Tick Stages Research Articles

Curcuma longa essential oil as an acaricidal agent for the control of cattle ectoparasitic tick - Rhipicephalus (Boophilus) annulatus

well known for its insecticidal, anti-inflammatory, antioxidant, anticancer, anti-rheumatic and antibiotic properties, Turmeric (Curcuma longa L.) Essential oil (EO), is effective in repelling and controlling many different pest species. The present study evaluates in vitro efficacy of turmeric EO against ectoparasitic tick, Rhipicephalus (Boophilus)annulatus collected from their natural host, domesticated cows. Repellency and toxicity of the EO on ectoparasitic ticks was analyzed with petri dish choice bioassay and AIT (Adult immersion test) against adult engorged females and nymphal stages of ticks. The Repellency Concentration (RC50) and Lethal Concentration (LC50) reproductive index, inhibition of oviposition and egg hatchability of treated ticks were estimated. GC-MS analysis identified Ar-turmerone as the major phytochemical, which induces adulticidal and repellant properties of EO. The nymphal stages of the ticks exhibited greater repellency on application of EO than the adult stage. Also, EO induced effective mortality in adult ticks. Further, this lethal concentration is capable of producing a decreased output in reproductive parameters namely, fecundity, % of oviposition and egg hatchability in surviving ticks thereby considerably reducing Rhipicephalus (Boophilus) R(B). annulatus population on its host. This study reveals the potency C. longa EO to be used as an effective pest control agent against R (B). annulatus infestation that can serve as an alternative to synthetic pesticides.

In vitro assessment of assembly and sex pheromones in the control of larval stages of brown dog ticks

The increasing incidence of tick-borne diseases and the growing resistance to conventional acaricides underscore the urgent need for innovative and sustainable tick management strategies. This study investigates the potential of assembly and sex pheromones for the control of larval stages of Rhipicephalus sanguineus, the brown dog tick, which poses significant health risks to dogs. The ticks were collected from various canine hosts in Thrissur, Kerala and subjected to Petri-dish bioassays using vapour patches impregnated with synthetic assembly pheromone (AP) and sex pheromone (SP), both individually and in combination. The efficacy of these semiochemicals was assessed based on the attraction and clustering behaviour of unfed larvae and partially fed adult ticks over a 24-hour period. Results demonstrated a significantly higher attraction to AP-impregnated patches, with notable efficacy observed in causing tick aggregation, particularly beyond 30 min of exposure. While SP also showed potential in attracting ticks, the combination of SP and AP did not result in a synergistic effect. The study highlights the potential of using semiochemicals as an environmentally sustainable alternative to traditional acaricides, highlighting their role in integrated pest management strategies Keywords: Rhipicephalus sanguineus, adenine, guanine, xanthine, 2,6-DCP, Petri-dish bioassay

Abundance Trends of Immature Stages of Ticks at Different Distances from Hiking Trails from a Natural Park in North-Western Italy.

Hiking trails may act as hotspots at the wildlife-human interface, posing an acarological risk for people and their pets. Ticks that are maintained in the environment by wild animals may quest on people walking along the trails. Assessing the risk of tick bites for people involved in outdoor activities is a further step in mitigating the risk of tick-borne diseases. This work describes the variation of tick abundance along a gradient of distances from hiking trails, where wildlife passage is favored by higher accessibility. Hiking trails with dense vegetation on the sides were sampled for ticks along a 100 m dragging transect, located in a natural park in North-Western Italy. Additional transects were replicated at 1, 2 and 4 m away from the trail on both sides. After morphological identification, descriptive statistics and modeling were applied to determine the abundance patterns across distances. Larvae were most abundant near the trail, peaking at 1 m and dropping sharply at further distances. Nymphs showed a more gradual and consistent decrease at progressing distance from the trail. Few adults were collected, preventing the identification of a clear trend. With higher tick abundance, the immediate vicinity of hiking trails may represent a source of acarological risk for humans and pets.

Development of novel multi-protein chimeric immunogens that protect against infection with the Lyme disease agent, Borreliella burgdorferi.

