Project description:The objective of this study was to evaluate the diversity and prevalence of tick-borne protists in the Republic of Korea via DNA barcoding using 18S rRNA gene fragments and PCR. Between 2021 and 2022, questing ticks were collected using the flagging method, with a total of 13,375 ticks collected and pooled into 1003 samples. Of these, 50 tick pools were selected for DNA barcoding targeting the V4 and V9 regions of 18S rRNA using the MiSeq platform. A taxonomic analysis of the amplicon sequence variants identified three genera of protozoa, namely Hepatozoon canis, Theileria luwenshuni, and Gregarine sp. However, the number and abundance of protists detected were different depending on the primer sets, and T. gondii was not identified in DNA barcoding. Furthermore, conventional PCR confirmed the presence of H. canis, Toxoplasma gondii, T. luwenshuni, and Theileria sp. in the collected ticks. This study identified H. canis and T. gondii in Ixodes nipponensis for the first time. It demonstrated that the results of DNA barcoding using 18S rRNA gene fragments can vary depending on the primer sets and further optimization is required for library construction to identify tick-borne protists in ticks. Despite these limitations, the findings highlight the potential of DNA barcoding using 18S rRNA gene fragments for screening the diversity of tick-borne protists in ticks.
Project description:Ticks are important vectors of various pathogens that result in clinical illnesses in humans and domestic and wild animals. Information regarding tick infestations and pathogens transmitted by ticks is important for the identification and prevention of disease. This study was a large-scale investigation of ticks collected from dogs and their associated environments in the Republic of Korea (ROK). It included detecting six prevalent tick-borne pathogens (Anaplasma spp., A. platys, Borrelia spp., Babesia gibsoni, Ehrlichia canis, and E. chaffeensis). A total of 2293 ticks (1110 pools) were collected. Haemaphysalis longicornis (98.60%) was the most frequently collected tick species, followed by Ixodes nipponensis (0.96%) and H. flava (0.44%). Anaplasma spp. (24/1110 tick pools; 2.16%) and Borrelia spp. (4/1110 tick pools; 0.36%) were detected. The phylogenetic analyses using 16S rRNA genes revealed that the Anaplasma spp. detected in this study were closely associated with A. phagocytophilum reported in humans and rodents in the ROK. Borrelia spp. showed phylogenetic relationships with B. theileri and B. miyamotoi in ticks and humans in Mali and Russia. These results demonstrate the importance of tick-borne disease surveillance and control in dogs in the ROK.
Project description:ObjectivesIn this study, we demonstrated that TBEV-infected ticks have been distributed in the ROK, combined with our previous results. These results suggest that TBEV may exist in the ROK, and H. longicornis, H. flava, and I. nipponensis may be potential vectors of TBEV. In addition, these results emphasize the need for further epidemiological research of TBEV.MethodsWe examined for the presence of RNA of TBEV by reverse transcriptase-nested polymerase chain reaction (RT-nested PCR) using ixodid ticks captured in 25 localities of 10 provinces. Ticks were collected by the flagging and dragging method or using sentinel BG traps at forests, grass thickets, and grassland. A total of 13,053 ticks belonging to two genera and four species were collected and pooled (1292 pools), according to collection site, species of tick, and developmental stage.ResultsAmong 1292 pools, the envelope (E) protein gene of TBEV was detected using RT-nested PCR in 10 pools (3 pools of the 1,331 adult ticks and 7 pools of the 11,169 nymph ticks) collected from Gangwon-do province, Jeonrabuk-do province, and Jeju Island. The minimum infection rates for TBEV of Haemaphysalis longicornis, Haemaphysalis flava, and Ixodes nipponensis were 0.06%, 0.17%, and 2.38%, respectively. Phylogenetic analysis based on the partial E protein gene was performed to identify relationships between the TBEV strains. This showed that 10 Korean strains clustered with the Western subtype.ConclusionIn this study, we investigated the prevalence of tick-borne encephalitis virus (TBEV) in ixodid ticks from various regions of the Republic of Korea (ROK) during 2011-2012 to identify whether TBEV is circulating and to determine the endemic regions of TBEV.
Project description:In this study, we investigated the presence of tick-borne pathogens in ticks removed from tick-bitten humans in the southwestern provinces of the Republic of Korea (ROK). We identified 33 ticks from three tick species, namely Amblyomma testudinarium (60.6%), Haemaphysalis longicornis (27.3%), and Ixodes nipponensis (12.1%) in order of occurrence via morphology and 16S rDNA-targeting polymerase chain reaction (PCR). Tick-borne pathogens were detected in 16 ticks using pathogen-specific PCR. From the results, 12 ticks (36.4%) tested positive for spotted fever group (SFG) Rickettsia: Rickettsia monacensis (1/12), R. tamurae (8/12), and Candidatus Rickettsia jingxinensis (3/12). Three ticks (9.1%) were positive for Anaplasma phagocytophilum. In addition, three ticks (9.1%) tested positive for Babesia gibsoni (1/3) and B. microti (2/3). In conclusion, we identified three tick species; the most common species was A. testudinarium, followed by H. longicornis and I. nipponensis. SFG Rickettsia, A. phagocytophilum, and Babesia spp. were the most frequently detected pathogens in ticks removed from tick-bitten humans. To our knowledge, this is the first report of R. tamurae and Ca. R. jingxinensis detection in Korea. The present results will contribute to the understanding of tick-borne infections in animals and humans in the ROK.
