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1.
Nat Commun ; 12(1): 5539, 2021 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-34545081

RESUMO

The increasing burden of tick-borne orthonairovirus infections, such as Crimean-Congo hemorrhagic fever, is becoming a global concern for public health. In the present study, we identify a novel orthonairovirus, designated Yezo virus (YEZV), from two patients showing acute febrile illness with thrombocytopenia and leukopenia after tick bite in Hokkaido, Japan, in 2019 and 2020, respectively. YEZV is phylogenetically grouped with Sulina virus detected in Ixodes ricinus ticks in Romania. YEZV infection has been confirmed in seven patients from 2014-2020, four of whom were co-infected with Borrelia spp. Antibodies to YEZV are found in wild deer and raccoons, and YEZV RNAs have been detected in ticks from Hokkaido. In this work, we demonstrate that YEZV is highly likely to be the causative pathogen of febrile illness, representing the first report of an endemic infection associated with an orthonairovirus potentially transmitted by ticks in Japan.


Assuntos
Febre/epidemiologia , Febre/virologia , Nairovirus/fisiologia , Adulto , Animais , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Febre/sangue , Genoma Viral , Humanos , Ixodes/virologia , Japão/epidemiologia , Contagem de Leucócitos , Masculino , Pessoa de Meia-Idade , Nairovirus/genética , Nairovirus/imunologia , Nairovirus/ultraestrutura , Filogenia , RNA Viral/genética , Vírion/ultraestrutura
2.
Ticks Tick Borne Dis ; 12(6): 101800, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34352531

RESUMO

Lyme borreliosis is a zoonotic tick-borne infection representing the most frequent vector-borne disease in the northern hemisphere. The Mediterranean rim is generally described as unsuitable for the European vector, Ixodes ricinus. We conducted an epidemiological study to assess whether I. ricinus was present and study its infection status for tick-borne bacteria. Ticks originating from southeastern France were obtained from flagging sampling and removed from animals and tick-bitten patients. Species level identification used morphological keys and MALDI-TOF MS. Quantitative PCR and sequencing assays were used to detect and identify tick-associated bacteria (Borrelia, Rickettsia, Anaplasmataceae, Bartonella, Coxiella burnetii) in each specimen. A total of 1232 ticks were collected in several localities. Among these, 863 were identified as I. ricinus (70%). Bacterial screening allowed identification of Lyme group Borrelia among I. ricinus ticks originating from various regional areas. Other emerging tick-borne pathogens like Borrelia miyamotoi and Rickettsia species were also detected. The Alpes-Maritimes region, part of the French Riviera, harbours I. ricinus ticks infected with Lyme group Borrelia and several other tick-borne bacterial agents. Clinicians and outdoor activity participants should be aware of the local Lyme borreliosis transmission risk.


Assuntos
Distribuição Animal , Doenças Transmissíveis Emergentes/epidemiologia , Ixodes , Doenças Transmitidas por Carrapatos/epidemiologia , Animais , Doenças Transmissíveis Emergentes/microbiologia , Doenças Transmissíveis Emergentes/parasitologia , Doenças Transmissíveis Emergentes/virologia , França/epidemiologia , Ixodes/microbiologia , Ixodes/parasitologia , Ixodes/fisiologia , Ixodes/virologia , Doenças Transmitidas por Carrapatos/microbiologia , Doenças Transmitidas por Carrapatos/parasitologia , Doenças Transmitidas por Carrapatos/virologia
3.
Ticks Tick Borne Dis ; 12(5): 101759, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34161869

RESUMO

In Europe, the hard tick Ixodes ricinus is considered the most important vector of human zoonotic diseases. Human pathogenic agents spread by I. ricinus in Sweden include Borrelia burgdorferi sensu lato (s.l.), Anaplasma phagocytophilum, Rickettsia helvetica, the recently described Neoehrlichia mikurensis, Borrelia miyamotoi, tick-borne encephalitis virus (TBEV), and Babesia spp. (Babesia microti, Babesia venatorum and Babesia divergens). Since these pathogens share the same vector, co-infections with more than one tick-borne pathogen may occur and thus complicate the diagnosis and clinical management of the patient due to possibly altered symptomatology. Borrelia burgdorferi s.l., TBEV and B. miyamotoi are well-known to cause infections of the central nervous system (CNS), whereas the abilities of other tick-borne pathogens to invade the CNS are largely unknown. The aim of this study was to investigate the presence and clinical impact of tick-borne pathogens other than B. burgdorferi s.l. in the cerebrospinal fluid (CSF) and serum samples of patients who were under investigation for Lyme neuroborreliosis (LNB) in a tick-endemic region of South-eastern Sweden. CSF and serum samples from 600 patients, recruited from the Regions of Östergötland County, Jönköping County and Kalmar County in South-eastern Sweden and investigated for LNB during the period of 2009-2013, were retrospectively collected for analysis. The samples were analysed by real-time PCR for the presence of nucleic acid from B. burgdorferi s.l., B. miyamotoi, A. phagocytophilum, Rickettsia spp., N. mikurensis, TBEV and Babesia spp. Serological analyses were conducted in CSF and serum samples for all patients regarding B. burgdorferi s.l., and for the patients with CSF mononuclear pleocytosis, analyses of antibodies to B. miyamotoi, A. phagocytophilum, spotted fever group (SFG) rickettsiae, TBEV and B. microti in serum were performed. The medical charts of all the patients with CSF mononuclear pleocytosis and patients with positive PCR findings were reviewed. Of the 600 patients, 55 (9%) presented with CSF mononuclear pleocytosis, 13 (2%) of whom had Borrelia-specific antibodies in the CSF. One patient was PCR-positive for N. mikurensis, and another one was PCR-positive for Borrelia spp. in serum. No pathogens were detected by PCR in the CSF samples. Four patients had serum antibodies to B. miyamotoi, four patients to A. phagocytophilum, five patients to SFG rickettsiae, and six patients to TBEV. One patient, with antibodies to SFG rickettsiae, had both clinical and laboratory signs suggestive of a current infection. Nine patients had serum antibodies to more than one pathogen, although none of these was assessed as a current co-infection. We can conclude from this study that tick-borne co-infections are uncommon in patients who are being investigated for suspected LNB in South-eastern Sweden, an area endemic for borreliosis and TBE.


