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  • Prevalence of tick-borne encephalitis virus and Borrelia burgdorferi sensu lato in Ixodes ricinus ticks in Lower Bavaria and Upper Palatinate, Germany
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2020-01-15
    Dana Zubriková; Maria Wittmann; Václav Hönig; Pavel Švec; Bronislava Víchová; Sandra Essbauer; Gerhard Dobler; Libor Grubhoffer; Kurt Pfister

    Lyme borreliosis and tick-borne encephalitis (TBE) are the most common tick-borne diseases in Germany. We collected Ixodes ricinus ticks from 16 high-risk and four low-risk sites distributed in Lower Bavaria and Upper Palatinate based on the number of human TBE cases recorded at the Robert Koch Institute from 2001 to 2009. A total of 8805 questing ticks (8203 nymphs, 602 adults) were collected in 2010 and examined in pools for the presence of tick-borne encephalitis virus (TBEV) using real-time RT–PCR. Overall TBEV prevalence evaluated as the minimum infection rate (MIR) was 0.26% (23 positive pools/8805 ticks in 1029 pools). TBEV was detected at seven of the 16 high-risk sites, where MIR ranged from 0.16 to 2.86%. A total of 3969 ticks were examined by PCR for infection with Borrelia burgdorferi sensu lato (s.l.) targeting the 5S-23S rRNA intergenic spacer (IGS) region. IGS nucleotide sequences were used to determine genospecies. Selected positive Borrelia samples were subjected to PCR and sequencing targeting the OspA gene, providing 46 sequences for molecular phylogenetic analysis. Of the 3969 questing ticks, 506 (12.7%) were positive for B. burgdorferi s.l. Seven B. burgdorferi s.l. genospecies were identified: B. afzelii (41.3%), B. garinii (19%), B. valaisiana (13.8%), Borrelia burgdorferi sensu stricto (11.1%), B. spielmanii (0.4%), B. lusitaniae (0.2%), and Candidatus B. finlandensis (0.6%). Mixed infections were identified in 13.6% of the ticks. The rate of infection in questing ticks varied among sites from 5.6% (72 examined, four positive) to 29.5% (88 examined, 26 positive). B. burgdorferi s.l. occurred at all 20 sites, whereas TBEV was detected only at the high-risk sites where more human TBE cases were reported compared to low-risk sites.

    更新日期:2020-01-15
  • Turkey tick news: A molecular investigation into the presence of tick-borne pathogens in host-seeking ticks in Anatolia; initial evidence of putative vectors and pathogens, and footsteps of a secretly rising vector tick, Haemaphysalis parva
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2020-01-14
    Ömer Orkun; Ayşe Çakmak; Serpil Nalbantoğlu; Zafer Karaer

    This Turkey-based study investigated the presence of various tick-borne microorganisms in a broad-range of host-seeking ticks (n = 1019) that exhibit both hunter and ambusher characteristics. All collected ticks were analyzed individually via PCR-sequencing, resulting in the identification of 18 different microorganisms: six Babesia spp., including one putative novel species (Ba. occultans, Ba. crassa, Ba. rossi, Babesia sp. tavsan1, Babesia sp. tavsan2, and Babesia sp. nov.); six SFG rickettsiae (Ri. aeschlimannii, Ri. s. mongolitimonae, Ri. slovaca, Ri. raoultii, Ri. monacensis, and Ri. hoogstraalii); two Borrelia burgdorferi sensu lato spp. (Bo. afzelii and Bo. lusitaniae); two unnamed Hepatozoon spp.; Theileria annulata; and Hemolivia mauritanica. This provided evidence for the natural transstadial survival of these tick-borne microorganisms in adult ticks (in addition a nymph) of Turkey. Surprisingly, this study determined the presence of five different microorganisms (Ba. crassa, Ba. rossi, Babesia sp. Ucbas, Hepatozoon sp., and Ri. hoogstraalii) in host-seeking Haemaphysalis parva adults, for which poor data exist on its vectorial competence. Therefore, this study provides important data indicating the potential vectorial capacity of Ha. parva. This study also revealed the presence of the close ecological and evolutionary relationships between two important vector ticks, Hyalomma marginatum and Hy. aegyptium and determined genetic variations (distinct phylogenetic divergences inside the main clades) in some pathogenic SFG rickettsiae that are found in these ticks. Additionally, the presence of two Babesia species described very recently in hares with unknown vectors, namely Babesia sp. tavsan1 and Babesia sp. tavsan2, were detected for the first time in ticks. Finally, two unnamed Hepatozoon spp. were detected in Haemaphysalis ticks and their phylogenetic positions were demonstrated. Consequently, this study provides important data on the diversity of tick-borne microorganisms in host-seeking ticks and on potentially novel microorganisms (Babesia and Hepatozoon species) and their possible vectors (Ha. parva, Ha. sulcata, Hy. aegyptium, Hy. marginatum, and Rh. turanicus).

    更新日期:2020-01-14
  • A novel type 1 cystatin involved in the regulation of Rhipicephalus microplus midgut cysteine proteases
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2020-01-13
    Stephen Lu; Leticia A. da Rocha; Ricardo J.S. Torquato; Itabajara da Silva Vaz Junior; Monica Florin-Christensen; Aparecida S. Tanaka

    Rhipicephalus microplus is a cattle ectoparasite found in tropical and subtropical regions around the world with great impact on livestock production. R. microplus can also harbor pathogens, such as Babesia sp. and Anaplasma sp. which further compromise cattle production. Blood meal acquisition and digestion are key steps for tick development. In ticks, digestion takes place inside midgut cells and is mediated by aspartic and cysteine peptidases and, therefore, regulated by their inhibitors. Cystatins are a family of cysteine peptidases inhibitors found in several organisms and have been associated in ticks with blood acquisition, blood digestion, modulation of host immune response and tick immunity. In this work, we characterized a novel R. microplus type 1 cystatin, named Rmcystatin-1b. The inhibitor transcripts were found to be highly expressed in the midgut of partially and fully engorged females and they appear to be modulated at different days post-detachment. Purified recombinant Rmcystatin-1b displayed inhibitory activity towards typical cysteine peptidases with high affinity. Moreover, rRmcystatin-1b was able to inhibit native R. microplus cysteine peptidases and RNAi-mediated knockdown of the cystatin transcripts resulted in increased proteolytic activity. Moreover, rRmcystatin-1b was able to interfere with B. bovis growth in vitro. Taken together our data strongly suggest that Rmcystatin-1b is a regulator of blood digestion in R. microplus midgut.

    更新日期:2020-01-13
  • New record of Rickettsia vini in Ixodes lividus ticks from Lithuania
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2020-01-09
    Vesta Matulaityte; Algimantas Paulauskas; Maksim Bratchikov; Jana Radzijevskaja

    Ixodes lividus Koch, 1844 (Ixodida: Ixodidae) ticks are parasites specific to the sand martin (Riparia riparia). The distribution range of I. lividus covers Europe and Asia and they are found wherever sand martins nest. Borrelia burgdorferi sensu stricto, Borrelia garinii and Rickettsia vini have recently been detected in I. lividus ticks in Central Europe. The aim of this study was to investigate the presence of Rickettsia spp. (Rickettsiales: Rickettsiaceae) and Borrelia spp. (Spirochaetales: Spirochaetaceae) in I. lividus ticks in Lithuania. A total of 2622 non-engorged I. lividus from two different colonies comprising 40 sand martin nests were collected in Lithuania in 2013 and 2015. Rickettsial DNA was detected in 106 of the 117 pooled larvae samples, in all examined seven nymphs, four females and one male specimen. Sequence analysis of partial gltA, ompA and htrA genes showed 99-100 % identity with the corresponding R. vini sequences deposited in GenBank. None of I. lividus tested was infected with Borrelia burgdorferi sensu lato. This is the first time that the presence of R. vini has been reported in Lithuania.

    更新日期:2020-01-09
  • Candidatus Neoehrlichia mikurensis is widespread in questing Ixodes ricinus ticks in the Czech Republic
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2020-01-09
    Jaroslav Ondruš; Alena Balážová; Vojtech Baláž; Kristína Zechmeisterová; Adam Novobilský; Pavel Široký

    Candidatus Neoehrlichia mikurensis, the causative agent of tick-borne “neoehrlichiosis” has recently been reported in humans, mammals and ticks in Europe. The aim of this study was to map the distribution of this bacterium in questing ticks in the Czech Republic. A total of 13,325 Ixodes ricinus including 445 larvae, 5270 nymphs and 7610 adults were collected from vegetation by flagging in 140 Czech towns and villages from every region of the Czech Republic. The ticks were pooled into 2665 groups of 5 individuals respecting life stage or sex and tested for the presence of Ca. Neoehrlichia mikurensis by conventional PCR targeting of the groEL gene. The bacterium was detected in 533/2665 pools and 125/140 areas screened, showing an overall estimated prevalence of 4.4% in ticks of all life stages. Phylogenetic analysis revealed only small genetic diversity among the strains found. Two pools of questing larvae tested positive, suggesting transovarial transmission. According to this study, Ca. Neoehrlichia mikurensis is another tick-borne pathogen widespread in I. ricinus ticks in the Czech Republic.

    更新日期:2020-01-09
  • Ehrlichia canis TRP36 diversity in naturally infected-dogs from an urban area of ​​Colombia
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2020-01-07
    Esteban Arroyave; Juan D. Rodas-González; Xiaofeng Zhang; Marcelo B. Labruna; María S. González; Jorge A. Fernández-Silva; Jere W. McBride

    Ehrlichia canis is the etiologic agent of a highly prevalent tick-borne disease, canine monocytic ehrlichiosis (CME). Four defined E. canis genotypes based on the trp36 gene sequences have been reported, three of them identified in North or South America. The diversity of E. canis has been investigated using genetic and serologic approaches based on distinct 36 kDa tandem repeat protein (trp36) gene sequences that have been reported. The main objectives of this study were to determine the prevalence of E. canis infection in dogs from Medellín, Colombia by PCR and determine the E. canis diversity using molecular and serologic approaches. Blood was collected from dogs (n = 300) with clinical signs of CME for PCR detection of E. canis 16S rRNA, dsb and trp36 DNA. Phylogenetic analysis of trp36 gene sequences was performed using MEGA. A serological evaluation was performed using immunofluorescence microscopy and ELISA with species-specific peptides from E. canis TRP19 and TRP36 (3 genotypes) and E. chaffeensis (TRP32). E. canis DNA (16S rRNA and/or dsb) was detected in 18% (53/300) of dogs by PCR amplification. The trp36 gene was amplified and sequenced from 35/53 16S rRNA/dsb PCR positive samples revealing three genotypes: United States (US; n = 21), Costa Rica (CR; n = 11), and Brazil (BR; n = 3). All dogs with detectable trp36 DNA (n = 35) had anti-E. canis TRP19 and TRP36 peptide antibodies that corresponded to the genotype detected by PCR. Dogs that had antibodies to the TRP19 peptide (82/300; 38%), also had antibodies to one or more genotype-specific TRP36 peptides. Based on TRP36 serology, the dogs exhibited highest frequency of infection with the US genogroup (US = 26), followed by the CR genogroup (CR = 19) and the BR genogroup (BR = 11). Notably, 26/53 trp36 PCR positive dogs had detectable antibodies to multiple E. canis genotypes (US/BR/CR = 8, BR/CR = 7, US/CR = 6 and US/BR = 5) suggesting coinfection or multiple sequential infections with different genotypes. Colombian dogs did not have antibodies to E. chaffeensis as determined by a TRP32 species-specific ELISA. Our results demonstrate the presence of three previously defined genotypes in North and South America in Colombian dogs (US, BR, CR). These results also demonstrate that TRP19 and TRP36 serology can provide valuable information regarding E. canis exposure and the potential genotype(s) involved in infection.

    更新日期:2020-01-07
  • A simultaneous differential detection of canine blood parasites: multiplex high-resolution melting analysis (mHRM)
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2020-01-03
    Kittisak Buddhachat; Tirawit Meerod; Waranee Pradit; Puntita Siengdee; Siriwadee Chomdej; Korakot Nganvongpanit
    更新日期:2020-01-04
  • Ixodes scapularis saliva components that elicit responses associated with acquired tick-resistance
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2020-01-03
    Sukanya Narasimhan; Cheyne Kurokawa; Husrev Diktas; Norma Olivares Strank; Jiří Černý; Kristen Murfin; Yongguo Cao; Geoff Lynn; Jos Trentleman; Ming-Jie Wu; Kathy DePonte; Fred Kantor; Juan Anguita; Joppe Hovius; Erol Fikrig

    Ticks and tick-borne diseases are on the rise world-wide and vaccines to prevent transmission of tick-borne diseases is an urgent public health need. Tick transmission of pathogens to the mammalian host occurs during tick feeding. Therefore, it is reasoned that vaccine targeting of tick proteins essential for feeding would thwart tick feeding and consequently prevent pathogen transmission. The phenomenon of acquired tick-immunity, wherein, repeated tick infestations of non-natural hosts results in the development of host immune responses detrimental to the tick feeding has served as a robust paradigm in the pursuit of tick salivary antigens that may be vaccine targeted. While several salivary antigens have been identified, immunity elicited against these antigens have only provided modest tick rejection. This has raised the possibility that acquired tick-immunity is directed against tick components other than tick salivary antigens. Using Ixodes scapularis, the blacklegged tick, that vectors several human pathogens, we demonstrate that immunity directed against tick salivary glycoproteins is indeed sufficient to recapitulate the phenomenon of tick-resistance. These observations emphasize the utility of tick salivary glycoproteins as viable vaccine targets to thwart tick feeding and direct our search for anti-tick vaccine candidates.

