Molecular screening and genetic diversity of tick-borne pathogens associated with dogs and livestock ticks in Egypt.

BACKGROUND: The Middle East and North Africa (MENA) offer optimal climatic conditions for tick reproduction and dispersal. Research on tick-borne pathogens in this region is scarce. Despite recent advances in the characterization and taxonomic explanation of various tick-borne illnesses affecting animals in Egypt, no comprehensive examination of TBP (tick-borne pathogen) statuses has been performed. Therefore, the present study aims to detect the prevalence of pathogens harbored by ticks in Egypt. METHODOLOGY/PRINCIPAL FINDINGS: A four-year PCR-based study was conducted to detect a wide range of tick-borne pathogens (TBPs) harbored by three economically important tick species in Egypt. Approximately 86.7% (902/1,040) of the investigated Hyalomma dromedarii ticks from camels were found positive with Candidatus Anaplasma camelii (18.8%), Ehrlichia ruminantium (16.5%), Rickettsia africae (12.6%), Theileria annulata (11.9%), Mycoplasma arginini (9.9%), Borrelia burgdorferi (7.7%), Spiroplasma-like endosymbiont (4.0%), Hepatozoon canis (2.4%), Coxiella burnetii (1.6%) and Leishmania infantum (1.3%). Double co-infections were recorded in 3.0% (27/902) of Hy. dromedarii ticks, triple co-infections (simultaneous infection of the tick by three pathogen species) were found in 9.6% (87/902) of Hy. dromedarii ticks, whereas multiple co-infections (simultaneous infection of the tick by ≥ four pathogen species) comprised 12% (108/902). Out of 1,435 investigated Rhipicephalus rutilus ticks collected from dogs and sheep, 816 (56.9%) ticks harbored Babesia canis vogeli (17.1%), Rickettsia conorii (16.2%), Ehrlichia canis (15.4%), H. canis (13.6%), Bo. burgdorferi (9.7%), L. infantum (8.4%), C. burnetii (7.3%) and Trypanosoma evansi (6.6%) in dogs, and 242 (16.9%) ticks harbored Theileria lestoquardi (21.6%), Theileria ovis (20.0%) and Eh. ruminantium (0.3%) in sheep. Double, triple, and multiple co-infections represented 11% (90/816), 7.6% (62/816), and 10.3% (84/816), respectively in Rh. rutilus from dogs, whereas double and triple co-infections represented 30.2% (73/242) and 2.1% (5/242), respectively in Rh. rutilus from sheep. Approximately 92.5% (1,355/1,465) of Rhipicephalus annulatus ticks of cattle carried a burden of Anaplasma marginale (21.3%), Babesia bigemina (18.2%), Babesia bovis (14.0%), Borrelia theleri (12.8%), R. africae (12.4%), Th. annulata (8.7%), Bo. burgdorferi (2.7%), and Eh. ruminantium (2.5%). Double, triple, and multiple co-infections represented 1.8% (25/1,355), 11.5% (156/1,355), and 12.9% (175/1,355), respectively. The detected pathogens' sequences had 98.76-100% similarity to the available database with genetic divergence ranged between 0.0001 to 0.0009% to closest sequences from other African, Asian, and European countries. Phylogenetic analysis revealed close similarities between the detected pathogens and other isolates mostly from African and Asian countries. CONCLUSIONS/SIGNIFICANCE: Continuous PCR-detection of pathogens transmitted by ticks is necessary to overcome the consequences of these infection to the hosts. More restrictions should be applied from the Egyptian authorities on animal importations to limit the emergence and re-emergence of tick-borne pathogens in the country. This is the first in-depth investigation of TBPs in Egypt.

Tissue-specific localization of tick-borne pathogens in ticks collected from camels in Kenya: insights into vector competence.

