a new tick-borne encephalitis-like virus infecting new england deer ticks, ixodes determine if eastern north american ixodes dammini, like related ticks in eurasia, maintain tick-borne encephalitis group viruses, we analyzed ticks collected from sites where the agent of lyme disease is zoonotic. two viral isolates were obtained by inoculating mice with homogenates from tick salivary glands. the virus, which was described by reverse transcriptase polymerase chain reaction and direct sequencing of the amplification products, was similar to, but distinct from, powassan virus ...19979204297
diagnosis of acute deer tick virus encephalitis.deer tick virus (dtv) is a tick-borne flavivirus that has only recently been appreciated as a cause of viral encephalitis. we describe the clinical presentation of a patient who had dtv encephalitis diagnosed before death and survived for 8 months despite severe neurologic dysfunction.201323166187
changing epidemiology of powassan encephalitis in north america suggests the emergence of the deer tick virus subtype. 201324124795
emerging cases of powassan virus encephalitis in new england: clinical presentation, imaging, and review of the literature.powassan virus (powv) is a rarely diagnosed cause of encephalitis in the united states. in the northeast, it is transmitted by ixodes scapularis, the same vector that transmits lyme disease. the prevalence of powv among animal hosts and vectors has been increasing. we present 8 cases of powv encephalitis from massachusetts and new hampshire in 2013-2015.201626668338
lyme disease coinfections in the united states.lyme disease in north america is caused by infection with the spirochetal bacterium borrelia burgdorferi and transmitted by ixodes scapularis and ixodes pacificus ticks. these ticks also have the potential to transmit a rapidly expanding list of other pathogenic bacteria, viruses, and parasites, including anaplasma phagocytophilum, babesia microti, deer tick (powassan) virus, borrelia miyamotoi, and the ehrlichia muris-like organism. coinfections with b burgdorferi and these other agents are oft ...201526593260
human pathogens associated with the blacklegged tick ixodes scapularis: a systematic review.the blacklegged tick ixodes scapularis transmits borrelia burgdorferi (sensu stricto) in eastern north america; however, the agent of lyme disease is not the sole pathogen harbored by the blacklegged tick. the blacklegged tick is expanding its range into areas of southern canada such as ontario, an area where exposure to blacklegged tick bites and tick-borne pathogens is increasing. we performed a systematic review to evaluate the public health risks posed by expanding blacklegged tick populatio ...201627151067
potential role of deer tick virus in powassan encephalitis cases in lyme disease-endemic areas of new york, u.s.a.powassan virus, a member of the tick-borne encephalitis group of flaviviruses, encompasses 2 lineages with separate enzootic cycles. the prototype lineage of powassan virus (powv) is principally maintained between ixodes cookei ticks and the groundhog (marmota momax) or striped skunk (mephitis mephitis), whereas the deer tick virus (dtv) lineage is believed to be maintained between ixodes scapularis ticks and the white-footed mouse (peromyscus leucopus). we report 14 cases of powassan encephalit ...201324274334
persistence of pathogens with short infectious periods in seasonal tick populations: the relative importance of three transmission routes.the flaviviruses causing tick-borne encephalitis (tbe) persist at low but consistent levels in tick populations, despite short infectious periods in their mammalian hosts and transmission periods constrained by distinctly seasonal tick life cycles. in addition to systemic and vertical transmission, cofeeding transmission has been proposed as an important route for the persistence of tbe-causing viruses. because cofeeding transmission requires ticks to feed simultaneously, the timing of tick acti ...201020668521
powassan/deer tick virus and borrelia burgdorferi infection in wisconsin tick populations.powassan/deer tick virus (powv/dtv) is an emerging cause of arboviral neuroinvasive disease in the upper midwest. these studies describe the prevalence and geographic distribution of wisconsin ticks carrying powv/dtv as well as the high frequency of ixodes scapularis ticks coinfected with both powv/dtv and borrelia burgdorferi, the causative agent of lyme disease. these findings suggest that concurrent transmission of powv/dtv and b. burgdorferi from coinfected ticks is likely to occur in humans ...201728488932
isolation of deer tick virus (powassan virus, lineage ii) from ixodes scapularis and detection of antibody in vertebrate hosts sampled in the hudson valley, new york state.deer tick virus, dtv, is a genetically and ecologically distinct lineage of powassan virus (powv) also known as lineage ii powv. human incidence of pow encephalitis has increased in the last 15 years potentially due to the emergence of dtv, particularly in the hudson valley of new york state. we initiated an extensive sampling campaign to determine whether powv was extant throughout the hudson valley in tick vectors and/or vertebrate hosts.201324016533
