 205–9. http://dx.doi.org/10.33073/pjm-2012-026.
Testo completoAbstract (sommario):
Ixodes ricinus and other representatives of the order Ixodida are vectors of typical pathogens: Borrelia burgdorferi sensu lato, Anaplasma phagocytophilium, Babesia spp., a tick-borne encephalitis virus, and other microorganisms which are important from a medical and veterinary point of view. The presented study focuses on the verification of nonspecific bacterial flora of I. ricinus. We analyzed ticks collected in a forest region in Silesia, an industrial district in Poland. Methods of classical microbiology and biochemical assays (API 20 NE test, API Staph test and MICRONAUT System) were used for isolation and identification of microorganisms living on the body surface of I. ricinus and inside ticks. The results show the presence of various bacteria on the surface and inside ticks' bodies. During the study, we isolated Acinetobacter lwoffi, Pseudomonas fluorescens, Aeromonas hydrophila, Achromobacter denitrificans, Alcaligenes faecalis, Stenotrophomonas maltophilia, Pseudomonas oryzihabitans, Micrococcus spp., Kocuria varians, Staphylococcus lentus, Kocuria kristinae, Streptococcus pneumoniae, Rhizobium radiobacter, Staphylococcus xylosus. Majority of the isolated species are non-pathogenic environmental microorganisms, but some of the isolated bacterial strains could cause severe infections.
35
Poupon, Marie-Angèle, Elena Lommano, Pierre-François Humair, Véronique Douet, Olivier Rais, Michael Schaad, Lukas Jenni e Lise Gern. "Prevalence of Borrelia burgdorferi Sensu Lato in Ticks Collected from Migratory Birds in Switzerland". Applied and Environmental Microbiology 72, n. 1 (gennaio 2006): 976–79. http://dx.doi.org/10.1128/aem.72.1.976-979.2006.
Testo completoAbstract (sommario):
ABSTRACT The prevalence of ticks infected by Borrelia burgdorferi sensu lato on birds during their migrations was studied in Switzerland. A total of 1,270 birds captured at two sites were examined for tick infestation. Ixodes ricinus was the dominant tick species. Prevalences of tick infestation were 6% and 18.2% for birds migrating northward and southward, respectively. Borrelia valaisiana was the species detected most frequently in ticks, followed by Borrelia garinii and Borrelia lusitaniae. Among birds infested by infected ticks, 23% (6/26) were infested by B. lusitaniae-infected larvae. Migratory birds appear to be reservoir hosts for B. lusitaniae.
36
Wijnveld, Michiel, Anna-Margarita Schötta, Theresa Stelzer, Georg Duscher, Michael Leschnik, Hannes Stockinger, Per-Eric Lindgren e Gerold Stanek. "Novel Protozoans in Austria Revealed through the Use of Dogs as Sentinels for Ticks and Tick-Borne Pathogens". Microorganisms 9, n. 7 (28 giugno 2021): 1392. http://dx.doi.org/10.3390/microorganisms9071392.
Testo completoAbstract (sommario):
We previously isolated and cultivated the novel Rickettsia raoultii strain Jongejan. This prompted us to ask whether this strain is unique or more widely present in Austria. To assess this issue, we retrospectively screened ticks collected from dogs in 2008. Of these collected ticks, we randomly selected 75 (47 females and 28 males) Dermacentor reticulatus, 44 (21 females, 7 males, and 16 nymphs) Haemaphysalis concinna, and 55 (52 females and 3 males) ticks of the Ixodes ricinus complex. Subsequently, these ticks were individually screened for the presence of tick-borne pathogens using the reverse line blot hybridization assay. In our current study, we detected DNA from the following microbes in D. reticulatus: Anaplasma phagocytophilum, Borrelia lusitaniae, Borrelia spielmanii, Borrelia valaisiana, and R. raoultii, all of which were R. raoultii strain Jongejan. In H. concinna, we found DNA of a Babesia sp., Rickettsia helvetica, and an organism closely related to Theileria capreoli. Lastly, I. ricinus was positive for Anaplasma phagocytophilum, Borrelia afzelii, Borrelia burgdorferi sensu stricto, Borrelia garinii/Borrelia bavariensis, B. lusitaniae, B. spielmanii, B. valaisiana, Candidatus Neoehrlichia mikurensis, Rickettsia helvetica, Rickettsia monacensis, and Theileria (Babesia) microti DNA. The detection of DNA of the Babesia sp. and an organism closely related to Theileria capreoli, both found in H. concinna ticks, is novel for Austria.