Lyme disease is the most common tick-borne disease in North America. A vaccine for use in humans is not available. Here, we detail the development of two chimeric vaccine antigens, BAF and Chv2M. BAF elicits Abs that target proteins and protein variants produced by Borreliella species in ticks (OspB and OspA) and mammals (FtlA/B). OspB serves as the backbone structure for the BAF chimeric. Two OspA221-240 epitope-containing domain (ECD) variants (#A1 and #A15) were inserted into a loop in OspB. The N-terminal region of the FtlA protein was joined to the C-terminus of the chimeric. The second chimeric, Chv2M, consists of L5 (loop 5) and H5 (helix 5) ECDs derived from diverse OspC proteins. Borreliella species produce OspC upon exposure to the bloodmeal and during early infection in mammals. Here, we demonstrate that BAF and Chv2M are potent immunogens that elicit Abs that bind to each component protein (FtlA, FtlB, OspB, and multiple OspA and OspC variants). Anti-BAF and anti-Chv2M Abs kill Borreliella burgdorferi strains through Ab-mediated complement-dependent and complement-independent mechanisms. Eighty percent (32/40) of mice that received a three-dose vaccine regimen were protected from infection with B. burgdorferi B31. Efficacy increased to 90% (18/20) when the amount of Chv2M was increased in the third vaccine dose. Readouts for infection were flaB PCR and seroconversion to VlsE. This study establishes proof of principle for a chimeric immunogen vaccine formulation that elicits Abs to multiple targets on the B. burgdorferi cell surface produced during tick and mammalian stages of the enzootic cycle.IMPORTANCELyme disease is a growing public health threat across parts of the Northern Hemisphere. Regions that can support sustained tick populations are expanding, and the incidence of tick-borne diseases is increasing. In light of the increasing risk of Lyme disease, effective preventive strategies are needed. Most vaccine development efforts have focused on outer surface protein A, a Borreliella burgdorferi protein produced only in ticks. Herein, we describe the development of a novel vaccine formulation consisting of two multivalent chimeric proteins that are immunogenic and elicit antibodies with bactericidal activity that target several cell surface proteins produced by the Lyme disease spirochetes in feeding ticks and mammals. In a broader sense, this study advances efforts to develop custom-designed vaccinogens comprised of epitope-containing domains from multiple proteins.

Parasitic system Ixodes persulcatus (Ixodinae) – Borrelia garinii – small mammals in the northwest of Russia

Relationships between members of the parasitic system formed by the taiga tick Ixodes persulcatus (Schulze, 1930) at the preimaginal developmental stages, Borrelia garinii and small mammals were studied. Transovarial transmission of B. garinii in the taiga tick was not found. In natural biotopes of northwestern Russia, small mammals that were hosts of the preimaginal stages of Ixodes persulcatus included Myodes glareolus (Schreber, 1780) (52–53%), Sorex araneus Linnaeus, 1758 (33–34%), and Apodemus uralensis (Pallas, 1811) (14%). Larvae and nymphs were most numerous on hosts at the beginning of the season, in May and June. Subsequently, their number decreased by 5–10 times and slightly increased in September. In populations, up to 31.9% of M. glareolus individuals and 20.5% of A. uralensis individuals were infected with B. garinii. The aggregated type of distribution of taiga tick larvae and nymphs on hosts has been revealed. Infection of the main part of hungry larvae and nymphs occurred at the beginning of the activity season after wintering when feeding on overwintered infected hosts. This period is the key in circulation (exchange between vectors and reservoir hosts) and the preservation of B. garinii in the natural focus of borreliosis in northwestern Russia. Vertical transmission of B. garinii is possible from larvae and nymphs fed at the beginning of the season to nymphs and adult ticks that had molted in August-September, respectively. Horizontal transmission of the pathogen from small mammals, especially the bank vole, to larvae and nymphs, and vice versa, ensures the circulation and persistence of B. garinii in natural foci. The question of the preservation of the pathogen in overwintering preimaginal stages of ticks requires further research.

Molecular cloning, identification, transcriptional analysis, and silencing of enolase on the life cycle of Haemaphysalis longicornis (Acari, Ixodidae) tick.