Background: Tick-borne pathogen (TBP) surveillance studies often use whole-tick homogenates when inferring tick-pathogen associations. However, localized TBP infections within tick tissues (saliva, hemolymph, salivary glands, and midgut) can inform pathogen transmission mechanisms and are key to disentangling pathogen detection from vector competence. Methods: We screened 278 camel blood samples and 504 tick tissue samples derived from 126 camel ticks sampled in two Kenyan counties (Laikipia and Marsabit) for Anaplasma, Ehrlichia, Coxiella, Rickettsia, Theileria, and Babesia by PCR-HRM analysis. Results: Candidatus Anaplasma camelii infections were common in camels (91%), but absent in all samples from Rhipicephalus pulchellus, Amblyomma gemma, Hyalomma dromedarii, and Hyalomma rufipes ticks. We detected Ehrlichia ruminantium in all tissues of the four tick species, but Rickettsia aeschlimannii was only found in Hy. rufipes (all tissues). Rickettsia africae was highest in Am. gemma (62.5%), mainly in the hemolymph (45%) and less frequently in the midgut (27.5%) and lowest in Rh. pulchellus (29.4%), where midgut and hemolymph detection rates were 17.6% and 11.8%, respectively. Similarly, in Hy. dromedarii, R. africae was mainly detected in the midgut (41.7%) but was absent in the hemolymph. Rickettsia africae was not detected in Hy. rufipes. No Coxiella, Theileria, or Babesia spp. were detected in this study. Conclusions: The tissue-specific localization of R. africae, found mainly in the hemolymph of Am. gemma, is congruent with the role of this tick species as its transmission vector. Thus, occurrence of TBPs in the hemolymph could serve as a predictor of vector competence of TBP transmission, especially in comparison to detection rates in the midgut, from which they must cross tissue barriers to effectively replicate and disseminate across tick tissues. Further studies should focus on exploring the distribution of TBPs within tick tissues to enhance knowledge of TBP epidemiology and to distinguish competent vectors from dead-end hosts.

Molecular survey of Piroplasmida, Hepatozoon spp. and Anaplasmataceae in anemic and thrombocytopenic dogs from Uruguay.

Canine tick-borne diseases, such as babesiosis, rangeliosis, hepatozoonosis, anaplasmosis and ehrlichiosis, are of veterinarian relevance, causing mild or severe clinical cases that can lead to the death of the dog. The aim of this study was detecting tick-borne protozoan and rickettsial infections in dogs with anemia and/or thrombocytopenia in Uruguay. A total of 803 domestic dogs were evaluated, and 10% were found positive (detected by PCR) at least for one hemoparasite. Sequence analysis confirmed the presence of four hemoprotozoan species: Rangelia vitalii, Babesia vogeli, Hepatozoon canis and Hepatozoon americanum, and the rickettsial Anaplasma platys. The most detected hemoparasite was R. vitalii, followed by H. canis and A. platys. This is the first report of B. vogeli in Uruguay and the second report of H. americanum in dogs from South America. The results highlight the importance for veterinarians to include hemoparasitic diseases in their differential diagnosis of agents causing anemia and thrombocytopenia.

Detection of tick-borne pathogens in Rhipicephalus bursa ticks collected from the autochthonous Garrano breed of horses in Portugal.

The Garrano is a semi-feral horse breed native to several mountains in the northern Iberian Peninsula. Despite being endangered, this unique breed of pony has managed to survive in the wild and continues to be selectively bred, highlighting their remarkable resilience and adaptability to harsh environments. Wildlife plays a critical role in the survival of tick vectors in their natural habitats and the transfer of tick-borne pathogens, as they can serve as reservoir hosts for many agents and amplifiers for these vectors. The semi-feral lifestyle of the Garrano horses makes them particularly vulnerable to exposure to numerous tick species throughout the year. Therefore, the aim of this study was to investigate the occurrence of Anaplasma, Ehrlichia, Babesia, Theileria, and spotted fever rickettsiae in the Garrano horse ticks to obtain a knowledge of circulating agents in this host population. The collected ticks (n = 455) were identified as Rhipicephalus bursa. DNA specimens were organized in pools of 5 ticks, for molecular screening. Pools PCR results confirmed the presence of Candidatus Rickettsia barbariae (n = 12 for the ompB gene, n = 11 for the ompA gene and n = 6 for the gltA gene), Babesia bigemina (n = 1), Babesia caballi (n = 3), Theileria equi (n = 15) and Theileria haneyi (n = 1).These results confirm the circulation of an emerging rickettsial spotted fever group member, Candidatus R. barbariae, in R. bursa ticks. Our findings demonstrated that Candidatus R. barbariae co-circulates with B. bigemina and T. equi, which are vectored by R. bursa. We are reporting for the first time, the detection of T. haneyi among R. bursa ticks feeding in the Garrano horses in Portugal. Surveillance studies for tick-borne infections are essential to provide information that can facilitate the implementation of preventive and control strategies.