Assuntos
Infecções por Borrelia , Coinfecção , Neuroborreliose de Lyme , Anaplasma phagocytophilum/isolamento & purificação , Animais , Borrelia/isolamento & purificação , Infecções por Borrelia/sangue , Infecções por Borrelia/líquido cefalorraquidiano , Borrelia burgdorferi/isolamento & purificação , Vírus da Encefalite Transmitidos por Carrapatos/isolamento & purificação , Humanos , Ixodes/microbiologia , Ixodes/virologia , Neuroborreliose de Lyme/sangue , Neuroborreliose de Lyme/líquido cefalorraquidiano , Neuroborreliose de Lyme/diagnóstico , Patologia Molecular , Reação em Cadeia da Polimerase , Estudos Retrospectivos , Suécia , Doenças Transmitidas por Carrapatos/sangue , Doenças Transmitidas por Carrapatos/líquido cefalorraquidiano , Doenças Transmitidas por Carrapatos/diagnóstico , Zoonoses/complicações , Zoonoses/diagnóstico
4.
Acta Trop ; 221: 106012, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34126090

RESUMO

The seasonal distribution of hard ticks was investigated in 2018 in Gyeongbuk Province, Republic of Korea. Ticks were assayed for severe fever with thrombocytopenia syndrome virus (SFTSV). Ticks were collected monthly using CO2-baited traps from April to November in four habitats (grasslands, grave sites, hiking trails, and mixed forests). Based on morphological and molecular identification, Haemaphysalis longicornis was the most commonly collected species, followed by H. flava and Ixodes nipponensis. Ticks were more commonly collected in grassland habitats, followed by the grave sites, hiking trails, and mixed forests. Peak numbers of nymphs and adults of H. longicornis occurred in May and June, respectively, and Haemaphysalis larvae were collected from August to October. A total of 9/187 (4.8%) pools were positive for SFTSV between June and October in 2018. Phylogenetic analysis of partial fragments of the SFTSV obtained in this study showed that all positive virus samples clustered into genotype B.


Assuntos
Ixodidae/virologia , Phlebovirus/isolamento & purificação , Estações do Ano , Animais , Ecossistema , Ixodes/virologia , Filogenia , República da Coreia
5.
Virus Genes ; 57(4): 395-399, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34086153

RESUMO

According to modern classification, tick-borne flaviviruses have been divided into a mammalian tick-borne virus group and a seabird tick-borne virus group (STBVG). The STBVG includes the Tyuleniy virus, Meaban virus, Saumarez Reef virus, and the recently discovered Kama virus (KAMV). The latter was isolated from Ixodes lividus, an obligate parasitic tick of the sand martin (Riparia riparia), in 1989 in the central part of the Russian Plain. In 2014, based on molecular genetic analysis, it was shown that KAMV is a new virus belonging to STBVG, genus Flavivirus, fam. Flaviviridae. Very little is known about the Kama virus concerning its range, vectors, and reservoir hosts. GenBank contains a single sequence of the complete genome of this virus. In the present study, the complete genome sequences of two strains, isolated in 1983 in the Omsk region (Western Siberia) from gamasid mites in the nests of rooks (Corvus frugilegus), have been determined. Phylogenetic analyses of their genomes showed a close relationship both with each other (approx. 98.9% nucleotide identity) and with KAMV isolated in European Russia (approx. 98.4% nucleotide identity). The ecological features of KAMV that are due to the species of the vector (gamasid mites) and its hosts (colonial birds of the mainland of Eurasia) indicate that KAMV is an atypical representative STBVG.


