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  1. Fulltext The dynamics of the microbiome in Ixodidae are shaped by tick ontogeny and pathogens in Sarawak, Malaysian Borneo
    Lau ACC, Mohamed WMA, Nakao R, Onuma M, Qiu Y, Nakajima N, et al.
    Microb Genom, 2023 Feb;9(2).
    PMID: 36757789 DOI: 10.1099/mgen.0.000954
    Tick-borne diseases have recently been considered a potential emerging public health threat in Malaysia; however, fundamental studies into tick-borne pathogens and microbiome appear limited. In this study, six tick species (Ixodes granulatus, Haemaphysalis hystricis, Haemaphysalis shimoga, Dermacentor compactus, Dermacentor steini and Dermacentor atrosignatus) collected from two primary forests and an oil palm plantation in Sarawak, Malaysian Borneo, were used for microbiome analysis targeting bacterial 16S rDNA using next-generation sequencing (NGS). In addition, bacterial species were further characterized in conventional PCRs to identify potential pathogens. Sequences generated from NGS were first filtered with the Decontam package in R before subsequent microbial diversity analyses. Alpha and beta analyses revealed that the genus Dermacentor had the highest microbial diversity, and H. shimoga significantly differed in microbial composition from other tick species. Alpha and beta diversities were also significantly different between developmental stages of H. shimoga. Furthermore, we observed that some bacterial groups were significantly more abundant in certain tick species and developmental stages of H. shimoga. We tested the relative abundances using pairwise linear discriminant analysis effect size (LEfSe), which also revealed significant microbial composition differences between Borrelia-positive and Borrelia-negative I. granulatus ticks. Finally, pathogenic and potentially pathogenic bacteria circulating in different tick species, such as Rickettsia heilongjiangensis, Ehrlichia sp., Anaplasma sp. and Bartonella spp. were characterized by PCR and sequencing. Moreover, Coxiella and Francisella-like potential symbionts were identified from H. shimoga and D. steini, respectively. More studies are required to unravel the factors associated with the variations observed in this study.
    Matched MeSH terms: Ixodes*
  2. A checklist of the ticks of Malaysia (Acari: Argasidae, Ixodidae), with lists of known associated hosts, geographical distribution, type localities, human infestations and pathogens
    Kazim AR, Houssaini J, Tappe D, Heo CC
    Zootaxa, 2022 Sep 30;5190(4):485-530.
    PMID: 37045359 DOI: 10.11646/zootaxa.5190.4.2
    Studies of ticks in Malaysia from past articles were reviewed, resulting in a list of 47 species belonging to seven genera (Argas, Ornithodoros, Amblyomma, Dermacentor, Haemaphysalis, Ixodes, and Rhipicephalus). The most prevalent genus in Malaysia is Haemaphysalis (20 species), followed by Amblyomma (eight species) and Dermacentor (seven species). Out of 47 species, only 28 have bitten humans, mostly belonging to Haemaphysalis. The most researched tick-borne pathogens in Malaysia are Rickettsia and Anaplasma, and most research was focused on the tropical-lineage brown dog ticks, R. sanguineus sensu lato, and the cattle ticks, Haemaphysalis bispinosa and Rhipicephalus microplus. 18 species were excluded from the list due to lack of definite records or dubious findings: Ornithodoros mimon, O. turicata, Amblyomma breviscutatum, A. clypeolatum, A. integrum, A. maculatum, Dermacentor marginatum, D. taiwanensis, Haemaphysalis birmaniae, H. flava, H. humerosa, H. longicornis, H. punctata, H. sulcata, Ixodes holocyclus, Rhipicephalus appendiculatus, R. annulatus and R. bursa. This paper presents the first complete and updated list for Dermacentor and Ixodes tick species in Malaysia since Kohls (1957).
    Matched MeSH terms: Ixodes*
  3. Fulltext Natural Clerodendrum-derived tick repellent: learning from Nepali culture
    Mazuecos L, Contreras M, Kasaija PD, Manandhar P, Grąźlewska W, Guisantes-Batan E, et al.
    Exp Appl Acarol, 2023 Jun;90(1-2):83-98.