Ticks, blood-sucking ectoparasites, spread diseases to humans and animals. Haemaphysalis longicornis is a significant vector for tick-borne diseases in medical and veterinary contexts. Identifying protective antigens in H. longicornis for an anti-tick vaccine is a key tick control strategy. Enolase, a multifunctional protein, significantly converts D-2-phosphoglycerate and phosphoenolpyruvate in glycolysis and gluconeogenesis in cell cytoplasm. This study cloned a complete open reading frame (ORF) of enolase from the H. longicornis tick and characterized its transcriptional and silencing effect. We amplified the full-length cDNA of the enolase gene using rapid amplification of cDNA ends. The complete cDNA, with an ORF of 1,297 nucleotides, encoded a 432-amino acid polypeptide. Enolase of the Jeju strain H. longicornis exhibited the highest sequence similarity with H. flava (98%), followed by Dermacentor silvarum (82%). The enolase motifs identified included N-terminal and C-terminal regions, magnesium binding sites, and several phosphorylation sites. Reverse transcription-polymerase chain reaction (RT-PCR) analysis indicated that enolase mRNA transcripts were expressed across all developmental stages of ticks and organs such as salivary gland and midgut. RT-PCR showed higher transcript levels in syn-ganglia, suggesting that synganglion nerves influence enolase,s role in tick salivary glands. We injected enolase double-stranded RNA into adult unfed female ticks, after which they were subsequently fed with normal unfed males until they spontaneously dropped off. RNA interference significantly (P<0.05) reduced feeding and reproduction, along with abnormalities in eggs (no embryos) and hatching. These findings suggest enolase is a promising target for future tick control strategies.

Rearing of Rhipicephalus annulatus ticks on rabbits for the biological transmission of Anaplasma marginale.

Anaplasma marginale is an obligate intraerythrocytic rickettsial parasite that infects cattle in tropical and subtropical regions. There is no evidence that A. marginale inoculation can be used to culture Rhipicephalus annulatus in rabbits. This study aimed to determine the molting of R. annulatus larvae, nymphs, and adults on rabbits as well as nymphs and adults of R. annulatus on calves with or without A. marginale. Transstadial, horizontal, and transovarial transmissions of A. marginale in R. annulatus reared on rabbits and calves were evaluated. Engorged female ticks were collected from field samples of A. marginale-infected and non-infected cattle. We divided the eight rabbits into two groups: A and B. Group A rabbits were infected with A. marginale through parenteral inoculation, whereas Group B rabbits were kept as a control. The "clean rabbits" in Group B were observed for tick rearing without A. marginale. Polymerase chain reaction was used to screen A. marginale in rabbits and stages of tick. The complete life cycle of R. annulatus with or without A. marginale was observed on rabbits. A 6.5-day longer life cycle was observed in ticks harboring A. marginale than in ticks without A. marginale. To observe transstadial transmission, transstadial, horizontal, and transovarial transmissions of A. marginale in R. annulatus ticks were experimentally observed in one clean calf fed separately with infected nymphs and female adult ticks. We experimentally observed transovarian, transstadial, and transovarial transmission of A. marginale in R. annulatus ticks as a biological vector reared on calves and rabbits. We used rabbits as a model animal for rearing R. annulatus ticks and culture of A. marginale.

Vector competence of Ixodes ricinus instars for the transmission of Borrelia burgdorferi sensu lato in different small mammalian hosts

BackgroundMany pathogens and parasites can infect multiple host species, and the competence of different hosts as pathogen reservoirs is key to understanding their epidemiology. Small mammals are important hosts for the instar stages of Ixodes ricinus ticks, the principal vector of Lyme disease in Europe. Small mammals also act as reservoirs of Borrelia afzelii, the most common genospecies of the Borrelia burgdorferi sensu lato (s.l.) spirochetes causing Lyme disease in Europe. However, we lack quantitative estimates on whether different small mammal species are equally suitable hosts for feeding I. ricinus and whether they show differences in pathogen transmission from host to tick.MethodsHere, we analysed the feeding success and prevalence of B. burgdorferi s.l. infections in 12,987 instar I. ricinus found on captured small mammals with known infection status in Norway (2018–2022).ResultsWe found that larvae were more likely to acquire a blood meal from common shrews (Sorex araneus, 46%) compared to bank voles (Myodes glareolus, 31%) and wood mice (Apodemus sylvaticus, 36%). Nymphs tended to be more likely to acquire a blood meal from wood mice (66%) compared to bank voles (54%). Common shrews harboured few nymphs (n=19). Furthermore, we found that larvae feeding on infected bank voles (11%) were more likely to be infected with B. burgdorferi s.l. than larvae on infected common shrews (7%) or wood mice (4%).ConclusionsOur study provides quantitative evidence of differences in suitability for the instar stages of I. ricinus across taxa of small mammals and highlights how even known small mammal host species can differ in their ability to feed ticks and infect larval ticks with the pathogen causing Lyme disease.Graphical