Assuntos
Vírus da Encefalite Transmitidos por Carrapatos/genética , Infecções por Flavivirus/genética , Flavivirus/genética , Genoma Viral/genética , Animais , Antígenos Virais/genética , Aves , Vírus da Encefalite Transmitidos por Carrapatos/patogenicidade , Flavivirus/patogenicidade , Infecções por Flavivirus/patologia , Infecções por Flavivirus/virologia , Humanos , Ixodes/genética , Ixodes/virologia , Conformação de Ácido Nucleico
6.
FEBS Lett ; 595(12): 1622-1638, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33960414

RESUMO

Ixodes scapularis ticks feed on humans and other vertebrate hosts and transmit several pathogens of public health concern. Tick saliva is a complex mixture of bioactive proteins, lipids and immunomodulators, such as I. scapularis sphingomyelinase (IsSMase)-like protein, an ortholog of dermonecrotoxin SMase D found in the venom of Loxosceles spp. of spiders. IsSMase modulates the host immune response towards Th2, which suppresses Th1-mediated cytokines to facilitate pathogen transmission. Arboviruses utilize exosomes for their transmission from tick to the vertebrate host, and exosomes derived from tick saliva/salivary glands suppress C-X-C motif chemokine ligand 12 and interleukin-8 immune response(s) in human skin to delay wound healing and repair processes. IsSMase affects also viral replication and exosome biogenesis, thereby inhibiting tick-to-vertebrate host transmission of pathogenic exosomes. In this review, we elaborate on exosomes and their biogenesis as potential candidates for developing novel control measure(s) to combat tick-borne diseases. Such targets could help with the development of an efficient anti-tick vaccine for preventing the transmission of tick-borne pathogens.


Assuntos
Infecções por Arbovirus , Arbovírus/imunologia , Proteínas de Artrópodes/imunologia , Fatores Imunológicos/imunologia , Ixodes , Esfingomielina Fosfodiesterase/imunologia , Animais , Infecções por Arbovirus/imunologia , Infecções por Arbovirus/prevenção & controle , Infecções por Arbovirus/transmissão , Humanos , Ixodes/imunologia , Ixodes/virologia , Glândulas Salivares/imunologia , Glândulas Salivares/virologia , Células Th1/imunologia , Células Th2/imunologia
7.
Acta Vet Scand ; 63(1): 16, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33827636

RESUMO

BACKGROUND: The vector-borne human viral zoonosis tick-borne encephalitis (TBE) is of growing concern in Sweden. The area where TBE is considered endemic has expanded, with an increasing geographical distribution of Ixodes ricinus as the tick vector and a rising number of reported TBE cases in humans. Efforts to map TBE risk areas have been carried out by sentinel monitoring, mainly based on individual sampling and analysis of wild and domestic animals, as well as ticks, for tick-borne encephalitis virus (TBEV). However, the interpretation of the geographical distribution has been hampered by the patchy and focal nature of TBEV occurrence. This study presents TBEV surveillance data based on antibody analysis of bulk tank milk collected from dairy herds located throughout Sweden before (May) and after (November) the vector season. A commercial TBEV antibody ELISA was modified and evaluated for use in this study. RESULTS: The initial comparative TBEV antibody analysis revealed a good correlation between milk and serum antibody levels from individually sampled cows. Also, the TBEV-antibody levels for the mean-herd serum showed good comparability with TBEV antibody levels from bulk tank milk, thus indicating good predictability of seroprevalence when analysing bulk tank milk from a herd. Analyses of bulk tank milk samples collected from 616 herds in May and 560 herds in November showed a geographical distribution of TBEV seropositive herds that was largely consistent with reported human TBE cases. A few TBEV-reactive herds were also found outside known locations of human TBE cases. CONCLUSION: Serological examination of bulk tank milk from dairy cattle herds may be a useful sentinel surveillance method to identify geographical presence of TBEV. In contrast to individual sampling this method allows a large number of animals to be monitored. TBEV seropositive herds were mainly found in coastal areas of southern Sweden similar to human TBE cases. However, some antibody-reactive herds were found outside known TBE areas at the time of the study.


Assuntos
Doenças dos Bovinos/epidemiologia , Vírus da Encefalite Transmitidos por Carrapatos/isolamento & purificação , Encefalite Transmitida por Carrapatos/veterinária , Animais , Anticorpos Antivirais/sangue , Bovinos , Doenças dos Bovinos/virologia , Indústria de Laticínios , Demografia , Vírus da Encefalite Transmitidos por Carrapatos/imunologia , Encefalite Transmitida por Carrapatos/epidemiologia , Feminino , Ixodes/virologia , Leite/virologia , Fatores de Risco , Estudos Soroepidemiológicos , Suécia/epidemiologia
8.
Viruses ; 13(3)2021 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-33799742

RESUMO

The genus Flavivirus includes related, unclassified segmented flavi-like viruses, two segments of which have homology with flavivirus RNA-dependent RNA polymerase NS5 and RNA helicase-protease NS3. This group includes such viruses as Jingmen tick virus, Alongshan virus, Yanggou tick virus and others. We detected the Yanggou tick virus in Dermacentor nuttalli and Dermacentor marginatus ticks in two neighbouring regions of Russia. The virus prevalence ranged from 0.5% to 8.0%. We detected RNA of the Alongshan virus in 44 individuals or pools of various tick species in eight regions of Russia. The virus prevalence ranged from 0.6% to 7.8%. We demonstrated the successful replication of the Yanggou tick virus and Alongshan virus in IRE/CTVM19 and HAE/CTVM8 tick cell lines without a cytopathic effect. According to the phylogenetic analysis, we divided the Alongshan virus into two groups: an Ixodes persulcatus group and an Ixodes ricinus group. In addition, the I. persulcatus group can be divided into European and Asian subgroups. We found amino acid signatures specific to the I. ricinus and I. persulcatus groups and also distinguished between the European and Asian subgroups of the I. persulcatus group.