    更新日期:2020-01-04
  • RNA virome analysis of questing ticks from Hokuriku District, Japan, and the evolutionary dynamics of tick-borne phleboviruses
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-12-27
    Daisuke Kobayashi; Katsunori Murota; Kentaro Itokawa; Hiroko Ejiri; Michael Amoa-Bosompem; Astri Nur Faizah; Mamoru Watanabe; Yoshihide Maekawa; Toshihiko Hayashi; Shinichi Noda; Takeo Yamauchi; Osamu Komagata; Kyoko Sawabe; Haruhiko Isawa

    Tick-borne viruses have emerged recently in many parts of the world, and the discoveries of novel tick-borne viruses have been accelerated by the development of high-throughput sequencing technology. In this study, a cost-efficient small benchtop next-generation sequencer, the Illumina MiniSeq, was used for the RNA virome analysis of questing ticks collected from Hokuriku District, Japan, and assessed for their potential utility in a tick-borne virus surveillance system. We detected two phleboviruses [Kabuto Mountain virus (KAMV) and Okutama tick virus (OKTV)], a coltivirus [Tarumizu tick virus (TarTV)], and a novel iflavirus [Hamaphysalis flava iflavirus (HfIFV)] from tick homogenates and/or cell culture supernatants after virus isolation processes. The number of sequence reads from KAMV and TarTV markedly increased when cell culture supernatants were used, indicating a successful isolation of these viruses. In contrast, OKTV and HfIFV were detected only in tick homogenates but not from cell culture supernatants, suggesting a failure to isolate these viruses. Furthermore, we performed genomic and phylogenetic analyzes of these detected viruses. OKTV and some phleboviruses discovered recently by NGS-based methods were probably deficient in the M genome segment, which are herein proposed as M segment-deficient phlebovirus (MdPV). A phylogenetic analysis of phleboviruses, including MdPV, suggested that Uukuniemi and Kaisodi group viruses and kabutoviruses evolved from an ancestral MdPV, which provides insights into the evolutionary dynamics of phleboviruses as emerging pathogens.

    更新日期:2019-12-27
  • Theileria annulata transformation altered cell surface molecules expression and endocytic function of monocyte-derived dendritic cells
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-12-26
    Junlong Liu; Muhammad Rashid; Jinming Wang; Aihong Liu; Guiquan Guan; YouQuan Li; Lan He; Hong Yin; Jianxun Luo

    Theileria annulata is a protozoan parasite transmitted by ticks to cattle. The most important processes of T. annulata are the infection and transformation of host monocytes, which promote cells division and generate a neoplastic phenotype. Dendritic cells play an important role in the development of adaptive immune responses against parasites and are traditionally classified into four types. One type of dendritic cell derived from afferent lymph was successfully transformed by T. annulata in vitro in previously report. However, whether the monocyte-derived dendritic cells could be transformed and how the endocytic function is affected by T. annulata infection were not yet known. Bovine dendritic cells (DCs) derived from blood CD14+ monocytes were cocultured with T. annulata sporozoites in vitro. On day 15 post infection, rounded and continuously proliferating cells were observed. The effect of this transformation on cell phenotype was studied using immunostaining and flow cytometry. After transformation, the cells maintained the expression of the DC-specific marker CD11c, but it was down-regulated as were the expression of CD11b, CD14 and CD86. In contrast, CD205, CD45 and MHC class Ⅱ molecules were upregulated in transformed cells. The levels of CD172a, CD21, CD40 and CD80 expression were very low in the transformed cells (<1%). However, the transformed cells maintained high expression levels of MHC Ⅰ (>99%). In addition, the normal and transformed DCs were cocultured with OVA-FITC antigen to compare the differences of the endocytic functions between these two types of cells. The results revealed that the endocytic functions of MoDCs were significantly inhibited after transformation by T. annulata.

    更新日期:2019-12-27
  • Partial characterization of the voltage-gated sodium channel gene and molecular detection of permethrin resistance in Rhipicephalus annulatus (Say, 1821)
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-12-26
    Guilherme M. Klafke; Hannah C. Moreno; Jason P. Tidwell; Robert J. Miller; Donald B. Thomas; Teresa P. Feria-Arroyo; Adalberto A. Pérez de León

    The cattle tick, Rhipicephalus annulatus (Say) is a vector of bovine babesiosis and responsible for direct and indirect losses to cattle producing areas located in temperate and subtropical dry regions. Resistance against pyrethroids has been reported for this species in Asia and Africa, but never before in North America. An outbreak strain, Rio Lado, collected close to the border between Mexico and the United States, in Maverick County, Texas, showed low level of resistance to permethrin, a pyrethroid pesticide. We used genomic material from different strains of cattle ticks collected within the Permanent Quarantine Zone (Rio Lado, Vega and Klein Grass strains) to partially characterize the coding gene of the voltage-gated sodium channel (Na-channel), target-site of pyrethroid pesticides, and search for putative mutations associated with resistance using quantitative PCR high resolution melt (HRM) analysis. The two amplified fragments, corresponding to domains II and III of the Na-channel, were 100% identical to its ortholog in Rhipicephalus microplus (Canestrini). No nucleotide polymorphisms in the Na-channel gene were observed in the pyrethroid-resistant Rio Lado strain, when compared to the susceptible strains Klein Grass and Vega. This study reports the first case of pyrethroid resistance in R. annulatus collected in the United States. Also, we provide new genomic data for this species of tick that allows for the development of a new method to screen for mutations associated with pyrethroid resistance.

    更新日期:2019-12-27
  • Experimental infection of Monodelphis domestica with Rickettsia parkeri
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-12-24
    Matheus Dias Cordeiro; Bruna de Azevedo Baêta; Marcio Barizon Cepeda; Adivaldo Henrique da Fonseca

    This study aimed to evaluate the infection of the marsupial Monodelphis domestica (the gray short-tailed opossum) by Rickettsia parkeri and its role as an amplifier of the bacterium for Amblyomma ticks. Ten M. domestica males were inoculated with phosphate-buffered saline (PBS) and 106 Vero cells infected with R. parkeri. In seven animals, inoculation was intramuscular, and in three intraperitoneal. One male (control) received 1 ml of the same vehicle used for inoculation intraperitoneally. The three animals inoculated intraperitoneally were infested with uninfected A. sculptum larvae and nymphs between the 2nd and 9th day post-infection (DPI). Parasitemia was monitored from the 3rd to 9th DPI by polymerase chain reaction, using primers for 17 kDa and ompA. The animals were also clinically evaluated. Of the animals infected intramuscularly, only one was blood-positive by the 5th DPI. The three animals infected intraperitoneally were blood-positive on the 2nd, 5th, 7th, and 9th DPI. Of the ten pools of recovered engorged ticks, six had positive bands. The kidney, liver, heart, and spleen of an intramuscularly infected animal were also positive. The rectal temperature of the animals tested increased only in the first three DPI. The animals inoculated intraperitoneally showed prostration, bristled hair, and weight loss. The study found that R. parkeri was capable of infecting M. domestica, which developed rickettsemia and caused infection in xenodiagnostic ticks.

    更新日期:2019-12-25
  • Comparative survival of the engorged stages of Amblyomma dubitatum and Amblyomma sculptum in the laboratory: implications for Brazilian spotted fever epidemiology
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-12-23
    Hermes R. Luz; Alejandro Ramírez-Hernández; Hector R. Benatti; Diego G. Ramirez; Matias P.J. Szabó; Marcelo B. Labruna

    Brazilian spotted fever (BSF), caused by the bacterium Rickettsia rickettsii, is transmitted to humans mainly by the tick Amblyomma sculptum in southeastern Brazil. In most BSF-endemic areas A. sculptum populations are sustained chiefly by capybaras (Hydrochoerus hydrochaeris), which are also the host of another tick species, Amblyomma dubitatum, not implicated in R. rickettsii transmission. Herein, we evaluated the effects of relative humidity (RH), temperature, and water immersion on the successful development of the engorged stages of A. dubitatum and compared them with recently published data under the same experimental conditions for A. sculptum. We showed that free-living developmental stages (engorged larvae, nymphs and females, and eggs) of A. dubitatum had higher survival rates when these stages were submerged in water for different periods of times (24 to 72 h). On the other hand, higher survival rates were observed for A. sculptum when ticks were incubated at lower RH values, 65 or 78%, regardless of summer or winter mean temperatures. These results suggest that A. dubitatum is more adapted to humid habitats and seasonally flooding soils than A. sculptum, whereas this latter species should be more adapted than A. dubitatum to drier habitats. The implications of these results for the spatial distribution of A. dubitatum and A. sculptum, in relation to BSF epidemiology, are discussed.

    更新日期:2019-12-23
  • Borrelia prevalence and species distribution in ticks removed from humans in Germany, 2013-2017
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-12-23
    Andrea Springer; Marie-Kristin Raulf; Volker Fingerle; Christina Strube

    Lyme borreliosis caused by spirochaetes of the Borrelia burgdorferi sensu lato (s.l.) complex is the most common tick-borne disease in Europe. In addition, the relapsing-fever spirochaete Borrelia miyamotoi, which has been associated with febrile illness and meningoencephalitis in immunocompromised persons, is present in Europe. This study investigated Borrelia prevalence and species distribution in ticks removed from humans and sent as diagnostic material to the Institute for Parasitology, University of Veterinary Medicine Hannover, in 2013-2017. A probe-based real-time PCRwas carried out and Borrelia-positive samples were subjected to species determination by reverse line blot (RLB), including a B. miyamotoi-specific probe. The overall Borrelia-infection rate as determined by real-time PCR was 20.02% (510/2547, 95% CI: 18.48-21.63%), with annual prevalences ranging from 17.17% (90/524, 95% CI: 14.04-20.68%) in 2014 to 24.12% (96/398, 95% CI: 19.99-28.63%) in 2015. In total, 271/475 (57.1%) positive samples available for RLB were successfully differentiated. Borrelia afzelii was detected in 30.53% of cases (145/475, 95% CI: 26.41-34.89), followed by B. garinii/B. bavariensis (13.26% [63/475], 95% CI: 10.34-16.65). Borrelia valaisiana occurred in 5.89% (28/475, 95% CI: 3.95-8.41), B. spielmanii in 4.63% (22/475, 95% CI: 2.93-6.93), B. burgdorferi sensu stricto (s.s.)/B. carolinensis in 2.32% (11/475, 95% CI: 1.16-4.11), B. lusitaniae in 0.63% (3/475, 95% CI: 0.13-1.83) and B. bisettiae in 0.42% (2/475, 95% CI: 0.05-1.51) of positive ticks. Borrelia kurtenbachii was not detected, while B. miyamotoi was identified in 7.37% (35/475, 95% CI: 5.19-10.10) of real-time PCR-positive samples. Sanger sequencing of B. garinii/B. bavariensis-positive ticks revealed that the majority were B. garinii-infections (50/52 successfully amplified samples), while only 2 ticks were infected with B. bavariensis. Furthermore, 6/12 B. burgdorferi s.s./B. carolinensis-positive samples could be differentiated; all of them were identified as B. burgdorferi sensu stricto. Thirty-nine ticks (8.21%, 95% CI: 5.90-11.05) were coinfected with two different species. Comparison of the species distribution between ticks removed from humans in 2015 and questing ticks collected in the same year and the same area revealed a significantly higher B. afzelii-prevalence in diagnostic tick samples than in questing ticks, confirming previous observations. The obtained data indicate that Borrelia prevalence fluctuated in the same range as observed in a previous study, analysing the period from 2006 to 2012. Detection of B. miyamotoi in 7.37% of Borrelia-positive samples points to the fact that clinicians should be aware of this pathogen as a differential diagnosis in cases of febrile illness.

    更新日期:2019-12-23
  • Rapid identification of Babesia canis and Babesia gibsoni (Asian genotype) in canine blood samples using a customized portable real-time PCR analyzer and TaqMan-based assay
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-12-23
    Chun-Yen Kuo; Chihyu Zhao; TsunLi Cheng; Chih-Cheng Tsou; Yi-Chen Li; Yong Zhang; Ming-Che Hsieh; Song-Bin Haung; Wen-Ying Chen

    Canine babesiosis is a serious infectious disease in subtropical and tropical regions. Typically, clinical detection of canine babesiosis is performed by blood smear observation or the traditional polymerase chain reaction (PCR). Herein, we developed a new TaqMan-based real-time PCR assay combined with a customized portable real-time PCR platform for a rapid and accurate detection of canine babesiosis. Two new primer/probe pairs (B18S and BITS1) were designed based on 18S ribosomal RNA and an internal transcribed spacer 1 (ITS1) sequence to differentiate Babesia canis and B. gibsoni (Asian genotype) DNAs from canine blood samples. Additionally, a corresponding customized compact real-time PCR platform with low 6-carboxyfluorescein fluorescence detection (≤5 nM), including a fast and accurate thermal cycling ability with a user-friendly interface for thermal control and data analysis, was designed for the limited space use. Both assays (B18S and BITS1) demonstrated a sensitivity of 100 copies/reaction based on the 95% confidence interval evaluation method. The self-developed customized portable real-time PCR analyzer presented high repeatability and reproducibility with the TaqMan-based assay. Moreover, 501 clinical specimens were collected for evaluating the performance of the proposed PCR. The positive and negative predictive values were 90% (18 of 20) and 100% (226 of 226), respectively, for samples suspected with B. canis infection and 98% (55 of 56) and 100% (199 of 199), respectively, for samples suspected with B. gibsoni infection.