    PMID: 37285111 DOI: 10.1007/s10493-023-00804-4
    Ticks attaching to ear canals of humans and animals are the cause of otoacariasis, common in rural areas of Nepal. The plant Clerodendrum viscosum is used in multiple indigenous systems of medicine by ethnic communities in the Indo-Nepali-Malaysian region. Visiting the Chitwan National Park, we learned that in indigenous medicine, flower extract of C. viscosum is utilized to treat digestive disorders and extracts from leaves as tick repellent to prevent ticks from invading or to remove them from the ear canal. The objective of our study was to provide support to indigenous medicine by characterizing the in vivo effect of leave extracts on ticks under laboratory conditions and its phytochemical composition. We collected plant parts of C. viscosum (leaves and flowers) and mango (Mangifera indica) leaves at the Chitwan National Park, previously associated with repellent activity to characterize their effect on Ixodes ricinus ticks by in vivo bioassays. A Q-ToF high-resolution analysis (HPLC-ESI-QToF) was conducted to elucidate phenolic compounds with potential repellent activity. Clerodendrum viscosum and M. indica leaf extracts had the highest tick repellent efficacy (%E = 80-100%) with significant differences when compared to C. viscosum flowers extracts (%E = 20-60%) and phosphate-buffered saline. Phytochemicals with tick repellent function as caffeic acid, fumaric acid and p-coumaric acid glucoside were identified in C. viscosum leaf extracts by HPLC-ESI-QToF, but not in non-repellent flower extracts. These results support the Nepali indigenous medicine application of C. viscosum leaf extracts to repel ticks. Additional research is needed for the development of natural and green repellent formulations to reduce the risks associated with ticks resistant to acaricides.
    Matched MeSH terms: Ixodes*
  4. Fulltext Mini review: surveillance of Lyme borreliosis in Southeast Asia and method of diagnosis
    Teh KJ, Tang HY, Lim LS, Pung HS, Gan SY, Lai NS
    Eur Rev Med Pharmacol Sci, 2023 May;27(10):4378-4385.
    PMID: 37259718 DOI: 10.26355/eurrev_202305_32443
    Lyme borreliosis is caused by the Gram-negative spirochetes Borrelia spp., particularly Borrelia burgdorferi sensu lato complex. The disease is transmitted through the bite of the infected black-legged Ixodes tick. Lyme borreliosis extensively occurs in the Northern Hemisphere, mainly in the United States. Lyme borreliosis cases are also detected in Asian countries including Korea, Nepal, China, Taiwan, and Japan. However, there is an inadequate understanding of Lyme borreliosis in the Southeast Asian region. Hence, this review aims to provide a brief update on the prevalence of Lyme borreliosis infection in Southeast Asia based on the latest literature on this issue. Lyme borreliosis has been discovered in human serum in Indonesia, Malaysia, and Singapore. The human serum samples were mainly examined with ELISA test using Borrelia spp. IgG and IgM antigens. Borrelia spp. also has been detected in ticks found on host animals such as Sundamys muelleri and Python in Malaysia, Thailand, and Laos. Polymerase chain reaction (PCR) is used to detect the presence of Borrelia DNAs in the samples. The published studies have demonstrated that Borrelia spp. exists in Southeast Asia and although the incidence is relatively low, it is believed that Lyme disease cases are under-reported.
    Matched MeSH terms: Ixodes*
  5. Detection of a Borrelia sp. From Ixodes granulatus Ticks Collected From Rodents in Malaysia
    Khoo JJ, Ishak SN, Lim FS, Mohd-Taib FS, Khor CS, Loong SK, et al.
    J Med Entomol, 2018 10 25;55(6):1642-1647.
    PMID: 30137379 DOI: 10.1093/jme/tjy122
    The Borrelia genus consists of spirochete bacteria known to cause Lyme disease (LD) and relapsing fever in humans. Borrelia pathogens are commonly transmitted via arthropod vectors such as ticks, mites, or lice. Here, we report the molecular screening of LD group Borrelia sp. from ticks (Acari: Ixodidae) collected from rodents trapped in recreational forests and a semiurban residential area in the Selangor state in Malaysia. Of 156 adult ticks surveyed, 72 ticks were determined as positive for Borrelia sp. by polymerase chain reaction (PCR). All Borrelia PCR-positive ticks belonged to the Ixodes granulatus Supino species. Borrelia sp. was not detected in other tick species examined, including Dermacentor sp. and Amblyomma sp. ticks. Thirteen Borrelia PCR-positive tick samples were selected for further sequence analyses. Phylogenetic analyses of partial flaB gene sequences revealed that the Borrelia sp. were closely related to the LD group borreliae, Borrelia yangtzensis; a novel Borrelia genospecies reported in East Asian countries including Japan, Taiwan, and China. To our knowledge, this is the first report of Borrelia sp. related to Borrelia yangtzensis detected in Malaysia and Southeast Asia. The zoonotic potential of the Borrelia sp. reported here merits further investigation, as it may explain the previously reported serological evidence for borrelial infections in Malaysia.