Assuntos
Dermacentor/virologia , Infecções por Flaviviridae/epidemiologia , Flaviviridae/genética , Ixodes/virologia , Proteínas não Estruturais Virais/genética , Substituição de Aminoácidos/genética , Animais , Vetores Aracnídeos/virologia , Linhagem Celular , Culicidae/virologia , Flaviviridae/isolamento & purificação , Filogenia , RNA Helicases/genética , RNA Viral/genética , Federação Russa/epidemiologia , Serina Endopeptidases/genética
9.
Parasit Vectors ; 14(1): 144, 2021 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-33676573

RESUMO

BACKGROUND: Louping ill virus (LIV) and tick-borne encephalitis virus (TBEV) are tick-borne flaviviruses that are both transmitted by the major European tick, Ixodes ricinus. Despite the importance of I. ricinus as an arthropod vector, its capacity to acquire and subsequently transmit viruses, known as vector competence, is poorly understood. At the molecular scale, vector competence is governed in part by binary interactions established between viral and cellular proteins within infected tick cells. METHODS: To investigate virus-vector protein-protein interactions (PPIs), the entire set of open reading frames for LIV and TBEV was screened against an I. ricinus cDNA library established from three embryonic tick cell lines using yeast two-hybrid methodology (Y2H). PPIs revealed for each viral bait were retested in yeast by applying a gap repair (GR) strategy, and notably against the cognate protein of both viruses, to determine whether the PPIs were specific for a single virus or common to both. The interacting tick proteins were identified by automatic BLASTX, and in silico analyses were performed to expose the biological processes targeted by LIV and TBEV. RESULTS: For each virus, we identified 24 different PPIs involving six viral proteins and 22 unique tick proteins, with all PPIs being common to both viruses. According to our data, several viral proteins (pM, M, NS2A, NS4A, 2K and NS5) target multiple tick protein modules implicated in critical biological pathways. Of note, the NS5 and pM viral proteins establish PPI with several tumor necrosis factor (TNF) receptor-associated factor (TRAF) proteins, which are essential adaptor proteins at the nexus of multiple signal transduction pathways. CONCLUSION: We provide the first description of the TBEV/LIV-I. ricinus PPI network, and indeed of any PPI network involving a tick-borne virus and its tick vector. While further investigation will be needed to elucidate the role of each tick protein in the replication cycle of tick-borne flaviviruses, our study provides a foundation for understanding the vector competence of I. ricinus at the molecular level. Indeed, certain PPIs may represent molecular determinants of vector competence of I. ricinus for TBEV and LIV, and potentially for other tick-borne flaviviruses.


Assuntos
Proteínas de Artrópodes/metabolismo , Vírus da Encefalite Transmitidos por Carrapatos/genética , Vírus da Encefalite Transmitidos por Carrapatos/fisiologia , Interações entre Hospedeiro e Microrganismos , Ixodes/genética , Ixodes/virologia , Proteínas Virais/metabolismo , Animais , Proteínas de Artrópodes/genética , Feminino , Biblioteca Gênica , Fases de Leitura Aberta , Domínios e Motivos de Interação entre Proteínas , Proteínas Virais/genética
10.
Ticks Tick Borne Dis ; 12(3): 101670, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33571754

RESUMO

Although travel-related tick-borne encephalitis (TBE) cases have been increasingly registered worldwide, very few published case studies are available to date. The present report describes a travel-related TBE case and provides genotypic characterization of two viral isolates. Laboratory diagnostics were based on complement fixation test and virus isolation. This report is unique because the TBE case was first confirmed by virus isolation from the engorged tick and only later from the patient's blood. Moreover, this case demonstrated a successful prophylaxis performed on day 8 post tick exposure although it is generally recommended that anti-TBEV immunoglobulins should be administered not later than on day 4 after tick bite. Sequences of E protein gene fragments were used to phylogenetically characterize the two isolates. The results demonstrated that both viral isolates belonged to clusteron 3A (Zausaev group) of the Asian lineage of the TBEV Siberian subtype. The synonymous nucleotide substitution, C351 T, was identified in E protein gene fragments of TBEV 88 and TBEV 89, which could have been induced by virus transmission. A few important take-home messages can be gleaned from the reported case. First, travelers should be aware of TBE endemic areas that they plan to visit and be proactive when exposed to Ixodes ticks. Second, medical practitioners should always consider travel history and potential tick exposure of patients. Lastly, engorged Ixodes spp. ticks removed from the patients, who have arrived from endemic areas, should be tested for TBEV even in the absence of TBE clinical signs.