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Liz, Jorge S., Laurence Anderes, John W. Sumner, Robert F. Massung, Lise Gern, Bernard Rutti e Michel Brossard. "PCR Detection of Granulocytic Ehrlichiae in Ixodes ricinus Ticks and Wild Small Mammals in Western Switzerland". Journal of Clinical Microbiology 38, n. 3 (2000): 1002–7. http://dx.doi.org/10.1128/jcm.38.3.1002-1007.2000.
Testo completoAbstract (sommario):
The presence of granulocytic ehrlichiae was demonstrated by PCR inIxodes ricinus ticks and wild small mammals in Switzerland in two areas of endemicity for bovine ehrlichiosis. Six ticks (three females and three nymphs) (1.4%) of 417 I. ricinus ticks collected by flagging vegetation contained ehrlichial DNA. A total of 201 small mammals from five species, wood mouse (Apodemus sylvaticus), yellow-necked mouse (Apodemus flavicollis), earth vole (Pitymys subterraneus), bank vole (Clethrionomys glareolus), and common shrew (Sorex araneus), were trapped. The analysis of I. ricinus mammals collected on 116 small mammals showed that nine C. glareolus voles and two A. sylvaticus mice hosted infected tick larvae. In these rodents, granulocytic ehrlichia infection was also detected in blood, spleen, liver, and ear samples. Further examinations of 190 small mammals without ticks or with noninfected ticks showed the presence of ehrlichial DNA in spleen and other tissues from six additional C. glareolus, three A. flavicollis, and one S. araneus mammals. This study suggests thatA. sylvaticus, A. flavicollis, S. araneus, and particularly C. glareolus are likely to be natural reservoirs for granulocytic ehrlichiae. Partial 16S rRNA gene sequences of granulocytic ehrlichiae from ticks and rodents showed a high degree of homology (99 to 100%) with granulocytic ehrlichiae isolated from humans. In contrast, groESL heat shock operon sequence analysis showed a strong divergence (approximately 5%) between the sequences in samples derived from rodents and those derived from samples from questing ticks or from other published ehrlichia sequences. Dual infections with granulocytic ehrlichia andBorrelia burgdorferi were found in ticks and small mammals.
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Luu, Lisa, Ana M. Palomar, Gemma Farrington, Anna-Katarina Schilling, Shonnette Premchand-Branker, John McGarry, Benjamin L. Makepeace, Anna Meredith e Lesley Bell-Sakyi. "Bacterial Pathogens and Symbionts Harboured by Ixodes ricinus Ticks Parasitising Red Squirrels in the United Kingdom". Pathogens 10, n. 4 (11 aprile 2021): 458. http://dx.doi.org/10.3390/pathogens10040458.