1776. Coinfection of severe fever with thrombocytopenia syndrome virus and Coxiella burnetii infection by the developmental stage of hard ticks in the subtropical region of South Korea

Abstract Background Severe fever with thrombocytopenia syndrome virus (SFTSV) is transmitted through tick bites. Ticks are potential vectors for the bacterium Coxiella burnetii (C. burnetii) that causes Query fever. Here, we analyzed SFTSV and C. burnetii co-infection rates in ticks in rural areas of Jeju Island, South Korea. Methods Free ticks were collected from the natural environment of the island between 2016 and 2019, and SFTSV RNA was extracted. Additionally, ribosomal RNA gene sequencing was used to identify Coxiella species. Results Haemaphysalis longicornis (H. longicornis) was the most common tick species followed by H. flava. Tick number gradually increased from April, peaked in August, and was lowest in March. Of all the collected ticks, 82.6% (2,851/3,458) were nymphs, 17.9% (639/3,458) adults, and 0.1% (4/3,458) larvae. SFTSV-infected ticks comprised 12.6% of all ticks; their numbers were the lowest in November–December, increased from January, and were mostly identified in the adult stage during June–August. C. burnetii infections were detected in 4.4% of the SFTSV-infected H. longicornis ticks. Coxiella burnetii co-infection was mainly observed in the nymph stage of H. longicornis, with the highest infection rate in January, followed by December and November. Conclusion Our findings suggest that Jeju Island has a high SFTSV and potential C. burnetii infection in ticks. This study provides important insights regarding SFTS and Q fever risk to humans in South Korea. Disclosures All Authors: No reported disclosures

Acaricidal effect of crude aqueous extract of Nicotiana tabacum along with turmeric and Annona leaf extract on cattle ticks

The ectoparasites produces severe economic and production loss in farm animal’s through tick bites, sucking of blood, tick worry, tick toxicosis, tick paralysis and transmission of haemoprotozoan diseases. Ticks developed resistance against chemical acaricides and also the residues of chemical acaricide producing environmental pollution. The herbal based acaricide used as biocontrol agent for protecting environment particularly hilly area. As per indigenous technical knowledge records, the Nicotiana tabacum was a traditional control remedy for control of ectoparasites in India. In vitro acaricidal efficacy of crude aqueous leaf extract of Nicotiana tabacum along with neem and turmeric followed by Annona leaves on immature and adult stages of Rhipicephalus sp. was carried out at different concentrations of with different time interval. These extract combo had a significant effect on the mortality of nymphal and adult stages of ticks. The 70%, 80% and 90% mortality of Nymphal and adult stages of ticks at 24-36 hours post treatment with 40%, 50% 70% concentration of herbal extract in invitro assay. The mortality rates of ticks increased with the increasing the extract concentrations both in vivo and in vitro. Nicotiana tabacum causes paralysis of ticks and leads to detachment from the body of animal and concluded that Nicotiana tabacum along with turmeric and annona extract is effective biocontrol agent for controlling ectoparasites without any environmental pollution and harmful side effect in animal health.