Assuntos
Vírus da Encefalite Transmitidos por Carrapatos/classificação , Ixodes/virologia , Sequência de Aminoácidos , Animais , Vírus da Encefalite Transmitidos por Carrapatos/isolamento & purificação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Filogenia , Federação Russa , Alinhamento de Sequência , Viagem , Ucrânia , Proteínas do Envelope Viral/análise
11.
PLoS One ; 16(1): e0244668, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33411799

RESUMO

BACKGROUND: Tick-borne encephalitis (TBE) is the most important tick-borne viral disease in Eurasia and causes disease in humans and in a number of animals, among them dogs and horses. There is still no good correlation between tick numbers, weather conditions and human cases. There is the hypothesis that co-feeding due to simultaneous occurrence of larvae and nymphs may be a factor for the increased transmission of the virus in nature and for human disease. Based on long-term data from a natural TBEV focus, phylogenetic results and meteorological data we sought to challenge this hypothesis. METHODS: Ticks from an identified TBE natural focus were sampled monthly from 04/2009 to 12/2018. Ticks were identified and pooled. Pools were tested by RT-qPCR. Positive pools were confirmed by virus isolation and/or sequencing of additional genes (E gene, NS2 gene). Temperature data such as the decadal (10-day) mean daily maximum air temperature (DMDMAT) were obtained from a nearby weather station and statistical correlations between tick occurrence and minimal infection rates (MIR) were calculated. RESULTS: In the study period from 04/2009 to 12/2018 a total of 15,530 ticks (2,226 females, 2,268 males, 11,036 nymphs) were collected. The overall MIR in nymphs over the whole period was 77/15,530 (0.49%), ranging from 0.09% (2009) to 1.36% (2015). The overall MIR of female ticks was 0.76% (17/2,226 ticks), range 0.14% (2013) to 3.59% (2016). The overall MIR of males was 0.57% (13/2,268 ticks), range from 0.26% (2009) to 0.97% (2015). The number of nymphs was statistically associated with a later start of spring/vegetation period, indicated by the onset of forsythia flowering. CONCLUSION: There was no particular correlation between DMDMAT dynamics in spring and/or autumn and the MIR of nymphs or adult ticks detected. However, there was a positive correlation between the number of nymphs and the number of reported human TBE cases in the following months, but not in the following year. The hypothesis of the importance of co-feeding of larvae and nymphs for the maintenance of transmission cycle of TBEV in nature is not supported by our findings.


Assuntos
Clima , Encefalite Transmitida por Carrapatos/epidemiologia , Ixodes/virologia , Temperatura , Animais , Vetores Aracnídeos/virologia , Encefalite Transmitida por Carrapatos/virologia , Alemanha/epidemiologia , Humanos , Incidência , Ninfa/virologia , Dinâmica Populacional , Estações do Ano
12.
Ticks Tick Borne Dis ; 12(1): 101606, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33189912

RESUMO

Tick-borne encephalitis virus (TBEV) is the etiologic agent of tick-borne encephalitis (TBE) and transmitted by Ixodes ricinus (Linnaeus, 1758) in Europe. The geographical distribution of I. ricinus in the Palearctic region covers also northern Africa, including northwestern Tunisia. While the eco-epidemiology of TBE in Europe is well documented, no data concerning TBEV from northern Africa are available. We investigated whether TBEV is circulating in Tunisia. A total of 877 adult I. ricinus collected from northwestern Tunisia were examined in pools for the presence of TBEV by nRT-PCR. Viral RNA was detected in one pool of three engorged ticks, yielding a minimum infection rate of 0.11 % (1/877). Phylogenetic analysis showed that the Tunisian TBEV strain belongs to the European lineage. We report for the first time the presence of TBEV in I. ricinus from northern Africa. Therefore, more studies are needed to assess the public health importance of TBEV in northern Africa.


Assuntos
Vírus da Encefalite Transmitidos por Carrapatos/isolamento & purificação , Ixodes/virologia , Animais , Bovinos/parasitologia , Feminino , Florestas , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Árvores , Tunísia
13.
Vector Borne Zoonotic Dis ; 21(1): 6-10, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33107810

RESUMO

Pathogens transmitted by ticks cause several important diseases in humans, including Lyme disease, the incidence of which has been increasing in Belarus. Between April and October 2017, a total of 504 questing Ixodid ticks (77% Ixodes ricinus and 23% Dermacentor reticulatus) were collected from six regions and city of Minsk, in Belarus. All ticks were analyzed by RT-PCR amplification for the presence of Borrelia burgdorferi sensu lato, tick-borne encephalitis virus (TBEV), Anaplasma phagocytophillum, Ehrlihia muris, and Borrelia miyamotoi. B. burgdorferi s.l. and Rickettsia spp. were the most commonly detected tick-borne pathogens, with prevalence rates of 31.08% and 33.7%, respectively. A. phagocytophillum was found in 104 (20.63%), and 107 (21.2%) ticks were positive for E. muris. TBEV was detected in 83 (16.47%). Circulation of Borrelia miyamotoi spirochete in I. ricinus ticks in Brest, Gomel, and Minsk region was detected for the first time. Our data provide a basis for further studies to determine the distribution and abundance of different tick species in Belarus and therefore a capacity to predict where cases of important tick-borne diseases may occur.