Testo completoAbstract (sommario):
Red squirrels (Sciurus vulgaris) are native to most of Eurasia; in much of the United Kingdom, they have been supplanted by the non-native grey squirrel, and are considered an endangered species. Very little is known about the range of tick-borne pathogens to which UK red squirrels are exposed. As part of trap-and-release surveys examining prevalence of Mycobacterium spp. in red squirrel populations on two UK islands, Ixodes ricinus ticks were removed from squirrels and PCR screened for Borrelia spp., intracellular arthropod-borne bacteria and the parasitic wasp Ixodiphagus hookeri. At both sites, the most commonly encountered tick-transmitted bacterium was Borrelia burgdorferi sensu lato (overall minimum prevalence 12.7%), followed by Anaplasma phagocytophilum (overall minimum prevalence 1.6%). Single ticks infected with Spiroplasma were found at both sites, and single ticks infected with Borrelia miyamotoi or an Ehrlichia sp. at one site. Ticks harbouring Wolbachia (overall minimum prevalence 15.2%) were all positive for I. hookeri. Our study shows that UK red squirrels are potentially exposed to a variety of bacterial pathogens via feeding ticks. The effects on the health and survival of this already vulnerable wildlife species are unknown, and further studies are needed to evaluate the threat posed to red squirrels by Borrelia and other tick-borne pathogens.
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Junttila, Juha, Miikka Peltomaa, Hanna Soini, Merja Marjamäki e Matti K. Viljanen. "Prevalence of Borrelia burgdorferi inIxodes ricinus Ticks in Urban Recreational Areas of Helsinki". Journal of Clinical Microbiology 37, n. 5 (1999): 1361–65. http://dx.doi.org/10.1128/jcm.37.5.1361-1365.1999.
Testo completoAbstract (sommario):
Lyme borreliosis, an infection caused by the tick-borne spirocheteBorrelia burgdorferi, is a major health problem for populations in areas of endemicity in the Northern Hemisphere. In the present study we assessed the density of ticks and the prevalence ofB. burgdorferi sensu lato among ticks in popular urban recreational areas of Helsinki, Finland. Altogether 1,688 Ixodes ricinus ticks were collected from five areas located within 5 km of the downtown section of Helsinki, and 726 of them (303 nymphs, 189 females, and 234 males) were randomly chosen for laboratory analysis. The midguts of the ticks were divided into three pieces, one for dark-field microscopy, one for cultivation in BSK-II medium, and one for PCR analysis. Ticks were found in all the study areas; their densities varied from 1 to 36 per 100 m along which a cloth was dragged. The rate of tick infection with B. burgdorferi sensu lato varied from 19 to 55%, with the average being 32%. Borellia afzelii was the most predominant genospecies in all the areas, and no B. burgdorferi sensu stricto isolates were detected. Only two ticks were concurrently infected with both B. afzelii and Borrelia garinii. Dark-field microscopy gave more positive results for B. burgdorferi than did cultivation or PCR analysis. However, the agreement between all three methods was fairly good. We conclude that Lyme borreliosis can be contracted even in urban environments not populated with large mammals like deer or elk. The disease should be taken into account in the differential diagnosis of certain symptoms of patients from these areas, and the use of measures to improve the awareness of the general population and health care officials of the risk of contracting the disease is warranted.
40
Richter, Dania, e Franz-Rainer Matuschka. "Elimination of Lyme Disease Spirochetes from Ticks Feeding on Domestic Ruminants". Applied and Environmental Microbiology 76, n. 22 (24 settembre 2010): 7650–52. http://dx.doi.org/10.1128/aem.01649-10.
Testo completoAbstract (sommario):
ABSTRACT To determine whether and which spirochetes are cleared from Ixodes ricinus ticks during feeding on ruminants, ticks were removed from goats and cattle grazing on tick-infested pastures. Although about a quarter of ticks questing on the pasture were infected by spirochetes, no molted ticks that had previously engorged to repletion on ruminants harbored Lyme disease spirochetes. Borrelia miyamotoi spirochetes, however, appear not to be eliminated. Thus, the more subadult ticks are diverted from reservoir-competent hosts to zooprophylactic ruminants, the smaller the risk of infection by Lyme disease spirochetes is.
41
Reye, Anna L., Olatunbosun G. Arinola, Judith M. Hübschen e Claude P. Muller. "Pathogen Prevalence in Ticks Collected from the Vegetation and Livestock in Nigeria". Applied and Environmental Microbiology 78, n. 8 (10 febbraio 2012): 2562–68. http://dx.doi.org/10.1128/aem.06686-11.
