Search Results (65)

Ticks and tick-borne diseases pose a significant threat to public health. The Tumen River Basin is located at the junction of China, North Korea and Russia, whose warm climate and favorable ecological environment are suitable for the growth and reproduction of ticks. At the same time, the cattle industry in this region is highly developed, with cattle serving as the primary economic source for the area. This study performed an epidemiological investigation and analysis of pathogens carried by ticks and cattle in the Tumen River basin. A total of 913 ticks and 247 bovine blood samples were collected from seven cities primarily focused on cattle farming in the Tumen River basin. Morphological and molecular biological identification of ticks was carried out to determine the distribution of ticks and their pathogens in the region. Through the detection of pathogens carried by cattle blood samples in the surrounding area, the correlation with tick distribution was confirmed. The species and distribution of ticks of different genders and in different collection environments, and the infection of pathogens in bovine blood samples were statistically analyzed. The results showed that the 913 ticks had 5 species, including Haemaphysalis longicornis, Haemaphysalis concinna, Haemaphysalis japonica, Dermacentor silvarum and Ixodes persulcatus. Three pathogens, Babesia ovata, Theileria orientalis and Theileria sinensis, were detected in the blood samples of vector ticks and cattle. These results provide a theoretical basis for the prevention and control of ticks and tick-borne diseases in the Tumen River basin. Full article

Haemaphysalis longicornis (Asian longhorned tick) is an invasive species recently established in the United States and a potential vector for pathogens. This study included 620 H. longicornis collected in southern Pennsylvania from 2022 to 2023 with the aim of investigating the microbial community and host preferences of these ticks along with any association with newly emerging pathogens. To assess specific emerging pathogen carriage, all collected ticks were screened for Theileria orientalis and Anaplasma marginale by targeted PCR. To evaluate host use and broader pathogen diversity, a subset of 56 partially engorged ticks was analyzed by cytochrome b PCR and tested with a multiplex Luminex xMAP^® panel for 16 tick-borne pathogens. A subset of these partially engorged (44) H. longicornis were further examined by Oxford Nanopore metatranscriptomic sequencing. Sequencing identified a bacterial community dominated by Coxiella-like endosymbionts, with additional genera including Acinetobacter, Sphingomonas, Pseudomonas, Staphylococcus, Escherichia, Klebsiella, and Wolinella. Neither targeted screening nor sequencing detected recognized human or veterinary pathogens. Blood meal analysis of partially engorged ticks indicated deer (Odocoileus spp.) as primary hosts. The feeding behavior of H. longicornis and its known role as an established vector for pathogens highlight the need for continued surveillance. Full article

Severe fever with thrombocytopenia syndrome virus (SFTSV) is an emerging tick-borne bunyavirus that causes a severe viral hemorrhagic fever (SFTS), with a very high case mortality rate, expanding epidemic areas, and increasing incidence. Due to the lack of an effective drug or vaccine for SFTS, reducing the incidence and mortality of SFTS primarily relies on decreasing the density of ticks and the number of their host animals. However, which tick species and vertebrate animal serve as the major reservoir and animal host of SFTSV are not clearly understood. In May of 2023 and June of 2024, we collected 2437 ticks from domesticated animals and grassland in Suizhou City, a prefecture of Hubei Province in central China. A total of 195 domesticated animal blood samples were collected, including 152 goats, 26 cattle, and 17 dogs. Ticks were grouped for RNA extraction according to their life stages and feeding status. RNA from each animal’s blood and each group of ticks was extracted with an RNA extraction kit and tested for SFTSV with RT-PCR. Ticks were classified according to morphology, and representative ticks of each stage were confirmed with PCR amplification and DNA sequencing of the mitochondrial 16S RNA gene. Among the collected ticks, the majority were from goats (72.7%, 1772/2437), and Haemaphysalis longicornis was predominant, accounting for 99.47% (2425/2437), and other tick species were very rare, with 0.45% (11/2437) Rhipicephalus microplus, and 0.04% (1/2437) H. flava and Ixodes sinensis, respectively. We found SFTSV RNA in H. longicornis ticks with a minimum infection rate of 0.17% (4/2424) and in one goat (0.66%,1/152). In summary, we demonstrated that the H. longicornis tick is positive for SFTSV and that the goat is the major host of Haemaphysalis longicornis in Suizhou, central China. Our study suggests that controlling ticks on goats may play an important role in preventing SFTSV infection in China. Full article

