Relapsing fever spirochete in seabird tick, Japan.
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ABSTRACT:
SUBMITTER: Takano A
PROVIDER: S-EPMC2819885 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:During 2012-2013, a total of 4325 host-seeking adult ticks belonging to the genus Ixodes were collected from various localities of Hokkaido, the northernmost island of Japan. Tick lysates were subjected to real-time PCR assay to detect borrelial infection. The assay was designed for specific detection of the Relapsing fever spirochete Borrelia miyamotoi and for unspecific detection of Lyme disease-related spirochetes. Overall prevalence of B. miyamotoi was 2% (71/3532) in Ixodes persulcatus, 4.3% (5/117) in Ixodes pavlovskyi and 0.1% (1/676) in Ixodes ovatus. The prevalence in I. persulcatus and I. pavlovskyi ticks were significantly higher than in I. ovatus. Co-infections with Lyme disease-related spirochetes were found in all of the tick species. During this investigation, we obtained 6 isolates of B. miyamotoi from I. persulcatus and I. pavlovskyi by culture in BSK-M medium. Phylogenetic trees of B. miyamotoi inferred from each of 3 housekeeping genes (glpQ, 16S rDNA, and flaB) demonstrated that the Hokkaido isolates were clustered with Russian B. miyamotoi, but were distinguishable from North American and European B. miyamotoi. A multilocus sequence analysis using 8 genes (clpA, clpX, nifS, pepX, pyrG, recG, rplB, and uvrA) suggested that all Japanese B. miyamotoi isolates, including past isolates, were genetically clonal, although these were isolated from different tick and vertebrate sources. From these results, B. miyamotoi-infected ticks are widely distributed throughout Hokkaido. Female I. persulcatus are responsible for most human tick-bites, thereby I. persulcatus is likely the most important vector of indigenous relapsing fever from tick bites in Hokkaido.
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Project description:Borrelia miyamotoi is a relapsing fever spirochete that shares the same vector as Lyme disease causing Borrelia. This epidemiological study of B. miyamotoi was conducted in rodent reservoirs, tick vectors and human populations simultaneously. A total of 640 rodents and 43 ticks were collected from Phop Phra district, Tak province, Thailand. The prevalence rate for all Borrelia species was 2.3% and for B. miyamotoi was 1.1% in the rodent population, while the prevalence rate was quite high in ticks collected from rodents with an infection rate of 14.5% (95% CI: 6.3-27.6%). Borrelia miyamotoi was detected in Ixodes granulatus collected from Mus caroli and Berylmys bowersi, and was also detected in several rodent species (Bandicota indica, Mus spp., and Leopoldamys sabanus) that live in a cultivated land, increasing the risk of human exposure. Phylogenetic analysis revealed that the B. miyamotoi isolates detected in rodents and I. granulatus ticks in this study were similar to isolates detected in European countries. Further investigation was conducted to determine the serological reactivity to B. miyamotoi in human samples received from Phop Phra hospital, Tak province and in rodents captured from Phop Phra district using an in-house, direct enzyme-linked immunosorbent assay (ELISA) assay with B. miyamotoi recombinant glycerophosphodiester-phosphodiesterase (rGlpQ) protein as coated antigen. The results showed that 17.9% (15/84) of human patients and 9.0% (41/456) of captured rodents had serological reactivity to B. miyamotoi rGlpQ protein in the study area. While a low level of IgG antibody titers (100-200) was observed in the majority of seroreactive samples, higher titers (400-1,600) were also detected in both humans and rodents. This study provides the first evidence of B. miyamotoi exposure in human and rodent populations in Thailand and the possible roles of local rodent species and Ixodes granulatus tick in its enzootic transmission cycle in nature.