Cross-alteration of murine skin and tick microbiome concomitant with pathogen transmission after Ixodes ricinus bite

BackgroundTicks are major vectors of diseases affecting humans such as Lyme disease or domestic animals such as anaplasmosis. Cross-alteration of the vertebrate host skin microbiome and the tick microbiome may be essential during the process of tick feeding and for the mechanism of pathogen transmission. However, it has been poorly investigated.MethodsWe used mice bitten by field-collected ticks (nymphs and adult ticks) in different experimental conditions to investigate, by 16S rRNA gene metabarcoding, the impact of blood feeding on both the mouse skin microbiome and the tick microbiome. We also investigated by PCR and 16S rRNA gene metabarcoding, the diversity of microorganisms transmitted to the host during the process of tick bite at the skin interface and the dissemination of the pathogen in host tissues (blood, heart, and spleen).ResultsMost of the commensal bacteria present in the skin of control mice were replaced during the blood-feeding process by bacteria originating from the ticks. The microbiome of the ticks was also impacted by the blood feeding. Several pathogens including tick-borne pathogens (Borrelia/Borreliella, Anaplasma, Neoehrlichia, Rickettsia) and opportunistic bacteria (Williamsia) were transmitted to the skin microbiome and some of them disseminated to the blood or spleen of the mice. In the different experiments of this study, skin microbiome alteration and Borrelia/Borreliella transmission were different depending on the tick stages (nymphs or adult female ticks).ConclusionsHost skin microbiome at the bite site was deeply impacted by the tick bite, to an extent which suggests a role in the tick feeding, in the pathogen transmission, and a potentially important impact on the skin physiopathology. The diversified taxonomic profiles of the tick microbiome were also modified by the blood feeding.FNmPmXVvH5C8zJYmhgJpvuVideo

Anti-tick vaccine candidate subolesin is important for blood feeding and innate immune gene expression in soft ticks.

Subolesin is a conserved molecule in both hard and soft ticks and is considered as an effective candidate molecule for the development of anti-tick vaccine. Previous studies have reported the role of subolesin in blood feeding, reproduction, development, and gene expression in hard ticks. However, studies addressing the role of subolesin in soft ticks are limited. In this study, we report that subolesin is not only important in soft tick Ornithodoros turicata americanus blood feeding but also in the regulation of innate immune gene expression in these ticks. We identified and characterized several putative innate immune genes including Toll, Lysozyme precursor (Lp), fibrinogen-domain containing protein (FDP), cystatin and ML-domain containing protein (MLD) in O. turicata americanus ticks. Quantitative real-time polymerase chain reaction analysis revealed the expression of these genes in both O. turicata americanus salivary glands and midgut and in all developmental stages of these soft ticks. Significantly increased expression of fdp was noted in salivary glands and midgut upon O. turicata americanus blood feeding. Furthermore, RNAi-mediated knockdown of O. turicata americanus subolesin expression affected blood feeding and innate immune gene expression in these ticks. Significant downregulation of toll, lp, fdp, cystatin, and mld transcripts was evident in sub-dsRNA-treated ticks when compared to the levels noted in mock-dsRNA-treated control. Collectively, our study not only reports identification and characterization of various innate immune genes in O. turicata americanus ticks but also provides evidence on the role of subolesin in blood feeding and innate immune gene expression in these medically important ticks.

In Silico Exploration and Experimental Validation of Camellia sinensis Extract against Rhipicephalus microplus and Sarcoptes scabiei: An Integrated Approach.

Sarcoptes scabiei is an ectoparasite of humans and animals that causes scabies. The Rhipicephalus (Boophilus) microplus is a blood-sucking ectoparasite that transmits various pathogens. These two parasites have caused great losses to a country's dairy and agriculture sectors. The aim of this study was to determine the in vitro and in silico efficacy of Camellia sinensis plant extracts. Different concentrations of C. sinensis ethanolic plant extracts were prepared using the maceration method and were used against mites and ticks (in adult immersion test AIT and larval packet test LPT) to evaluate their in vitro acaricidal activity. Additionally, in silico molecular docking was performed to investigate the inhibitory interactions between the phytochemicals of the plant and S. scabiei and R. microplus glutathione transferase proteins (SsGST and RmGST). This study observed that the plant extract showed high efficacy in vitro against mites and different tick stages in adult immersion and larval packet tests. Additionally, the in silico study revealed a strong binding interaction between ellagic acid and SsGST protein, with a binding energy of -7.3 kcal/mol, with respect to permethrin (-6.7 kcal/mol), whereas quercetin and RmGST resulted in a docking score of -8.6 kcal/mol compared to deltamethrin (-8.2 kcal/mol). Overall, this study explored the potential of C. sinensis as a natural alternative for controlling tick and mite infestations and provided insights into the inhibitory mechanisms of its phytochemicals.