    更新日期:2019-12-23
  • Woodchip borders at the forest ecotone as an environmental control measure to reduce questing tick density along recreational trails in Ottawa, Canada
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-12-20
    Roman McKay; Benoit Talbot; Andreea Statculescu; Alexander Stone; Manisha A. Kulkarni

    Recent studies have highlighted the occurrence and distribution of Ixodes scapularis ticks infected with Borrelia burgdorferi sensu stricto (s.s.) around the city of Ottawa, Ontario, Canada, and the need for strategies to mitigate the risk of human exposure and infection. We conducted a field study from July to October 2018 to examine the effectiveness of ecotonal woodchip borders as an environmental control method to suppress the density of host-seeking ticks along recreational trails in Ottawa. We used an experimental design with ten 100-m trail replicates randomized to intervention or control groups, and monitored questing tick density at weekly intervals in mid-summer and early fall. We compared questing tick density between woodchip-treated and untreated trails using a mixed-effects Poisson regression model. Of the 138 I. scapularis ticks collected, there were 86 adult and nymphal ticks, 37 (43%) of which were positive for B. burgdorferi s.s. A total of 58 Haemaphysalis leporispalustris were also collected. Mean combined adult and nymphal I. scapularis density was 1.15 (1.40 standard deviation; SD) per 100 m in the control group compared to 0.28 (0.56 SD) per 100 m in the intervention group, reflecting a 75% reduction in questing tick density on trail replicates treated with woodchip borders (p < 0.001). An effect of the intervention was observed in both sampling periods. This study indicates that woodchip borders may be an effective strategy to suppress questing tick density along trail margins where recreational trail users are more active, thereby reducing the likelihood of tick encounters.

    更新日期:2019-12-20
  • Molecular genotyping and epidemiology of equine piroplasmids in South Africa
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-12-16
    Raksha Vasantrai Bhoora; Nicola Elaine Collins; Leonhard Schnittger; Christo Troskie; Ratselane Marumo; Karien Labuschagne; Rae Marvin Smith; Desire Lee Dalton; Sikhumbuzo Mbizeni

    Recently reported substantial genetic diversity within Theileria equi 18S rRNA gene sequences has led to the identification of five genotypes A, B, C, D, and E, complicating molecular and serological diagnosis. In addition, T. haneyi has lately been reported as a species closely related to the T. equi 18S rRNA genotype C (Knowles et al., 2018). Theileria spp. of this group have a monophyletic origin and are therefore referred to as Equus group to distinguish them from the remaining Theileria lineages (Jalovecka et al., 2019). In this study, we report on the development of genotype-specific quantitative real-time PCR assays capable of detecting and distinguishing between each parasite genotype. Alignment of complete 18S rRNA sequences available on GenBank allowed for the design of a single primer pair and five TaqMan minor groove binder (MGB™) probes specific for each genotype (A-E). The assays, evaluated as qPCR simplex and two qPCR multiplex formats (Multiplex EP-ABC and Multiplex EP-DE), were shown to be both efficient and specific in the detection of T. equi genotypes. The developed qPCR assays were used to study (i) the intra-specific diversity of parasite genotypes within horse and zebra, (ii) the inter-specific differences in parasite genotype diversity in horses as compared to zebra, and (iii) the geographic distribution of T. equi 18S rRNA genotypes in South Africa. In addition, (iv) the presence of T. haneyi in South Africa was evaluated. An assessment of 342 equine field samples comprising 149 field horses, 55 racehorses, and 138 wild zebra confirmed the previously reported presence of T. equi 18S rRNA genotypes A, B, C, and D, and absence of genotype E in South African equids. Theileria equi genotypes A, B, C, and D, were detected in zebra, whereas only genotypes A, C and D, could be identified in field horses, and only genotypes A and C in racehorses. Genotypes B and D were the dominant genotypes identified in zebra in South Africa, while horses were predominantly infected with T. equi genotypes A and C. The greater diversity of T. equi genotypes in zebra suggests that it is an ancestral host for this piroplasmid lineage. Importantly, evidence is presented that each identified T. equi genotype segregates independently in each of the three studied equid populations reinforcing the notion that they represent individual separate entities corresponding to species. Preliminary investigations of the relationship between T. equi genotype C infections and Theileria haneyi, suggest that in addition to the five currently known T. equi genotypes, South African equids are also infected with T. haneyi.

    更新日期:2019-12-17
  • " style="font-size: 14px;line-height: 14px;"> Development and application of a multiplex TaqMan® real-time qPCR assay for the simultaneous detection of anaplasma marginale and theileria annulata and molecular characterization of anaplasma marginale from cattle in Western Cuba."/>
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-12-16
    Adrian Alberto Díaz-Sánchez; Marina L. Meli; Dasiel Obregón Álvarez; Osvaldo Fonseca-Rodríguez; Alejandro Cabezas-Cruz; Regina Hofmann-Lehmann; Belkis Corona-González

    Anaplasmosis and theileriosis are considered the most important tick-borne diseases for livestock production worldwide, causing significant economic losses in tropical and subtropical regions. The present study was aimed to develop a multiplex TaqMan® qPCR assay to simultaneously detect Anaplasma marginale and Theileria annulata and to applied it to investigate naturally infected cattle in Cuba. The assay was highly specific, sensible, and efficient; it was more sensitive than a well-established nested PCR and detected 1 DNA copy of each target. Consistent repeatability and reproducibility within and between multiplex qPCR runs was shown. A total of 223 blood samples collected in western Cuba were analyzed for haemoparasites infection in cattle. The multiplex qPCR assay detected A. marginale in 213 samples (95.5%; CI: 95%; 91.9%–97.5%), but all samples were negative for T. annulata. Additionally, the genetic diversity of A. marginale was assessed using 16S rRNA, MSP1a and MSP4 nucleotide and protein sequences. The MSP1a tandem repeats ranged from three to five, and twelve different MSP1a tandem repeats of A. marginale were found, which presented genotypes C, E, and G in the 5ʹUTR microsatellite region. Phylogenetic analysis using the msp4 gene showed that Cuban strains were closely related to others previously reported in Mexico, Brazil and Asian countries. The multiplex qPCR described here proved to be a rapid, specific and cost-effective mean for the simultaneous detection of A. marginale and T. annulata. Further epidemiological studies using this assay will improve the surveillance of the associated diseases in regions where they are endemic.

    更新日期:2019-12-17
  • Bacterial communities in Haemaphysalis, Dermacentor and Amblyomma ticks collected from wild boar of an Orang Asli Community in Malaysia
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-12-14
    Fang Shiang Lim; Jing Jing Khoo; Kim Kee Tan; Nurhafiza Zainal; Shih Keng Loong; Chee Sieng Khor; Sazaly AbuBakar

    Ticks are hematophagous vectors of arthropod-borne disease agents globally. In Malaysia, despite seroprevalence studies indicating the presence of tick-borne diseases among the indigenous people, the etiological agents of these diseases are still unclear. These indigenous people, also known as the Orang Asli, still live in forested areas with frequent contact with wildlife. Wild boar are ubiquitously found in the forested areas where the Orang Asli communities are located and are commonly hunted as a food supplement. In this study, we aim to determine the tick species parasitizing wild boar from an Orang Asli community, and explore the tick-associated bacterial communities using 16 s rRNA amplicon sequencing on the Ion Torrent PGMTM platform. A total of 72 ticks were collected from three wild boar and were morphologically identified as Haemaphysalis hystricis (n = 32), Dermacentor compactus (n = 15), Amblyomma testudinarium (n = 13), Dermacentor steini (n = 10) and Dermacentor atrosignatus (n = 2). Across all tick samples, 910 bacterial taxa were identified. Although the bacterial communities were not significantly distinct between tick species in beta-diversity analyses, Coxiella, Rickettsia and Francisella were detected at high relative abundance in H. hystricis, D. compactus and D. steini respectively. Many other bacterial genera, including those that have been described in many different tick species, were also identified, including Pseudomonas, Acinetobacter, Staphylococcus and Corynebacterium. Beta-diversity analyses also showed that the bacterial communities were separated based on the animal host from which the ticks were collected from, suggesting that the bacterial communities here may be influenced by the animal skin microflora, host blood or the environment. PCR screening confirmed the presence of Rickettsia sp. related to spotted fever group Rickettsia in some of the ticks. This study provides baseline knowledge of the microbiome of H. hystricis, D. atrosignatus, D. compactus, D. steini and A. testudinarium parasitizing wild boar in this region. The information gained in this study provides the basis to target our efforts in H. hystricis, D. compactus and D. steini for the future investigation of vector competence and the zoonotic potential for the Coxiella, Rickettsia and Francisella detected here, as well as their implications for the risks of tick-borne diseases among the Orang Asli communities.

    更新日期:2019-12-17
  • Vector competence studies with hard ticks and Borrelia burgdorferi sensu lato spirochetes: a review
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-12-14
    Eisen Lars

    Use of emerging technology allowing for identification of genetic material from pathogens and endosymbionts in ticks collected from humans, domestic animals, wildlife, or the environment has resulted in an avalanche of new data on tick-microorganism associations. This rapidly growing stream of new information is a tremendous resource but also presents challenges, including how detection of pathogen genetic material in ticks should best be interpreted. There is a tendency in the more recent published literature to incorrectly use the term “vector” based on detection of pathogen genetic material from tick species not experimentally confirmed to serve as vectors of the pathogen in question. To serve as a vector of a horizontally maintained pathogen, such as a Borrelia burgdorferi sensu lato (s.l.) Lyme borreliosis spirochete, the tick species in question must be capable of acquiring the pathogen while feeding in the larval or nymphal stage on an infectious host, maintaining it transstadially through the molt, and then transmitting the pathogen to a naïve host while feeding in the subsequent nymphal or adult stage. This review examines the experimental evidence for and against species of hard (ixodid) ticks from different genera to serve as vectors of B. burgdorferi s.l. spirochetes. Of the 18 Ixodes species ticks evaluated to date, 13 were experimentally confirmed as vectors of B. burgdorferi s.l. spirochetes. These studies focused primarily on the three major Lyme borreliosis agents: Borrelia burgdorferi sensu stricto, Borrelia afzelii, and Borrelia garinii. In striking contrast, none of 8 tick species from other genera (1 Amblyomma species, 5 Dermacentor species, and 2 Haemaphysalis species) evaluated to date were unequivocally experimentally confirmed as vectors of B. burgdorferi s.l. spirochetes. The strength of the evidence for or against each tick species to serve as a vector of B. burgdorferi s.l. spirochetes is discussed together with key knowledge gaps and research challenges.

    更新日期:2019-12-17
  • Molecular detection and phylogenetic analysis of canine tick-borne pathogens from Korea
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-12-07
    Min-Goo Seo, Oh-Deog Kwon, Dongmi Kwak

    Ticks transmit more pathogens than any other arthropod vector and are of paramount veterinary and zoonotic significance. Domestic dogs are an important reservoir of zoonotic agents, particularly because of their close contact with humans. Previous studies in Korea have examined canine tick-borne pathogens (CTBP) by ELISA and real-time PCR methods. However, phylogenetic information on CTBP in Korea is lacking. This study assessed the prevalence, risk factors, and co-infectivity of CTBP such as piroplasms, rickettsiae, Coxiella burnetii, hepatozoa, hemotropic mycoplasmas, and Borrelia spp., using PCR and phylogenetic analyses. Of the 510 dogs tested, three CTBP, including Anaplasma phagocytophilum 16S rRNA (13; 2.6%), Hepatozoon canis 18S rRNA (2; 0.4%), and Mycoplasma haemocanis 16S rRNA (1; 0.2%) were detected. PCR adapted to amplify A. phagocytophilum msp2 and groEL genes generated amplicons thereof in two out of 13 positive dogs. One shelter dog was co-infected with A. phagocytophilum and M. haemocanis. However, Ehrlichia spp., Rickettsia spp., C. burnetii, Borrelia spp., Babesia spp., and Theileria spp. pathogens were not detected. To the best of our knowledge, this is the first study to undertake a phylogenetic analysis of H. canis and M. haemocanis in dogs reared in Korea. Although previous studies have improved our understanding of evolutionary behaviors and host-pathogen relations of CTBP, additional investigations are required to pin down vectors and reservoirs of CTBP in Korea. A surveillance system for arthropod vectors and CTBP in dogs should be established to monitor pathogen distribution and mitigate pathogen spread proactively, such as with ectoparasite medications in dogs.

    更新日期:2019-12-07
  • A soft tick Ornithodoros moubata salivary protein OmCI is a potent inhibitor to prevent avian complement activation
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-12-06
    Amber M. Frye, Thomas M. Hart, Danielle M. Tufts, Sanjay Ram, Maria A. Diuk-Wasser, Peter Kraiczy, Anna M. Blom, Yi-Pin Lin

    Complement is a key first line innate host defense system in the blood of vertebrates. Upon activation, this powerful defense mechanism can elicit inflammatory responses, lyse non-self-cells, or mark them for opsonophagocytic removal. Blood-feeding arthropods thus require the ability to block host complement activation in the bloodmeal to prevent undesired cell or tissue damage during feeding. The soft tick Ornithodoros moubata produces a complement inhibitory protein, OmCI. This protein binds to a mammalian complement protein C5 and blocks further activation of complement cascades, which results in the prevention of complement-mediated bacterial killing through membrane attack complex. Interestingly, the amino acids involved in OmCI binding are highly conserved among mammalian and avian C5, but the ability of this protein to inhibit the complement from birds remains unclear. Here we demonstrated that OmCI is capable of preventing quail complement-mediated erythrocyte lysis, inhibiting the capability of this animal’s complement to eliminate a serum-sensitive Lyme disease bacterial strain. We also found that the ability of OmCI to inhibit quail complement-mediated killing of Lyme disease bacteria can be extended to different domestic and wild birds. Our results illustrate the utility of OmCI to block bird complement. These results provide the foundation for further use of this protein as a tool to study the molecular basis of avian complement and pathogen evasion to such a defense mechanism.