The cytochrome p450 gene family is widely involved in various biological processes in arthropods. Tick p450s are often associated with chemical acaricides, but knowledge of their involvement in the metabolism of plant-derived essential oil components is limited. In this study, we identified the non-redundant number of p450 transcripts (NRNPTs) from Haemaphysalis longicornis and Hyalomma asiaticum under the Cymbopogon citratus essential oil (CCEO) and terpinolene stress using de novo transcriptome data, respectively. In this study, we identified and characterized the NRNPTs of Ha. longicornis and Hy. asiaticum. Their gene expression patterns and biological functions under CCEO and terpinolene stress were further analyzed. Finally, Hy. asiaticum NRNPTs (87) were more numerous than Ha. longicornis (58). Phylogenetic analyses showed that NRNPTs of both Hy. asiaticum and Ha. longicornis could be categorized in clan 2, clan 3, clan 4, and clan mito, this data comes from the NRNPTs. Phylogenetic analyses showed that NRNPTs of both Hy. asiaticum and Ha. longicornis could be categorized in clan 2, clan 3, clan 4, and clan mito. p450 members of both were most distributed in clan 3. In addition, one Hy. asiaticum NRNPT was identified as belonging to the new classification clan 20 (HyasCYP20A1). The biological functions and pathways of p450 family members enriched in Hy. asiaticum and Ha. longicornis under different exogenous substance stresses were different, and the expression patterns of these genes were inconsistent. Molecular docking results showed that Ha. longicornis p450 members (HaloCYP3A4 and HaloCYP4B1), which were significantly up-regulated under CCEO stress, as well as Hy. asiaticum HyasCYP24A1 and HyasCYP4V2 (the HaloCYP3A4 and HaloCYP4B1 homologous genes), encode proteins that differ in their ability to metabolize CCEO components, but they all bind well to Germacrene D and naphthalene. Our study enriches the knowledge of the involvement of p450 family members of different tick species in the metabolism of essential oil components of plants, and provides a theoretical basis for further in-depth studies on the function of tick p450 enzymes. Full article

Ticks are hematophagous ectoparasites capable of transmitting a wide array of pathogens. The recent proliferation and geographic expansion of tick populations have intensified concerns regarding the escalating risk of tick-borne pathogen transmission. Among these, Anaplasma phagocytophilum poses a notable threat to both public and veterinary health due to its zoonotic potential. In this study, a total of 4316 ticks were collected from 16 pasture sites near livestock farms in Gyeonggi and Gangwon Provinces, Republic of Korea, between April and October 2024. Molecular epidemiological analysis was subsequently performed. Of the 400 tick pools tested, Ixodes nipponensis accounted for two Anaplasma-positive pools, Haemaphysalis spp. larvae for two pools, and Haemaphysalis longicornis for one pool. This study is the first to examine the infection rate of A. phagocytophilum in ticks collected from pasture sites near livestock farms in Gyeonggi and Gangwon Provinces. Although the observed infection rate was low, the presence of A. phagocytophilum in regions with potential human exposure emphasizes the risk of transmission. Importantly, the detection of A. phagocytophilum in larval-stage ticks suggests the possibility of transovarial transmission, meriting further investigation. These findings underscore the need for conducting surveillance and targeted preventive strategies to reduce the burden of tick-borne diseases in livestock-associated settings. Full article