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Project description:Borrelia turicatae is a causative agent of tick-borne relapsing fever (TBRF) in the subtropics and tropics of the United States and Latin America. Historically, B. turicatae was thought to be maintained in enzootic cycles in rural areas. However, there is growing evidence that suggests the pathogen has established endemic foci in densely populated regions of Texas. With the growth of homelessness in the state and human activity in city parks, it was important to implement field collection efforts to identify areas where B. turicatae and its vector circulate. Between 2017 and 2020 we collected Ornithodoros turicata ticks in suburban and urban areas including public and private parks and recreational spaces. Ticks were fed on naïve mice and spirochetes were isolated from the blood. Multilocus sequence typing (MLST) was performed on eight newly obtained isolates and included previously reported sequences. The four chromosomal loci targeted for MLST were 16S ribosomal RNA (rrs), flagellin B (flaB), DNA gyrase B (gyrB), and the intergenic spacer (IGS). Given the complexity of Borrelia genomes, plasmid diversity was also evaluated. These studies indicate that the IGS locus segregates B. turicatae into four genomic types and plasmid diversity is extensive between isolates. Furthermore, B. turicatae and its vector have established endemic foci in parks and recreational areas in densely populated settings of Texas.
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Project description:Direct amplification and sequencing of the 16S rRNA gene and a variable region of the flagellin gene from fetal liver-associated spirochetes belonging to the Borrelia parkeri-B. turicatae tick-borne relapsing fever spirochete group with a late-term abortion in a mare are described.
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Project description:Vector competence refers to the ability of an arthropod to acquire, maintain, and successfully transmit a microbial pathogen. Tick-borne relapsing fever (TBRF) spirochetes are globally distributed pathogens, and most species are transmitted by argasid ticks of the genus Ornithodoros. A defining characteristic in vector competence is an apparent specificity of a species of TBRF spirochete to a given tick species. In arid regions of the southern United States, Borrelia turicatae is the primary cause of TBRF. Interestingly, there are two populations of the tick vector distributed throughout this region. Ornithodoros turicata is a western population that ranges from California to Texas. There is a gap through Louisiana, Mississippi, and Alabama where the tick has not been identified. An isolated eastern population exists in Florida and was designated a subspecies, O. turicata americanus. A knowledge gap that exists is the poor understanding of vector competence between western and eastern populations of ticks for B. turicatae. In this study, we generated uninfected colonies of O. turicata that originated in Texas and Kansas and of O. turicataamericanus. B. turicatae acquisition, maintenance through the molt, and subsequent transmission were evaluated. Our findings revealed significant differences in murine infection after feeding infected O. turicata and O. turicataamericanus ticks on the animals. Interestingly, the salivary glands of both tick populations were colonized with B. turicatae to similar densities. Our results suggest that the salivary glands of the tick colonies assessed in this study impact vector competence of the evaluated B. turicatae isolates.IMPORTANCE Several knowledge gaps exist in the vector competence of various geographical populations of O. turicata that transmit B. turicatae A western population of this tick is distributed from California to Texas, and an eastern population exists in Florida. Utilizing western and eastern populations of the vector, we studied acquisition and transmission of two B. turicatae isolates. Regardless of the isolate used, infection frequencies were poor in mice after the eastern population feeding on them. Since salivary gland colonization is essential for B. turicatae transmission, these tissues were further evaluated. Interestingly, the salivary glands from the two populations were similarly colonized with B. turicatae. These findings suggest the role of tick saliva in the establishment of infection and that the salivary glands may be a bottleneck for successful transmission.