Testo completoAbstract (sommario):
ABSTRACTTicks are important disease vectors that can cause considerable economic losses by affecting animal health and productivity, especially in tropical and subtropical regions. In this study, we investigated the prevalence and diversity of bacterial and protozoan tick-borne pathogens in ticks collected from the vegetation and cattle in Nigeria by PCR. The infection rates of questing ticks were 3.1% forRickettsiaspecies, 0.1% forCoxiella burnetiiand 0.4% forBorreliaspecies. Other pathogens, such asBabesia,Theileria,Anaplasma, andEhrlichiaspecies, were not detected in ticks from the vegetation. Feeding ticks collected from cattle displayed infection rates of 12.5% forRickettsiaspecies, 14% forCoxiella burnetii, 5.9% forAnaplasmaspecies, 5.1% forEhrlichiaspecies, and 2.9% forTheileria mutans. BabesiaandBorreliaspecies were not detected in ticks collected from cattle. Mixed infections were found only in feeding ticks and mainlyRickettsiaspecies andCoxiella burnetiiwere involved. The diversity of tick-borne pathogens in Nigeria was higher in feeding than in questing ticks, suggesting that cattle serve as reservoirs for at least some of the pathogens studied, in particularC. burnetii. The total estimated herd infection rates of 20.6% for aRickettsia africae-like species, 27% forCoxiella burnetii, and 8.5% forAnaplasma marginale/centralesuggest that these pathogens may have considerable implications for human and animal health.
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Artigas-Jerónimo, Sara, Margarita Villar, Alejandro Cabezas-Cruz, Grégory Caignard, Damien Vitour, Jennifer Richardson, Sandrine Lacour et al. "Tick Importin-α Is Implicated in the Interactome and Regulome of the Cofactor Subolesin". Pathogens 10, n. 4 (11 aprile 2021): 457. http://dx.doi.org/10.3390/pathogens10040457.
Testo completoAbstract (sommario):
Ticks and tick-borne diseases (TBDs) represent a burden for human and animal health worldwide. Currently, vaccines constitute the safest and most effective approach to control ticks and TBDs. Subolesin (SUB) has been identified as a vaccine antigen for the control of tick infestations and pathogen infection and transmission. The characterization of the molecular function of SUB and the identification of tick proteins interacting with SUB may provide the basis for the discovery of novel antigens and for the rational design of novel anti-tick vaccines. In the present study, we used the yeast two-hybrid system (Y2H) as an unbiased approach to identify tick SUB-interacting proteins in an Ixodes ricinus cDNA library, and studied the possible role of SUB as a chromatin remodeler through direct interaction with histones. The Y2H screening identified Importin-α as a potential SUB-interacting protein, which was confirmed in vitro in a protein pull-down assay. The sub gene expression levels in tick midgut and fat body were significantly higher in unfed than fed female ticks, however, the importin-α expression levels did not vary between unfed and fed ticks but tended to be higher in the ovary when compared to those in other organs. The effect of importin-α RNAi was characterized in I. ricinus under artificial feeding conditions. Both sub and importin-α gene knockdown was observed in all tick tissues and, while tick weight was significantly lower in sub RNAi-treated ticks than in controls, importin-α RNAi did not affect tick feeding or oviposition, suggesting that SUB is able to exert its function in the absence of Importin-α. Furthermore, SUB was shown to physically interact with histone 4, which was corroborated by protein pull-down and western blot analysis. These results confirm that by interacting with numerous tick proteins, SUB is a key cofactor of the tick interactome and regulome. Further studies are needed to elucidate the nature of the SUB-Importin-α interaction and the biological processes and functional implications that this interaction may have.