Distribution and pathogen prevalence of field-collected ticks from south-western Korea: a study from 2019 to 2022.

Hard ticks are known vectors of various pathogens, including the severe fever with thrombocytopenia syndrome virus, Rickettsia spp., Coxiella burnetii, Borrelia spp., Anaplasma phagocytophilum, and Ehrlichia spp. This study aims to investigate the distribution and prevalence of tick-borne pathogens in southwestern Korea from 2019 to 2022. A total of 13,280 ticks were collected during the study period, with H. longicornis accounting for 86.1% of the collected ticks. H. flava, I. nipponensis and A. testudinarium comprised 9.4%, 3.6%, and 0.8% of the ticks, respectively. Among 983 pools tested, Rickettsia spp. (216 pools, 1.6% MIR) were the most prevalent pathogens across all tick species, with R. japonica and R. monacensis frequently detected in I. nipponensis and Haemaphysalis spp., respectively. Borrelia spp. (28 pools, 0.2% MIR) were predominantly detected in I. nipponensis (27 pools, 13.8% MIR, P < 0.001). Co-infections, mainly involving Rickettsia monacensis and Borrelia afzelii, were detected in I. nipponensis. Notably, this study identified R. monacensis for the first time in A. testudinarium in South Korea. These findings offer valuable insights into the tick population and associated pathogens in the region, underscoring the importance of tick-borne disease surveillance and prevention measures.

Hematological and plasma profiles and ticks and tick-borne pathogens in wild Formosan black bears (Ursus thibetanus formosanus).

BACKGROUND: The endangered Formosan black bear (Ursus thibetanus formosanus) is the largest native carnivorous mammal in Taiwan. Diseases, poor management, illegal hunting, and habitat destruction are serious threats to the survival of bear populations. However, studies on the impact of diseases on bear populations are limited. Therefore, this study aimed to establish a database of the hematological and plasma profiles of free-ranging Formosan black bears and investigate the occurrence of ectoparasites, blood parasites, and vector-borne pathogens. METHODS: Formosan black bears were captured in Yushan National Park (YNP) and Daxueshan Forest Recreation Area (DSY) in Taiwan. Blood samples were collected from each bear for hematological analysis and plasma biochemistry using a hematology analyzer. Parasites and pathogens were detected using a thin blood smear with Wright-Giemsa staining and polymerase chain reaction (PCR) assay. Additionally, macroscopic ectoparasites were collected from bears to detect blood parasites and other pathogens. Moreover, the relationships between the bear variables (sex, age, and occurrence of parasites or pathogens), ectoparasites, and infectious agents were also analyzed. RESULTS: In all, 21 wild bears (14 in YNP and 7 in DSY) were captured and released during the satellite tracking studies. Hematological analysis and plasma biochemistry indicated significant differences in white blood cells (WBC), segments, creatine kinase (CK), and lactate dehydrogenase (LDH) levels between foot snare and culvert-captured bears. Additionally, there were significant differences in total plasma protein (TPP), creatinine, Ca2+, Mg2+, and K+ levels between male and female bears. Moreover, pathogen-infected bears had significantly higher erythrocyte sedimentation rate (ESR; 30 min and 1 h) and globulin levels than uninfected bears. In total, 240 ticks were collected from 13 bears, among which eight adult tick species were identified, including Haemaphysalis flava, Haemaphysalis hystricis, Amblyomma testudinarium, Ixodes ovatus, Dermacentor taiwanensis, Haemaphysalis longicornis, Ixodes acutitarsus, Amblyomma javanense, and nymphs belonging to Haemaphysalis spp. PCR revealed that 13 (61.90%) and 8 (38.10%) bears harbored Hepatozoon ursi and Babesia DNA, respectively. Among the ticks examined, 157 (65.41%) and 128 (53.33%) samples were positive for H. ursi and Babesia, respectively. CONCLUSIONS: To the best of our knowledge, this is the first study to establish a database of the hematological and plasma profiles of wild Formosan black bears and investigate ectoparasite infestation and Hepatozoon and Babesia spp. INFECTION: In conclusion, these findings may serve as a reference for monitoring the health and population of locally endangered bears.

