Search Results (462)

Ticks are haematophagous ectoparasites and vectors of a diverse range of pathogens, exerting substantial impacts on wildlife, domestic animals and public health. In Australia, despite the country’s rich and unique biodiversity, a comprehensive understanding of ticks and tick-borne pathogens associated with wildlife remains limited. Environmental change, urban expansion and climate variability are increasingly disrupting wildlife habitats, potentially intensifying interactions between wildlife hosts, ticks and humans. A broad evidence synthesis of studies published between January 1940 and March 2024 was conducted, retrieving 133 eligible records from Web of Science, CABI Abstracts and PubMed databases. Fifty tick species parasitising 160 wildlife species were identified, predominantly from the genera Ixodes, Amblyomma and Haemaphysalis. The most commonly reported hosts included marsupials, particularly bandicoots, wallabies and possums, with notable tick species being Ixodes tasmani, Ixodes holocyclus and Amblyomma triguttatum. Microorganism records were relatively limited and mostly represented molecular detections or reported associations, including Babesia, Borrelia, Coxiella, Rickettsia and Theileria species, rather than confirmed vector competence, reservoir status or pathogenicity. Key limitations included geographic sampling biases towards eastern Australia, limited molecular identification of ticks and infrequent pathogen screening, particularly regarding the ecology, epidemiology and molecular diversity of host–vector–microorganism interactions. Improved surveillance, expanded molecular characterisation, and integrated One Health investigations are required to better understand the ecological and public health significance of these host–vector–microorganism interactions. Full article

Spotted fever group (SFG) rickettsioses are emerging zoonotic diseases of increasing relevance in Latin America, yet the specific species involved in human infections remain poorly defined in many endemic regions. This study aimed to determine the most probable antigen among SFG-seroreactive febrile patients from Villeta, Colombia. A panel of 25 convalescent-phase serum samples previously identified as positive for SFG Rickettsia spp. antibodies was analyzed by indirect immunofluorescence assay using antigens of Rickettsia rickettsii, R. amblyommatis and R. parkeri. Antibody titers were compared to identify differential seroreactivity patterns. Overall, 44% (11/25) of the samples showed differential antibody titers against one of the tested antigens. Among these, nine (36%) exhibited higher titers to R. parkeri and two (8%) to R. amblyommatis, while none showed exclusive reactivity to R. rickettsii. The remaining 56% (14/25) presented similar titers across antigens, consistent with indeterminate or cross-reactive SFG responses. Antibody titers ranged from 1:128 to 1:4096, with R. parkeri showing the strongest reactivity. These findings suggest R. parkeri or a highly related Rickettsia species as the predominant probable antigen in Villeta, highlighting its potential role in mild rickettsial infections and emphasizing the need for eco-epidemiological studies to identify local vectors and reservoirs. Full article

Rocky Mountain spotted fever (RMSF), caused by Rickettsia rickettsii, is a potentially severe tick-borne disease affecting both dogs and humans. While commercial in-clinic diagnostic tests have improved the detection of several common canine tick-borne diseases, RMSF is not routinely included in many point-of-care screening panels. In addition, infected dogs may present with subtle or nonspecific clinical signs, making diagnosis challenging. This retrospective observational study evaluated the occurrence of PCR-confirmed Rickettsia rickettsii infection in dogs presented to a veterinary lameness and performance referral center. From March 2022 through February 2024, a convenience sample of 51 dogs underwent RMSF testing as part of their diagnostic evaluation. Blood samples were analyzed using a commercial vector-borne disease PCR panel. Overall, 13 of 51 dogs (25.5%) were PCR-positive for Rickettsia rickettsii. Thirty-six dogs originated from North Carolina and South Carolina, of which 13 (36.1%) were PCR-positive. These findings suggest that RMSF should be considered among the differential diagnoses in dogs presenting with unexplained lameness, reduced athletic performance, or other nonspecific clinical concerns in regions where tick-borne diseases are common. The identification of PCR-confirmed Rickettsia rickettsii infection in this referral population highlights the potential value of expanded vector-borne disease testing. Full article

