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molecular characterization of a defensin gene from a hard tick, dermacentor silvarum.ticks are distributed worldwide and considered as vectors of many human diseases. tick defensins, a family of antimicrobial peptides, form the first line of defense against pathogens.201525588982
asymptomatic "candidatus neoehrlichia mikurensis" infections in immunocompetent humans.in europe, human infections with "candidatus neoehrlichia mikurensis" have mainly been restricted to immunocompromised patients. we report here the first cases of asymptomatic "ca. neoehrlichia mikurensis" infection in immunocompetent humans (5/316 [1.6%] were infected). due to the potential threats of infections with "ca. neoehrlichia mikurensis" in healthy persons to the safety of the blood supply, further study of this phenomenon is required.201424899023
survey of coxiella burnetii in ticks collected from dogs in japan.for a survey of coxiella burnetii, the q fever agent, ticks infesting companion dogs were collected in aomori, tochigi, gifu and okinawa prefectures, japan. a total of 261 ticks were collected, and their species were identified morphologically. five tick species were identified: ixodes ovatus, haemaphysalis concinna, h. flava, h. longicornis and rhipicephalus sanguineus. total dna was extracted from them individually followed by real-time pcr to detect a c. burnetii-specific gene. the results of ...201323558956
genetic diversity of theileria orientalis in tick vectors detected in hokkaido and okinawa, japan.in the present study, we investigated the possible tick vectors that can transmit theileria orientalis in eastern hokkaido, japan. questing ticks collected from three different districts, taiki, otofuke, and shin-hidaka, of hokkaido included ixodes persulcatus, haemaphysalis megaspinosa, haemaphysalis douglasi, and ixodes ovatus, while all the ticks collected from yonaguni island of okinawa were identified as haemaphysalis longicornis. when the ticks were screened by polymerase chain reaction (p ...201222824416
a nationwide survey of ixodid tick species recovered from domestic dogs and cats in japan in 2011.a nationwide survey of ixodid ticks was performed in 2011, during which a total of 4237 and 298 ticks were recovered from 1162 dogs and 136 cats, respectively. haemaphysalis longicornis was the most frequently found tick species on canine hosts (739 dogs), followed by h. flava (166), ixodes ovatus (139), and rhipicephalus sanguineus sensu lato (70). h. hystricis, h. japonica, h. megaspinosa, h. formosensis, h. campanulata, h. ias, i. nipponensis, i. persulcatus, and amblyomma testudinarium were ...201425155339
new species of ehrlichia isolated from rhipicephalus (boophilus) microplus shows an ortholog of the e. canis major immunogenic glycoprotein gp36 with a new sequence of tandem repeats.ehrlichia species are the etiological agents of emerging and life-threatening tick-borne human zoonoses that inflict serious and fatal infections in companion animals and livestock. the aim of this paper was to phylogeneticaly characterise a new species of ehrlichia isolated from rhipicephalus (boophilus) microplus from minas gerais, brazil.201223231731
detachment of hard ticks (acari: ixodidae) from hunted sika deer (cervus nippon).ixodid ticks were collected from 13 sika deer, cervus n.nippon, shot in the boso peninsula in central japan from late february to early march 1999. haemaphysalis megaspinosa was the most abundant species of the adults collected, although haemaphysalis longicornis, h. flava, h. kitaokai, h. cornigera, ixodes ovatus, and amblyomma testudinarium were also collected. males were more abundant than females for h. longicornis, h. megaspinosa, h. flava, and h. kitaokai. ticks that had inserted their hyp ...201424659518
type i interferon contributes to noncanonical inflammasome activation, mediates immunopathology, and impairs protective immunity during fatal infection with lipopolysaccharide-negative ehrlichiae.ehrlichia species are intracellular bacteria that cause fatal ehrlichiosis, mimicking toxic shock syndrome in humans and mice. virulent ehrlichiae induce inflammasome activation leading to caspase-1 cleavage and il-18 secretion, which contribute to development of fatal ehrlichiosis. we show that fatal infection triggers expression of inflammasome components, activates caspase-1 and caspase-11, and induces host-cell death and secretion of il-1β, il-1α, and type i interferon (ifn-i). wild-type and ...201425481711
