Search Results (211)

Ticks are important vectors of pathogens affecting humans and animals, posing a serious threat to health. For the first time, we studied the metagenomic profile of the microbial composition of Hyalomma scupense and Hyalomma asiaticum ticks in Kazakhstan. A total of 94 adult H. asiaticum and H. scupense ticks collected from randomly selected cattle in Kazakhstan in 2023 were analyzed. 16S rRNA gene sequencing was performed using the Ion Torrent NGS platform. Taxonomic classification was carried out in the BV-BRC platform with the Kraken2 database. Metagenomic analysis revealed 26 bacterial genera, including both pathogenic and symbiotic taxa. In H. scupense, the dominant groups were Francisella (89.0%), Staphylococcus (76.0%) and Candidatus Midichloria (61.0%), while in H. asiaticum, they were Francisella (99.0% and 95.0%) and Helcococcus (65.0%). In male H. scupense, the proportion of Francisella reached 89%, whereas in females, it varied from 2% to 28%. In H. asiaticum, Helcococcus accounted for 65% in males compared to 11% in females. This is the first report on the metagenomic profile of the microbiota of H. scupense and H. asiaticum in Kazakhstan. The detection of pathogens indicates a risk of their transmission to humans and animals and highlights the need to develop new tick control strategies. Full article

Rickettsia rickettsii is the most virulent agent of the genus Rickettsia that causes one of the most relevant vector-borne diseases in the Americas (RRSF). RRSF manifests with many non-specific acute clinical symptoms complicating its diagnosis and can lead to death if not treated appropriately. RRSF has been reported in Canada, the United States of America, Mexico, Costa Rica, Panama, Colombia, Brazil, and Argentina. In addition to R. rickettsii, mild and severe spotted fever group rickettsioses (SFGR) have been reported in the Americas; however, the true prevalence of these diseases is unknown. In Panama, RRSF have been reported in four of 14 provinces during two outbreak periods: five cases including two fatalities were identified in 1950–1951, and 23 cases including 17 fatalities between 2004 and 2025. This paper presents the clinical characterization of a fatal case of RRSF in Coclé province and a severe case of SFGR in a mountainous area of the Gnäbe Buglé Indigenous Comarca (GBIC). Laboratory confirmation was performed by molecular analysis of tissues obtained from necropsies in the case of RRSF and by immunofluorescence assay (IFA) in the case of SFGR. Furthermore, this paper identifies existing gaps in the initial clinical suspicion and pertinent to SFGR in Panama, which may be applicable to other countries in the region. In the last 21 years, cases have occurred upon contact with ticks in rural areas (13), urban and suburban locations (7), rural woodlands (2), and forests (1). Provinces with more cases are Panamá (7 of 23, 6 died), Coclé (5 of 23, 5 died), Colón (3 of 23, 1 died), Panamá Oeste (1 of 23, 1 died), and GBIC (7 of 23, 4 died), including a cluster of seven cases in 2019. Therefore, Coclé province is considered one of the endemic areas for RRSF in Panama, while the latest cases from the GBIC since 2019 indicate that mountainous areas are an eco-epidemiological scenario to include in the transmission of these diseases. Although this disease has a low prevalence, patients who present symptoms commonly associated with more common diseases such as dengue, other arboviruses, malaria, and leptospirosis, among others, should be included in the diagnostic suspicion. Without diagnostic suspicion and adequate treatment, the patient can die. Full article