    更新日期:2019-12-07
  • Effects of cattle grazing on Ixodes ricinus-borne disease risk in forest areas of the Netherlands
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-12-06
    Hein Sprong, Sander Moonen, Sipke E. van Wieren, Tim R. Hofmeester

    Cattle grazing has been suggested to reduce the risk for Lyme borreliosis by decreasing the density of questing Ixodes ricinus infected with Borrelia burgdorferi sensu lato. We tested the hypotheses that cattle grazing used in woodland management decreases the density of questing I. ricinus, and that it decreases the nympal infection prevalence of B. burgdorferi sensu lato. We further expected the nympal infection prevalence of tick-borne pathogens that utilize cattle as amplifying hosts, namely Anaplasma phagocytophilum, and Babesia sensu stricto, to increase. To test these hypotheses, we compared the densities of questing I. ricinus between twenty pairs of plots in grazed and ungrazed forest areas. The density of I. ricinus adults, but not nymphs, was lower in areas grazed by cattle than in ungrazed areas. Nymphs were tested for the presence of Borrelia burgdorferi s.l., Borrelia miyamotoi, Anaplasma phagocytophilum, and Babesia s.s. DNA from twelve paired areas. Anaplasma phagocytophilum and Babesia s.s. from qPCR-positive tick lysates were identified further to the ecotype and species level, respectively, by DNA sequencing. The infection prevalence of A. phagocytophilum was lower, and infection prevalence of Babesia s.s., identified as Babesia venatorum, was higher in grazed areas. In contrast, infection prevalence with B. burgdorferi s.l. or B. miyamotoi did not differ between grazed and ungrazed areas. As a consequence, conventional cattle grazing in forested areas had no effect on the densities of questing nymphs infected with B. burgdorferi s.l. and B. miyamotoi. Similarly, we found no effect of cattle grazing on the density of infected nymphs with B. venatorum. The marked difference in the densities of questing nymphs infected with A. phagocytophilum could potentially be explained by the presence of a higher density of roe deer (Capreolus capreolus) in ungrazed areas, as the majority of typed A. phagocytophilum from ungrazed areas were the non-zoonotic ecotype II, which is associated with roe deer.

    更新日期:2019-12-07
  • Spatial and temporal trends of Mediterranean spotted fever in Spain, 2005-2015
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-12-03
    Adriana Romaní Vidal, Beatriz Fernández-Martínez, Zaida Herrador, Inmaculada León Gómez, Diana Gómez Barroso

    Background Mediterranean spotted fever (MSF) is a zoonotic disease caused by Rickettsia conorii and transmitted by Rhipicephalus sanguineus sensu lato. The aim of this study is to understand the epidemiology and trends regarding the disease in Spain, based on notifications to the Spanish National Epidemiology Surveillance Network (RENAVE) and the National Hospital Discharge Database (CMBD) between 2005 and 2015. Methods We carried out a retrospective cross-sectional study of the cases and the outbreaks reported to the RENAVE and of those found in the CMBD between January 1st, 2005 and December 31st, 2015. We studied the characteristics of the cases and analyzed their spatio-temporal distribution. Results 1603 cases notified to the RENAVE and 1789 cases registered in the CMBD were analyzed. The most affected group were men between 45 and 64. There were 8 MSF outbreaks during the study period. RENAVE registered lower rates until 2012, when it was decided that MSF in Spain would become a notifiable disease. Across the temporal series we saw that there was seasonality with an increase in cases in summer, and an overall upward trend according to the RENAVE data and descending according to the CMBD. The geographic distribution was heterogeneous throughout the territory, with maximum rates in La Rioja at 1.87 cases and 2.01 cases per 100,000 inhabitants according to the RENAVE and the CMBD, respectively. Conclusions It is of great importance to continue monitoring the disease since it appears to be endemic throughout Spain. There is a need for a common strategy on monitoring and reporting, which would facilitate a more accurate picture on the MSF epidemiological scenario. Entomological information will be of added value.

    更新日期:2019-12-04
  • Prevalence and molecular characterization of Anaplasma phagocytophilum in roe deer (Capreolus capreolus) from Spain
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-12-03
    Susana Remesar, Pablo Díaz, Alberto Prieto, David García-Dios, Gonzalo Fernández, Ceferino M. López, Rosario Panadero, Pablo Díez-Baños, Patrocinio Morrondo

    Anaplasma phagocytophilum can infect a wide range of vertebrates; nevertheless, some genetic variants are associated with particular species of tick vectors and animal hosts. It has been suggested that roe deer (Capreolus capreolus) mainly acts as a reservoir of several A. phagocytophilum non-pathogenic variants for other animal species. The aim of this study was to determine the prevalence and identify the genetic variants of A. phagocytophilum in roe deer from Spain in order to assess host-pathogen associations and their pathogenic potential. The spleens of 212 roe deer hunted in Spain were individually collected and analysed by a commercial qPCR kit in order to detect the presence of A. phagocytophilum DNA. Positive samples were further characterized at groESL, 16S rRNA and msp2 partial genes. The possible influence of several intrinsic (age and sex) and extrinsic factors (ecological area) on A. phagocytophilum prevalence was analysed using a logistic regression. Overall, 41.5% of the samples resulted positive to A. phagocytophilum. The percentage of infected roe deer was significantly higher in the Mediterranean and Oceanic areas than in the Continental and Mountain regions; nevertheless, prevalence was not related to age or sex. Sequence analysis at groESL and 16S rRNA genes allowed the identification of three ecotypes (I to III) and four variants (“Y”, “X”, “W”, “I”), respectively. A high percentage of roe deer from Spain is infected with different variants of A. phagocytophilum; these results have implications for public and animal health since some of these ecotypes and variants have been previously identified in both human and animal clinical cases.

    更新日期:2019-12-04
  • Lyme disease in children: Data from the Canadian Paediatric Surveillance Program
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-11-30
    Nicholas H. Ogden, Salima Gasmi, Jules K. Koffi, Michelle Barton, L. Robbin Lindsay, Joanne M. Langley

    Background Lyme disease (LD) is an infectious disease that is emerging in eastern and central Canada associated with the spread of the tick vectorIxodes scapularis. National surveillance shows that children are an at-risk age group. Objectives To study the epidemiology of LD in Canadian children using the Canadian Paediatric Surveillance Program (CPSP) to better understand exposure history, clinical manifestations, diagnosis and treatment of paediatric LD cases in Canada. Methods A structured questionnaire was completed by paediatricians for each LD case reported as part of the Canadian Paediatric Surveillance Program from 2014-2017. Results There were 95 cases that met inclusion criteria as confirmed or probable cases. The median age was 7 years; of these 38% were 5 to 9 years and 35% were 10-15 years of age. Most cases were acquired in known Canadian endemic locations; 5 were acquired during travel to the US. Most cases were reported from Nova Scotia and Ontario (46% and 38% respectively). The most common clinical presentation was arthritis (59% of all cases), which is a manifestation of the late disseminated stage of LD. Late disseminated disease presented through the year, whereas early LD (Erythema migrans) and early disseminated LD presented during the summer and fall. Antibiotic choice and duration of therapy generally followed accepted guidelines. Conclusion This study of the clinical spectrum of LD in Canadian children underlines the need for preventive measures to protect children in Canada from emerging LD, and the need for health care provider awareness.

    更新日期:2019-11-30
  • Coxiella burnetii and Francisella tularensis in wild small mammals from the Czech Republic
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-11-29
    Eva Bártová, Hana Lya Kučerov, Alena Žákovská, Marie Budíková, Helena Nejezchlebová

    Wild rodents are an important source of the tick-borne pathogens Coxiella burnetii and Francisella tularensis. The aim of our study was to assess the prevalence of antibodies and possible coexistence of these pathogens in wild small mammals from three localities in the Czech Republic. A total of 614 wild small mammals (324 Apodemus flavicollis, 145 Myodes glareolus, 50 Sorex araneus, 48 A. sylvaticus, 40 A. agrarius, six Microtus arvalis and one Talpa europaea) were trapped between 2012 and 2015. Their sera or heart extracts were examined by modified indirect enzyme-linked immunosorbent assay, with the detection of antibodies against C. burnetii and F. tularensis in 12% and 7% of animals, respectively; coinfection was identified in 4.4% of animals. The prevalence of C. burnetii and F. tularensis antibodies statistically differed according to animal species and sex (p < 0.05); the seroprevalence of C. burnetii (p < 0.05) also differed in the sampling period. The highest prevalence of antibodies against C. burnetii and F. tularensis was detected in the case of M. glareolus (24% and 14%, respectively).

    更新日期:2019-11-30
  • Newly identified DNA methyltransferases of Ixodes ricinus ticks
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-11-29
    Kateryna Kotsarenko, Pavlina Vechtova, Zuzana Hammerova, Natalia Langova, Lenka Malinovska, Michaela Wimmerova, Jan Sterba, Libor Grubhoffer

    DNA methylation at the fifth position of cytosine (5mC) and at the sixth position of adenine (6 mA) plays an important role in the regulation of the gene expression and, in eukaryotes, is essential for normal development. For Ixodes ricinus, the most common European arthropod vector of human and animal pathogens, the DNA methylation profile and the role of DNA methylation in tick development are still under discussion. Our goal was to analyze the status of I. ricinus DNA methylation at different life stages and identify enzymes that produce this type of DNA modification. We found that 5mC and 6 mA are present in I. ricinus genomic DNA at all life stages. In the transcriptome of I. ricinus, we identified the sequences of the putative IrDNMT1, IrDNMT3, and IrDAMT enzymes, and bioinformatic analysis and three-dimensional modeling predicted their DNA methylation activity. This confirms that I. ricinus possesses a complete DNA methylation toolkit. Our results suggest that DNA methylation is important for the physiology and transstadial development of ticks.

    更新日期:2019-11-30
  • Synonymy of Ixodes aragaoi with Ixodes fuscipes, and reinstatement of Ixodes spinosus (Acari: Ixodidae)
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-11-29
    Marcelo B. Labruna, Valeria C. Onofrio, Darci M. Barros-Battesti, Sergio L. Gianizella, José M. Venzal, Alberto A. Guglielmone

    Ixodes fuscipes Koch, 1844, described from Brazil, has been considered a valid species with records from Brazil and Peru. Ixodes spinosus Neumann, 1899, also described from Brazil, has been considered a synonym of I. fuscipes. In 2014, Ixodes aragaoi Fonseca 1935 was redescribed as a valid species for Brazil and Uruguay. Until the present study, one major difference between the females of I. fuscipes and I. aragaoi was the horn-like auriculae in the former versus the ridge-like auriculae in the later, but this morphological difference was not supported after examination of the holotype of I. fuscipes and a syntype female of I. spinosus. Surprisingly, we found the type of I. fuscipes to have ridge-like auriculae, in contrast to the horn-like auriculae of I. spinosus. Comparisons of the I. fuscipes holotype with the syntypes of I. aragaoi revealed that they correspond to the same species. Therefore, we redescribe I. fuscipes, relegate I. aragaoi to a junior synonym of I. fuscipes, and reinstate I. spinosus as a valid species. After examining all lots of I. fuscipes in four tick collections, no specimen was recognized as I. fuscipes when compared with the type specimen of this taxon. On the other hand, specimens previously identified as I. aragaoi are now confirmed as I. fuscipes, with bona fide records for Brazil and Uruguay. Some of the specimens previously reported as I. fuscipes are now confirmed as I. spinosus, with records in two Brazilian biomes, Amazon and Atlantic rainforest. We present lists of the ticks examined in this study, with their current taxonomic status.

    更新日期:2019-11-30
  • Co-infection of bacteria and protozoan parasites in Ixodes ricinus nymphs collected in the Alsace region, France
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-06-08
    Amira Nebbak, Handi Dahmana, Lionel Almeras, Didier Raoult, Nathalie Boulanger, Benoit Jaulhac, Oleg Mediannikov, Philippe Parola

    Fifty nymphal Ixodes ricinus ticks collected in Alsace, France, identified by morphological criteria and using MALDI-TOF MS, were tested by PCR to detect tick-associated bacteria and protozoan parasites. Seventy percent (35/50) of ticks contained at least one microorganism; 26% (9/35) contained two or more species. Several human pathogens were identified including Borrelia burgdorferi s.s. (4%), Borrelia afzelii (2%), Borrelia garinii (2%), Borrelia valaisiana (4%), Borrelia miyamotoi (2%), Rickettsia helvetica (6%) and “Babesia venatorum” (2%). Bartonella spp. (10%) and a Wolbachia spp. (8%) were also detected. The most common co-infections involved Anaplasmataceae with Borrelia spp. (4%), Anaplasmataceae with Bartonella spp. (6%) and Anaplasmataceae with Rickettsia spp. (6%). Co-infection involving three different groups of bacteria was seen between bacteria of the family Anaplasmataceae, Borrelia spp. and Bartonella spp. (2%). Results highlight the panel of infectious agents carried by Ixodes ricinus. Co-infection suggests the possibility of transmission of more than one pathogen to human and animals during tick blood feeding.