Project description:The horse industry has grown rapidly as a leisure industry in the Republic of Korea (ROK) in parallel with an increased demand for equestrian activities. As a result, there has been an increase in horse breeding and equestrian population and potential exposure to ticks and their associated pathogens. To provide a better understanding of the potential disease risks of veterinary and medical importance, a study was conducted to determine the geographical distribution and diversity of ticks collected from horses and vegetation associated with horse racetracks/ranches throughout the ROK. This included a survey of five associated common pathogens, Anaplasma phagocytophilum, Ehrlichia chaffeensis, Borrelia spp., Babesia caballi, and Theileria equi. A total 9220 ticks were collected from horses and associated pastures. Ticks were identified to species, stage of development, and sex. Two species of ticks, Haemaphysalis longicornis (99.9%) and Ixodes nipponensis (0.1%) were identified. Two of the target pathogens, A. phagocytophilum and Borrelia spp., were detected in 5/1409 tick pools (0.35%) and 4/1409 pools (0.28%) of H. longicornis, respectively, both of which are zoonotic pathogens of medical importance. The results of 16S rRNA phylogenetic analysis of A. phagocytophilum showed a close relationship to strains distributed in China, USA, Germany, Italy, Turkey, and Poland. Borrelia spp. showed a close relationship, based on 16S rRNA gene, to the strains reported from the USA (B. burgdorferi and B. americana) and Japan (B. tanukii and B. garinii). These results provide information about the potential risks of veterinary and medical importance and the development of mitigation strategies for disease prevention.
Project description:In order to investigate the prevalence of tick-borne infectious agents among ticks, ticks comprising five species from two genera (Hemaphysalis spp. and Ixodes spp.) were screened using molecular techniques. Ticks (3,135) were collected from small wild-caught mammals or by dragging/flagging in the Republic of Korea (ROK) and were pooled into a total of 1,638 samples (1 to 27 ticks per pool). From the 1,638 tick samples, species-specific fragments of Anaplasma phagocytophilum (1 sample), Anaplasma platys (52 samples), Ehrlichia chaffeensis (29 samples), Ehrlichia ewingii (2 samples), Ehrlichia canis (18 samples), and Rickettsia rickettsii (28 samples) were amplified by PCR assay. Twenty-one pooled and individual tick samples had mixed infections of two (15 samples) or three (6 samples) pathogens. In addition, 424 spleen samples from small captured mammals (389 rodents, 33 insectivores, and 2 weasels) were screened for selected zoonotic pathogens. Species-specific DNA fragments of A. phagocytophilum (110 samples), A. platys (68 samples), E. chaffeensis (8 samples), E. ewingii (26 samples), E. canis (51 samples), and Rickettsia sp. (22 samples) were amplified by PCR assay. One hundred thirty small mammals had single infections, while 4, 14, and 21 striped field mice (Apodemus agrarius) had mixed infections of four, three, and two pathogens, respectively. Phylogenetic analysis based on nucleotide sequence comparison also revealed that Korean strains of E. chaffeensis clustered closely with those from China and the United States, while the Rickettsia (rOmpA) sequences clustered within a clade together with a Chinese strain. These results suggest that these agents should be considered in differential diagnosis while examining cases of acute febrile illnesses in humans as well as animals in the ROK.
Project description:The prevalence of tick-borne encephalitis virus (TBEV) in southern Korea was determined by collecting ticks using tick drags. A total of 4,077 of 6,788 ticks collected were pooled (649 pools) according to collection site, species, and developmental stage and assayed for TBEV. The TBEV protein E and NS5 gene fragments were detected using RT-nested PCR in six pools of nymphs collected from Jeju Island (2,491 ticks). The minimum field detection rates for TBEV were 0.17% and 0.14% for Haemaphysalis longicornis and Haemayphysalis. flava nymphs, respectively. The 252 bp NS5 and 477 bp protein E gene amplicons were sequenced. Phylogenetic analysis showed that the NS5 and protein E genes of the Jeju strain were clustered with Western subtype (98.0% and 99.4% identity, respectively). The Western subtype of TBEV is endemic in Korea, including Jeju Island. The study of vector and zoonotic host susceptibility to TBEV is required to better understand its potential impact on public health.