Tick-borne diseases in Europe: Current prevention, control tools and the promise of aptamers.

In Europe, tick-borne diseases (TBDs) cause significant morbidity and mortality, affecting both human and animal health. Ticks can transmit a wide variety of pathogens (bacteria, viruses, and parasites) and feed on many vertebrate hosts. The incidence and public health burden of TBDs are tending to intensify in Europe due to various factors, mainly anthropogenic and often combined. Early detection of tick-borne pathogens (TBPs), preventive measures and treatment are of great importance to control TBDs and their expansion. However, there are various limitations in terms of the sensitivity and/or specificity of detection and prevention methods, and even in terms of feasibility. Aptamers are single-stranded DNA or RNA that could address these issues as they are able to bind with high affinity and specificity to a wide range of targets (e.g., proteins, small compounds, and cells) due to their unique three-dimensional structure. To date, aptamers have been selected against TBPs such as tick-borne encephalitis virus, Francisella tularensis, and Rickettsia typhi. These studies have demonstrated the benefits of aptamer-based assays for pathogen detection and medical diagnosis. In this review, we address the applications of aptamers to TBDs and discuss their potential for improving prevention measures (use of chemical acaricides, vaccination), diagnosis and therapeutic strategies to control TBDs.

Prevalence of tick-borne pathogens in ticks collected from the wild mountain ungulates mouflon and chamois in 4 regions of France.

Ticks are major vectors of various pathogens of health importance, such as bacteria, viruses and parasites. The problems associated with ticks and vector-borne pathogens are increasing in mountain areas, particularly in connection with global climate change. We collected ticks (n = 2,081) from chamois and mouflon in 4 mountainous areas of France. We identified 6 tick species: Ixodes ricinus, Rhipicephalus bursa, Rh. sanguineus s.l., Haemaphysalis sulcata, H. punctata and Dermacentor marginatus. We observed a strong variation in tick species composition among the study sites, linked in particular to the climate of the sites. We then analysed 791 ticks for DNA of vector-borne pathogens: Babesia/Theileria spp., Borrelia burgdorferi s.l., Anaplasma phagocytophilum, A. marginale, A. ovis, and Rickettsia of the spotted fever group (SFG). Theileria ovis was detected only in Corsica in Rh. bursa. Babesia venatorum (2 sites), Borrelia burgdorferi s.l. (B. afzelii and B. garinii; 2 sites) and Anaplasma phagocytophilum (3 sites) were detected in I. ricinus. Anaplasma ovis was detected at one site in I. ricinus and Rh. sanguineus s.l. SFG Rickettsia were detected at all the study sites: R. monacensis and R. helvetica in I. ricinus at the 3 sites where this tick is present; R. massiliae in Rh. sanguineus s.l. (1 site); and R. hoogstraalii and Candidatus R. barbariae in Rh. bursa in Corsica. These results show that there is a risk of tick-borne diseases for humans and domestic and wild animals frequenting these mountain areas.