Novel insights regarding the safety and efficacy of pyrethroid-coated nanoparticles against Hyalomma ticks

Nanoparticles have been shown to inhibit major life cycle stages of ticks, indicative of the promising application of nanomaterials against hard ticks. The study thus probed into one of the alternative options to curtail Hyalomma by employing nanocomposites consisting of pyrethroids (cypermethrin and deltamethrin) coated nanoparticles of iron oxides and iron sulfides keeping alongside the evaluation of their toxicity through plant and mammalian cell lines. The nanoparticles used in this study were roughly spherical in morphology and exhibited various size dimensions upon characterization using SEM, EDX, and FTIR. The application of nanomaterials on female ovipositioning tick showed a decline up to 15% (females ovipositioned) in deltamethrin-coated FeO NPs, whereas this decline was up to 18% in Cyp-FeS NPs and up to 5% in Cyp-FeO NPs. Similarly, the larval hatching was also impacted, leading to a hatching percentage of 5% and only 1% by application of Cyp-FeS NPs and Cyp-FeO NPs, respectively. Similarly, the larval groups had LC90 of 4.1 and 4.73 mg/L for the Cyp-FeO NPs and Cyp-FeS NPs groups. The delta-FeO NPs and delta-FeS NPs demonstrated a promising effect against adult ticks, showing LC50= 3.5 mg/L, LC90= 6.7 mg/L and LC50= 3.8 mg/L, LC90= 7.9 mg/L, respectively. MTT assay revealed that the pyrethroids coupled with iron oxide nanoparticles showed the least cytotoxicity even at the highest concentration (10–1 µL) among other nanomaterials. The study thus concluded a safer spectrum of non-target effects of pyrethroids-coated nanomaterials in addition to their significant anti-tick activity.

Tick Activity, Host Range, and Tick-Borne Pathogen Prevalence in Mountain Habitats of the Western Carpathians, Poland.

In mountainous regions, diverse ecosystems provide a habitat for numerous species of organisms. In this study, we focused on ixodid ticks and their presence in the Western Carpathians, Poland. Our objectives were to investigate the impact of environmental factors on tick occurrence and activity, the prevalence of vectored pathogens, and tick hosts, and their role as reservoir organisms for tick-borne pathogens (TBPs). To this end, we collected ticks from the vegetation and from animals (Apodemus agrarius, A. flavicollis, Capreolus capreolus, Microtus spp., Myodes glareolus, Ovis aries). In addition, we collected blood samples from rodents. The collected material underwent molecular analysis, utilizing the high-throughput microfluidic real-time PCR technique, to detect the presence of TBPs. Our findings confirmed the occurrence of only two species of ixodid ticks in the study area: the dominant Ixodes ricinus, and Dermacentor reticulatus with very limited abundance. Temperature significantly influenced tick activity, and the number of I. ricinus nymphs varied with altitude. We also observed a circadian pattern of questing activity in I. ricinus ticks. The main hosts for juvenile tick stages were M. glareolus and A. agrarius, while adult stages were frequently found on C. capreolus. I. ricinus ticks collected from the vegetation were often infected with Rickettsia helvetica (up to 35.71%), Borrelia afzelii (up to 28.57%), and Ehrlichia spp. (up to 9.52%). In contrast, juvenile stages frequently carried Bartonella spp. (up to 10.00%), Mycoplasma spp. (up to 16.67%) and R. helvetica (up to 16.67%). Moreover, we detected genetic material of Mycoplasma spp. (up to 100.00%), Ehrlichia spp. (up to 35.71%), Bartonella spp. (up to 25.00%), and Borrelia spp. (up to 6.25%) in rodent blood samples. The obtained results indicate A. agrarius and M. glareolus as reservoir animals for TBPs in the studied region.