early induction of interleukin-10 limits antigen-specific cd4⁺ t cell expansion, function, and secondary recall responses during persistent phagosomal infection.diverse pathogens have evolved to survive and replicate in the endosomes or phagosomes of the host cells and establish persistent infection. ehrlichiae are gram-negative, intracellular bacteria that are transmitted by ticks. ehrlichiae reside in the endosomes of the host phagocytic or endothelial cells and establish persistent infection in their vertebrate reservoir hosts. cd4(+) t cells play a critical role in protection against phagosomal infections. in the present study, we investigated the e ...201425024370
an animal model of a newly emerging human ehrlichiosis.human ehrlichioses are emerging life-threatening diseases transmitted by ticks. animal models have been developed to study disease development; however, there is no valid small animal model that uses a human ehrlichial pathogen. the objective of this study was to develop a mouse model for ehrlichiosis with the newly discovered human pathogen, ehrlichia muris-like agent (emla).201424990203
a molecular survey of babesia species and detection of a new babesia species by dna related to b. venatorum from white yaks in tianzhu, china.bovine babesiosis is a tick-transmitted disease caused by different species of babesia. the white yak is a unique yak breed that lives only in tianzhu in the tibetan autonomous county, gansu province, in northwestern china. previous research using the elisa method has confirmed that the white yak could become infected with b. bigemina. the objective of this study was the molecular detection and identification of babesia species in white yaks. a total of 409 white yak blood samples were collected ...201728352260
complete genome sequence of ehrlichia muris strain as145t, a model monocytotropic ehrlichia strain.we report here the complete genome sequence of ehrlichia muris strain as145(t), which was isolated from a wild mouse in 1983 in japan. e. muris establishes persistent infections in laboratory mice and is widely used as a surrogate pathogen in a murine model of ehrlichiosis.201424482514
the omentum is a site of protective igm production during intracellular bacterial infection.infection of mice with the bacterium ehrlichia muris elicits a protective t cell-independent (ti) igm response mediated primarily by a population of cd11c-expressing plasmablasts in the spleen. although splenic marginal zone (mz) b cells are considered to be important for ti responses to blood-borne pathogens, mz b cells were not responsible for generating plasmablasts in response to ehrlichia muris. moreover, antigen-specific serum igm was decreased only modestly in splenectomized mice and in m ...201525776744
the role of cd8 t lymphocytes in rickettsial infections.arthropod-borne obligately intracellular bacteria pose a difficult challenge to the immune system. the genera rickettsia, orientia, ehrlichia, and anaplasma evolved mechanisms of immune evasion, and each interacts differently with the immune system. the roles of cd8 t cells include protective immunity and immunopathology. in rickettsia infections, cd8 t cells are protective mediated in part by cytotoxicity toward infected cells. in contrast, tnf-α overproduction by cd8 t cells is pathogenic in l ...201525823954
ehrlichia chaffeensis uses its surface protein etpe to bind gpi-anchored protein dnase x and trigger entry into mammalian cells.ehrlichia chaffeensis, an obligatory intracellular rickettsial pathogen, enters and replicates in monocytes/macrophages and several non-phagocytic cells. e. chaffeensis entry into mammalian cells is essential not only for causing the emerging zoonosis, human monocytic ehrlichiosis, but also for its survival. it remains unclear if e. chaffeensis has evolved a specific surface protein that functions as an 'invasin' to mediate its entry. we report a novel entry triggering protein of ehrlichia, etpe ...201324098122
prevalence of lyme borrelia in ixodes persulcatus ticks from an area with a confirmed case of lyme disease.in this study, the prevalence of borrelia infections in ixodes ticks from a site in hokkaido, japan, with confirmed cases of lyme disease was determined by a pcr method capable of detecting and differentiating between strains of pathogenic borrelia, with particular emphasis on borrelia garinii (b. garinii) and borrelia afzelli (b. afzelli), using tick-derived dna extracts as template. a total of 338 ticks, inclusive of 284 ixodes persulcatus (i. persulcatus), were collected by flagging vegetatio ...201323047332