Title: Prévalence d'agents pathogènes vectorisés chez des tiques collectées chez des ongulés sauvages (mouflons, chamois) dans 4 zones montagneuses en France. Abstract: Les tiques sont des vecteurs majeurs de différents agents pathogènes d'importance sanitaire, tels que des bactéries, des virus et des parasites. Les problématiques liées aux tiques et aux pathogènes vectorisés augmentent en zones de montagne, en lien notamment avec le réchauffement climatique. Nous avons collecté des tiques (n = 2 081) sur des chamois et des mouflons dans 4 zones montagneuses en France. Six espèces ont été identifiées : Ixodes ricinus, Rhipicephalus bursa, Rh. sanguineus s.l., Haemaphysalis sulcata, H. punctata et Dermacentor marginatus. Nous avons observé une forte variation de la composition en espèces de tiques entre les sites d'étude, en lien notamment avec le climat des sites. Nous avons ensuite recherché les ADN d'agents pathogènes vectorisés sur 791 tiques : Babesia/Theileria spp, Borrelia burgdorferi s.l., Anaplasma phagocytophilum, A. marginale, A. ovis, et de Rickettsia du groupe des fièvres boutonneuses (SFG). Theileria ovis a été détecté uniquement en Corse chez Rh. bursa. Babesia venatorum (2 sites), Borrelia burgdorferi s.l. (B. afzelii and B. garinii; 2 sites) et Anaplasma phagocytophilum (3 sites) ont été détectés chez I. ricinus. Anaplasma ovis a été détecté dans un site chez I. ricinus et Rh. sanguineus s.l.. Les Rickettsia SFG ont été détectées dans tous les sites d'étude : Rickettsia monacensis et R. helvetica chez I. ricinus dans les 3 sites où cette tique est présente; R. massiliae chez Rh. sanguineus s.l. (1 site); et R. hoogstraalii et Candidatus R. barbariae chez Rh. bursa en Corse. Ces résultats montrent un risque de transmission de maladies par les tiques pour les personnes et les animaux domestiques et sauvages fréquentant ces zones de montagne.

Tick-Borne Diseases.

Ticks are responsible for the vast majority of vector-borne illnesses in the United States. The number of reported tick-borne disease (TBD) cases has more than doubled in the past 20 years. The majority of TBD cases occur in warm weather months in individuals with recent outdoor activities in wooded areas. The risk of contracting a TBD is also highly dependent on geographic location. Between 24 and 48 hours of tick attachment is required for most disease transmission to occur. Only 50% to 70% of patients with a TBD will recall being bitten by a tick, and TBDs are often initially misdiagnosed as a viral illness. Most TBDs are easily treated when diagnosed early in their course.

Tick-borne bacterial agents in Hyalomma asiaticum ticks from Xinjiang Uygur Autonomous Region, Northwest China.

BACKGROUND: Hyalomma ticks are widely distributed in semi-arid zones in Northwest China. They have been reported to harbor a large number of zoonotic pathogens. METHODS: In this study, a total of 334 Hyalomma asiaticum ticks infesting domestic animals were collected from four locations in Xinjiang, Northwest China, and the bacterial agents in them were investigated. RESULTS: A putative novel Borrelia species was identified in ticks from all four locations, with an overall positive rate of 6.59%. Rickettsia sibirica subsp. mongolitimonae, a human pathogen frequently reported in Europe, was detected for the second time in China. Two Ehrlichia species (Ehrlichia minasensis and Ehrlichia sp.) were identified. Furthermore, two Anaplasma species were characterized in this study: Candidatus Anaplasma camelii and Anaplasma sp. closely related to Candidatus Anaplasma boleense. It is the first report of Candidatus Anaplasma camelii in China. CONCLUSIONS: Six bacterial agents were reported in this study, many of which are possible or validated pathogens for humans and animals. The presence of these bacterial agents may suggest a potential risk for One Health in this area.

RPA-CRISPR/Cas12a assay for the diagnosis of bovine Anaplasma marginale infection.

Anaplasma marginale infection is one of the most common tick-borne diseases, causing a substantial loss in the beef and dairy production industries. Once infected, the pathogen remains in the cattle for life, allowing the parasites to spread to healthy animals. Since clinical manifestations of anaplasmosis occur late in the disease, a sensitive, accurate, and affordable pathogen identification is crucial in preventing and controlling the infection. To this end, we developed an RPA-CRISPR/Cas12a assay specific to A. marginale infection in bovines targeting the msp4 gene. Our assay is performed at one moderately high temperature, producing fluorescent signals or positive readout of a lateral flow dipstick, which is as sensitive as conventional PCR-based DNA amplification. This RPA-CRISPR/Cas12a assay can detect as few as 4 copies/µl of Anaplasma using msp4 marker without cross-reactivity to other common bovine pathogens. Lyophilized components of the assay can be stored at room temperature for an extended period, indicating its potential for field diagnosis and low-resource settings of anaplasmosis in bovines.