Ticks are important arthropod vectors that transmit various pathogens to humans, livestock, and wildlife, thereby contributing significantly to the global burden of vector-borne diseases. The tick microbiome, consisting of bacteria, viruses, protozoa, and other microorganisms, plays a crucial role in pathogen transmission dynamics and the emergence of new zoonotic diseases. This review examines the characteristics of tick vectors, the composition and dynamics of tick-associated microbiomes, and their implications for zoonotic disease transmission. We analyze current knowledge of tick-borne pathogens, including Borrelia burgdorferi sensu lato, Rickettsia species, Anaplasma species, and Coxiella species, and highlight the potential for microbiome constituents to serve as reservoirs for emerging pathogens. The complex interactions between tick hosts, their microbiomes, and vertebrate hosts create opportunities for pathogen evolution and interspecies transmission. Recent advances in molecular techniques have revealed previously unknown microbial diversity within tick populations, suggesting that many potential zoonotic pathogens remain undiscovered. We discuss future research directions, including field screening methodologies for pathogen detection, microbiome-based risk assessment approaches, and the development of novel prevention strategies, including tick vaccines. Full article

Bemisia tabaci is a globally destructive agricultural pest and an efficient vector of begomoviruses, which cause recurrent epidemics across South Asia, including cotton leaf curl disease in Pakistan. Increasing evidence shows that bacterial endosymbionts play a central role in shaping whitefly biology, population dynamics, and vector competence. However, the distribution of these symbionts remains poorly resolved in Pakistan, a region where begomoviruses are persistent and widespread. This study investigated the cryptic species diversity, secondary endosymbiont composition and their infection frequency in B. tabaci populations collected from major agricultural regions of Pakistan. A total of 274 adult whiteflies belonging to Asia II-1 (n = 199), MEAM-1 (n = 67), Asia I (n = 7), and Asia II-8 (n = 1) were screened using a symbiont-specific PCR assay for six endosymbionts. The primary endosymbiont Candidatus Portiera aleyrodidarum was detected in all individuals, whereas five secondary endosymbionts (Arsenophonus, Cardinium, Hamiltonella, Wolbachia and Rickettsia) were identified with distinct cryptic species- and region-specific patterns. Notably, Arsenophonus was the most prevalent endosymbiont, occurring in 68% of Asia II-1, 100% of Asia I, and 21% of MEAM-1 individuals, with the highest regional prevalence in Punjab (80%) and Khyber Pakhtunkhwa (77%). Logistic regression analyses confirmed significantly higher infection probabilities in indigenous Asia II-1 populations. Network analysis revealed structured co-occurrence patterns, including strong negative associations between Arsenophonus and Hamiltonella. Phylogenetic analyses revealed close relatedness of Pakistani Arsenophonus strains to those reported from neighboring regions, indicating regional community rather than unique local diversification. The dominance of Arsenophonus in Pakistani whitefly populations is of particular significance, given its role in protecting begomoviruses within the insect vector and its implication in facilitating virus persistence and transmission. This study, for the first time in Pakistan, provides a comprehensive assessment of endosymbiont–cryptic species associations in Pakistani B. tabaci populations and highlights the dominant prevalence of Arsenophonus as a potential key player in local virus vector dynamics. Full article

Typhus (FBT), caused by Rickettsia typhi, rarely causes neurological disease. Herein, we describe neurological involvement in two cases of FBT. In the first case, an adult presented with persistent fever which deteriorated into status epilepticus. He was successfully treated with doxycycline and made a complete recovery. In the second case, a patient suffered an ischemic stroke and had a protracted clinical course but ultimately made a near complete recovery. In addition to these cases, we conducted a comprehensive narrative review of 43 cases of neurologic involvement in FBT reported from 1989 to 2025. Cases were excluded if there were pathologic discrepancies with typical cases of FBT. Presentations ranged from cranial nerve palsies to meningitis and fulminant encephalitis. This review highlights the spectrum of CNS complications associated with FBT and underscores the importance of early recognition and treatment with doxycycline to improve outcomes. Given the potential severity of neurologic involvement, clinicians in endemic areas should maintain a high index of suspicion for FBT in patients presenting with a febrile illness and neurologic symptoms. Full article

This study investigated the prevalence and molecular characteristics of canine vector-borne pathogens (CVBPs) circulating in diverse dog populations in Thailand by using molecular diagnostic methods. A total of 400 blood samples were collected from four groups (n = 100 each): stray dogs (Group A), vector-borne disease–suspected companion dogs (Group B), healthy companion dogs presenting for routine examination (Group C), and companion dogs presenting with non-vector-borne illnesses (Group D). The overall infection rate was 46.25%. Ehrlichia spp. were the most frequently detected pathogens (23.5%), followed by Babesia spp. (16.5%), Rickettsia spp. (15.0%), and Anaplasma spp. (11.5%). The prevalence differed markedly among groups, including group A (88.0%), group B (54.0%), group C (27.0%) and group D (16.0%) (p < 0.05). DNA sequence analysis showed 100% identity with GenBank™ reference sequences, confirming the presence of Ehrlichia canis, Rickettsia asembonensis, Babesia vogeli, and Anaplasma platys. The detection of CVBPs across all groups demonstrates free-roaming and owned dogs serve as reservoirs for substantial ongoing infections and pose potential zoonotic implications to humans. Overall, these findings emphasize the importance of sustained molecular surveillance, improved vector control strategies, and proactive monitoring of high-risk dog populations to reduce the burden of CVBPs in Thailand. Full article