    更新日期:2019-11-18
  • Ixodes persulcatus/pavlovskyi natural hybrids in Siberia: Occurrence in sympatric areas and infection by a wide range of tick-transmitted agents
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-06-21
    Vera Rar, Natalia Livanova, Yuliya Sabitova, Yana Igolkina, Sergey Tkachev, Artem Tikunov, Igor Babkin, Irina Golovljova, Victor Panov, Nina Tikunova

    Ixodes persulcatus and Ixodes pavlovskyi ticks, two closely related species of the I. ricinus - I. persulcatus group, are widely distributed in the southern part of Western Siberia. Recently, the existence of natural hybrids of I. persulcatus and I. pavlovskyi ticks has been demonstrated. The aim of this study was to evaluate the abundance of I. persulcatus/pavlovskyi hybrids in several locations with different ratios of parental tick species and to investigate the prevalence and genetic variability of a wide range of infectious agents in these hybrids compared to the parental tick species. Natural hybrids of I. persulcatus and I. pavlovskyi ticks were identified in all examined locations in Altai and Novosibirsk, Western Siberia, Russia. The abundance of hybrids varied from 7% to 40% in different locations and was maximal in a location with similar proportions of I. persulcatus and I. pavlovskyi ticks. For the first time, it was shown that hybrids can be infected with the same agents as their parental tick species: tick-borne encephalitis and Kemerovo viruses, Borrelia afzelii, Borrelia bavariensis, Borrelia garinii, Borrelia miyamotoi, Rickettsia helvetica, Rickettsia raoultii, Rickettsia sibirica, “Candidatus Rickettsia tarasevichiae”, Anaplasma phagocytophilum, Ehrlichia muris, “Candidatus Neoehrlichia mikurensis”, and Babesia microti. The prevalence of most bacterial agents in hybrids was intermediate compared to their parental tick species. Most genetic variants of the identified agents have been previously found in the parental tick species. Wide distribution of I. persulcatus/pavlovskyi natural hybrids implies that I. persulcatus, I. pavlovskyi and their hybrids coexist in all I. persulcatus - I. pavlovskyi sympatric areas.

    更新日期:2019-11-18
  • Ticks (Ixodida: Argasidae, Ixodidae) of Brazil: Updated species checklist and taxonomic keys
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-06-17
    Filipe Dantas-Torres, Thiago Fernandes Martins, Sebastián Muñoz-Leal, Valeria Castilho Onofrio, Darci Moraes Barros-Battesti

    Ticks are ectoparasites of great medical and veterinary significance in the neotropical region. In Brazil, they are responsible for enormous economic losses to the livestock industry and also for considerable morbidity and mortality in companion animals and humans. Therefore, recognizing the identity of a given species is important, not only from a biodiversity perspective, but also from the medical and veterinary standpoints. The Brazilian tick fauna is one of the most diverse and well-studied in the neotropical region. In the past few years, several new species were discovered and/or recorded for the first time in this country. The main objectives of this study were to provide an updated list of tick species occurring in Brazil and taxonomic keys for their identification. The updated list of Brazilian ticks includes 70 species, 47 in the family Ixodidae and 23 in the family Argasidae. The genera Amblyomma (32 spp.) and Ornithodoros (18 spp.) are the most representative. Updated taxonomic keys for the identification of ticks of Brazil are provided. Finally, the medico-veterinary significance of ticks occurring in this country is briefly discussed.

    更新日期:2019-11-18
  • Genetic diversity of Borrelia garinii from Ixodes uriae collected in seabird colonies of the northwestern Atlantic Ocean
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-06-25
    Hannah J. Munro, Nicholas H. Ogden, Samir Mechai, L. Robbin Lindsay, Gregory J. Robertson, Hugh Whitney, Andrew S. Lang

    The occurrence of Borrelia garinii in seabird ticks, Ixodes uriae, associated with different species of colonial seabirds has been studied since the early 1990s. Research on the population structure of this bacterium in ticks from seabird colonies in the northeastern Atlantic Ocean has revealed admixture between marine and terrestrial tick populations. We studied B. garinii genetic diversity and population structure in I. uriae collected from seabird colonies in the northwestern Atlantic Ocean, in Newfoundland and Labrador, Canada. We applied a multi-locus sequence typing (MLST) scheme to B. garinii found in ticks from four species of seabirds. The B. garinii strains found in this seabird colony ecosystem were diverse. Some were very similar to strains from Asia and Europe, including some obtained from human clinical samples, while others formed a divergent group specific to this region of the Atlantic Ocean. Our findings highlight the genetic complexity of B. garinii circulating in seabird ticks and their avian hosts but also demonstrate surprisingly close connections between B. garinii in this ecosystem and terrestrial sources in Eurasia. Genetic similarities among B. garinii from seabird ticks and humans indicate the possibility that B. garinii circulating within seabird tick-avian host transmission cycles could directly, or indirectly via connectivity with terrestrial transmission cycles, have consequences for human health.

    更新日期:2019-11-18
  • Lyme borreliosis incidence in Lombardy, Italy (2000–2015): Spatiotemporal analysis and environmental risk factors
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-07-03
    Sergio A. Zanzani, Sara G. Rimoldi, MariaTeresa Manfredi, Romualdo Grande, Alessia L. Gazzonis, Stefania Merli, Emanuela Olivieri, Vania Giacomet, Spinello Antinori, Giuliana Cislaghi, Giovanna Bestetti, Katiuscia Nan, Vittorio Sala, Maria R. Gismondo, Chiara Atzori, Eleonora De Faveri

    Lyme borreliosis cases have been reported from Lombardy in northern Italy, where Ixodes ricinus is the main vector of Borrelia burgdorferi sensu lato. However, spatial and temporal variation in the incidence of Lyme borreliosis is not well understood. In the present study, based on new notified cases of Lyme borreliosis from 2000 to 2015, an average of 1.24 new cases per million residents per year was documented. New cases, georeferenced at the municipal level, were analyzed by retrospective space-time analysis (using SaTScan v. 9.3.1); and land cover, extrapolated from a Corine Land Cover dataset (using QGIS 2.8.1), was used to implement an environmental risk factor analysis. Firstly, a temporal high-risk cluster was detected in Lombardy: the relative risk of Lyme borreliosis was 3.73 times higher during 2008–2015 compared with the entire study period. Moreover, in a spatiotemporal high-risk cluster with a circular base, land cover consisting of wildland-urban interface, meadow, forest and meadow-forest transition were significantly higher compared to low-risk areas. Results of the present study demonstrate that the incidence of Lyme borreliosis is increasing in Lombardy and that environmental conditions are suitable for I. ricinus ticks infected with B. burgdorferi s.l.: citizens and health systems should be aware of Lyme borreliosis to reduce tick bites with personal protective behaviors and to avoid misdiagnosis, particularly within the area including the observed high-risk cluster. Economic resources should be invested to inform about methods to prevent tick bites, how to check people and pets after frequenting risk areas, and ways of removing the biting ticks when they are found.

    更新日期:2019-11-18
  • Novel Ehrlichia sp. detected in Magellanic penguins (Sphenicus magellanicus) and in the seabird tick Ixodes uriae from Magdalena Island, southern Chile
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-06-25
    Sebastián Muñoz-Leal, Yara S. Clemes, Marcos G. Lopes, Igor C.L. Acosta, Maria Carolina A. Serpa, Luis Felipe S.P. Mayorga, Solange M. Gennari, Daniel González-Acuña, Marcelo B. Labruna

    Ehrlichia spp. are obligatory intracellular microorganisms that infect hematopoietic, endothelial or blood cells of mammals. Ticks are the only vectors of these agents in nature. To date, the role of birds and their associated ticks as reservoirs of ehrlichiae remains almost unexplored. In this study, we performed a molecular screening for bacteria of Anaplasmataceae family in samples of spleen (n = 72) and lung (n = 17), recovered from 72 carcasses of Magellanic penguins (Spheniscus magellanicus) in Brazil and Chile. One apparently unengorged tick (Ixodes uriae) was also collected while wandering upon one of the carcasses and submitted to molecular analyses as well. Through conventional and nested PCR protocols three genes (16S rRNA, dsb and groEL) of a new Ehrlichia sp. were partially characterized upon organs of three penguins and in the tick coming from Magdalena Island (Chile). First matches after BLASTn comparisons showed that our sequences share 99.4% (16S rRNA), 94.6% (groEL) and 79.3% (dsb) of identity with “Candidatus Ehrlichia ornithorhynchi”, Ehrlichia sp. NS101 and Ehrlichia canis CCZ, respectively. Matrixes of genetic distance including other representatives of the Ehrlichia genus point a 99.4%, 94.0%, and 80.0% of identity with 16S rRNA, groEL and dsb genes from Ehrlichia sp. It25, Ehrlichia sp. NS101, and Ehrlichia chaffeensis San Louis, respectively. A Bayesian phylogenetic analysis of Anaplasmataceae 16S rRNA gene places the detected Ehrlichia sp. into a group with Ehrlichia sp. BAT and Ehrlichia sp. Natal. Although depicting different topologies, Bayesian unrooted phylogenetic trees constructed for groEL and dsb genes position this Ehrlichia sp. into well-supported branches, which reinforces the finding of a new taxon. For the moment, any pathogenic effect of this new Ehrlichia sp. on penguins is still unknown. However, this fact becomes important to assess from a conservation point of view since populations of Magellanic penguins are currently threatened and in an ongoing decrease.

    更新日期:2019-11-18
  • Serologic survey of the Crimean-Congo haemorrhagic fever virus infection among wild rodents in Hungary
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-07-08
    Fanni Földes, Mónika Madai, Viktória Németh, Brigitta Zana, Henrietta Papp, Gábor Kemenesi, Ildikó Bock-Marquette, Győző Horváth, Róbert Herczeg, Ferenc Jakab

    Crimean-Congo haemorrhagic fever virus (CCHFV) is a tick-borne pathogen, which causes an increasing number of severe infections in many parts of Africa, Asia and in Europe. The virus is primarily transmitted by ticks, however, the spectrum of natural hosts regarding CCHFV includes a wide variety of domestic and wild animals. Although the presence of CCHFV was hypothesized in Hungary, data in support of CCHFV prevalence has thus far, proven insufficient. In the present study, rodents belonging to four species, the yellow-necked mouse (Apodemus flavicollis), the striped field mouse (A. agrarius), the wood mouse (A. sylvaticus) and the bank vole (Myodes glareolus), were all systematically trapped in the Mecsek Mountain region (Southwest Hungary), from 2011 through 2013. Rodent sera were collected and screened for CCHFV antibodies with dot-blot pre-screening and immunofluorescence assay. Among the 2085 tested rodents, 20 (0.96%) were positive for IgG antibody against CCHFV. Seroprevalence was the highest (1.25%) in A. flavicollis serum samples. Distinctly, we now provide the first data regarding CCHFV occurrence and seroprevalence among wild rodents in Hungary. This observation represents a need for large-scale surveillance to effectively assess the enzootic background and the potential public health risk of CCHFV in Hungary.

    更新日期:2019-11-18
  • A new species of Amblyomma (Acari: Ixodidae) associated with monkeys and passerines of the Atlantic rainforest biome, Southeastern Brazil
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-07-12
    Thiago F. Martins, Hermes R. Luz, Sebastián Muñoz-Leal, Diego G. Ramirez, Liliane Milanelo, Sandro Marques, Thais C. Sanches, Valeria C. Onofrio, Igor da C.L.Acosta, Hector R. Benatti, Ralph Maturano, Philipe B. de Oliveira, George R. Albuquerque, Arlei Marcili, Walter Flausino, Luis F. Silveira, Douglas McIntosh, João Luiz H. Faccini, Marcelo B. Labruna

    Recent studies have reported several larvae of an unidentified Amblyomma species on passerine birds in Atlantic rainforest fragments in southeastern Brazil. These larvae yielded a unique 16S rRNA haplotype designated as Amblyomma sp. haplotype Nazaré, which showed nucleotide identity levels of 91% to Amblyomma parkeri Fonseca & Aragão, 1952 and 88% to Amblyomma longirostre (Koch, 1844). Herein, we describe Amblyomma sp. haplotype Nazaré as a new species, Amblyomma romarioi n. sp. Martins, Luz & Labruna, through a formal description of the male and female adult stages. Amblyomma romarioi is morphologically and genetically most closely related to A. parkeri, A. longirostre and Amblyomma geayi Neumann, 1899. Among males, the rectangular basis capituli and rounded coxa I spurs separates A. romarioi from A. parkeri, A. longirostre, and A. geayi, which have basis capituli triangular or slightly hexagonal, and pointed coxa I spurs. Among females, the V-shaped genital aperture and coxa I rounded spurs of A. romarioi contrasts to the U-shaped genital aperture and coxa I pointed spurs in A. parkeri, A. longirostre, and A. geayi. Larvae of A. romarioi have been collected on 24 species of passerines. The few records of nymphs and adults were on the black-fronted titi monkey Callicebus nigrifrons (Spix, 1823). The current distribution of A. romarioi is restricted to the Brazilian Atlantic rainforest, southeastern Brazil, in areas with altitude between 363 and 1600 m, within the distribution of C. nigrifrons. We discuss ecological features of Amblyomma romarioi, comparatively to A. parkeri, A. longirostre and A. geayi. The present study increases the Brazilian tick fauna to 74 species.