Tick species diversity and potential distribution alternation of dominant ticks under different climate scenarios in Xinjiang, China.

Ticks are a hematophagous parasite and a vector of pathogens for numerous human and animal diseases of significant importance. The expansion of tick distribution and the increased risk of tick-borne diseases due to global climate change necessitates further study of the spatial distribution trend of ticks and their potential influencing factors. This study constructed a dataset of tick species distribution in Xinjiang for 60 years based on literature database retrieval and historical data collection (January 1963-January 2023). The distribution data were extracted, corrected, and deduplicated. The dominant tick species were selected for analysis using the MaxEnt model to assess their potential distribution in different periods under the current and BCC-CSM2.MR mode scenarios. The results indicated that there are eight genera and 48 species of ticks in 108 cities and counties of Xinjiang, with Hyalomma asiaticum, Rhipicephalus turanicus, Dermacentor marginatus, and Haemaphysalis punctatus being the top four dominant species. The MaxEnt model analysis revealed that the suitability areas of the four dominant ticks were mainly distributed in the north of Xinjiang, in areas such as Altay and Tacheng Prefecture. Over the next four periods, the medium and high suitable areas within the potential distribution range of the four tick species will expand towards the northwest. Additionally, new suitability areas will emerge in Altay, Changji Hui Autonomous Prefecture, and other local areas. The 60-year tick dataset in this study provides a map of preliminary tick distribution in Xinjiang, with a diverse array of tick species and distribution patterns throughout the area. In addition, the MaxEnt model revealed the spatial change characteristics and future distribution trend of ticks in Xinjiang, which can provide an instrumental data reference for tick monitoring and tick-borne disease risk prediction not only in the region but also in other countries participating in the Belt and Road Initiative.

Rhipicephalus sanguineus from Hungarian dogs: Tick identification and detection of tick-borne pathogens.

The brown dog tick, Rhipicephalus sanguineus is a complex of tick species with an unsettled species concept. In Europe, R. sanguineus is considered mainly a Mediterranean tick with sporadic findings in central and northern Europe. R. sanguineus is known as a vector of a range of pathogens of medical and veterinary importance, most of which not yet reported as autochthonous in Hungary. A total of 1839 ticks collected by veterinarians from dogs and cats were obtained in Hungary. The study aims at precise determination of ticks identified as R. sanguineus and detection of pathogens in collected ticks. All ticks were morphologically determined and 169 individuals were identified as R. sanguineus. A subset of 15 ticks was selected for molecular analysis (16S rDNA, 12S rDNA, COI). Phylogenetic analyses invariably placed sequences of all three markers into a single haplotype identified as R. sanguineus sensu stricto. All 169 brown dog ticks were tested for the presence of A. platys, E. canis, R. conorii, B. vogeli and H. canis. None of the investigated ticks was positive for the screened pathogens, though A. phagocytophilum sequence was detected in a single tick.

A case of tick-borne Yezo virus infection: Concurrent detection in the patient and tick.

A 76-year-old woman infected with Yezo virus (YEZV) developed liver dysfunction and thrombocytopenia following a tick bite. Despite the severity of her elevated liver enzymes and reduced platelet counts, the patient's condition improved spontaneously without any specific treatment. To our knowledge, this represents the first documented case where the YEZV genome was detected simultaneously in a patient's serum and the tick (Ixodes persulcatus) that bit the patient. This dual detection not only supports the hypothesis that YEZV is a tick-borne pathogen but also underscores the importance of awareness and diagnostic readiness for emerging tick-borne diseases, particularly in regions where these ticks are prevalent.

Accounting for missing ticks: Use (or lack thereof) of hierarchical models in tick ecology studies.