Argasid ticks Ornithodoros erraticus and Ornithodoros moubata are major vectors of zoonotic pathogens, including the African swine fever virus and relapsing fever Borrelia spp., and their control is essential to reduce disease transmission. In this study, we evaluated the immunogenicity and protective efficacy of four Ornithodoros tick antigens formulated as mRNA–lipid nanoparticles (mRNA-LNPs): OeSOD, OeTSP1, OmPLA2, and Om86. Rabbits were immunised with three doses of each mRNA-LNP construct, and immune responses and tick biological parameters were assessed following infestation with both tick species. All mRNA-LNP constructs induced antigen-specific IgG responses that recognised native proteins in tick saliva and midgut extracts. Vaccination resulted in significant reductions in female oviposition and fertility, which correlated with antibody levels, and yielded protective efficacies of 21.9–41.6% against O. moubata and 23.1–41.6% against O. erraticus. Notably, the mRNA-LNPs of OeSOD and OeTSP1 outperformed their recombinant counterparts against O. moubata, and Om86 mRNA-LNP conferred markedly improved protection against both O. moubata and O. erraticus. These findings highlight the potential of mRNA-LNP vaccines to induce effective anti-argasid tick immunity and provide a promising platform for the development of sustainable strategies to control argasid ticks and associated pathogens. Full article

Tick infestation represents a significant constraint on livestock productivity in Saudi Arabia; however, there remains a substantial gap in research addressing tick species diversity, distribution, and their direct effects on milk production. This study aimed to morphologically and molecularly identify tick species infesting dairy cattle, quantify the impact of tick infestation on milk yield and composition, and contribute to the limited understanding of tick ecology and its economic implications in the region. Ticks were collected from infested cows and identified morphologically using taxonomic keys. Molecular identification was performed via PCR amplification of the mitochondrial cytochrome c oxidase subunit I (COI) gene. Milk production and quality parameters were assessed in tick-infested and healthy cows in Hafar Al-Batin, Eastern Saudi Arabia. Morphological and genetic analyses confirmed Hyalomma anatolicum as the predominant tick species in the study area, with COI sequences showing high similarity to regional isolates. Tick-infested cows exhibited substantial reductions in milk yield, fat, calcium, and potassium levels, indicating significant metabolic disruptions. Blood biochemical analysis revealed elevated levels of liver enzymes [aspartate aminotransferase (AST) increased by 238.6%, gamma-glutamyl transferase (GGT) by 155.7%], renal markers [creatinine increased by 788.9%, urea by 130.0%], and electrolyte imbalances [serum calcium decreased by 39.5%, potassium by 45.2%]. Hematological findings included increased white blood cell (WBC) and red blood cell (RBC) counts by 44.9% and 124.7%, respectively, along with a 53.1% decrease in hemoglobin (HGB), suggesting a systemic inflammatory response and possible anemia. This study is among the first to genetically confirm the presence of H. anatolicum in Hafar Al-Batin using molecular tools, thereby enhancing the accuracy of species-level identification and highlighting the physiological impact of tick burden on dairy productivity. Full article

Several diseases caused by tick-borne pathogens, including Lyme borreliosis (LB) and spotted fever group rickettsioses, are endemic in the Balkan Peninsula, positioned between Central Europe and the Middle East. This cross-sectional study aimed to assess serological exposure to Borrelia spp. and spotted fever group Rickettsiae (SFGR) among individuals with recent tick bites and healthy controls in two Balkan countries—Serbia and North Macedonia. Serum samples from 223 participants were tested for anti-Borrelia and anti-SFGR IgG antibodies. SFGR exposure was significantly higher in tick-exposed individuals from Skopje (North Macedonia) compared to those from Novi Sad (Serbia) (30.9% vs. 8.0%; p = 0.003). In contrast, anti-Borrelia IgG was more frequently detected in Novi Sad, though differences did not reach statistical significance. The findings support a north-to-south gradient in Borrelia exposure and a reverse trend for SFGR, consistent with earlier studies and regional tick infection data. Given the high SFGR exposure and limited clinical reporting in North Macedonia, the results highlight the likelihood that tick-borne rickettsioses remain under-recognized. Additionally, Borrelia exposure in North Macedonia warrants further investigation. These findings emphasize the need for enhanced tick-borne disease surveillance, identification of endemic zones, and improved diagnostic and public health infrastructure in both countries. Full article