To investigate the repellent efficacy of commercially available mosquito repellents in China against Haemaphysalis longicornis, four representative DEET-based repellents and biont-derived repellents were selected. This study utilized a modified circular filter paper method repellent testing device to establish an evaluation system for assessing the repellent effects of each product against three developmental stages of H. longicornis: larvae, nymphs, and adults. In our study, for DEET-based repellents, Johnson demonstrated the highest repellency against larvae within 1 h, with an average repellency rate exceeding 80.14%. Yamei and Johnson exhibited repellency rates more than 91.11% for nymphs within 1 h, surpassing the other two DEET products. Repellency rates of Longliqi and Xiaohuanxiong fluctuated between 80.95% and 100% at different time points. Yamei, Longliqi, and Johnson achieved 100% repellency to adults within 1 h, while Xiaohuanxiong showed slightly lower efficacy. The four biont-derived repellents showed significant variations in efficacy: larval-stage repellency ranged from 14.29% to 88.89%, nymphal-stage repellency from 57.89% to 100%, and adult-stage repellency from 50% to 79.49%. CaliforniaBaby exhibited the highest efficacy, comparable or superior to DEET-based products, whereas Longhu demonstrated the weakest repellency and poor persistence. We further conducted a persistence test for CaliforniaBaby and found that it maintained >75% repellency against H. longicornis for 6 h. This study provides scientific evidence for selecting tick repellents in practice, offers guidance for purchasing commercial biont-derived tick repellents, and serves as a reference for developing safer, more effective tick repellents. Full article

Carvacrol derived from Origanum vulgare oil was evaluated for its acaricidal efficacy and mechanism of action against Haemaphysalis longicornis, a primary vector of severe fever with a thrombocytopenia syndrome. Essential oils extracted from O. vulgare leaves cultivated in Germany, Albania, and Iran were analyzed. Among them, the German oil exhibited the highest acaricidal potency due to its elevated carvacrol content (83.38%). Carvacrol was isolated and its identity was confirmed using GC/MS, NMR, and FT-IR analyses. Carvacrol demonstrated significant toxicity across all developmental stages of H. longicornis, with LC₅₀ values of 3.47, 8.21, and 15.27 μg/cm³ for larvae, nymphs, and adults, respectively—representing 4.4-, 3.5-, and 3.2-fold higher potency compared to diethyltoluamide. The acaricidal mechanism of carvacrol involved multiple pathways: (i) inhibition of acetylcholinesterase activity by up to 85.4%, leading to neural disruption; (ii) suppression of cytochrome P450 monooxygenases (47.4% reduction), α-esterase (24.8% reduction), and β-esterase (28.6% reduction); and (iii) disruption of neural signaling pathways critical for survival. Chemical analysis confirmed carvacrol as the predominant active component in O. vulgare oil, with additional contributions from thymol and thymoquinone. Although its concentration in Iranian oil was lower, thymoquinone demonstrated the highest acaricidal potency (4.98 μg/cm³). Nevertheless, the abundance and superior efficacy of carvacrol establish it as the primary component contributing to the oil’s bioactivity. This study demonstrates that carvacrol is a promising eco-friendly alternative to synthetic acaricides for the control of H. longicornis. Its ability to inhibit acetylcholinesterase activity and suppress detoxifying enzymes suggests potential for overcoming resistance mechanisms associated with synthetic chemicals. Further studies should focus on optimizing the formulations and applying them in the field to improve efficacy. Full article

As crucial vectors that transmit pathogens to humans and livestock, ticks pose substantial global health threats and economic burdens. We analyzed 328 tick genomes to explore the population’s genetic structure and the adaptive evolution of H. longicornis and R. microplus, two tick species with distinct life cycle characteristics. We observed distinct genetic structures in H. longicornis and R. microplus. Gene flow estimation revealed a closer genetic connection in R. microplus than H. longicornis, which was facilitated by geographical proximity. Notably, we identified a set of candidate genes associated with possible adaptations. Specifically, the immune-related gene DUOX and the iron transport gene ACO1 showed significant signals of natural selection in R. microplus. Similarly, H. longicornis exhibited selection in pyridoxal-phosphate-dependent enzyme genes associated with heme synthesis. Moreover, we observed significant correlations between the abundance of pathogens, such as Rickettsia and Francisella, and specific tick genotypes, which highlights the role of R. microplus in maintaining these pathogens and its adaptations that influence immune responses and iron metabolism, suggesting potential coevolution between vectors and pathogens. Our study highlights the vital genes involved in tick blood feeding and immunity, and it provides insights into the coevolution of ticks and tick-borne pathogens. Full article