    更新日期:2019-11-18
  • Improving specific detection and updating phylogenetic data related to Anaplasma platys-like strains infecting camels (Camelus dromedarius) and their ticks
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-07-12
    Rachid Selmi, Mourad Ben Said, Mokhtar Dhibi, Houcine Ben Yahia, Lilia Messadi

    In camels and their infesting ectoparasites, specific detection of pathogenic Anaplasma platys and genetically related strains (A. platys-like strains) remains problematic. This requires sequencing of the hemi-nested PCR products specific to A. platys and related strains. In this study, a PCR/RFLP method, earlier developed for specific detection of A. platys-like strains in animal species other than camels, was adapted in order to subtype A. platys-like strains isolated from camels and their ticks and to differentiate them from pathogenic A. platys without going through a sequencing step. This approach was used for investigating the infections with A. platys and related strains in 412 Camelus dromedarius camels and 334 feeding ticks from five Tunisian governorates. Microscopic examination using Giemsa-stained blood smears was performed in order to specify which types of cells were infected. Ticks were identified as Hyalomma dromedarii (n = 164, 49%), H. impeltatum (n = 161, 48.3%) and H. excavatum (n = 9, 2.7%). A. platys was not detected in any of the tested camels or ticks. The overall prevalence of A. platys-like strains was 5.6% (23/412) in camels and microscopic examination of infected cells showed a tropism for neutrophil granulocytes. One tick identified as H. dromedarii out of 327 analyzed ticks was found to be infected with A. platys-like strains (0.3%). Alignment, identity comparison and phylogenetic analysis of the 16S rRNA partial sequences obtained in this study suggest that Tunisian dromedaries and feeding ticks are infected with different Anaplasma strains genetically related to A. platys. Sequence analysis and phylogenetic study based on the groEL gene confirm the RFLP results and show that camel strains formed a separate sub-cluster relatively close to A. platys-like strains infecting Tunisian cattle. This adapted RFLP assay allows fast and specific detection of pathogenic A. platys and A. platys-like strains in camels and infesting ticks and has the intrinsic potential of revealing co-infections with these two types of bacteria in the same sample, reducing the time and costs associated with cloning and sequencing during molecular diagnosis.

    更新日期:2019-11-18
  • Multi-locus phylogenetic analysis groups the New World bacterium Rickettsia sp. strain ApPR with the Old World species R. africae; proposal of “Candidatus Rickettsia paranaensis”
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-07-12
    Maristela Peckle, Hermes R. Luz, Marcelo B. Labruna, Maria Carolina A. Serpa, Stanley Lima, Ralph Maturano, João L.H. Faccini, Douglas McIntosh

    Rickettsia parkeri sensu stricto (s.s.) is an emerging human pathogen in the Americas. Comprehension of the etiology of R. parkeri infections in South America is complicated by the existence of genetic variants (Atlantic rainforest, NOD and Parvitarsum) of this species that are associated with specific groups of Amblyomma ticks. The rickettsial bacterium strain ApPR was first reported in Amblyomma parkeri ticks in Southern Brazil in 2012 and was considered, based on sequencing of fragments of the gltA, htrA, ompA and ompB genes, to represent yet another genetic variant of R. parkeri. In the current work, a multi-locus phylogenetic analysis employing additional genes and intragenic regions was performed using DNA extracted from (a) larvae of A. parkeri and Amblyomma species haplotype Nazaré ticks collected from wild birds, (b) a nymph of Amblyomma sp. haplotype Nazaré recovered from a monkey (Callicebus nigrifons), representing the first report of that tick parasitizing a non-human primate and (c) from a cultured isolate of ApPR, isolated from colony-reared adults of Amblyomma geayi. Phylogenetic inference performed using Maximum-likelihood (ML), Maximum Parsimony (MP) and Bayesian (B) methods, consistently placed strain ApPR outside the New World R. parkeri complex and instead grouped it in proximity to the Old World species Rickettsia africae and Rickettsia sibirica. Estimates of evolutionary divergence provided additional support for the inferred phylogenetic relationship. Given the clear evolutionary distance between strain ApPR and R. parkeri we propose the recognition of “Candidatus Rickettsia paranaensis”.

    更新日期:2019-11-18
  • Severe babesiosis caused by Babesia divergens in a host with intact spleen, Russia, 2018
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-07-16
    Irina V. Kukina, Olga P. Zelya, Tatiana M. Guzeeva, Ludmila S. Karan, Irina A. Perkovskaya, Nina I. Tymoshenko, Marina V. Guzeeva

    We report a case of severe babesiosis caused by the bovine pathogen Babesia divergens with the development of multisystem failure in a splenic host. Immunosuppression other than splenectomy can also predispose people to B. divergens. There was heavy multiple invasion of up to 14 parasites inside the erythrocyte, which had not been previously observed even in asplenic hosts. The piroplasm 18S rRNA sequence from our patient was identical B. divergens EU lineage with identity 99.5–100%.

    更新日期:2019-11-18
  • Phenology of Amblyomma sculptum in a degraded area of Atlantic rainforest in north-eastern Brazil
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-07-15
    Filipe Dantas-Torres, Marcela Ferreira Melo, Kamila Gaudêncio da Silva Sales, Fernando José da Silva, Luciana Aguiar Figueredo, Marcelo Bahia Labruna

    Amblyomma sculptum is the principal vector of Rickettsia rickettsii, the main agent of spotted fever rickettsiosis in Brazil. Little information is available regarding the population dynamics of this tick in some regions, including north-eastern Brazil, where cases of spotted fever rickettsioses are increasingly reported. Herein, we studied the phenology of A. sculptum in a rural area in north-eastern Brazil. Ticks were collected from the environment, using dry ice-baited traps, monthly for two consecutive years. In total, 1500 ticks were collected: 94 females (6.3%), 74 males (4.9%), 468 nymphs (31.2%), and 864 larvae (57.6%). All nymphs and females were identified as A. sculptum. Males were tentatively identified as A. sculptum and larvae as Amblyomma spp. Ticks were more numerous during spring and summer, followed by autumn and winter. Peaks of larvae and nymphs were recorded during summer and spring, respectively, whereas adults were more frequently collected in spring. A total of 380 ticks were tested by PCR for the gltA gene of Rickettsia spp., but none of them were positive. While our results revealed a seasonal pattern for A. sculptum in north-eastern Brazil that is distinct from the seasonal pattern in south-eastern Brazil, we caution that the observed pattern could have been biased by the relatively low number of ticks collected. Finally, the absence of Rickettsia-infected ticks does not rule out the possibility that rickettsial organisms are circulating in the study area and further long-term studies are warranted.

    更新日期:2019-11-18
  • First detection of tick-borne encephalitis virus in Ixodes ricinus ticks and their rodent hosts in Moscow, Russia
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-07-30
    Marat Makenov, Lyudmila Karan, Natalia Shashina, Marina Akhmetshina, Olga Zhurenkova, Ivan Kholodilov, Galina Karganova, Nina Smirnova, Yana Grigoreva, Yanina Yankovskaya, Marina Fyodorova

    Here, we report the first confirmed autochthonous tick-borne encephalitis case diagnosed in Moscow in 2016 and describe the detection of tick-borne encephalitis virus (TBEV) in ticks and small mammals in a Moscow park. The paper includes data from two patients who were bitten by TBEV-infected ticks in Moscow city; one of these cases led to the development of the meningeal form of TBE. Both TBEV-infected ticks attacked patients in the same area. We collected ticks and trapped small mammals in this area in 2017. All samples were screened for the presence of pathogens causing tick-borne diseases by PCR. The TBEV-positive ticks and small mammals’ tissue samples were subjected to virus isolation. The sequencing of the complete polyprotein gene of the positive samples was performed. A total of 227 questing ticks were collected. TBEV was detected in five specimens of Ixodes ricinus. We trapped 44 small mammals, mainly bank voles (Myodes glareolus) and pygmy field mice (Apodemus uralensis). Two samples of brain tissue from bank voles yielded a positive signal in RT-PCR for TBEV. We obtained six virus isolates from the ticks and brain tissue of a bank vole. Complete genome sequencing showed that the obtained isolates belong to the European subtype and have low diversity with sequence identities as high as 99.9%. GPS tracking showed that the maximum distance between the exact locations where the TBEV-positive ticks were collected was 185 m. We assume that the forest park had been free of TBEV and that the virus was recently introduced.

    更新日期:2019-11-18
  • Knowledge, attitudes, and behaviors regarding tick-borne disease prevention in endemic areas
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-07-29
    Sara Niesobecki, AmberJean Hansen, Heather Rutz, Shaylee Mehta, Katherine Feldman, James Meek, Linda Niccolai, Sarah Hook, Alison Hinckley

    As part of a TickNET collaboration we evaluated the knowledge, attitudes, and behaviors related to tick-borne disease (TBD) prevention among persons living in endemic areas of Connecticut (CT) and Maryland (MD). Up-to-date information on the use of various prevention methods, as well as attitudes toward available and potential prevention options, is critical for effective promotion of recommended behaviors. During 2016–2017, printed invitations were mailed via the post office to 27,029 households requesting participation in an online survey regarding knowledge of TBD, risk perceptions, and prevention behaviors. Prevention behaviors included tick checks, showering/bathing, insect repellents, pet tick control, and chemical or natural pesticide use on residential properties. Associations of sociodemographic characteristics and knowledge and attitude variables with prevention behaviors were assessed in unadjusted analyses and multivariable models to calculate adjusted odds ratios (aOR). Participants were also asked if they would be willing to get a Lyme disease (LD) vaccine, if one becomes available. Overall, 1883 (7%) persons completed the survey. Participants reported using preventive behaviors most of the time or always as follows: pet tick control (83%), tick checks (58%), showering/bathing (42%), insect repellent (31%), and chemical (23%) or natural (15%) pesticides on property. Self-rated knowledge of LD, perceived prevalence of LD, perceived severity of LD, and perceived likelihood of contracting LD or another TBD were significantly (p < 0.05) associated with performing a tick check [aOR 2.5, aOR 1.71, aOR 1.36, aOR 1.83, respectively]. Female gender and perceived prevalence of LD were significantly associated with applying insect repellent [aOR 1.56, aOR 1.64, respectively]. Perceived prevalence of LD was significantly associated with showering or bathing, insect repellents, and pet tick control [aOR 1.42, aOR 1.64, aOR 1.92, respectively]. Income > $100,000 was significantly associated with applying a chemical or natural pesticide to one’s property [aOR 1.29, aOR 1.40, respectively]. A majority of respondents (84%) reported that they were very likely or somewhat likely to get a LD vaccine if one were available. Few behaviors (tick checks and pet tick control) were reported to be practiced by more than half of the respondents living in LD endemic areas. Perceived prevalence of LD was the only factor associated with performing most of the prevention behaviors (tick checks, showering/bathing, use of insect repellents, and pet tick control). Use of chemical or natural pesticides appears to be driven by income. Greater efforts are needed to encourage use of prevention behaviors in endemic areas, and this may be facilitated by increasing awareness of local prevalence.

    更新日期:2019-11-18
  • Real-time PCR assay with an endogenous internal amplification control for detection and quantification of Anaplasma marginale in bovine blood
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-11-18
    Svetlana N. Kovalchuk, Anna V. Babii, Anna L. Arkhipova

    Bovine anaplasmosis is a tick-borne rickettsial disease, causing significant economic losses in many countries. The main causative agent of bovine anaplasmosis is Anaplasma marginale (Rickettsiales, Anaplasmataceae). To date, several PCR assays for A. marginale DNA detection were proposed, but most of them do not provide an internal amplification control, which allows to prevent false-negative results and is required for reliability of the results of pathogen DNA detection by PCR assay. In the present study, a real-time PCR assay based on the species-specific and highly conserved fragment of msp1a gene was developed for detection and quantification of A. marginale in bovine blood. The real-time PCR assay is able to detect as few as one copу of msp1α gene per reaction. To prevent false-negative results, simultaneous amplification and detection of the bovine genomic DNA fragment as an endogenous internal amplification control (IAC) was provided. The assay can be used as a highly specific and sensitive method for detection and quantification of A. marginale in infected cattle, and for the evaluation of the efficacy of anti-rickettsial drugs and anaplasmosis vaccines.

    更新日期:2019-11-18
  • GENETIC DIVERSITY OF KEMEROVO VIRUS AND PHYLOGENETIC RELATIONSHIPS WITHIN THE GREAT ISLAND VIRUS GENETIC GROUP
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-11-17
    Marina V. Safonova, Anatoly P. Gmyl, Alexander N. Lukashev, Anna S. Speranskaya, Alexey D. Neverov, Gennady G. Fedonin, Ekaterina V. Pimkina, Alina D. Matsvay, Kamil F. Khafizov, Galina G. Karganova, Lubov I. Kozlovskaya, Anna V. Valdokhina, Victoria P. Bulanenko, Vladimir G. Dedkov

    Kemerovo virus (KEMV) is a member of the Great Island virus genetic group, belonging to the tick-borne arboviruses of the genus Orbivirus within the family Reoviridae. Nine strains of KEMV, which were isolated from various locations in Russia, were sequenced by high-throughput sequencing to study their intraspecific diversity and the interspecific relationships of viruses within the Great Island genetic group. For the first time, multiple reassortment within KEMV was reliably demonstrated. Different types of independently emerged alternative reading frames in segment 9 and heterogeneity of the viral population in one of the KEMV strains were found. The hypothesis of the role of an alternative open reading frame (ORF) in segment 9 in KEMV cellular tropism was not confirmed in this study.

    更新日期:2019-11-18
  • Controversies in bacterial taxonomy: The example of the genus Borrelia
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-11-17
    Gabriele Margos, Volker Fingerle, Sally Cutler, Alexander Gofton, Brian Stevenson, Agustín Estrada-Peña

    In this paper we survey key issues in bacterial taxonomy and review the literature regarding the recent genus separation proposed for the genus Borrelia. We discuss how information on members of the genus Borrelia is increasing but detailed knowledge on the relevant features is available only for a small subset of species. The data accumulated here show that there is considerable overlap in ecology, clinical aspects and molecular features between clades that argue against splitting of the genus Borrelia.