Host-utilization differences between larval and nymphal deer ticks in northeastern U.S. sites enzootic for Borrelia burgdorferi sensu stricto

In the northeastern U.S., Borrelia burgdorferi sensu stricto, the agent of Lyme disease, is maintained between vertebrate hosts and subadult deer ticks (the northern clade of Ixodes scapularis, formerly known as Ixodes dammini). Theoretical arguments suggest that the force of transmission would be greatest when infected nymphal ticks focus their bites on the same host as the uninfected larvae. Stage-specific differences in host utilization would reduce the force of transmission, but to date such differences remain understudied. We determined the host utilization differences of larval and nymphal deer ticks using bloodmeal analysis of host-seeking nymphs and adults collected from 5 field sites in New England. Matched cohorts of ticks (nymphs=506, adults=451), i.e. ticks that had fed during the same summer season, were used to control for yearly host population variations. Infection status of all ticks was determined by real time PCR. Nymphal deer ticks were more likely to have fed on birds and sciurids (13% vs 3%, and 41% vs 9%, respectively p<0.001) and larvae were more likely to have fed on shrews (26% vs 3%, p<0.001). Similarly, ticks that had fed on a mouse or a shrew as larvae were likely to become infected (OR= 3.195, 95% CI [1.9, 5.1] and OR=2.5[1.6,3.8] respectively), and they were positively associated with infection prevalence at our sites. However, very few nymphs fed on shrews, and they were not associated with infection, raising the question of how uninfected shrews acquire infection each year. Sciurids did not appear to contribute to the enzootic cycle at our sites, which may be due to the low numbers of larvae that fed on them. Sciurid-fed ticks of either stage were not associated with infection. Both stages of ticks were less likely to be infected if they had fed on deer (OR=0.08 [0.02.0.3] and OR=0.4 [0.2,0.7] tested as nymphs and adults, respectively) and thus deer likely served to reduce the force of transmission at our sites. Site-specific analysis of differential host utilization by subadult deer ticks may contribute to appropriate targeting of interventions and thereby promote reducing risk of acquiring Lyme disease and the other deer tick-transmitted infections.

Longitudinal map of transcriptome changes in the Lyme pathogen Borrelia burgdorferi during tick-borne transmission

Borrelia burgdorferi (Bb), the causative agent of Lyme disease, adapts to vastly different environments as it cycles between tick vector and vertebrate host. During a tick bloodmeal, Bb alters its gene expression to prepare for vertebrate infection; however, the full range of transcriptional changes that occur over several days inside of the tick are technically challenging to capture. We developed an experimental approach to enrich Bb cells to longitudinally define their global transcriptomic landscape inside nymphal Ixodes scapularis ticks during a transmitting bloodmeal. We identified 192 Bb genes that substantially change expression over the course of the bloodmeal from 1 to 4 days after host attachment. The majority of upregulated genes encode proteins found at the cell envelope or proteins of unknown function, including 45 outer surface lipoproteins embedded in the unusual protein-rich coat of Bb. As these proteins may facilitate Bb interactions with the host, we utilized mass spectrometry to identify candidate tick proteins that physically associate with Bb. The Bb enrichment methodology along with the ex vivo Bb transcriptomes and candidate tick interacting proteins presented here provide a resource to facilitate investigations into key determinants of Bb priming and transmission during the tick stage of its unique transmission cycle.

Longitudinal map of transcriptome changes in the Lyme pathogen Borrelia burgdorferi during tick-borne transmission.

Borrelia burgdorferi (Bb), the causative agent of Lyme disease, adapts to vastly different environments as it cycles between tick vector and vertebrate host. During a tick bloodmeal, Bb alters its gene expression to prepare for vertebrate infection; however, the full range of transcriptional changes that occur over several days inside of the tick are technically challenging to capture. We developed an experimental approach to enrich Bb cells to longitudinally define their global transcriptomic landscape inside nymphal Ixodes scapularis ticks during a transmitting bloodmeal. We identified 192 Bb genes that substantially change expression over the course of the bloodmeal from 1 to 4 days after host attachment. The majority of upregulated genes encode proteins found at the cell envelope or proteins of unknown function, including 45 outer surface lipoproteins embedded in the unusual protein-rich coat of Bb. As these proteins may facilitate Bb interactions with the host, we utilized mass spectrometry to identify candidate tick proteins that physically associate with Bb. The Bb enrichment methodology along with the ex vivo Bb transcriptomes and candidate tick interacting proteins presented here provide a resource to facilitate investigations into key determinants of Bb priming and transmission during the tick stage of its unique transmission cycle.