Southeast Asia (SEA) faces persistent gaps in regional understanding and control of ticks and tick-borne diseases (TBDs) despite recent advances (2023–2025). The second international symposium on ticks and TBDs in SEA (Singapore, August 2025), following the inaugural 2023 meeting in Cambodia, served as a catalyst for regional exchange that informed this perspective. SEA’s ecological and host diversity supports complex tick–host–pathogen networks, yet evidence remains fragmented due to uneven sampling that has largely focused on livestock and peri-urban environments. Key constraints include limited taxonomic resolution driven by outdated or incomplete identification keys, under-sampling of soft ticks (Argasidae), and the absence of harmonized, open-access regional reference resources (including DNA barcodes and MALDI-TOF MS spectral databases). While MALDI-TOF MS, proteomics, AI-assisted identification, and next-generation sequencing/metagenomics are increasingly applied, their broader regional uptake is limited by the absence of harmonized, open-access reference resources (including DNA barcodes and MALDI-TOF MS spectral databases). Broad ecological surveys and integrated animal and human surveillance remain limited, and vector competence studies are constrained by the scarcity of SEA-derived tick colonies and cell lines. Regional data and recent findings (2024–2026) confirm circulation of multiple TBPs (including Anaplasma, Babesia, Borrelia, Coxiella, Ehrlichia, Rickettsia, and Theileria) and highlight emerging viral findings, including southward reports of Bandavirus dabieense. Human infestations and non-communicable tick bite outcomes (e.g., tick paralysis and alpha-gal syndrome) are recognized but remain under-reported due to low clinical awareness and limited diagnostics. Importantly, the diagnostic chain is further disrupted by missed/insufficient specimen collection at the point of care, and by constrained capacity to identify (especially immature) ticks to species level—limitations compounded by the absence of harmonized, open-access regional reference resources. The symposium identified six priorities: (1) full completion and regional validation of tick identification keys for adults (in progress) and immatures (to be initiated), plus an open-access DNA barcode library anchored by curated, voucher-based collections from all SEA countries; (2) harmonization of molecular and proteomic diagnostic platforms, including expansion of regional MALDI-TOF MS and NGS protocols and reference databases; (3) development of tick colonies and cell lines from locally prevalent species to support vector competence, vaccine, and acaricide testing; (4) expansion of One Health surveillance with enhanced ecological sampling at wildlife–livestock–human interfaces; (5) establishment of open-access, region-wide data platforms for integrated tick, TBP, and ecological metadata sharing; and (6) sustained investment in human resources, training, and policy advocacy to raise research and public health visibility of ticks and TBDs. Full article

Tick-borne diseases are a growing public health concern in the Mediterranean. Brijuni National Park (BNP), a unique, highly visited island ecosystem characterized by increased large game host density and diverse Mediterranean habitats, presents an elevated risk for pathogen co-circulation. This study addresses the lack of spatial and epidemiological data to accurately assess human exposure risk in this environment. We performed a detailed geospatial and epidemiological risk mapping of pathogen co-circulation in BNP. A total of 587 hard ticks were collected across 26 georeferenced micro-locations (2020–2022). Ticks were morphologically identified and subsequently screened for six key zoonotic bacterial pathogens using qPCR. The Minimal Infection Rate (MIR) and a Co-infection Rate (CR) were calculated. Geographic Information System (GIS) mapping was utilized to map ecological determinants of risk. Ixodes ricinus was the overwhelmingly dominant vector (94.0%), peaking in spring, with activity absent in summer. Recorded diverse tick fauna also included Hyalomma marginatum (3%), Haemaphysalis punctata (2%), Ixodes frontalis (0.8%) and Rhipicephalus sanguineus (0.2%). Active circulation of Borrelia burgdorferi s.l. (Bbsl), Anaplasma phagocytophilum, and Ehrlichia canis were confirmed. Bbsl presented the highest MIR (3.05). The Co-infection Rate (CR) was notably high at 29.41%, with triple co-infections (Bbsl, A. phagocytophilum, E. canis) concentrated in cultivated mosaics and holm oak forests (Quercus ilex L.). The highest number of ticks was recovered from ecotone zones, accounting for 50.0% of the total catch, confirming them as high-risk interfaces. The absence of Rickettsia conorii may be attributed to the strict control/absence of its primary host (domestic dogs). The presence of the exotic vector H. marginatum was also confirmed. The high rate of co-infection and the spatial concentration of risk in specific habitats underscore an elevated and complex public health risk in BNP, closely linked to habitat structure and increased game host density. This research provides an essential geospatial framework for targeted ‘One Health’ management, prioritizing vector control in ecotone zones and dense forest refugia. Urgent surveillance for the exotic H. marginatum is warranted to monitor the potential risk of Crimean-Congo Hemorrhagic Fever. Full article