the prevalence of zoonotic tick-borne pathogens in ixodes scapularis collected in the hudson valley, new york state.ixodes scapularis, the blacklegged tick, is capable of transmitting the pathogens that cause lyme disease (borrelia burgdorferi), babesiosis (babesia microti), anaplasmosis (anaplasma phagocytophilum), and to a lesser extent powassan encephalitis (deer tick virus [dtv]). these pathogens represent significant public health problems, but little is known about the occurrence and co-infection prevalence of these pathogens in i. scapularis. here, we used standard pcr and pathogen-specific primers to ...201424689680
rapid identification of vector-borne flaviviruses by mass spectrometry.flaviviruses are a highly diverse group of rna viruses classified within the genus flavivirus, family flaviviridae. most flaviviruses are arthropod-borne, requiring a mosquito or tick vector. several flaviviruses are highly pathogenic to humans; however, their high genetic diversity and immunological relatedness makes them extremely challenging to diagnose. in this study, we developed and evaluated a broad-range flavivirus assay designed to detect both tick- and mosquito-borne flaviviruses by us ...201020412852
phylogeny of north american powassan determine whether powassan virus (pow) and deer tick virus (dtv) constitute distinct flaviviral populations transmitted by ixodid ticks in north america, we analysed diverse nucleotide sequences from 16 strains of these viruses. two distinct genetic lineages are evident, which may be defined by geographical and host associations. the nucleotide and amino acid sequences of lineage one (comprising new york and canadian pow isolates) are highly conserved across time and space, but those of linea ...200111413377
a focus of deer tick virus transmission in the northcentral united states.we screened salivary glands from adult deer ticks collected near spooner and hayward, wisconsin, to determine whether deer tick virus, a recently described flavivirus, occurs with other tickborne agents in the upper midwest. intraacinar inclusions suggestive of replicating virus were detected in 4 (4.6%) of 87 ticks. the virus was isolated by suckling-mouse inoculation.199910460180
update on powassan virus: emergence of a north american tick-borne flavivirus.powassan virus (pow) (flaviviridae: flavivirus) is the cause of rare but severe neuroinvasive disease in north america and russia. the virus is transmitted among small- and medium-sized mammals by ixodid ticks. human infections occur via spillover from the main transmission cycle(s). since the late 1990s, the incidence of human disease seems to be increasing. in addition, pow constitutes a genetically diverse group of virus genotypes, including deer tick virus, that are maintained in distinct en ...201019961325
management approaches for suspected and established lyme disease used at the lyme disease diagnostic center.2015 marks the 27th year that the lyme disease diagnostic center, located in new york state in the united states, has provided care for patients with suspected or established deer tick-transmitted infections. there are five deer tick-transmitted infectious in this geographic area of which lyme disease is the most common.for patients with erythema migrans, we do not obtain any laboratory testing. however, if the patient is febrile at the time of the visit or reports rigors and high-grade fevers, ...201626768265
powassan virus: an emerging arbovirus of public health concern in north america.powassan virus (powv, flaviviridae) is the only north american member of the tick-borne encephalitis serogroup of flaviviruses. it is transmitted to small- and medium-sized mammals by ixodes scapularis, ixodes cookei, and several other ixodes tick species. humans become infected with powv during spillover transmission from the natural transmission cycles. in humans, powv is the causative agent of a severe neuroinvasive illness with 50% of survivors displaying long-term neurological sequelae. pow ...201728498740
nucleotide sequencing and serological evidence that the recently recognized deer tick virus is a genotype of powassan virus.deer tick virus (dtv) is a recently recognized north american virus isolated from ixodes dammini ticks. nucleotide sequencing of fragments of structural and non-structural protein genes suggested that this virus was most closely related to the tick-borne flavivirus powassan (pow), which causes potentially fatal encephalitis in humans. to determine whether dtv represents a new and distinct member of the flavivirus genus of the family flaviviridae, we sequenced the structural protein genes and 5' ...200111551648
powassan virus in mammals, alaska and new mexico, u.s.a., and russia, 2004-2007.powassan virus is endemic to the united states, canada, and the russian far east. we report serologic evidence of circulation of this virus in alaska, new mexico, and siberia. these data support further studies of viral ecology in rapidly changing arctic environments.024274336