Assuntos
Dermacentor/microbiologia , Ixodes/microbiologia , Doenças Transmitidas por Carrapatos/epidemiologia , Anaplasma phagocytophilum/genética , Anaplasma phagocytophilum/isolamento & purificação , Animais , Borrelia/genética , Borrelia/isolamento & purificação , Borrelia burgdorferi/genética , Borrelia burgdorferi/isolamento & purificação , Dermacentor/virologia , Ehrlichia/genética , Ehrlichia/isolamento & purificação , Vírus da Encefalite Transmitidos por Carrapatos/genética , Vírus da Encefalite Transmitidos por Carrapatos/isolamento & purificação , Feminino , Ixodes/virologia , Masculino , Prevalência , República de Belarus/epidemiologia
14.
Ticks Tick Borne Dis ; 12(1): 101594, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33120252

RESUMO

The Baltic States are the region in Europe where tick-borne encephalitis (TBE) is most endemic, with one-third of the European TBE cases detected in Lithuania, Latvia and Estonia. With the Czech Republic and Germany, Lithuania has among the highest population incidences of TBE. Ticks from the Ixodidae family are the main vectors of the TBE virus (TBEV) in Europe. However, there is still a lack of data on the prevalence of TBEV in ticks in different parts of Lithuania. This study analysed the current prevalence of TBEV in the two most common tick species distributed in Lithuania: Ixodes ricinus and Dermacentor reticulatus. Questing I. ricinus (n = 7170) and D. reticulatus (n = 1676) ticks were collected from 81 locations in all ten counties of Lithuania between 2017 and 2019. The presence of TBEV was analysed using a real-time reverse transcription polymerase chain reaction (RT-PCR) and TBEV prevalence in ticks was calculated as the minimum infection rate (MIR). TBEV was detected in the three developmental stages (adults, nymphs and larvae) of I. ricinus and in D. reticulatus adults. The MIR of TBEV in the total sample of I. ricinus was 0.4 % (28/7170) and for D. reticulatus was also estimated to be 0.4 % (6/1676). TBEV-infected ticks were found in 16 locations in seven counties, with MIR ranging from 0.1 % to 1.0 %. The TBEV strains detected belong to the European subtype. To the best of the authors' knowledge, this is the first report on the prevalence of TBEV in unfed D. reticulatus ticks and in I. ricinus unfed larvae in Lithuania.


Assuntos
Dermacentor/virologia , Vírus da Encefalite Transmitidos por Carrapatos/isolamento & purificação , Ixodes/virologia , Animais , Dermacentor/crescimento & desenvolvimento , Feminino , Ixodes/crescimento & desenvolvimento , Larva , Lituânia , Masculino , Ninfa
15.
Parasit Vectors ; 13(1): 607, 2020 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-33272317

RESUMO

BACKGROUND: Birds can act as reservoirs of tick-borne pathogens and can also disperse pathogen-containing ticks to both nearby and remote localities. The aims of this study were to estimate tick infestation patterns on migratory birds and the prevalence of different Borrelia species and tick-borne encephalitis virus (TBEV) in ticks removed from birds in south-eastern Sweden. METHODS: Ticks were collected from resident and migratory birds captured at the Ottenby Bird Observatory, Öland, Sweden, from March to November 2009. Ticks were molecularly identified to species, and morphologically to developmental stage, and the presence of Borrelia bacteria and TBEV was determined by quantitative real-time PCR. RESULTS: A total of 1339 ticks in the genera Haemaphysalis, Hyalomma, and Ixodes was recorded of which I. ricinus was the most abundant species. Important tick hosts were the European robin (Erithacus rubecula), Blackbird (Turdus merula), Tree pipit (Anthus trivialis), Eurasian wren (Troglodytes troglodytes), Common redstart (Phoenicurus phoenicurus), Willow warbler (Phylloscopus trochilus), and Common whitethroat (Sylvia communis). Borrelia bacteria were detected in 25% (285/1,124) of the detached ticks available for analysis. Seven Borrelia species (B. afzelii, B. burgdorferi (s.s.), B. garinii, B. lusitaniae, B. turdi, B. valaisiana, and B. miyamotoi) were identified. B. turdi was recorded for the first time in ticks in Sweden. The number of Borrelia cells per tick ranged from 2.0 × 100 to 7.0 × 105. B. miyamotoi-containing ticks contained a significantly higher median number of Borrelia cells than B. burgdorferi (s.l.)-containing ticks. B. garinii and B. miyamotoi were the most prevalent Borrelia species in tick larvae. Larvae of I. ricinus with B. garinii were removed from seven bird species, particularly S. communis and A. trivialis, which may suggest that the larvae had contracted the Borrelia bacteria from or via these birds. Also, a high percentage of tick larvae containing B. miyamotoi was removed from E. rubecula. All ticks were negative for TBEV. CONCLUSIONS: The results corroborate the view that the contributions of birds to human disease are substantial, particularly as blood hosts for ticks and for their short-, medium-, and long-distance dispersal. Moreover, several ground-foraging bird species appear to be important for the maintenance and dispersal of Borrelia species. The absence of TBEV in the ticks conforms to other similar studies.