Rickettsia, Anaplasma, and Ehrlichia species are emerging tick-borne pathogens that cause zoonotic diseases, including rickettsiosis, anaplasmosis, and ehrlichiosis in both human and animal populations. This study aimed to investigate the prevalence of these pathogens in cattle-associated ticks from Ganzhou City, Jiangxi Province, China. Through molecular characterization using multilocus sequence analysis (16S rRNA, gltA, groEL, and ompA genes), we analyzed 392 Rhipicephalus microplus ticks collected from March to September in 2022. The PCR results showed that eight Rickettsiales bacteria were detected, including two species of Rickettsia (51/392, 13.0%), four species of Anaplasma (52/392, 13.3%), and two species of Ehrlichia (70/392, 17.9%). Notably, the circulation of multiple pathogen species within R. microplus populations demonstrates significant microbial diversity in this region. Further consideration and investigation should be given to the possible occurrence of rickettsiosis, ehrlichiosis, and anaplasmosis in humans and domestic animals. Our study provides critical baseline data for developing targeted surveillance strategies and informing public health interventions against tick-borne diseases in southeastern China. Full article

Ixodiphagus hookeri (Howard, 1907) (Hymenoptera: Encyrtidae), a hyperparasitic wasp that parasitizes hard ticks, has been documented in various parts of Europe; however, data on its presence in southeastern regions has been lacking. This study provides the first molecular evidence of I. hookeri in ticks from the coastal areas of the Balkan Peninsula, specifically Croatia and Bulgaria. A total of 1043 questing ticks were collected between 2011 and 2013 across 15 locations. Molecular screening revealed I. hookeri DNA in Ixodes ricinus (Linnaeus, 1758) (Acari: Ixodidae) nymphs from inland Croatia (overall prevalence: 18.72%) and in Haemaphysalis concinna (Koch, 1844) (Acari: Ixodidae) nymphs and larvae from coastal Bulgaria (prevalence: 17.2%). All I. hookeri-positive samples were co-infected with Wolbachia spp. (Rickettsiales: Anaplasmataceae). This detection marks the southernmost record of I. hookeri in Central Europe, expanding its known range to the Balkan Peninsula and supporting its relevance as a potential natural enemy in integrated tick management strategies. Full article

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression by inhibiting or degrading messenger RNAs (mRNAs). In ticks, salivary miRNAs are proposed to play key roles in modulating host–vector interactions during blood feeding. Previously, we identified salivary miRNAs in Ornithodoros moubata and Ornithodoros erraticus, major vectors of African swine fever and tick-borne human relapsing fever. In this study, we investigated the regulatory roles of salivary miRNAs in tick biology. Salivary miRNA datasets were re-analysed to identify conserved miRNAs, and putative target genes were predicted using the sialotranscriptomes of both species. In silico predictions were validated through experimental inhibition of specific miRNAs using antagomirs. Knockdown of miR-375 and miR-1 significantly reduced blood intake, oviposition, and fertility, indicating their involvement in feeding and reproductive processes. Silencing miR-252b in O. moubata led to increased mortality, suggesting a critical role in survival. Notably, Metis1 was identified as a likely target of miR-252b, and its dysregulation may underlie the observed lethality in miR-252b-silenced ticks. These findings highlight the functional relevance of salivary miRNAs in tick physiology and host interaction, offering new perspectives for the development of innovative tick control strategies. Full article