H. longicornis is used as an experimental animal model for the study of three-host ticks due to its special life cycle and easy maintenance in the laboratory and in its reproduction. The life cycle of H. longicornis goes through a tightly regulated life cycle to adapt to the changing host and environment, and these stages of transition are also accompanied by proteome changes in the body. Here, we used the isobaric tags for a relative and absolute quantification (iTRAQ) technique to systematically describe and analyze the dynamic expression of the protein and the molecular basis of the proteome of H. longicornis in seven differential developmental stages (eggs, unfed larvae, engorged larvae, unfed nymphs, engorged nymphs unfed adults, and engorged adults). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of the differentially expressed proteins (DEPs) were used. In our study, A total of 2044 proteins were identified, and their expression profiles were classified at different developmental stages. In addition, it was found that tissue and organ development-related proteins and metabolism-related proteins were involved in different physiological processes throughout the life cycle through the GO and KEGG analysis of DEPs. More importantly, we found that the up-regulated proteins of engorged adult ticks were mainly related to yolk absorption, degradation, and ovarian development-related proteins. The abundance of the cuticle proteins in the unfed stages was significantly higher compared with those of the engorged ticks in the previous stages. We believe that our study has made a significant contribution to the research on H. longicornis, which is an important vector of SFTSV. In this study, we identified changes in the proteome throughout the H. longicornis development, and functional analysis highlighted the important roles of many key proteins in developmental events (ovarian development, the molting process, the development of midgut, the development and degeneration of salivary glands, etc.). The revelation of this data will provide a reference proteome for future research on tick functional proteins and candidate targets for elucidating H. longicornis development and developing new tick control strategies. Full article

Tick-borne diseases are a public health problem and a significant burden on the livestock industry. The seasonal abundance of ticks and tick-borne pathogens strongly correlates with the prevalence of these diseases. To investigate the seasonal variation in ticks and tick-borne pathogens, ticks were collected from Gangwon State, Korea, and the tick-borne pathogens Borrelia, Anaplasma, Babesia, and Theileria were examined. In total, 14,748 ticks were collected, comprising ticks from two genera and three species: Haemaphysalis longicornis, Haemaphysalis flava, and Ixodes nipponensis, with H. longicornis being the predominant species. Of 7445 ticks (455 pools) examined for pathogens, Theileria was detected in 61 pools, whereas Borrelia and Anaplasma were observed in 17 pools. H. longicornis nymphs and adults were collected beginning in April, with nymph numbers peaking in May and June and adult ticks peaking in June and July. In contrast, the larvae were collected in May and peaked in September. Tick-borne pathogens were detected in April, peaking in July and September. Borrelia, the causative agent of Lyme disease, exhibits a temporal association between its detection in ticks and its occurrence in humans. In conclusion, tick-borne diseases seem to be closely linked not only to changes in tick numbers throughout the seasons but also to the seasonal variations of the pathogens within them. Full article

To validate the prevalence and biodiversity of ticks and tick-borne pathogens in Chongqing, a total of 601 ticks were collected from dogs, cattle, and goats within the Ta-pa Mountain range in Chongqing, China. Five distinct tick species were identified, including Ixodes ovatus (1.66%, 10/601), I. acutitarsus (0.50%, 3/601), Haemaphysalis flava (10.32%, 62/601), Ha. hystricis (9.82%, 59/601), and Ha. longicornis (77.70%, 467/601). A suit of semi-nest PCR and nest PCR primers were custom-synthesized for the detection of tick-borne pathogens. The analysis yielded positive results for 7.15% Rickettsia (Candidatus R. principis, R. japonica, and R. raoultii), 3.49% Anaplasma (A. bovis and A. capra), 1.16% Ehrlichia, 1.83% Coxiella burnetii, and 3.49% protozoa (Theileria. capreoli, T. orientalis, T. luwenshuni, and Babesia sp.) in ticks. Notably, Ca. R. principis was identified for the first time in I. ovatus and Ha. longicornis. These findings underscore the significant prevalence and diversity of ticks and their associated pathogens within the Chongqing Ta-pa Mountain region. This study accordingly provides an extensive dataset that contributes to the epidemiological understanding and disease prevention strategies for tick-borne illnesses in the local area. Full article