43
Levin, Michael L., e Durland Fish. "Acquisition of Coinfection and Simultaneous Transmission of Borrelia burgdorferi and Ehrlichia phagocytophila by Ixodes scapularis Ticks". Infection and Immunity 68, n. 4 (1 aprile 2000): 2183–86. http://dx.doi.org/10.1128/iai.68.4.2183-2186.2000.
Testo completoAbstract (sommario):
ABSTRACT The agents of Lyme disease (Borrelia burgdorferi) and human granulocytic ehrlichiosis (Ehrlichia phagocytophila) are both transmitted by the tick Ixodes scapularis. In nature, ticks are often infected with both agents simultaneously. We studied whether previous infection with either Borrelia orEhrlichia in ticks would affect acquisition and transmission of a second pathogen. Ehrlichia-infectedI. scapularis nymphs were fed uponBorrelia-infected mice, and Borrelia-infectedI. scapularis nymphs were fed uponEhrlichia-infected mice. The efficiency with which previously infected nymphal ticks acquired a second pathogen from infected hosts was compared to that of uninfected ticks. An average of 51% ± 15% of ticks acquired Ehrlichia from infected mice regardless of their prior infection status with Borrelia. An average of 85% ± 10% of ticks acquired Borrelia from infected mice regardless of their prior infection status withEhrlichia. Also, we assessed the efficiency with which individual nymphs could transmit either agent alone, or both agents simultaneously, to individual susceptible hosts. An average of 76% ± 9% of Borrelia-infected ticks and 84% ± 10% ofEhrlichia-infected ticks transmitted these agents to mice regardless of the presence of the other pathogen. There was no evidence of interaction between the agents of Lyme disease and human granulocytic ehrlichiosis in I. scapularis ticks. The presence of either agent in the ticks did not affect acquisition of the other agent from an infected host. Transmission of the agents of Lyme disease and human granulocytic ehrlichiosis by individual ticks was equally efficient and independent. Dually infected ticks transmitted each pathogen to susceptible hosts as efficiently as ticks infected with only one pathogen.
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Hrnková, Johana, Irena Schneiderová, Marina Golovchenko, Libor Grubhoffer, Natalie Rudenko e Jiří Černý. "Role of Zoo-Housed Animals in the Ecology of Ticks and Tick-Borne Pathogens—A Review". Pathogens 10, n. 2 (16 febbraio 2021): 210. http://dx.doi.org/10.3390/pathogens10020210.
Testo completoAbstract (sommario):
Ticks are ubiquitous ectoparasites, feeding on representatives of all classes of terrestrial vertebrates and transmitting numerous pathogens of high human and veterinary medical importance. Exotic animals kept in zoological gardens, ranches, wildlife parks or farms may play an important role in the ecology of ticks and tick-borne pathogens (TBPs), as they may serve as hosts for local tick species. Moreover, they can develop diseases of varying severity after being infected by TBPs, and theoretically, can thus serve as reservoirs, thereby further propagating TBPs in local ecosystems. The definite role of these animals in the tick–host-pathogen network remains poorly investigated. This review provides a summary of the information currently available regarding ticks and TBPs in connection to captive local and exotic wildlife, with an emphasis on zoo-housed species.
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Policastro, Paul F., Sandra J. Raffel e Tom G. Schwan. "Borrelia hermsii Acquisition Order in Superinfected Ticks Determines Transmission Efficiency". Infection and Immunity 81, n. 8 (28 maggio 2013): 2899–908. http://dx.doi.org/10.1128/iai.00542-13.