stable prevalence of powassan virus in ixodes scapularis in a northern wisconsin focus.deer tick virus (dtv), a variant of powassan virus (powv), appears to be maintained in nature in an enzootic cycle between ixodes scapularis ticks and small mammals. although powv infection of human beings is rare, a recent report suggests increasing incidence and the possibility that powv may be an emerging tick-borne zoonosis. therefore, we assessed the long-term stability of the powv transmission cycle in northwestern wisconsin. adult i. scapularis and dermacentor variabilis were collected fr ...200819052313
seroprevalence of powassan virus in new england deer, 1979-2010.powassan virus and its subtype, deer tick virus, are closely related tick-borne flaviviruses that circulate in north america. the incidence of human infection by these agents appears to have increased in recent years. to define exposure patterns among white-tailed deer, potentially useful sentinels that are frequently parasitized by ticks, we screened serum samples collected during 1979-2010 in connecticut, maine, and vermont for neutralizing antibody by using a novel recombinant deer tick virus ...201323568288
prevalence and genetic characterization of powassan virus strains infecting ixodes scapularis in connecticut.a total of 30 powassan virus (powv) isolates from ixodes scapularis collected from bridgeport and north branford, ct in 2008, 2010, 2011, and 2012 and one earlier isolate from ixodes cookei collected in old lyme, ct in 1978 were characterized by phylogenetic analysis of their envelope gene sequences. powassan virus sequences segregated into two major groups termed the deer tick virus (dtv) and powassan (pow) lineages. the lineage from i. cookei was pow. the remaining viruses from i. scapularis g ...201222890037
molecular epidemiology of powassan virus in north america.powassan virus (pow) is a tick-borne flavivirus distributed in canada, the northern usa and the primorsky region of russia. pow is the only tick-borne flavivirus endemic to the western hemisphere, where it is transmitted mainly between ixodes cookei and groundhogs (marmota monax). deer tick virus (dtv), a genotype of pow that has been frequently isolated from deer ticks (ixodes scapularis), appears to be maintained in an enzootic cycle between these ticks and white-footed mice (peromyscus leucop ...201020631087
enzootic transmission of deer tick virus in new england and wisconsin determine whether rodents that are intensely exposed to the deer tick-transmitted agents of lyme disease, human granulocytic ehrlichiosis, and human babesiosis are also exposed to deer tick virus (dtv), we assayed serum samples from white-footed mice (peromyscus leucopus) and meadow voles (microtus pennsylvanicus) in sites densely infested by deer ticks. to conduct serosurveys, we developed an enzyme-linked immunosorbent assay (elisa) and western blot assay by cloning, expressing, and purifyi ...200011357992
serologic evidence of powassan virus infection in patients with suspected lyme disease(1).powassan virus (powv) lineage ii is an emerging tickborne flavivirus with an unknown seroprevalence in humans. in a lyme disease-endemic area, we examined the seroreactivity to powv in 2 patient cohorts and described the clinical features of the powv-seroreactive patients. powv disease might be less neuroinvasive than previously thought.201728726610
update and commentary on four emerging tick-borne infections: ehrlichia muris-like agent, borrelia miyamotoi, deer tick virus, heartland virus, and whether ticks play a role in transmission of bartonella henselae.emerging tick-borne infections continue to be observed in the united states and elsewhere. current information on the epidemiology, clinical and laboratory features, and treatment of infections due to ehrlichia muris-like agent, deer tick virus, borrelia miyamotoi sensu lato, and heartland virus was provided and critically reviewed. more research is needed to define the incidence and to understand the clinical and the laboratory features of these infections. there is also a growing need for the ...201525999230
fatal case of deer tick virus encephalitis.deer tick virus is related to powassan virus, a tickborne encephalitis virus. a 62-year-old man presented with a meningoencephalitis syndrome and eventually died. analyses of tissue samples obtained during surgery and at autopsy revealed a widespread necrotizing meningoencephalitis. nucleic acid was extracted from formalin-fixed tissue, and the presence of deer tick virus was verified on a flavivirus-specific polymerase-chain-reaction (pcr) assay, followed by sequence confirmation. immunohistoch ...200919439744
genomic sequencing of deer tick virus and phylogeny of powassan-related viruses of north america.powassan (pow) virus is responsible for central nervous system infection in humans in north america and the eastern parts of russia. recently, a new flavivirus, deer tick (dt) virus, related to pow virus was isolated in the united states, but neither its pathogenic potential in human nor the taxonomic relationship with pow virus has been elucidated. in this study, we obtained the near-full-length genomic sequence of the dt virus and complete sequences of 3 genomic regions of 15 strains of pow-re ...200111716135
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