The longhorned tick (LHT), Haemaphysalis longicornis Neumann (Acari: Ixodidae), is a serious invasive pest in North America where its geographical range is expanding with high densities associated with commercial animal production. There are only a few chemical pesticides available for LHT control, which can lead to the evolution of resistant strains. Diatomaceous earth (DE) was shown to be effective in killing some important tick species but was not examined for LHTs. When LHT nymphs were dipped for about 2–4 s into DE, transferred to Petri dishes (one tick/dish), and incubated at 30 °C and 70% relative humidity, the median survival time was 4.5 h. A locomotor activity assay showed that there was no difference in the overall distance traveled between the DE-treated and control ticks except during the first 2 h after exposure. In a field-simulated study in which a dose of 5.0 g DE/m² was applied to pine needle litter infested with LHT, all the LHTs were dead at 24 h with no control mortality. Scanning electron micrographs showed the mineral adhering to all surfaces of the tick. The results indicated that DE is effective in killing nymphal LHTs and could be an alternative to the use of chemical acaricides with the advantage of managing pesticide resistance through the killing by a different mode of action and could be used for organically certified animal husbandry. Full article

Haemaphysalis longicornis (Neumann), the Asian longhorned tick, is a species native to East Asia, but invasive to Australia, New Zealand, and most recently, the United States. It has spread rapidly across the eastern United States after being established in New Jersey in 2017. Aiding this rapid expansion is the ability of this tick to reproduce parthenogenically and feed on diverse host species. In cattle, this tick can cause heavy burdens and act as a vector for the pathogenic hemoprotozoan parasite Theileria orientalis, genotype Ikeda, creating economic losses that impact the cattle industry. Here, we report Asian longhorned ticks, collected from cattle, a dog, and pastures and morphologically identified at the Oklahoma Animal Disease Diagnostic Laboratory as H. longicornis before molecular confirmation through PCR amplification of the cox1 gene. Blood samples from infested cattle were collected and assessed molecularly for the presence of T. orientalis, with no pathogenic DNA detected. This report describes the first record of H. longicornis in Oklahoma and the farthest westward detection of this tick in the United States to date. Full article

Haemaphysalis longicornis is one of the most medically important carriers of various pathogens. Although H. longicornis is an important vector, only basic ecological and biological information has been obtained, primarily focusing on its abundance and distribution. This study determined the most active time and meteorological conditions for the diel activity of H. longicornis. The diel activity pattern of H. longicornis was the highest between 10:00 and 14:00, and the lowest between 22:00 and 02:00. The major activity temperature of H. longicornis was between 25 °C and 40 °C, with the highest activity at 35 °C. The relative humidity was between 30% and 70% during the active period. Temperature had the highest correlation with diel activity (R = 0.679), followed by humidity (R = −0.649) and light intensity (R = 0.572). Our results provide basic information for the development of tick-borne disease vector control programs and tick surveillance. Full article

Background: California hare coltivirus (CHCV) was isolated in California in 1976 from a hare. Despite its long history, it remained unclear whether CHCV was exclusively distributed in California with limited host ranges. Main body: By next-generation sequencing (NGS), we obtained a complete sequence of CHCV from Ixodes persulcatus collected in 2019 in northeast China. An expanded epidemiological investigation was subsequently performed on ticks belonging to four species (Ix. persulcatus, Haemaphysalis concinna, Devmacentor silvarum, Haemaphysalis longicornis) collected in northeastern China by applying CHCV-specific RT-PCR and sequencing. CHCV RNA-positive results were found in 1.56% of the tick samples. Positive ticks were obtained in three of four sampled locations, with the highest rate observed in Inner Mongolia (2.69%), followed by Heilongjiang (1.94%) and Jilin provinces (0.55%). All positive results were derived from Ix. persulcatus ticks (2.33%), while no positive detection was found in the other tick species, even at the same location. Sequence analysis revealed that the current CHCV showed a high genetic identity (>80% amino acid identity) with the previously reported CHCV in all segments except segment seven (64.59% amino acid identity). Phylogenetic analysis based on RNA-dependent RNA polymerase (RdRp) amino acid sequences demonstrated that both the current and previously reported CHCV strains were grouped phylogenetically into the genus Coltivirus. Both CHCV strains formed a distinct clade, clustering with three human pathogenic coltiviruses (Colorado tick fever virus, Salmon River virus, and Eyach virus), and were distant from the other coltiviruses. Conclusions: We report the identification and characterization of CHCV for the first time in Ix. persulcatus ticks, expanding the currently known geographic scope, host, and genetic heterogeneity in CHCV. Full article