Ticks of the genus Hyalomma are major ectoparasites of dromedary camels and serve as important vectors for diverse tick-borne pathogens (TBPs) affecting both animals and humans. In this study, we determined the tick species diversity and distribution and estimated the prevalence of TBPs in those ticks. A total of 780 ticks collected from camels in Bol, Chad, were identified into four species: Hyalomma dromedarii (49.0%), H. rufipes (22.6%), H. impeltatum (19.1%), and H. truncatum (9.4%). Sixty ticks were selected proportionally across the four Hyalomma species and screened for TBPs using PCR. Coxiella burnetii was detected in 11.7% of the ticks, and Rickettsia aeschlimannii in 1.7%. Anaplasmataceae-specific 16S rRNA primers detected Candidatus Midichloria mitochondrii, a tick endosymbiont, in 10% of the ticks. No protozoan pathogens (Theileria or Babesia) were detected. This study highlights the need for integrated surveillance of ticks and their associated microorganisms in Chadian camels to mitigate zoonotic and veterinary risks. Strengthening such efforts will support camel health and pastoral livelihoods in the region. Full article

Individuals in the southeastern United States of America (USA) have an increasing risk of contracting a tick-borne disease. Land use changes, changing climate, and redistribution of both ticks and their hosts make systematic tick and tick-borne pathogen investigation crucial for public health protection. Prior to 2020, South Carolina had limited data on tick species distribution and tick infection rates. In this work, we describe establishment of a sustainable tick and tick-borne pathogen collaborative network for South Carolina. A major determinant of program success was sharing work effort between the University of South Carolina, the South Carolina Department of Public Health, and key partners including state park employees, local veterinarians, students, and volunteers. The program collected questing ticks from public lands and host-attached ticks from animal shelters. Amblyomma americanum was the most commonly collected tick, with highest density in South Carolina’s southern coastal region. A greater tick species diversity was seen in animal shelter collected versus questing ticks. Pathogen testing results yielded a high presence of Rickettsia amblyommatis among Am. americanum ticks with several other Rickettsia spp. detected including Rickettsia parkeri, Candidatus R. andeanae, R. montanensis, and R. asembonensis. Additional Rickettsiales detected included multiple Ehrlichia and Anaplasma species, with higher presence in the state’s northern region. Borrelia burgdorferi sensu stricto was detected in one questing Ixodes keiransi from the southern coastal region. The current report presents the initial steps for pathogen and tick species surveillance in South Carolina, providing successes and pitfalls as a model for other states and regions to establish similar efforts to improve national tick surveillance. Full article

Among the 24 tick species documented in Slovakia, Ixodes ricinus is the most widespread and abundant. In some sites, 2–5 epidemiologically important tick species co-occur. Such sites represent hotspots for studying the co-circulation of tick-borne pathogens. Sympatric occurrence of five exophilic species (I. ricinus, Dermacentor reticulatus, D. marginatus, Haemaphysalis concinna, and H. inermis) was confirmed in the environs of the Žemberovce village (Levice region, south-western Slovakia). Here, the seasonal activity and abundance of questing ticks and the tick infestation of game and sheep were investigated. Questing ticks, spleens of game, and ticks removed from game and sheep were examined for the presence of tick-borne pathogens (Babesia spp., Theileria spp., Anaplasma phagocytophilum, Rickettsia spp., Borrelia burgdorferi s.l., and Borrelia miyamotoi) by molecular methods. Among the questing ticks, I. ricinus prevailed. Presence of Babesia crassa, B. microti, Rickettsia helvetica, R. raoultii, A. phagocytophilum, Borrelia afzelii, B. garinii, B. valaisiana, B. burgdorferi sensu stricto and B. miyamotoi was detected. Dermacentor marginatus, I. ricinus and H. concinna were collected from sheep. They were infected with A. phagocytophilum, A. ovis, R. slovaca, and R. raoultii. Anaplasma phagocytophilum was detected in all examined red deer and roe deer and in 55.6% of wild boar. All cervids were positive for Theileria spp. Infestation of game with all five tick species, with a predominance of I. ricinus, was confirmed. In these ticks, A. phagocytophilum, R. helvetica, R. raoultii, Babesia sp. hc-hlj212, B. crassa, B. microti, Babesia spp. and B. miyamotoi were detected. This study confirmed the presence of B. crassa in Slovakia for the first time. The investigated area, with the co-occurrence of five exophilic tick species and a wide spectrum of tick-borne pathogens, represents an epidemiologically important hotspot with the risk of infections of humans and domestic animals. Full article