Hard ticks are vectors of a wide range of pathogens, with tick-borne bacteria being among the most frequently detected. This study presents a first approach to the identification of human-biting ticks in the Basque Country (northern Iberian Peninsula), where previous research has mainly focused on ticks from vegetation and domestic and wild animals. The aim of this study was (i) to identify tick species collected in hospitals and health centres and (ii) to determine the presence and identify of pathogenic bacteria that they may carry using PCR, RLB and sequencing methods. A total of 181 ticks were collected and grouped in pools of one, two or three specimens, resulting in 157 samples. Morphological and molecular identification of collected ticks revealed that most specimens belonged to Ixodes ricinus (88.5%). Additionally, Rhipicephalus bursa, Haemaphysalis punctata, Dermacentor reticulatus and Dermacentor marginatus were also identified. A total of 25 samples (15.9%) tested positive for DNA from the targeted pathogens. The most prevalent vector-borne bacteria were Borrelia spp. (6.4%), followed by Rickettsia spp. (5.1%), Anaplasma phagocytophilum (2.5%) and Coxiella spp. (1.9%). Species identified included B. afzelii, B. garinii, B. miyamotoi, B. valaisiana, B. burgdorferi s. s., R. monacensis, “Candidatus R. rioja”, R. helvetica and R. massiliae. This study highlights the usefulness of combining molecular diagnostics with passive surveillance of human-attached ticks as an effective tool for regional monitoring of ticks and tick-borne pathogens. Full article

Ticks carry numerous pathogens that, if transmitted, can cause disease in humans and animals. Research on pathogens transmitted from ticks to humans is essential for improving public health strategies against tick-borne diseases (TBDs). In this study, Ixodes ricinus ticks found on humans were collected and examined between 2019 and 2024. This study is about the molecular characteristics of tick-borne pathogens (TBPs) in the region of northern Serbia, including Borrelia burgdorferi sensu lato (s.l.), Anaplasma phagocytophilum, and Coxiella burnetii. We identified B. burgdorferi s.l. as the most prevalent in ticks (20.45%). Molecular analysis identified two genospecies, B. afzelii and B. burgdorferi s.s., indicating genetic diversity among Borrelia spirochetes. A. phagocytophilum was detected in ticks with a prevalence of (1.62%), while C. burnetii was not found in any of the ticks. Our findings highlight the necessity of monitoring tick pathogens in ticks removed from humans. Serbia is an endemic region for some tick-borne diseases, such as Lyme disease. Regular surveillance of tick populations, with molecular identification of pathogens, offers insight into transmission dynamics, allowing for monitoring and public health interventions to be created if needed due to increased risk. Full article

Bovine anaplasmosis, caused by Anaplasma marginale, is a major tick-borne disease in tropical and subtropical regions of the world, leading to significant production losses. Prolonged convalescence periods are common and surviving animals often become subclinical carriers. This study aimed to detect and characterise A. marginale in bovines in smallholder dairy farms across diverse climatic zones of Pakistan using molecular methods. In total, 321 blood DNA samples from apparently healthy cattle (n = 174) and buffaloes (n = 147) from six districts in Pakistan were tested for A. marginale using a nested PCR assay, targeting part of the major surface protein B gene (msp1β) as a genetic marker, followed by agarose gel electrophoresis and selective sequencing of amplicons from test-positive samples. Of the 321 DNA samples tested, 135 (42.1%) were test-positive for A. marginale. Prevalence was significantly higher in cattle (64.4%; 112/174) than in buffaloes (15.6%; 23/147), and female bovines (43.5%; 108/248) were more frequently infected than males (37%; 27/73). Phylogenetic analysis of the msp1β sequence data (n = 42) revealed that A. marginale from Pakistan clustered with those from Brazil, Thailand, South Africa, and the USA. This study represents the first comprehensive investigation of A. marginale from bovines from diverse agroecological zones of Pakistan and will further stimulate population genetic studies of A. marginale and investigations into the economic impact of subclinical infections in bovines in smallholder farming systems. Full article