    Matched MeSH terms: Ixodes/microbiology*
  6. Molecular analysis of Ixodes granulatus, a possible vector tick for Borrelia burgdorferi sensu lato in Taiwan
    Chao LL, Wu WJ, Shih CM
    Exp Appl Acarol, 2009 Aug;48(4):329-44.
    PMID: 19184580 DOI: 10.1007/s10493-009-9244-4
    The genetic identity of Ixodes granulatus ticks was determined for the first time in Taiwan. The phylogenetic relationships were analyzed by comparing the sequences of mitochondrial 16S ribosomal DNA gene obtained from 19 strains of ticks representing seven species of Ixodes and two outgroup species (Rhipicephalus sanguineus and Haemaphysalis inermis). Four major clades could be easily distinguished by neighbour-joining analysis and were congruent by maximum-parsimony method. All these I. granulatus ticks of Taiwan were genetically affiliated to a monophyletic group with highly homogeneous sequences (92.2-99.3% similarity), and can be discriminated from other Ixodes species and other genera of ticks with a sequence divergence ranging from 11.7 to 30.8%. Moreover, intraspecific analysis revealed that two distinct lineages are evident between the same species of I. granulatus ticks collected from Taiwan and Malaysia. Our results demonstrate that all these I. granulatus ticks of Taiwan represent a unique lineage distinct from the common vector ticks (I. ricinus complex) for Borrelia burgdorferi spirochetes.
    Matched MeSH terms: Ixodes/genetics*; Ixodes/microbiology; Ixodes/ultrastructure
  7. First report of Haemaphysalis bispinosa, molecular-geographic relationships of Ixodes granulatus and a new Dermacentor species from Vietnam
    Hornok S, Kontschán J, Keve G, Takács N, Van Nguyen D, Ho KNP, et al.
    Parasit Vectors, 2025 Jan 23;18(1):21.
    PMID: 39849649 DOI: 10.1186/s13071-024-06641-7
    BACKGROUND: Vietnam and its region are regarded as an ixodid tick biodiversity hotspot for at least two genera: Haemaphysalis and Dermacentor. To contribute to our knowledge on the tick fauna of this country, ticks from these two genera as well as an Ixodes species were analyzed morphologically and their molecular-phylogenetic relationships were examined in taxonomic and geographical contexts.

    METHODS: For this study, seven Haemaphysalis sp. ticks were removed from dogs and collected from the vegetation. These showed morphological differences from congeneric species known to occur in Vietnam. In addition, three Ixodes sp. ticks were collected from pygmy slow lorises (Xanthonycticebus pygmaeus), and a Dermacentor female had been previously collected from the vegetation. After DNA extraction, these were molecularly or phylogenetically analyzed based on the cytochrome c oxidase subunit I (cox1) and 16S rRNA genes.

    RESULTS: The three species were morphologically identified as (i) Ixodes granulatus, which had nearly or exactly 100% sequence identities to conspecific ticks reported from large (approximately 2000 km) geographical distances but was more different (having lower, only 94.2% cox1 and 96.7% 16S rRNA sequence identity) from samples collected within 1000 km of Vietnam in Southern China and Malaysia, respectively; (ii) Haemaphysalis bispinosa, which showed 100% sequence identity to samples reported within both narrow and broad geographical ranges; and (iii) a new species, Dermacentor pseudotamokensis Hornok sp. nov., described here morphologically and shown to be phylogenetically a sister species to Dermacentor tamokensis.