Assuntos
Aves/parasitologia , Borrelia/isolamento & purificação , Vírus da Encefalite Transmitidos por Carrapatos/isolamento & purificação , Encefalite Transmitida por Carrapatos/transmissão , Ixodes/microbiologia , Ixodes/virologia , Doença de Lyme/transmissão , Migração Animal , Animais , Animais Selvagens/classificação , Animais Selvagens/parasitologia , Animais Selvagens/fisiologia , Aves/classificação , Aves/fisiologia , Borrelia/classificação , Borrelia/genética , Vírus da Encefalite Transmitidos por Carrapatos/classificação , Vírus da Encefalite Transmitidos por Carrapatos/genética , Encefalite Transmitida por Carrapatos/virologia , Humanos , Ixodes/classificação , Ixodes/fisiologia , Doença de Lyme/microbiologia , Estações do Ano , Suécia
16.
Curr Protoc Microbiol ; 59(1): e118, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33030816

RESUMO

Tick-borne viruses cause thousands of cases of disease worldwide every year. Specific countermeasures to many tick-borne viruses are not commercially available. Very little is known regarding tick-virus interactions and increasing this knowledge can lead to potential targets for countermeasure development. Virus infection of ex vivo organ cultures from ticks can provide an approach to identify susceptible cell types of tissue to infection. Additionally, these organ cultures can be used for functional genomic studies to pinpoint tick-specific genes involved in the virus lifecycle. Provided here are step-by-step procedures to set up basic tick organ cultures in combination with virus infection and/or functional genomic studies. These procedures can be adapted for future use to characterize other tick-borne pathogen infections as well as tick-specific biological processes. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Loading 96-well plates with gelfoam substrate Basic Protocol 2: Step-by-step aseptic dissection of unfed female/male Ixodes scapularis ticks for multiple organs Basic Protocol 3: Step-by-step aseptic dissection of fed female Ixodes scapularis ticks to remove salivary glands Basic Protocol 4: Metabolic viability analyses of tick organ cultures Basic Protocol 5: Virus infection of tick organ cultures Basic Protocol 6: Functional RNA interference analyses using tick organ cultures.


Assuntos
Dissecação/métodos , Ixodes/virologia , Técnicas de Cultura de Órgãos/métodos , Animais , Feminino , Masculino , Interferência de RNA , Glândulas Salivares , Doenças Transmitidas por Carrapatos
17.
PLoS Negl Trop Dis ; 14(10): e0008683, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33017410

RESUMO

Infected Ixodes scapularis (black-legged tick) transmit a host of serious pathogens via their bites, including Borrelia burgdorferi, Babesia microti, and tick-borne flaviviruses (TBFVs), such as Powassan virus (POWV). Although the role of female I. scapularis ticks in disease transmission is well characterized, the role of male ticks is poorly understood. Because the pathogens are delivered in tick saliva, we studied the capacity of male salivary glands (SGs) to support virus replication. Ex vivo cultures of SGs from unfed male I. scapularis were viable for more than a week and maintained the characteristic tissue architecture of lobular ducts and acini. When SG cultures were infected with the TBFVs Langat virus (LGTV) or POWV lineage II (deer tick virus), the production of infectious virus was demonstrated. Using a green fluorescent protein-tagged LGTV and confocal microscopy, we demonstrated LGTV infection within SG acinus types II and III. The presence of LGTV in the acini and lobular ducts of the cultures was also shown via immunohistochemistry. Furthermore, the identification by in situ hybridization of both positive and negative strand LGTV RNA confirmed that the virus was indeed replicating. Finally, transmission electron microscopy of infected SGs revealed virus particles packaged in vesicles or vacuoles adjacent to acinar lumina. These studies support the concept that SGs of male I. scapularis ticks support replication of TBFVs and may play a role in virus transmission, and further refine a useful model system for developing countermeasures against this important group of pathogens.


Assuntos
Infecções por Flavivirus/veterinária , Ixodes/virologia , Glândulas Salivares/virologia , Animais , Vírus da Encefalite Transmitidos por Carrapatos/crescimento & desenvolvimento , Infecções por Flavivirus/virologia , Masculino , Microscopia , Microscopia Eletrônica de Transmissão , Microscopia de Fluorescência
18.
Parasit Vectors ; 13(1): 504, 2020 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-33023633

RESUMO

BACKGROUND: In the South of Kazakhstan, Almaty Oblast' (region) is endemic for tick-borne encephalitis, with 0.16-0.32 cases/100,000 population between 2016-2018. The purpose of this study was to determine the prevalence and circulating subtypes of tick-borne encephalitis virus (TBEV) in Almaty Oblast' and Kyzylorda Oblast'. METHODS: In 2015 we investigated 2341 ticks from 7 sampling sites for the presence of TBEV. Ticks were pooled in 501 pools and isolated RNA was tested for the presence of TBEV by RT-qPCR. For the positive samples, the E gene was amplified, sequenced and a phylogenetic analysis was carried out. RESULTS: A total of 48 pools were TBEV-positive by the RT-qPCR. TBEV-positive ticks were only detected in three districts of Almaty Oblast' and not in Kyzylorda Oblast'. The positive TBEV pools were found within Ixodes persulcatus, Haemaphysalis punctata and Dermacentor marginatus. These tick species prevailed only in Almaty Oblast' whereas in Kyzylorda Oblast' Hyalomma asiaticum and D. marginatus are endemic. The minimum infection rates (MIR) in the sampling sites were 4.4% in Talgar, 2.8% in Tekeli and 1.1% in Yenbekshikazakh, respectively. The phylogenetic analysis of the generated sequences indicates that TBEV strains found in Almaty Oblast' clusters in the Siberian subtype within two different clades. CONCLUSIONS: We provided new data about the TBEV MIR in ticks in Almaty Oblast' and showed that TBEV clusters in the Siberian Subtype in two different clusters at the nucleotide level. These results indicate that there are different influences on the circulating TBEV strains in south-eastern Kazakhstan. These influences might be caused by different routes of the virus spread in ticks which might bring different genetic TBEV lineages to Kazakhstan. The new data about the virus distribution and vectors provided here will contribute to an improvement of monitoring of tick-borne infections and timely anti-epidemic measures in Kazakhstan.