    更新日期:2019-11-18
  • Immunosuppressive Effects of Sialostatin L1 and L2 Isolated from the Taiga Tick Ixodes persulcatus Schulze
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-11-10
    Yamato Sajiki, Satoru Konnai, Akie Ochi, Tomohiro Okagawa, Naftaly Githaka, Masayoshi Isezaki, Shinji Yamada, Takuya Ito, Shuji Ando, Hiroki Kawabata, Carlos Logullo, Itabajara da Silva Vaz, Naoya Maekawa, Shiro Murata, Kazuhiko Ohashi

    Tick saliva contains immunosuppressants which are important to obtain a blood meal and enhance the infectivity of tick-borne pathogens. In Japan, Ixodes persulcatus is a major vector for Lyme borreliosis pathogens, such as Borrelia garinii, as well as for those causing relapsing fever, such as B. miyamotoi. To date, little information is available on bioactive salivary molecules, produced by this tick. Thus, in this study, we identified two proteins, I. persulcatus derived sialostatin L1 (Ip-sL1) and sL2 (Ip-sL2), as orthologs of I. scapularis derived sL1 and sL2. cDNA clones of Ip-sL1 and Ip-sL2 shared a high identity with sequences of sL1 and sL2 isolated from the salivary glands of I. scapularis. Semi-quantitative PCR revealed that Ip-sL1 and Ip-sL2 were expressed in the salivary glands throughout the life of the tick. In addition, Ip-sL1 and Ip-sL2 were expressed even before the ticks started feeding, and their expression continued during blood feeding. Recombinant Ip-sL1 and Ip-sL2 were developed to characterize the proteins via biological and immunological analyses. These analyses revealed that both Ip-sL1 and Ip-sL2 had inhibitory effects on cathepsins L and S. Ip-sL1 and Ip-sL2 inhibited the production of IP-10, TNFα, and IL-6 by LPS-stimulated bone-marrow-derived dendritic cells (BMDCs). Additionally, Ip-sL1 significantly impaired BMDC maturation. Taken together, these results suggest that Ip-sL1 and Ip-sL2 confer immunosuppressive functions and appear to be involved in the transmission of pathogens by suppressing host immune responses, such as cytokine production and dendritic cell maturation. Therefore, further studies are warranted to investigate the immunosuppressive functions of Ip-sL1 and Ip-sL2 in detail to clarify their involvement in pathogen transmission via I. persulcatus.

    更新日期:2019-11-11
  • Epidemiological investigations of Crimean-Congo haemorrhagic fever virus infection in sheep and goats in Balochistan, Pakistan
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-11-09
    Khushal Khan Kasi, Miriam Andrada Sas, Carola Sauter-Louis, Felicitas von Arnim, Jörn Martin Gethmann, Ansgar Schulz, Kerstin Wernike, Martin H. Groschup, Franz J. Conraths

    Crimean-Congo haemorrhagic fever (CCHF) is a tick-borne zoonotic disease caused by the arbovirus Crimean-Congo haemorrhagic fever virus (CCHFV). Livestock serve as a transient reservoir for CCHFV, but do not show clinical signs. In this cross-sectional study, sheep and goats in Balochistan, Pakistan, were examined to determine the CCHFV seroprevalence, spatial distribution of seropositive sheep and goats, and to identify potential risk factors for seropositivity to CCHFV in these animals. To this end, farms and animals were selected by systematic sampling, blood samples from 800 sheep and 800 goats were collected and information regarding farm management and the kept animals were retrieved using a standard questionnaire. Sera were tested for antibodies against CCHFV in two independent ELISA formats and an immunofluorescence assay (IFA) following a hierarchical diagnostic decision tree. By these assays 149 (19%, 95%-CI: 16-21%) out of 800 sheep serum samples and 37 (5%, 95%-CI: 3-6%) out of 800 goat serum samples were positive for CCHFV-specific IgG antibodies. Interestingly, at least 8 (5%, 95%-CI: 2-10%) out of 160 sera pools were from CCHFV viraemic sheep, as sera (in pools of 5) tested positive for CCHFV genome by real-time PCR (RT-qPCR). Risk factor analysis revealed that the open type of housing (OR = 3.76, 95%-CI:1.57-9.56, p-value = 0.003), grazing (OR = 4.18, 95%-CI:1.79-10.37, p-value = 0.001), presence of vegetation in or around the farm (OR = 3.13, 95%-CI: 1.07-10.15, p-value = 0.043), lack of treatment against ticks (OR = 3.31, 95%-CI: 1.16-10.21, p-value = 0.029), absence of rural poultry (OR = 2.93, 95%-CI: 1.41-6.29, p-value = 0.004), animals with age ≥ 2 years (OR = 4.15, 95%-CI: 2.84-6.19, p-value<0.001), animals infested with ticks (OR = 2.35, 95%-CI: 1.59-3.52, p-value<0.001), and sheep species (OR = 4.72, 95%-CI:3.24-6.86, p-value<0.001) represented statistically significant risk factors associated with seropositivity to CCHFV. Taken together this study confirms the circulation of CCHFV in livestock in Balochistan, Pakistan. The identification of risk factors might help to reduce the risk of infection in sheep and goats, which may also mitigate the risk for human infection. An interesting option for reducing the risk of CCHFV infection in small ruminants is keeping also chickens, since they pick ticks that transmit CCHFV.

    更新日期:2019-11-11
  • Phylogenetic Analysis of Severe Fever with Thrombocytopenia Syndrome Virus in Korean Water Deer (Hydropotes inermis argyropus) in the Republic of Korea
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-11-08
    Hyun Seo Lee, Jisoo Kim, Kidong Son, Yongkwan Kim, Jusun Hwang, Hyesung Jeong, Tae-Young Ahn, Weon-Hwa Jheong

    Severe fever with thrombocytopenia syndrome (SFTS) is an emerging zoonotic tick-borne disease caused by SFTS virus, which circulates among ticks and their host animals, including wildlife. However, few studies have examined SFTS virus infection in wildlife present in the Republic of Korea (ROK). We evaluated SFTS virus infection in tissue samples from Korean water deer (Hydropotes inermis argyropus), one of the most common wild ungulates in ROK. In this study, we evaluated tissue samples of 129 water deer carcasses collected in 2017 and detected SFTS viral RNA by conventional PCR. SFTS viral RNA was found in 3 of the 129 carcasses, showing a prevalence of 2.3%; 2 of which were collected in Gyeongsangnam-do and 1 of which was in the Gangwon-do region. Among the 6 internal organs studied, only the spleen samples were positive. Phylogenetic analysis revealed close relationships between deer- and human-derived strains. The medium segments of the three positive cases clustered with genotype B, which is the predominant genotype in ROK. In the small segment, two cases clustered with genotype B, samples 17WD044 and 17WD065. The third sample, 17WD068 from Gangwon-do province, showed genotype A, which circulates mainly in China. The disagreement in the genotypes of the two tested segments suggests a potential reassortment between genotype A and B, resulting in genetic recombination as observed in sample 17WD068, which may be co-circulating in China and Korea. Further studies in wildlife and humans are necessary to understand the genetic characteristics of SFTS viruses circulating in ROK.

    更新日期:2019-11-08
  • Importance of equine piroplasmosis antibody presence in Spanish horses prior to export
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-11-08
    Eliazar Camino, Pilar Pozo, Abel Dorrego, Kelly Alejandra Carvajal, Aranzazu Buendia, Sergio Gonzalez, Lucia de Juan, Lucas Dominguez, Fatima Cruz-Lopez

    Serological analysis of equine piroplasmosis (EP), caused by Theileria equi and Babesia caballi, is included in the export testing requirements for most of the countries worldwide, thus involving a high economic impact on equine industry of EP-endemic countries, such as Spain. A total of 3368 serum samples from healthy horses collected prior to export between 2015 and 2018 in Spain were tested for antibodies against T. equi and B. caballi by using a competitive inhibition enzyme-linked immunosorbent assay (cELISA). The overall seroprevalence results in Spain revealed that almost a quarter of the horses analysed (24.1%; 95% CI 22.6-25.5) could not be exported to countries free from EP. The implementation of prevention measures such as the use of acaricides and daily checks for ticks in horses, as well as regular serological screening of horses in Spain would aid to increase the number of horses exported to other countries.

    更新日期:2019-11-08
  • Ticks biting humans in the Brazilian savannah: attachment sites and exposure risk in relation to species, life stage and season
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-11-08
    Matias Pablo Juan Szabó, Thiago Fernandes Martins, Amália Regina Mar Barbieri, Francisco Borges Costa, Herbert Sousa Soares, Graziela Virginia Tolesano-Pascoli, Khelma Torga, Danilo Gonçalves Saraiva, Vanessa do Nascimento Ramos, Carolina Fonseca Osava, Marcio Botelho de Castro, Marcelo Bahia Labruna

    Information about human tick bites in Brazil is mostly anecdotal. Published information is typically restricted to single tick infestation episodes and does not address human exposure occurring on a daily basis in natural, rural, or green urban areas. We present a comprehensive 2-yr study on human parasitism during a broad survey on ticks within a Brazilian savannah reserve. Overall, 439 tick bites were recorded from the following species: Amblyomma sculptum (n = 331 bites), Amblyomma parvum (n = 64), Amblyomma auricularium (n = 3), Rhipicephalus microplus (n = 2), Dermacentor nitens (n = 1) and 38 Amblyomma spp. ticks. Nymphs accounted for most tick bites (n = 292, 66.5% of all bites) and these were overwhelmingly A. sculptum (92.8% of nymphal bites). The main adult tick biting humans was A. parvum (n = 61, 50% of all adult tick bites) followed closely by A. sculptum (n = 58, 47.5% of all adult tick bites). Winter was the season with the highest percentage of tick bites (39.7% of all bites), followed by spring (32.4%); summer (18.9%) and autumn (9%). Amblyomma sculptum adult bites peaked in summer whereas nymphal bites occurred primarily in winter and spring. Amblyomma parvum adult bites peaked in spring and summer. The most common tick attachment sites included the waist, legs and belly, but A. parvum adults were recorded from the head of humans as well. A noteworthy observation was the lack of human parasitism by Amblyomma triste, the third most prevalent species in the environment. This tick species is a frequent human biter in both Uruguay and Argentina where it transmits a pathogen, Rickettsia parkeri, to humans.

    更新日期:2019-11-08
  • Molecular identification of protozoal and bacterial organisms in domestic animals and their infesting ticks from north-eastern Algeria
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-11-08
    Rima Sadeddine, Adama Zan Diarra, Maureen Laroche, Oleg Mediannikov, Souad Righi, Ahmed Benakhla, Handi Dahmana, Didier Raoult, Philippe Parola

    A molecular survey was undertaken to determine the presence of protozoal and bacterial organisms in 120 ticks and 87 blood samples collected from mammals in north-eastern Algeria. Eight tick species were morphologically identified including 70 Rhipicephalus (Boophilus) annulatus, 23 Rhipicephalus bursa, five Rhipicephalus sanguineus sensu lato, 11 Hyalomma impeltatum, five Hyalomma scupense, two Hyalommma marginatum, one Hyalomma anatolicum and three Ixodes ricinus. Quantitative PCR screening of the ticks showed that Theileria annulata, “Candidatus Ehrlichia urmitei”, Theileria buffeli and Anaplasma platys were detected in Rh. annulatus. Rickettsia massiliae and Anaplasma ovis were detected in Rh. sanguineus s.l. and Rh. bursa. Rickettsia aeschlimannii was detected in Hy. marginatum, Hy. scupense and Hy. impeltatum. Finally, “Candidatus Rickettsia barbariae” was detected in Rh. bursa. In the screening blood samples, Theileria equi, T.annulata, T. buffeli, Babesia bovis, Anaplasma marginale, A. ovis and Borrelia spp. were detected in cattle. Theileria ovis, T. annulata, and A. ovis were detected in sheep. In addition, A. ovis and T. equi were detected in goats and equidea respectively. In this study, T. equi and “Candidatus Rickettsia barbariae” were identified for the first time in Algeria as well as potential new species of Ehrlichia and Anaplasma. Although molecular detection does not indicate vector/reservoir competence when investigating ticks removed from animals, this study expands the knowledge of the microorganisms detected in ticks in north-east of Algeria.

    更新日期:2019-11-08
  • Genetic diversity and geographical distribution of the Siberian subtype of the tick-borne encephalitis virus
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-11-07
    S.E. Tkachev, I.V. Babkin, G.S. Chicherina, I.V. Kozlova, M.M. Verkhozina, T.V. Demina, O.V. Lisak, E.K. Doroshchenko, Yu.P. Dzhioev, O.V. Suntsova, P.S. Belokopytova, A.Yu. Tikunov, Yu.S. Savinova, A.I. Paramonov, V.V. Glupov, V.I. Zlobin, N.V. Tikunova

    The tick-borne encephalitis virus (TBEV), a member of the Flaviviridae family, is currently subdivided into three main subtypes—the European (TBEV-Eu), the Far-Eastern (TBEV-FE), and the Siberian (TBEV-Sib). The TBEV-Sib is the most common subtype and found in all regions where TBEV was detected, except for Central and Western Europe. Currently, four genetic lineages have been described within TBEV-Sib. In this study, detailed analysis of TBEV-Sib genetic diversity, geographic distribution, phylogeography and divergence time of different TBEV-Sib genetic lineages based on E gene fragments, complete genome sequences, and all currently available data in the GenBank database was performed. As a result, a novel Bosnia lineage within the TBEV-Sib was identified. It was demonstrated that the Zausaev lineage is the most widely distributed among the TBEV-Sib lineages, and was detected in all studied regions except the Far East. The Vasilchenko lineage was found from Western Siberia to the Far East. The Baltic lineage is presented from Europe to Western Siberia. The Obskaya lineage was found only in Western Siberia. TBEV strains from a newly described Bosnia lineage were detected in Bosnia, the Crimean peninsula, Kyrgyzstan and Kazakhstan. The greatest divergence of the TBEV-Sib genetic variants was observed in Western Siberia. Within the TBEV-Sib, the Obskaya lineage diverged from the common ancestor the earliest, after that the Bosnia lineage was separated, then the Baltic lineage, and the Zausaev and Vasilchenko lineages diverged most recently.