Testo completoAbstract (sommario):
ABSTRACTMultilocus sequence typing ofBorrelia hermsiiisolates reveals its divergence into two major genomic groups (GG), but no differences in transmission efficiency or host pathogenicity are associated with these genotypes. To compare GGI and GGII in the tick-host infection cycle, we first determined if spirochetes from the two groups could superinfect the tick vectorOrnithodoros hermsi. We infected mice with isolates from each group and fed ticks sequentially on these mice. We then fed the infected ticks on naive mice and measured GGI and GGII spirochete densities in vector and host, using quantitative PCR of genotype-specific chromosomal DNA sequences. Sequential feedings resulted in dual tick infections, showing that GGI or GGII primary acquisition did not block superinfection by a secondary agent. On transmission to naive mice at short intervals after acquisition, ticks with primary GGI and secondary GGII spirochete infections caused mixed GGI and GGII infections in mice. However, ticks with primary GGII and secondary GGI spirochete infections caused only GGII infections with all isolate pairs examined. At longer intervals after acquisition, the exclusion of GGI by GGII spirochetes declined and cotransmission predominated. We then examined GGI and GGII spirochetemia in mice following single inoculation and coinoculation by needle and found that GGI spirochete densities were reduced on multiple days when coinoculated with GGII. These findings indicate that dual GGI-GGII spirochete infections can persist in ticks and that transmission to a vertebrate host is dependent on the order of tick acquisition and the interval between acquisition and transmission events.
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Burrage, T. G., Z. Lu, J. G. Neilan, D. L. Rock e L. Zsak. "African Swine Fever Virus Multigene Family 360 Genes Affect Virus Replication and Generalization of Infection in Ornithodoros porcinus Ticks". Journal of Virology 78, n. 5 (1 marzo 2004): 2445–53. http://dx.doi.org/10.1128/jvi.78.5.2445-2453.2004.
Testo completoAbstract (sommario):
ABSTRACT Recently, we reported that African swine fever virus (ASFV) multigene family (MGF) 360 and 530 genes are significant swine macrophage host range determinants that function by promoting infected-cell survival. To examine the function of these genes in ASFV's arthropod host, Ornithodoros porcinus porcinus, an MGF360/530 gene deletion mutant (Pr4Δ35) was constructed from an ASFV isolate of tick origin, Pr4. Pr4Δ35 exhibited a significant growth defect in ticks. The deletion of six MGF360 and two MGF530 genes from Pr4 markedly reduced viral replication in infected ticks 100- to 1,000-fold. To define the minimal set of MGF360/530 genes required for tick host range, additional gene deletion mutants lacking individual or multiple MGF genes were constructed. The deletion mutant Pr4Δ3-C2, which lacked three MGF360 genes (3HL, 3Il, and 3LL), exhibited reduced viral growth in ticks. Pr4Δ3-C2 virus titers in ticks were significantly reduced 100- to 1,000-fold compared to control values at various times postinfection. In contrast to the parental virus, with which high levels of virus replication were observed in the tissues of infected adults, Pr4Δ3-C2 replication was not detected in the midgut, hemolymph, salivary gland, coxal gland, or reproductive organs at 15 weeks postinfection. These data indicate that ASFV MGF360 genes are significant tick host range determinants and that they are required for efficient virus replication and generalization of infection. The impaired virus replication of Pr4Δ3-C2 in the tick midgut likely accounts for the absence of the generalized infection that is necessary for the natural transmission of virus from ticks to pigs.
47
Portillo, Aránzazu, Ana M. Palomar, Paula Santibáñez e José A. Oteo. "Epidemiological Aspects of Crimean-Congo Hemorrhagic Fever in Western Europe: What about the Future?" Microorganisms 9, n. 3 (21 marzo 2021): 649. http://dx.doi.org/10.3390/microorganisms9030649.