Ixodid (hard) ticks play important ecosystem roles and have significant impacts on animal and human health via tick-borne diseases and physiological stress from parasitism. Tick occurrence, abundance, activity, and key life-history traits are highly influenced by host availability, weather, microclimate, and landscape features. As such, changes in the environment can have profound impacts on ticks, their hosts, and the spread of diseases. Researchers recognize that spatial and temporal factors influence activity and abundance and attempt to account for both by conducting replicate sampling bouts spread over the tick questing period. However, common field methods notoriously underestimate abundance, and it is unclear how (or if) tick studies model the confounding effects of factors influencing activity and abundance. This step is critical as unaccounted variance in detection can lead to biased estimates of occurrence and abundance. We performed a descriptive review to evaluate the extent to which studies account for the detection process while modeling tick data. We also categorized the types of analyses that are commonly used to model tick data. We used hierarchical models (HMs) that account for imperfect detection to analyze simulated and empirical tick data, demonstrating that inference is muddled when detection probability is not accounted for in the modeling process. Our review indicates that only 5 of 412 (1 %) papers explicitly accounted for imperfect detection while modeling ticks. By comparing HMs with the most common approaches used for modeling tick data (e.g., ANOVA), we show that population estimates are biased low for simulated and empirical data when using non-HMs, and that confounding occurs due to not explicitly modeling factors that influenced both detection and abundance. Our review and analysis of simulated and empirical data shows that it is important to account for our ability to detect ticks using field methods with imperfect detection. Not doing so leads to biased estimates of occurrence and abundance which could complicate our understanding of parasite-host relationships and the spread of tick-borne diseases. We highlight the resources available for learning HM approaches and applying them to analyzing tick data.

A next generation sequencing assay combining Ixodes species identification with pathogen detection to support tick surveillance efforts in the United States.

The burden of tick-borne diseases continues to increase in the United States. Tick surveillance has been implemented to monitor changes in the distribution and prevalence of human disease-causing pathogens in ticks that frequently bite humans. Such efforts require accurate identification of ticks to species and highly sensitive and specific assays that can detect and differentiate pathogens from genetically similar microbes in ticks that have not been demonstrated to be pathogenic in humans. We describe a modification to a next generation sequencing pathogen detection assay that includes a target that accurately identifies Ixodes ticks to species. We show that the replacement of internal control primers used to ensure assay performance with primers that also act as an internal control and can additionally differentiate tick species, retains high sensitivity and specificity, improves efficiency, and reduces costs by eliminating the need to run separate assays to screen for pathogens and for tick identification.

Novel clades of tick-borne pathogenic nairoviruses in Europe.

Members of the Orthonairovirus genus (family Nairoviridae) include many tick-borne viruses of significant human and animal health impact, with several recently-documented pathogenic viruses lacking sufficient epidemiological information. We screened 215 adult ticks of seven species collected in Bulgaria, Georgia, Latvia and Poland for orthonairoviruses, followed by nanopore sequencing (NS) for genome characterization. Initial generic amplification revealed Sulina virus (SULV, Orthonairovirus sulinaense), for which an updated amplification assay was used, revealing an overall prevalence of 2.7% in Ixodes ricinus ticks from Latvia. Three complete and additional partial SULV genomes were generated, that consistently formed a separate, distinct clade with further intragroup divergence in the maximum likelihood analyses. Comparisons with previously described viruses from Romania exhibited similar genome topologies, albeit with divergent motifs and cleavage sites on the glycoprotein precursor. Preliminary evidence of recombination involving the S segment was documented, in addition to variations in predicted viral glycoproteins. Generic screening further identified Tacheng tick virus 1 (TCTV1, Orthonairovirus tachengense), with documented human infections, in Dermacentor reticulatus ticks from Poland, with a prevalence of 0.9%. Subsequent NS and assembly provided the first complete TCTV1 genome outside of China, where it was originally described. Phylogenetic analysis of virus genome segments revealed TCTV1-Poland as a discrete taxon within the TCTV1 cluster in the Orthonairovirus genus, representing a geographically segregated clade. Comparable genome topology with TCTV1 from China was observed, aside from minor variations in the M segment. Similar to SULV, TCTV1 exhibited several mismatches on previously described screening primer binding sites, likely to prevent amplification. These findings indicate presence of novel TCTV1 and SULV clades in Eastern Europe, confirming the expansion of orthonairoviruses with pathogenic potential.