    更新日期:2019-11-08
  • Oogenesis and embryogenesis inhibition induced by two new ethyl-carbamates in the cattle tick Rhipicephalus microplus
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-11-07
    Sandra L. Iturbe-Requena, María G. Prado-Ochoa, Ana M. Velázquez-Sánchez, Fernando García-Hernández, Raquel Cossío-Bayúgar, Marco A. Muñoz-Guzmán, Enrique Ángeles, Fernando Alba-Hurtado

    The purpose of this work was to contribute to the understanding of the mechanism of action of two new ixodicides. The histological and ultrastructural alterations of Rhipicephalus microplus oocytes (San Alfonso strain) treated with two new ethyl-carbamates (ethyl-4-bromophenyl carbamate and ethyl-4-chlorophenyl carbamate) by the adult immersion test were evaluated by light microscopy and transmission electron microscopy. The effects of the carbamates on embryogenesis in eggs were evaluated by fluorescence microscopy using DAPI staining. Both ethyl-carbamates inhibited the maturation of most oocytes and induced a concentration-dependent decrease (r2 = 0.5, p < 0.05) in the embryonation percentage in the small number of eggs oviposited by treated ticks. Evident ultrastructural alterations were observed in the oocytes from ticks exposed to the ethyl-carbamates, including modification of the chorion structure, myelinic bodies and autophagic vacuoles that were associated with degenerated organelles (mitochondria, endoplasmic reticulum and yolk granules), nucleolus fragmentation and chromatin clumping in germinal vesicles. In conclusion, these ethyl-carbamates affect the reproductive potential of R. microplus due to their negative effects on oogenesis and their repercussions for embryonic development.

    更新日期:2019-11-08
  • Epidemiological aspects of Rickettsia parkeri in the Atlantic forest biome of Espírito Santo state, Brazil
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-11-06
    Álvaro A. Faccini-Martínez, Sebastián Muñoz-Leal, Felipe S. Krawczak, Igor C.L. Acosta, Thiago F. Martins, Maria Carolina A. Serpa, Amalia R.M. Barbieri, Juliana R. Tovar, Crispim Cerutti Junior, Marcelo B. Labruna

    Since 2010, a new rickettsiosis caused by Rickettsia parkeri, a species included in the spotted fever group (SFG) and transmitted by the tick Amblyomma ovale, has been described in Brazil. Considering that A. ovale does occur in the Espírito Santo state (ES), the present study aimed at preliminarily describing the epidemiology of R. parkeri in the Atlantic forest of this state. Between June 2016 and September 2018, 33 villages from nine municipalities of the ES were included in a study for the molecular detection and isolation of SFG rickettsiae from adult Amblyomma ticks collected on dogs with free access to the forest. Serologic screenings against SFG rickettsiae in these animals and their owners (humans) were performed through immunofluorescence assay (IFA) using antigens of Rickettsia rickettsii and R. parkeri. Additionally, local health secretariats were informed on clinical manifestations of R. parkeri infection and told to communicate any suspected case. A total of 280 adult ticks were collected and taxonomically classified as A. ovale (n = 152), Amblyomma aureolatum (n = 127) and Amblyomma sculptum (n = 1). Overall, Rickettsia DNA was detected in 12/266 ticks. The sequencing of PCR products revealed that 0.7% (1/144) and 0.8% (1/121) of the analyzed A. ovale and A. aureolatum ticks were infected by R. parkeri strain Atlantic rainforest, respectively, and 8.3% (10/121) of the A. aureolatum ticks infected by Rickettsia bellii. Among the above PCR-positive ticks, only one isolate from one A. aureolatum tick was successfully established in the laboratory. DNA extracted from the third passage of this isolate was designated as strain M9A and molecularly characterized using primers targeting the Rickettsia gltA gene, whose sequence matched 100% the corresponding sequences of R. bellii. Seroprevalence against SFG rickettsiae in sampled dogs (n = 83) was 41% or 57%, depending on the rickettsial antigen (R. rickettsii strain Taiaçu or R. parkeri strain Atlantic rainforest, respectively). A total of 37 (45%) canine sera showed titers to R. parkeri at least fourfold higher than to R. rickettsii antigen. Among humans, 10% (4/41) of the samples reacted to at least one rickettsial antigen, with the highest endpoint titer varying from 64 to 128 for R. rickettsii and R. parkeri; no human serum showed ≥4-fold difference between the highest endpoint titers. Finally, during the study period, suspicions on cases of R. parkeri-rickettsiosis were not informed by the health secretariats. Our results confirm the presence and exposure to R. parkeri strain Atlantic rainforest, associated with two anthropophilic tick species (A. ovale and A. aureolatum) parasitizing domestic dogs with unrestrained access to forest areas. Consequently, the occurrence of R. parkeri infection in humans inhabiting the Atlantic forests of ES should not be discarded.

    更新日期:2019-11-07
  • Completing the cycle: Haemaphysalis elliptica, the vector of Babesia rossi, is the most prevalent tick infesting black-backed jackals (Canis mesomelas), an indigenous reservoir host of B. rossi in South Africa
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-11-04
    Barend L. Penzhorn, Robert F. Harrison-White, Wilhelm H. Stoltsz

    In sub-Saharan Africa, virulent babesiosis in domestic dogs is primarily caused by Babesia rossi. Black-backed jackals (Canis mesomelas), indigenous hosts of B. rossi, are the most likely reservoir from which B. rossi became established in domestic dog populations in South Africa. Haemaphysalis elliptica is the only confirmed vector transmitting B. rossi to domestic dogs; very little was known about the prevalence of H. elliptica infestation in black-backed jackal populations. All jackals (n = 9) from a site in Gauteng Province, South Africa, were infested with H. elliptica, which was also the most numerous tick recovered. Rhipicephalus simus was the second-most prevalent tick. Low numbers of four other tick species were recovered. An extended dataset (n = 23) including published data on adult black-backed jackals (n = 14) from other parts of South Africa indicated that H. elliptica (74%) was the most prevalent species, followed by R. simus (44%). Published data from black-backed jackals (n = 12) in Kenya showed a prevalence of H. leachi (sensu lato) infestation of 93%. We conclude that where its ecological requirements are met, H. elliptica/leachi is the most prevalent tick infesting black-backed jackal population throughout their range. A comprehensive checklist, with discussion, is given for the 29 tick species reported from black-backed jackals in both southern and northeastern Africa.

    更新日期:2019-11-04
  • Microbiota assessment across different developmental stages of Dermacentor silvarum (Acari: Ixodidae) revealed stage-specific signatures
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-11-02
    Ruiling Zhang, Guangfu Yu, Zhendong Huang, Zhong Zhang

    Dermacentor silvarum is an important vector of tick-borne pathogens. The microbiota of ticks has been recognized to influence their development, fitness, and reproduction as well as the acquisition, establishment and transmission of pathogens. Eggs, larvae, nymphs and adults (females and males) of D. silvarum were used in this study to evaluate microbial community and diversity across different developmental stages. The results demonstrated that some developmental stages host different bacterial species, confirming that each stage of development could have a specific associated microbiota. Proteobacteria was the dominant phylum in most stages, while Actinobacteria was the most abundant in nymphs. The abundance of Brevibacterium significantly increased from the egg stage to the following stages, and there was a sharp increase in the abundance of this genus among nymphs. Eggs showed the highest microbial richness and diversity, and the microbial community of eggs exhibited high similarity to that of females. Moreover, the high abundance of Coxiella in eggs and females further indicated that members of this genus are vertically transmitted symbionts. Nymphs showed a microbial composition distinct from those of the other stages, and the microbial community associated with males possessed higher species richness and greater bacterial diversity than that of females. Further investigations are needed to determine the functions of the microbiota and provide information enabling a better understanding of the diversity of the microbial community at different life stages.

    更新日期:2019-11-04
  • Interpretation of the larval immersion test with ivermectin in populations of the cattle tick Rhipicephalus (Boophilus) microplus from Colombian farms
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-10-31
    Jenny J. Chaparro-Gutiérrez, David Villar, David J. Schaeffer

    Interpreting in vitro bioassays used to determine resistance against acaricides in Rhipicephalus microplus can be challenging without parallel in vivo studies that assess for lost efficacy. The larval immersion test (LIT) is currently the most widely used bioassay to detect ivermectin resistance. The objective of this study was to compare results of the LIT and a field trial using ivermectin in naturally infested cattle. Criteria to consider ticks as resistant with the LIT were based on discriminating doses (DD) and the ratio of lethal concentration (LC) in test populations over the LC of the susceptible Deutch strain, known as the resistance ratio (RR). Ticks were collected from 4 farms, two where ivermectin provided good control of tick infestations and two that claimed lack of efficacy. In two farms where administration of a long-acting ivermectin formulation reduced body tick counts to 45 and 25% of the initial counts at 10-days post-treatment, the RR50 and RR99 were approximately 6 and 20, respectively. The LC50 value approximated the DD for the two farms with claimed resistance, suggesting that about half of the population in each farm was resistant. These LIT values are equal to those reported for the most resistant ticks, which supports the use of the LIT to predict control failure in field situations. The two farms where ivermectin provided good control of tick infestations had LC50s similar to the susceptible strain, although for one farm the LC99 and RR99 suggested incipient resistance.

    更新日期:2019-11-01
  • Genetic diversity of Francisella tularensis in Poland with comments on MLVA genotyping and a proposition of a novel rapid v4-genotyping
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-10-31
    Kamila Formińska, Tomasz Wołkowicz, Klaudia Brodzik, Paweł Stefanoff, Elżbieta Gołąb, Aleksander Masny, Beata Osiak, Piotr Cieślik, Agata Bielawska-Drózd, Aleksandra Anna Zasada

    We investigated the genotypes of Francisella tularensis (F. tularensis) strains isolated in Poland during the period 1953–2013 and studied their genetic relationship to F. tularensis strains isolated in other countries using MLVA. We examined the mosquito and tick samples collected in Poland for the presence of F. tularensis DNA using PCR. Our results revealed a high genetic diversity among the strains of F. tularensis collected from Poland, suggesting that the bacterium is commonly found in the environment. However, we did not detect F. tularensis DNA in ticks and mosquitoes, showing that the arthropod bites might not be the main source of infection. We also propose the application of a practical assay called v4-genotyping that can be directly performed on the clinical and environmental samples. In addition, we discovered genetic variations among Schu S4 reference strains used in various laboratories and showed that MLVA analysis should not be based on amplicon sizes only because point mutations occurring within the MLVA loci might not always be manifested by a change in the amplicon size.

    更新日期:2019-11-01
  • Emerging tick-borne pathogens in the Nordic countries: A clinical and laboratory follow-up study of high-risk tick-bitten individuals.
    Ticks Tick Borne Dis. (IF 3.055) Pub Date : 2019-10-22
    Lukas Frans Ocias,Peter Wilhelmsson,Johanna Sjöwall,Anna Jonsson Henningsson,Marika Nordberg,Charlotte Sværke Jørgensen,Karen Angeliki Krogfelt,Pia Forsberg,Per-Eric Lindgren

    Despite the presence of several microorganisms, other than Borrelia burgdorferi sensu lato (Bbsl) and TBE virus, in Ixodes ricinus ticks from the Nordic countries, data is lacking on their pathogenic potential in humans. In this study, we wanted to investigate the aetiology and clinical manifestations of tick-transmitted infections in individuals seeking medical care following a tick-bite. The sampling frame was participants of a large-scale, prospective, multi-centre, follow-up study of tick-bitten volunteers recruited in Sweden, Finland and Norway in the years 2007-2015. Participants who sought medical care during the three-month follow-up period and from whom blood samples were collected during this healthcare visit (n = 92) were tested, using PCR, for exposure to spotted fever group (SFG) Rickettsia spp., Anaplasma phagocytophilum and Babesia spp. Moreover, 86 of these individuals had two serum samples, collected three months apart, tested serologically for six tick-borne microorganisms. The selected organisms - Bbsl, SFG rickettsiae, Anaplasma phagocytophilum, TBE virus, Babesia microti and Bartonella henselae - have all been detected in field-collected ticks from the Nordic countries. Medical records were reviewed and questionnaires were completed to determine clinical manifestations. We found Lyme borreliosis to be the most common tick-transmitted infection as seen in 46 (54%) of the 86 participants with available medical records. Among the 86 participants with paired sera, serological or molecular evidence of recent exposure to other microorganisms than Bbsl could be demonstrated in eight (9%). Five participants (6%) exhibited serological evidence of recent concomitant exposure to more than one tick-borne microorganism. Clinical presentations were mild with one exception (TBE). In conclusion, our data suggest a low risk of infection with tick-borne microorganisms, other than Bbsl, in immunocompetent tick-bitten persons from the examined regions, a low occurrence of co-infection and mostly mild or no overt clinical signs of infection in immunocompetent persons exposed to the studied agents.

    更新日期:2019-11-01
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