pcr detection of babesia ovata from questing ticks in japan.babesia ovata is a tick-transmitted hemoprotozoan parasite of cattle. in the present study, we analyzed tick dna samples (n=1459) prepared from questing ticks collected from various cattle pastures in hokkaido (shibecha, taiki, otofuke, memuro, and shin-hidaka districts) and okinawa (yonaguni island) prefectures of japan for b. ovata. when all the tick dna samples were screened by a previously described b. ovata-specific apical membrane antigen-1 (ama-1) gene-based polymerase chain reaction (pcr ...201424572609
detection of francisella tularensis and analysis of bacterial growth in ticks in japan.francisella tularensis is distributed in the northern hemisphere and it is the bacterial agent responsible for tularaemia, a zoonotic disease. we collected 4 527 samples of dna from ticks in japan, which were then analysed by real-time pcr and nested pcr. francisella dna was detected by real-time pcr in 2·15% (45/2 093) of ixodes ovatus, 0·66% (14/2 107) of i. persulcatus, 8·22% (6/73) of i. monospinosus and 0·72% (1/138) of haemaphysalis flava specimens. finally, francisella dna was detected by ...201627432517
tick surveillance for borrelia miyamotoi and phylogenetic analysis of isolates in mongolia and japan.borrelia miyamotoi, recently recognized as a human pathogenic spirochete, was isolated from ixodes persulcatus and i. ovatus in northern mongolia and honshu island, a major island in japan. although no human b. miyamotoi infections have been reported in mongolia, the prevalence of b. miyamotoi in ticks from mongolia is higher than that in ticks from hokkaido, japan, where human cases have been reported. moreover, the multi-locus sequence analysis of cultured isolates revealed that b. miyamotoi i ...201728768603
neutrophils mediate immunopathology and negatively regulate protective immune responses during fatal bacterial infection-induced toxic shock.ehrlichia chaffeensis is an obligate intracellular bacterium that infects primarily monocytes and macrophages and causes potentially fatal human monocytic ehrlichiosis (hme) that mimics toxic-shock-like syndrome in immunocompetent hosts. early recruitment of neutrophils to the sites of infection is critical for the control of bacterial infection and inflammatory responses. we recently observed rapid and sustained neutrophil recruitment at a primary site of infection (peritoneum) following lethal ...201323478316
tlr2 and nod2 mediate resistance or susceptibility to fatal intracellular ehrlichia infection in murine models of ehrlichiosis.our murine models of human monocytic ehrlichiosis (hme) have shown that severe and fatal ehrlichiosis is due to generation of pathogenic t cell responses causing immunopathology and multi-organ failure. however, the early events in the liver, the main site of infection, are not well understood. in this study, we examined the liver transcriptome during the course of lethal and nonlethal infections caused by ixodes ovatus ehrlichia and ehrlichia muris, respectively. on day 3 post-infection (p.i.), ...201323526993
a case of tick bite.a 30-year-old women suffered from right superior eyelid infestation of ixodes ovatus neumann, which was mechanically removed with forceps after application of benzine. no mouth parts were retained in the eyelid. removed mouth parts were examined by a scanning electron microscope. there were no complications except focal trichotylosis in the involved area. the mode of attachment of the tick to the host and the method of removal were discussed.19827154426
[identity of ixodes ovatus neumann, 1899 (acarina, ixodoidea)]. 200714152061
myd88-dependent inflammasome activation and autophagy inhibition contributes to ehrlichia-induced liver injury and toxic shock.severe hepatic inflammation is a common cause of acute liver injury following systemic infection with ehrlichia, obligate gram-negative intracellular bacteria that lack lipopolysaccharide (lps). we have previously shown that type i ifn (ifn-i) and inflammasome activation are key host-pathogenic mediators that promote excessive inflammation and liver damage following fatal ehrlichia infection. however, the underlying signals and mechanisms that regulate protective immunity and immunopathology dur ...201729049365
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