Testo completoAbstract (sommario):
Crimean-Congo hemorrhagic fever virus (CCHFV) is an arthropod-borne virus (arbovirus), mainly transmitted by ticks, belonging to the genus Orthonairovirus (family Nairoviridae, order Bunyavirales). CCHFV causes a potentially severe, or even fatal, human disease, and it is widely distributed in Africa, Asia, eastern Europe and, more recently, in South-western Europe. Until a few years ago, no cases of Crimean-Congo hemorrhagic fever (CCHF) had been reported in western Europe, with the exception of several travel-associated cases. In 2010, the CCHFV was reported for the first time in South-western Europe when viral RNA was obtained from Hyalomma lusitanicum ticks collected from deer in Cáceres (Spain). Migratory birds from Africa harboring CCHFV-infected ticks and flying to Spain appear to have contributed to the establishment of the virus (genotype III, Africa-3) in this country. In addition, the recent findings in a patient and in ticks from deer and wild boar of viral sequences similar to those from eastern Europe (genotype V, Europe-1), raise the possibility of the introduction of CCHFV into Spain through the animal trade, although the arrival by bird routes cannot be ruled out (Africa-4 has been also recently detected). The seropositive rates of animals detected in regions of South-western Spain suggest an established cycle of tick-host-tick in certain areas, and the segment reassortment detected in the sequenced virus from one patient evidences a high ability to adaptation of the virus. Different ixodid tick genera can be vectors and reservoirs of the virus, although Hyalomma spp. are particularly relevant for its maintenance. This tick genus is common in Mediterranean region but it is currently spreading to new areas, partly due to the climate change and movement of livestock or wild animals. Although to a lesser extent, travels with our pets (and their ticks) may be also a factor to be considered. As a consequence, the virus is expanding from the Balkan region to Central Europe and, more recently, to Western Europe where different genotypes are circulating. Thus, seven human cases confirmed by molecular methods have been reported in Spain from 2016 to August 2020, three of them with a fatal outcome. A One Health approach is essential for the surveillance of fauna and vector populations to assess the risk for humans and animals. We discuss the risk of CCHFV causing epidemic outbreaks in Western Europe.
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Stafford, Kirby C., Matthew L. Cartter, Louis A. Magnarelli, Starr-Hope Ertel e Patricia A. Mshar. "Temporal Correlations between Tick Abundance and Prevalence of Ticks Infected with Borrelia burgdorferi and Increasing Incidence of Lyme Disease". Journal of Clinical Microbiology 36, n. 5 (1998): 1240–44. http://dx.doi.org/10.1128/jcm.36.5.1240-1244.1998.
Testo completoAbstract (sommario):
The abundance of host-seeking Ixodes scapularis nymphs, the principal vector for the Lyme disease agent, Borrelia burgdorferi, in Old Lyme, Lyme, and East Haddam, Connecticut, was compared with the incidence of reported human Lyme disease in the 12-town area around the Connecticut River and the State of Connecticut for the period 1989 to 1996. Ticks were sampled from lawns and woodlands by dragging flannel over the vegetation and examined for the presence of B. burgdorferi by indirect fluorescent antibody staining. The infection rate of the nymphal ticks by B. burgdorferi during the 9-year period was 14.3% (of 3,866), ranging from 8.6% (1993) to 24.4% (1996). The incidence of Lyme disease was positively correlated with tick abundance in the 12 town area (r = 0.828) and the State of Connecticut (r = 0.741). An entomological risk index based upon the number of I. scapularis ticks infected by B. burgdorferi was highest in 1992, 1994, and 1996 and was highly correlated with the incidence of Lyme disease in Connecticut (r = 0.944). The number of Lyme disease cases has been influenced, in part, by annual changes in population densities ofI. scapularis and, presumably, a corresponding change in the risk of contact with infected ticks. Based upon tick activity and spirochetal infection rates, epidemiologically based Lyme disease case reports on a regional scale appear to reflect real trends in disease.
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Do, Thom, Pornkamol Phoosangwalthong, Ketsarin Kamyingkird, Chanya Kengradomkij, Wissanuwat Chimnoi e Tawin Inpankaew. "Molecular Detection of Tick-Borne Pathogens in Stray Dogs and Rhipicephalus sanguineus sensu lato Ticks from Bangkok, Thailand". Pathogens 10, n. 5 (6 maggio 2021): 561. http://dx.doi.org/10.3390/pathogens10050561.