Application of Cypermethrin-Coated ZnS and ZnO Nanoparticles against Rhipicephalus Ticks.

Rhipicephalus ticks are described as important ticks impacting the costs of livestock rearing and by-products sale. The prevalence and response of ticks towards cypermethrin sprays indicate the need to implement the rational use of acaricides. In our previous studies, ZnO nanoparticles were shown to inhibit the major life-cycle stages of Hyalomma ticks, indicative of promising application of nanomaterials against the hard ticks. The current study was designed to probe into one of alternative options to curtail Rhipicephalus ticks by employing cypermethrin-coated nanoparticles of ZnO (C-ZnO NPs) and ZnS (C-ZnS NPs). The nanocomposites showed a roughly spherical type of morphology and various size dimensions upon characterization using SEM and EDX. Female ovipositioning was declined up to only 48% in ZnS and up to 32% in ZnO NPs even after 28 days in vitro. Similarly, the larval hatching was also impacted, leading to a hatching percentage of 21% and 15% by application of C-ZnS NPs and C-ZnO NPs, respectively. The LC90 in female adult groups were 3.94 mg/L and 4.27 mg/L for the C-ZnO NPs and C-ZnS NPs groups, respectively. Similarly, the larval groups had LC90 of 8.63 and 8.95 mg/L for the C-ZnO NPs and C-ZnS NPs groups. The study is a proof of the concept for incorporating effective and safe nanocomposites as acaricides. The studies on the efficacy and spectrum of non-target effects of nanomaterial-based acaricides can further refine the research on finding novel alternatives for tick control.

Exposure of dogs and cats to Borrelia miyamotoi infected Ixodes ricinus ticks in urban areas of the city of Poznań, west-central Poland

Borrelia miyamotoi is an emerging human pathogen that causes a relapsing fever-like disease named B. miyamotoi disease. The bacterium belongs to the relapsing fever borreliae, and similar to spirochetes of the Borrelia burgdorferi sensu lato group, it is transmitted only by hard ticks of the Ixodes ricinus complex. To date, B. miyamotoi has not been demonstrated to cause illness in dogs or cats, and is poorly documented in veterinary medicine. The aim of this study was to determine the B. miyamotoi presence in (i) host-seeking ticks and (ii) engorged Ixodes sp. ticks collected from dogs and cats during their inspection in veterinary clinics of the city of Poznań, west-central Poland. Host-seeking ticks were sampled in dog walking areas localized in urban forested recreational sites of the city. In this study, 1,059 host-seeking and 837 engorged I. ricinus ticks collected from 680 tick-infested animals (567 dogs and 113 cats) were screened. Additionally, 31 I. hexagonus ticks (one larva, 13 nymphs, and 17 females) were collected from three cats; one larva and one nymph were collected from two dogs; and one dog was infested with a single Dermacentor reticulatus female.Borrelia DNA was identified by the amplification and sequencing of the V4 hypervariable region of the 16S rRNA gene and flaB gene fragments. DNA of B. miyamotoi was detected in 22 (2.1%) of the host-seeking ticks (in all developmental tick stages and in all study areas). In addition, the engorged I. ricinus ticks exhibited a similar B. miyamotoi presence (1.8%). Fifteen I. ricinus ticks collected from animals tested positive for the presence of B. miyamotoi DNA, and the DNA of B. miyamotoi was observed in three (9.1%; one female and two nymphs) I. hexagonus ticks. The single D. reticulatus female collected from a dog tested PCR-negative for the bacterium. The results of this study demonstrated the establishment and broad presence of the bacterium in tick populations from different urban ecosystems of the city of Poznań. The lack of difference in the mean infection presence of animal-derived and host-seeking I. ricinus ticks suggests that the systematic surveillance of pets may be useful for the evaluation of human exposure to B. miyamotoi infected ticks in urban areas. Additional studies are required to further elucidate the role of domestic and wild carnivores in the epidemiology of B. miyamotoi, which remains unknown.