Ticks - public health risks in urban green spaces.

BACKGROUND: Urban green spaces are important for human health, but they may expose visitors to tick-borne diseases. This not only presents a potential public health challenge but also undermines the expected public health gains from urban green spaces. The aim of this study is to assess the public health risk of tick-borne diseases in an urban green space used for recreation in Stockholm, Sweden. METHODS: We used a mixed method approach identifying both the magnitude of the tick hazard and the extent of the human exposure to tick-borne diseases. At six entry points to an urban green space, we sampled ticks and documented microhabitat conditions from five randomly assigned 2 m × 2 m plots. Surrounding habitat data was analyzed using geographical information system (GIS). Nymphs and adult ticks were tested for Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum using TaqMan qPCR. Positive B. burgdorferi (s.l.) ticks were further analyzed by nested PCR amplification and sequence analysis. Population census data and visitor count data were used to estimate the degree of human exposure to tick-borne diseases. To further understand the degree to which visitors get in contact with infected ticks we also conducted interviews with visitors to green spaces. RESULTS: High tick densities were commonly found in humid broadleaved forest with low field vegetation. High pathogen prevalence was significantly correlated with increasing proportions of artificial areas. Integrating the tick hazard with human exposure we found that the public health risk of tick-borne diseases was moderate to high at most of the studied entry points. Many of the visitors frequently used urban green spaces. Walking was the most common activity, but visitors also engaged in activities with higher risk for tick encounters. Individual protective measures were connected to specific recreational activities such as picking berries or mushrooms. CONCLUSIONS: The number of visitors can be combined with tick inventory data and molecular analyses of pathogen prevalence to make crude estimations of the public health risk of tick-borne diseases in urban green spaces. The risk of encountering infected ticks is omnipresent during recreational activities in urban green spaces, highlighting the need for public health campaigns to reduce the risk of tick-borne diseases.

Italian peninsula as a hybridization zone of Ixodes inopinatus and I. ricinus and the prevalence of tick-borne pathogens in I. inopinatus, I. ricinus, and their hybrids.

BACKGROUND: Ixodes inopinatus was described from Spain on the basis of morphology and partial sequencing of 16S ribosomal DNA. However, several studies suggested that morphological differences between I. inopinatus and Ixodes ricinus are minimal and that 16S rDNA lacks the power to distinguish the two species. Furthermore, nuclear and mitochondrial markers indicated evidence of hybridization between I. inopinatus and I. ricinus. In this study, we tested our hypothesis on tick dispersal from North Africa to Southern Europe and determined the prevalence of selected tick-borne pathogens (TBPs) in I. inopinatus, I. ricinus, and their hybrids. METHODS: Ticks were collected in Italy and Algeria by flagging, identified by sequencing of partial TROSPA and COI genes, and screened for Borrelia burgdorferi s.l., B. miyamotoi, Rickettsia spp., and Anaplasma phagocytophilum by polymerase chain reaction and sequencing of specific markers. RESULTS: Out of the 380 ticks, in Italy, 92 were I. ricinus, 3 were I. inopinatus, and 136 were hybrids of the two species. All 149 ticks from Algeria were I. inopinatus. Overall, 60% of ticks were positive for at least one TBP. Borrelia burgdorferi s.l. was detected in 19.5% of ticks, and it was significantly more prevalent in Ixodes ticks from Algeria than in ticks from Italy. Prevalence of Rickettsia spotted fever group (SFG) was 51.1%, with significantly greater prevalence in ticks from Algeria than in ticks from Italy. Borrelia miyamotoi and A. phagocytophilum were detected in low prevalence (0.9% and 5.2%, respectively) and only in ticks from Italy. CONCLUSIONS: This study indicates that I. inopinatus is a dominant species in Algeria, while I. ricinus and hybrids were common in Italy. The higher prevalence of B. burgdorferi s.l. and Rickettsia SFG in I. inopinatus compared with that in I. ricinus might be due to geographical and ecological differences between these two tick species. The role of I. inopinatus in the epidemiology of TBPs needs further investigation in the Mediterranean Basin.