Assuntos
Vírus da Encefalite Transmitidos por Carrapatos , Encefalite Transmitida por Carrapatos/epidemiologia , Ixodidae/virologia , Animais , Vetores Aracnídeos/virologia , Vírus da Encefalite Transmitidos por Carrapatos/genética , Vírus da Encefalite Transmitidos por Carrapatos/isolamento & purificação , Encefalite Transmitida por Carrapatos/transmissão , Genes Virais , Humanos , Ixodes/virologia , Cazaquistão/epidemiologia , Epidemiologia Molecular , Ninfa/virologia , Patologia Molecular/métodos , Filogenia , Reação em Cadeia da Polimerase em Tempo Real
19.
Sci Rep ; 10(1): 15478, 2020 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-32968088

RESUMO

Tick-borne encephalitis virus (TBEV) is endemic in twenty-seven European countries, transmitted via the bite of an infected tick. TBEV is the causative agent of one of the most important viral diseases of the central nervous system (CNS). In Germany, 890 human cases were registered between the years 2018-2019. The castor bean tick, Ixodes ricinus, is the TBEV vector with the highest importance in Central Europe, including Germany. Despite the nationwide distribution of this tick species, risk areas of TBEV are largely located in Southern Germany. To increase our understanding of TBEV-tick interactions, we collected ticks from different areas within Germany (Haselmühl/Bavaria, Hanover/Lower Saxony) and infected them via an in vitro feeding system. A TBEV isolate was obtained from an endemic focus in Haselmühl. In two experimental series conducted in 2018 and 2019, ticks sampled in Haselmühl (TBEV focus) showed higher artificial feeding rates, as well as higher TBEV infections rates than ticks from the non-endemic area (Hanover). Other than the tick origin, year and month of the infection experiment as well as co-infection with Borrelia spp., had a significant impact on TBEV Haselmühl infection rates. Taken together, these findings suggest that a specific adaptation of the tick populations to their respective TBEV virus isolates or vice versa, leads to higher TBEV infection rates in those ticks. Furthermore, co-infection with other tick-borne pathogens such as Borrelia spp. can lower TBEV infection rates in specific populations.


Assuntos
Vírus da Encefalite Transmitidos por Carrapatos , Ixodes/virologia , Animais , Borrelia/genética , Demografia , Vírus da Encefalite Transmitidos por Carrapatos/genética , Vírus da Encefalite Transmitidos por Carrapatos/fisiologia , Alemanha , Reação em Cadeia da Polimerase em Tempo Real , Rickettsia/genética , Estações do Ano
20.
Parasit Vectors ; 13(1): 406, 2020 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-32778148

RESUMO

INTRODUCTION: The most abundant and widespread tick species in Great Britain, Ixodes ricinus, is responsible for the transmission of a range of pathogens that cause disease in livestock. Empirical data on tick distribution and prevalence are required to inform farm management strategies. However, such data are largely unavailable; previous surveys have been rare and are usually relatively localised. METHODS: A retrospective questionnaire survey of farmers was used to assess the reported prevalence of ticks on livestock across Great Britain. Spatial scan statistics and kernel density maps were used to assess spatial clustering and identify areas of significantly elevated risk, independent of the underlying distribution of respondents. Logistic regression models were used to identify risk factors for tick presence. RESULTS: Tick infection risk to livestock is shown to be spatially aggregated, with areas of significantly elevated risk in north Wales, northwest England and western Scotland. Overall, the prevalence of farms reporting tick presence was 13% for sheep farms and 6% for cattle farms, but in "hot spot" clusters prevalence ranged between 48-100%. The prevalence of farms reporting tick-borne disease overall was 6% for sheep and 2% for cattle, but on farms reporting ticks, prevalence was 44% and 33% for sheep and cattle farms, respectively. Upland farming, larger flock sizes, region and the presence of sheep on cattle farms were all significant risk factors for tick presence. CONCLUSIONS: These data have important implications for assessing both the risk of tick-borne disease in livestock and optimising approaches to disease management. In particular, the study highlights the need for effective livestock tick control in upland regions and the southwest, and provides evidence for the importance of sheep as tick maintenance hosts.


Assuntos
Gado , Infestações por Carrapato/veterinária , Doenças Transmitidas por Carrapatos/veterinária , Animais , Bovinos , Monitoramento Epidemiológico/veterinária , Fazendeiros , Fazendas , Ixodes/microbiologia , Ixodes/parasitologia , Ixodes/virologia , Gado/microbiologia , Gado/parasitologia , Gado/virologia , Estudos Retrospectivos , Ovinos , Inquéritos e Questionários , Infestações por Carrapato/epidemiologia , Doenças Transmitidas por Carrapatos/epidemiologia
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