The spectrum of ixodid ticks that bite humans in Western Siberia has significantly changed over the past two decades. In this study, we determined tick species attacking people in the vicinity of Novosibirsk and the range of bacterial agents they were infected with. This study included 301 ticks taken from people and 46% were Ixodes pavlovskyi, followed by Ixodes persulcatus (19.6%), I. persulcatus/I. pavlovskyi interspecies hybrids (19.6%), Dermacentor reticulatus (12.8%), and single Dermacentor marginatus and Dermacentor nuttalli/Dermacentor silvarum. Human DNA was determined in ticks, first demonstrating that all Ixodes spp., including hybrids, can effectively feed on humans. The DNA of Borrelia spp., Rickettsia spp., and Anaplasmataceae bacteria was detected in different tick species. Borrelia garinii prevailed in Ixodes species, being found in 8.8% of ticks, whereas B. afzelii and B. bavariensis were found in single ticks. Borrelia miyamotoi was revealed in 3.7% of ticks. “Candidatus Rickettsia tarasevichiae” and R. raoultii were identified mainly in I. persulcatus and D. reticulatus (44.8% and 26.3%, respectively), while Rickettsia helvetica was found only in 2.2% I. pavlovskyi. The prevalence of Anaplasma phagocytophilum, Ehrlichia muris, and Neoehrlichia mikurensis did not exceed 2%. The obtained results indicate a high risk for humans to be infected with agents of Lyme borreliosis, primarily B. garinii. 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

Theileriosis is considered an economically important disease that may decrease productivity and cause a high mortality rate in livestock. Only a few studies have reported Theileria spp., such as T. sergenti and T. buffeli, in recent decades in Taiwan. In the present study, 401 ticks have been collected on Orchid Island in June 2022 and April 2023. Our environmental investigation for SFTSV unintentionally discovered T. luwenshuni in Haemaphysalis mageshimaensis on Orchid Island via PCR. The PCR products were sequenced, and the detected 18S rRNA gene sequences shared a 99.65–99.93% identity with T. luwenshuni sequences from ticks and ruminants in Myanmar and China. Despite the difficulty in clarifying the source of T. luwenshuni within neighboring regions, our findings provide an updated distribution of T. luwenshuni in Asia. This is not only the first time that T. luwenshuni was found in H. mageshimaensis but also the first report of T. luwenshuni on Orchid Island, Taiwan. Our study indicates that ruminants may be at risk of infection. Therefore, further investigations are needed to determine the distribution of T. luwenshuni among ruminants on Orchid Island and in Taiwan. Full article

This study explored the effects of antimicrobiota vaccines on the acquisition of Borrelia and Rickettsia, and on the microbiota composition of Ixodes ricinus ticks. Using a murine model, we investigated the immunological responses to live Staphylococcus epidermidis and multi-antigenic peptide (MAP) vaccines. Immunized mice were infected with either Borrelia afzelii or Rickettsia helvetica, and subsequently infested with pathogen-free I. ricinus nymphs. We monitored the tick feeding behavior, survival rates, and infection levels. Additionally, we employed comprehensive microbiota analyses, including the alpha and beta diversity assessments and microbial co-occurrence network construction. Our results indicate that both live S. epidermidis and MAP vaccines elicited significant antibody responses in mice, with notable bactericidal effects against S. epidermidis. The vaccination altered the feeding patterns and fitness of the ticks, with the Live vaccine group showing a higher weight and faster feeding time. Microbiota analysis revealed significant shifts in the beta diversity between vaccine groups, with distinct microbial networks and taxa abundances observed. Notably, the MAP vaccine group exhibited a more robust and complex network structure, while the Live vaccine group demonstrated resilience to microbial perturbations. However, the effects of antimicrobiota vaccination on Borrelia acquisition appeared taxon-dependent, as inferred from our results and previous findings on microbiota-driven pathogen refractoriness. Staphylococcus-based vaccines altered the microbiota composition but had no effect on B. afzelii infection, and yielded inconclusive results for R. helvetica. In contrast, previous studies suggest that E. coli-based microbiota modulation can induce a pathogen-refractory state, highlighting the importance of both bacterial species and peptide selection in shaping microbiota-driven pathogen susceptibility. However, a direct comparison under identical experimental conditions across multiple taxa is required to confirm this taxon-specific effect. These findings suggest that antimicrobiota vaccination influences tick fitness and microbiota assembly, but its effects on pathogen transmission depend on the bacterial taxon targeted and the selected peptide epitopes. This research provides insights into the need for strategic bacterial taxon selection to enhance vaccine efficacy in controlling tick-borne diseases. Full article