| S-EPMC6193384 | biostudies-literature
Project description:Borrelia hermsii is the primary cause of tick-borne relapsing fever in North America. When its tick vector, Ornithodoros hermsi, acquires these spirochetes from the blood of an infected mammal, the bacteria switch their outer surface from one of many bloodstream variable major proteins (Vmps) to a unique protein, Vtp (Vsp33). Vtp may be critical for successful tick transmission of B. hermsii; however, the gene encoding this protein has been described previously in only one isolate. Here we identified and sequenced the vtp gene in 31 isolates of B. hermsii collected over 40 years from localities throughout much of its known geographic distribution. Seven major Vtp types were found. Little or no sequence variation existed within types, but between them significant variation was observed, similar to the pattern of diversity described for the outer surface protein C (OspC) gene in Lyme disease spirochetes. The pattern of sequence relatedness among the Vtp types was incongruent in two branches compared to two genomic groups identified among the isolates by multilocus sequence typing of the 16S rRNA, flaB, gyrB, and glpQ genes. Therefore, both horizontal transfer and recombination within and between the two genomic groups were responsible for some of the variation observed in the vtp gene. O. hermsi ticks were capable of transmitting spirochetes in the newly identified genomic group. Therefore, given the longevity of the tick vector and persistent infection of spirochetes in ticks, these arthropods rather than mammals may be the likely host where the exchange of spirochetal DNA occurs.
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Project description:The relapsing fever spirochete Borrelia turicatae possesses a complex life cycle in its soft-bodied tick vector, Ornithodoros turicata. Spirochetes enter the tick midgut during a blood meal, and, during the following weeks, spirochetes disseminate throughout O. turicata. A population persists in the salivary glands allowing for rapid transmission to the mammalian hosts during tick feeding. Little is known about the physiological environment within the salivary glands acini in which B. turicatae persists. In this study, we examined the salivary gland transcriptome of O. turicata ticks and detected the expression of 57 genes involved in oxidant metabolism or antioxidant defences. We confirmed the expression of five of the most highly expressed genes, including glutathione peroxidase (gpx), thioredoxin peroxidase (tpx), manganese superoxide dismutase (sod-1), copper-zinc superoxide dismutase (sod-2), and catalase (cat) by reverse-transcriptase droplet digital polymerase chain reaction (RT-ddPCR). We also found distinct differences in the expression of these genes when comparing the salivary glands and midguts of unfed O. turicata ticks. Our results indicate that the salivary glands of unfed O. turicata nymphs are highly oxidative environments where reactive oxygen species (ROS) predominate, whereas midgut tissues comprise a primarily nitrosative environment where nitric oxide synthase is highly expressed. Additionally, B. turicatae was found to be hyperresistant to ROS compared with the Lyme disease spirochete Borrelia burgdorferi, suggesting it is uniquely adapted to the highly oxidative environment of O. turicata salivary gland acini.
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Project description:Borrelia miyamotoi is distantly related to B. burgdorferi and transmitted by the same hard-body tick species. We report 46 cases of B. miyamotoi infection in humans and compare the frequency and clinical manifestations of this infection with those caused by B. garinii and B. burgdorferi infection. All 46 patients lived in Russia and had influenza-like illness with fever as high as 39.5°C; relapsing febrile illness occurred in 5 (11%) and erythema migrans in 4 (9%). In Russia, the rate of B. miyamotoi infection in Ixodes persulcatus ticks was 1%-16%, similar to rates in I. ricinus ticks in western Europe and I. scapularis ticks in the United States. B. miyamotoi infection may cause relapsing fever and Lyme disease-like symptoms throughout the Holarctic region of the world because of the widespread prevalence of this pathogen in its ixodid tick vectors.
| S-EPMC3310649 | biostudies-literature
Project description:In March 2017, a patient became febrile within 4 days after visiting a rustic conference center in Austin, Texas, USA, where Austin Public Health suspected an outbreak of tickborne relapsing fever a month earlier. Evaluation of a patient blood smear and molecular diagnostic assays identified Borrelia turicatae as the causative agent. We could not gain access to the property to collect ticks. Thus, we focused efforts at a nearby public park, <1 mile from the suspected exposure site. We trapped Ornithodoros turicata ticks from 2 locations in the park, and laboratory evaluation resulted in cultivation of 3 B. turicatae isolates. Multilocus sequencing of 3 chromosomal loci (flaB, rrs, and gyrB) indicated that the isolates were identical to those of B. turicatae 91E135 (a tick isolate) and BTE5EL (a human isolate). We identified the endemicity of O. turicata ticks and likely emergence of B. turicatae in this city.
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