Project description:BackgroundThe importance of tick-borne diseases is increasing all over the world, including Turkey. The tick-borne disease outbreaks reported in recent years and the abundance of tick species and the existence of suitable habitats increase the importance of studies related to the epidemiology of ticks and tick-borne pathogens in Turkey. The aim of this study was to investigate the presence of and to determine the infection rates of some tick-borne pathogens, including Babesia spp., Borrelia burgdorferi sensu lato and spotted fever group rickettsiae in the ticks removed from humans in different parts of Ankara.Methodology/principal findingsA total of 169 ticks belonging to the genus Haemaphysalis, Hyalomma, Ixodes and Rhipicephalus were collected by removing from humans in different parts of Ankara. Ticks were molecularly screened for Babesia spp., Borrelia burgdorferi sensu lato and spotted fever group rickettsiae by PCR and sequencing analysis. We detected 4 Babesia spp.; B. crassa, B. major, B. occultans and B. rossi, one Borrelia spp.; B. burgdorferi sensu stricto and 3 spotted fever group rickettsiae; R. aeschlimannii, R. slovaca and R. hoogstraalii in the tick specimens analyzed. This is the report showing the presence of B. rossi in a region that is out of Africa and in the host species Ha. parva. In addition, B. crassa, for which limited information is available on its distribution and vector species, and B. occultans, for which no conclusive information is available on its presence in Turkey, were identified in Ha. parva and H. marginatum, respectively. Two human pathogenic rickettsia species (R. aeschlimannii and R. slovaca) were detected with a high prevalence in ticks. Additionally, B. burgdorferi sensu stricto was detected in unusual tick species (H. marginatum, H. excavatum, Hyalomma spp. (nymph) and Ha. parva).Conclusions/significanceThis study investigates both the distribution of several tick-borne pathogens affecting humans and animals, and the presence of new tick-borne pathogens in Turkey. More epidemiological studies are warranted for B. rossi, which is very pathogenic for dogs, because the presented results suggest that B. rossi might have a wide distribution in Turkey. Furthermore, we recommend that tick-borne pathogens, especially R. aeschlimannii, R. slovaca, and B. burgdorferi sensu stricto, should be taken into consideration in patients who had a tick bite in Turkey.
Project description:BackgroundTicks (order Ixodida) are ectoparasites, vectors and reservoirs of many infectious agents affecting humans and domestic animals. However, the lack of information on tick genomic diversity leaves significant gaps in the understanding of the evolution of ticks and associated bacteria.ResultsWe collected > 20,000 contemporary and historical (up to 60 years of preservation) tick samples representing a wide range of tick biodiversity across diverse geographic regions in China. Metagenomic sequencing was performed on individual ticks to obtain the complete or near-complete mitochondrial (mt) genome sequences from 46 tick species, among which mitochondrial genomes of 23 species were recovered for the first time. These new mt genomes data greatly expanded the diversity of many tick groups and revealed five cryptic species. Utilizing the same metagenomic sequence data we identified divergent and abundant bacteria in Haemaphysalis, Ixodes, Dermacentor and Carios ticks, including nine species of pathogenetic bacteria and potentially new species within the genus Borrelia. We also used these data to explore the evolutionary relationship between ticks and their associated bacteria, revealing a pattern of long-term co-divergence relationship between ticks and Rickettsia and Coxiella bacteria.ConclusionsIn sum, our study provides important new information on the genetic diversity of ticks based on an analysis of mitochondrial DNA as well as on the prevalence of tick-borne pathogens in China. It also sheds new light on the long-term evolutionary and ecological relationships between ticks and their associated bacteria.
Project description:BackgroundThe composition of the microbial flora associated with ixodid ticks has been studied in several species, revealing the importance of geographical origin, developmental stage(s) and feeding status of the tick, as well as substantial differences between tissues and organs. Studying the microbiome in the correct context and scale is therefore necessary for understanding the interactions between tick-borne pathogens and other microorganisms as well as other aspects of tick biology.MethodsIn the present study the microbial flora of whole Ixodes ricinus, I. persulcatus and I. trianguliceps ticks were analyzed with 16S rRNA amplicon sequencing. Additionally, tick organs (midguts, Malpighian tubules, ovaries, salivary glands) from flat and engorged I. ricinus female ticks were examined with the same methodology.ResultsThe most abundant bacteria belonged to the group of Proteobacteria (Cand. Midichloria mitochondrii and Cand. Lariskella). 16S amplicon sequencing of dissected tick organs provided more information on the diversity of I. ricinus-associated microbial flora, especially when organs were collected from engorged ticks. Bacterial genera significantly associated with tick feeding status as well as genera associated with the presence of tick-borne pathogens were identified.ConclusionsThese results contribute to the knowledge of microbial flora associated with ixodid ticks in their northernmost distribution limit in Europe and opens new perspectives for other investigations on the function of these bacteria, including those using other approaches like in vitro cultivation and in vitro models.