Testo completoAbstract (sommario):
Canine tick-borne pathogens (CTBPs) such as Babesia vogeli, Ehrlichia canis, Anaplasma platys, Hepatozoon canis, and Mycoplasma haemocanis are important pathogens in dogs worldwide. Rhipicephalus sanguineus sensu lato, the main vector of several CTBPs, is the most common tick species found on dogs in Thailand. The present study identified CTBPs in dogs and ticks infested dogs. Samples (360 dog blood samples and 85 individual ticks) were collected from stray dogs residing in 37 temples from 24 districts in Bangkok and screened for CTBPs using molecular techniques. The most common CTBP found infecting dogs in this study was Ehrlichia canis (38.3%) followed by Mycoplasma haemocanis (34.2%), Hepatozoon canis (19.7%), Babesia vogeli (18.1%), and Anaplasma platys (13.9%), respectively. Furthermore, A. platys (22.4%) was the most common CTBP in ticks followed by M. haemocanis (18.8%), B. vogeli (9.4%), H. canis (5.9%), and E. canis (2.4%), respectively. The detection of CTBPs from the present study highlights the potential risk of infections that may occur in stray dogs and their ticks residing in Bangkok temples. These findings underline the importance of performing active surveys to understand the complexity of distributions of CTBPs in dogs and their ticks in Thailand.
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Kleiboeker, S. B., G. A. Scoles, T. G. Burrage e J. H. Sur. "African Swine Fever Virus Replication in the Midgut Epithelium Is Required for Infection of OrnithodorosTicks". Journal of Virology 73, n. 10 (1 ottobre 1999): 8587–98. http://dx.doi.org/10.1128/jvi.73.10.8587-8598.1999.
Testo completoAbstract (sommario):
ABSTRACT Although the Malawi Lil20/1 (MAL) strain of African swine fever virus (ASFV) was isolated from Ornithodoros sp. ticks, our attempts to experimentally infect ticks by feeding them this strain failed. Ten different collections of Ornithodorus porcinus porcinus ticks and one collection of O. porcinus domesticus ticks were orally exposed to a high titer of MAL. At 3 weeks postinoculation (p.i.), <25% of the ticks contained detectable virus, with viral titers of <4 log10 50% hemadsorbing doses/ml. Viral titers declined to undetectability in >90% of the ticks by 5 weeks p.i. To further study the growth defect, O. porcinus porcinus ticks were orally exposed to MAL and assayed at regular intervals p.i. Whole-tick viral titers dramatically declined (>1,000-fold) between 2 and 6 days p.i., and by 18 days p.i., viral titers were below the detection limit. In contrast, viral titers of ticks orally exposed to a tick-competent ASFV isolate, Pretoriuskop/96/4/1 (Pr4), increased 10-fold by 10 days p.i. and 50-fold by 14 days p.i. Early viral gene expression, but not extensive late gene expression or viral DNA synthesis, was detected in the midguts of ticks orally exposed to MAL. Ultrastructural analysis demonstrated that progeny virus was rarely present in ticks orally exposed to MAL and, when present, was associated with extensive cytopathology of phagocytic midgut epithelial cells. To determine if viral replication was restricted only in the midgut epithelium, parenteral inoculations into the hemocoel were performed. With inoculation by this route, a persistent infection was established although a delay in generalization of MAL was detected and viral titers in most tissues were typically 10- to 1,000-fold lower than those of ticks injected with Pr4. MAL was detected in both the salivary secretion and coxal fluid following feeding but less frequently and at a lower titer compared to Pr4. Transovarial transmission of MAL was not detected after two gonotrophic cycles. Ultrastructural analysis demonstrated that, when injected, MAL replicated in a number of cell types but failed to replicate in midgut epithelial cells. In contrast, ticks injected with Pr4 had replicating virus in midgut epithelial cells. Together, these results indicate that MAL replication is restricted in midgut epithelial cells. This finding demonstrates the importance of viral replication in the midgut for successful ASFV infection of the arthropod host.