    CONCLUSIONS: Haemaphysalis bispinosa shows genetic homogeneity in the whole of South and Southeast Asia, probably owing to its frequent association with domestic ruminants and dogs (i.e. frequently transported hosts). However, I. granulatus, the Asian rodent tick, has a mixed geographical pattern of haplotypes, probably because it may associate with either synanthropic or wild-living rodents as primary hosts. This tick species is recorded here, for the first time to our knowledge, as parasitizing lorises in Vietnam and its region. Based on phylogenetic analyses, D. pseudotamokensis Hornok sp. nov., recognized and described here for the first time, was almost certainly misidentified previously as Dermacentor steini, drawing attention to the need to barcode all Dermacentor spp. in Southern Asia.

    Matched MeSH terms: Ixodes/anatomy & histology; Ixodes/classification; Ixodes/genetics
  8. Fulltext Isolation and Characterization of a Novel Pathogenic Strain of Ehrlichia minasensis
    Moura de Aguiar D, Pessoa Araújo Junior J, Nakazato L, Bard E, Aguilar-Bultet L, Vorimore F, et al.
    Microorganisms, 2019 Nov 05;7(11).
    PMID: 31694172 DOI: 10.3390/microorganisms7110528
    The genus Ehrlichia is composed of tick-borne obligate intracellular gram-negative alphaproteobacteria of the family Anaplasmataceae. Ehrlichia includes important pathogens affecting canids (E. canis, E. chaffeensis, and E. ewingii), rodents (E. muris), and ruminants (E. ruminantium). Ehrlichiaminasensis, an Ehrlichia closely related to E. canis, was initially reported in Canada and Brazil. This bacterium has now been reported in Pakistan, Malaysia, China, Ethiopia, South Africa, and the Mediterranean island of Corsica, suggesting that E. minasensis has a wide geographical distribution. Previously, E. minasensis was found to cause clinical ehrlichiosis in an experimentally infected calf. The type strain E. minasensis UFMG-EV was successfully isolated from Rhipicephalus microplus ticks and propagated in the tick embryonic cell line of Ixodes scapularis (IDE8). However, the isolation and propagation of E. minasensis strains from cattle has remained elusive. In this study, the E. minasensis strain Cuiabá was isolated from an eight-month-old male calf of Holstein breed that was naturally infected with the bacterium. The calf presented clinical signs and hematological parameters of bovine ehrlichiosis. The in vitro culture of the agent was established in the canine cell line DH82. Ehrlichial morulae were observed using light and electron microscopy within DH82 cells. Total DNA was extracted, and the full genome of the E. minasensis strain Cuiabá was sequenced. A core-genome-based phylogenetic tree of Ehrlichia spp. and Anaplasma spp. confirmed that E. minasensis is a sister taxa of E. canis. A comparison of functional categories among Ehrlichia showed that E. minasensis has significantly less genes in the 'clustering-based subsystems' category, which includes functionally coupled genes for which the functional attributes are not well understood. Results strongly suggest that E. minasensis is a novel pathogen infecting cattle. The epidemiology of this Ehrlichia deserves further attention because these bacteria could be an overlooked cause of tick-borne bovine ehrlichiosis, with a wide distribution.
    Matched MeSH terms: Ixodes
  9. Fulltext Cerebral glucose hypometabolism in Tick-Borne Encephalitis, a pilot study in 10 Patients
    Dietmann A, Putzer D, Beer R, Helbok R, Pfausler B, Nordin AJ, et al.
    Int J Infect Dis, 2016 Oct;51:73-77.
    PMID: 27418580 DOI: 10.1016/j.ijid.2016.06.022
    BACKGROUND: Tick borne encephalitis (TBE) is an acute meningoencephalitis with or without myelitis caused by an RNA virus from the flavivirus family transmitted by Ixodes spp ticks. The neurotropic TBE virus infects preferentially large neurons in basal ganglia, anterior horns, medulla oblongata, Purkinje cells and thalamus. Brain metabolic changes related to radiologic and clinical findings have not been described so far.

    METHODS: Here we describe the clinical course of 10 consecutive TBE patients with outcome assessment at discharge and after 12 month using a modified Rankin Scale. Patients underwent cerebral MRI after confirmation of diagnosis and before discharge. (18)F-FDG PET/CT scans were performed within day 5 to day 14 after TBE diagnosis. Extended analysis of coagulation parameters by thrombelastometry (ROTEM® InTEM, ExTEM, FibTEM) was performed every other day after confirmation of TBE diagnosis up to day 10 after hospital admission or discharge.