Tick-borne diseases are an increasing public health concern in Europe, driven by climate change, landscape transformation, and expanding human activity. Urban green spaces provide suitable habitats for ticks and increase human exposure to tick-borne pathogens (TBPs), yet habitat-specific patterns in urban and suburban environments remain poorly characterized. This study examined tick distribution and TBPs prevalence across 11 urban and suburban sites in Kaunas County, Lithuania. A total of 1539 questing Ixodes ricinus ticks were collected and screened by real-time PCR for Borrelia spp., Anaplasma phagocytophilum, Neoehrlichia mikurensis, Rickettsia spp., and Babesia spp., with further species identification by sequencing. Borrelia spp. were most prevalent (24.43%), followed by Rickettsia spp. (7.60%), N. mikurensis (6.63%), A. phagocytophilum (3.64%), and Babesia spp. (2.53%). Tick density, pathogen prevalence, and species diversity varied among habitats, with higher values in forested and ecotonal areas, but notable infection rates were also observed in managed urban sites. Co-infections occurred in 18.8% of infected ticks. Our findings demonstrate that the circulation of TBPs in urban and suburban landscapes is shaped by local habitat features, host communities, and management intensity, highlighting the need for habitat-specific risk assessment in urban planning and public health. Full article

Spotted fever group (SFG) rickettsioses are tick-borne infectious diseases caused by more than 30 Rickettsia species. As ticks may harbor and transmit multiple pathogens during a single blood meal, sensitive and specific molecular detection methods are essential for early diagnosis. Conventional nested PCR is commonly used but is time-consuming and prone to cross-contamination due to multiple amplification steps. This study evaluated a dual-target one-step nested PCR assay developed as a rapid alternative to conventional nested PCR for SFG Rickettsia detection. Gene-specific primers targeting the Rickettsia outer membrane protein A (ompA) gene and the 17 kDa antigen gene were designed, with a Plasmodium falciparum thrombospondin-related anonymous protein (TRAP) gene included as an internal amplification control. Primer specificity was verified in silico, and assay performance was assessed using synthetic DNA templates. The dual-target one-step nested PCR achieved detection limits of 10 gene copies for the 17 kDa gene and 1000 gene copies for ompA, compared with 10 and 100,000 gene copies, respectively, using conventional nested PCR. Screening of 184 tick specimens identified one positive sample (0.54%) for the Rickettsia 17 kDa gene. Overall, the dual-target one-step nested PCR demonstrated comparable sensitivity to conventional nested PCR while reducing assay time and contamination risk, indicating its potential as a reliable tool for SFG Rickettsia detection. Full article

This study aimed primarily to evaluate the performance of two Conformité Européenne—In Vitro Diagnostic (CE-IVD) multiplex real-time PCR (rt-PCR) assays for the molecular identification of tick-borne pathogens (TBPs) of human interest on ticks removed from human skin and collected through a citizen science-based approach. As a secondary objective, the aggregated results were used to describe tick species distribution, developmental stages, and seasonal TBP circulation in 2024 in the considered area. The comparison was conducted on 116 tick samples collected in 2024 voluntarily delivered to a hospital in northeastern Italy. Detected TBPs were further confirmed with in-house-validated PCR methods and, where applicable, resolved to the species level. Clinically relevant pathogen species were identified as single infections or coinfections. Overall, 33.6% of tick samples tested positive for at least one TBP, and 6.9% showed coinfections. Kit B exhibited a higher detection rate for Borrelia spp. and Rickettsia spp. targets, partly reflecting its broader diagnostic specificity, while statistically significant differences in cycle threshold values were observed for Anaplasma phagocytophilum detection. The most frequently involved ticks were Ixodes ricinus nymphs, and the most represented area was Verona province. Late spring and early summer were identified as the periods with the highest tick conferment and pathogen diversity. Overall, the results support the use of multiplex real-time PCR commercial kits combined with citizen science-based tick collection as an effective approach for both diagnostic screening and regional surveillance of circulating ticks and TBPs. Full article