    RESULTS: All patients presented with a meningoencephalitic course of disease. Cerebral MRI scans showed unspecific findings at predilection areas in 3 patients. (18)F-FDG PET/CT showed increased glucose utilization in one patient and decreased (18)F-FDG uptake in seven patients. Changes in coagulation measured by standard parameters and thrombelastometry were not found in any of the patients.

    DISCUSSION: Glucose hypometabolism was present in 7 out of 10 TBE patients reflecting neuronal dysfunction in predilection areas of TBE virus infiltration responsible for development of clinical signs and symptoms.

    Matched MeSH terms: Ixodes/virology*
  10. Fulltext Detection of Langat virus by TaqMan real-time one-step qRT-PCR method
    Muhd Radzi SF, Rückert C, Sam SS, Teoh BT, Jee PF, Phoon WH, et al.
    Sci Rep, 2015;5:14007.
    PMID: 26360297 DOI: 10.1038/srep14007
    Langat virus (LGTV), one of the members of the tick-borne encephalitis virus (TBEV) complex, was firstly isolated from Ixodes granulatus ticks in Malaysia. However, the prevalence of LGTV in ticks in the region remains unknown. Surveillance for LGTV is therefore important and thus a tool for specific detection of LGTV is needed. In the present study, we developed a real-time quantitative reverse-transcription-polymerase chain reaction (qRT-PCR) for rapid detection of LGTV. Our findings showed that the developed qRT-PCR could detect LGTV at a titre as low as 0.1 FFU/ml. The detection limit of the qRT-PCR assay at 95% probability was 0.28 FFU/ml as determined by probit analysis (p ≤ 0.05). Besides, the designed primers and probe did not amplify ORF of the E genes for some closely related and more pathogenic viruses including TBEV, Louping ill virus, Omsk hemorrhagic fever virus (OHFV), Alkhurma virus (ALKV), Kyasanur Forest Disease virus (KFDV) and Powassan virus (POWV) which showed the acceptable specificity of the developed assay. The sensitivity of the developed method also has been confirmed by determining the LGTV in infected tick cell line as well as LGTV- spiked tick tissues.
    Matched MeSH terms: Ixodes
  11. The distribution of important sero-complexes of flaviviruses in Malaysia
    Kumar K, Arshad SS, Toung OP, Abba Y, Selvarajah GT, Abu J, et al.
    Trop Anim Health Prod, 2019 Mar;51(3):495-506.
    PMID: 30604332 DOI: 10.1007/s11250-018-01786-x
    Flaviviruses (FVs) are arthropod-borne viruses of medical and veterinary importance. Numerous species of FVs have been isolated from various host; mainly humans, animals, ticks, and mosquitoes. Certain FVs are extremely host-specific; at the same time, some FVs can infect an extensive range of species. Based on published literatures, 11 species of FVs have been detected from diverse host species in Malaysia. In humans, dengue virus and Japanese encephalitis virus have been reported since 1901 and 1942. In animals, the Batu Cave virus, Sitiawan virus, Carey Island, Tembusu virus, Duck Tembusu virus, and Japanese encephalitis viruses were isolated from various species. In mosquitoes, Japanese encephalitis virus and Kunjin virus were isolated from Culex spp., while Zika virus and Jugra virus were isolated from Aedes spp. In ticks, the Langat virus was isolated from Ixodes spp. One of the major challenges in the diagnosis of FVs is the presence of sero-complexes as a result of cross-reactivity with one or more FV species. Subsequently, the distribution of specific FVs among humans and animals in a specific population is problematic to assess and often require comprehensive and thorough analyses. Molecular assays such as quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and digital droplet RT-PCR (ddRT-PCR) have been used for the differentiation of flavivirus infections to increase the accuracy of epidemiological data for disease surveillance, monitoring, and control. In situations where sero-complexes are common in FVs, even sensitive assays such as qRT-pCR can produce false positive results. In this write up, an overview of the various FV sero-complexes reported in Malaysia to date and the challenges faced in diagnosis of FV infections are presented.
    Matched MeSH terms: Ixodes
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