| characterization of powassan viruses from far eastern russia. | we report the isolation and detailed characterization of the novel strain, partizansk/2006, of powassan virus (powv) from a human case of infection, which occurred in primorsky krai, russia, in 2006. comparative complete genome sequence analysis of the far eastern strains spassk-9 (1975), nadezdinsk-1991 and partizansk/2006 of powv revealed that these strains are 99.8% similar to the lb strain, which was isolated in canada in 1958. phylogenetic analysis of 5' utr sequences of five other strains ... | 2009 | 19363586 |
| 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 ... | 2009 | 19439744 |
| arbovirosis and potential transmission blocking vaccines. | infectious diseases caused by arboviruses (viruses transmitted by arthropods) are undergoing unprecedented epidemic activity and geographic expansion. with the recent introduction of west nile virus (1999), chikungunya virus (2013) and zika virus (2015) to the americas, stopping or even preventing the expansion of viruses into susceptible populations is an increasing concern. with a few exceptions, available vaccines protecting against arboviral infections are nonexistent and current disease pre ... | 2016 | 27664127 |
| insect-specific flaviviruses: a systematic review of their discovery, host range, mode of transmission, superinfection exclusion potential and genomic organization. | there has been a dramatic increase in the number of insect-specific flaviviruses (isfs) discovered in the last decade. historically, these viruses have generated limited interest due to their inability to infect vertebrate cells. this viewpoint has changed in recent years because some isfs have been shown to enhance or suppress the replication of medically important flaviviruses in co-infected mosquito cells. additionally, comparative studies between isfs and medically important flaviviruses can ... | 2015 | 25866904 |
| molecular detection of flaviviruses and alphaviruses in mosquitoes (diptera: culicidae) from coastal ecosystems in the colombian caribbean. | arboviruses belonging to the genera flavivirus and alphavirus were detected in mosquitoes in a rural area of san bernardo del viento (córdoba, colombia). a total of 22,180 mosquitoes were collected, sorted into 2,102 pools, and tested by generic/nested reverse transcription-polymerase chain reaction. venezuelan equine encephalitis virus, dengue virus, west nile virus, st. louis encephalitis virus, yellow fever virus, and culex flavivirus were detected and identified by sequencing. the detection ... | 2016 | 27706377 |
| arbovirus infections. | arbovirus (arthropod-borne virus) infections are increasingly important causes of neurologic disease in the united states through both endemic transmission and travel-associated infections. this article reviews the major arbovirus infections that can cause neurologic disease likely to be encountered in the united states. | 0 | 26633778 |
| powassan meningoencephalitis, new york, new york, usa. | disease caused by powassan virus (powv), a tick-borne flavivirus, ranges from asymptomatic to severe neurologic compromise and death. two cases of powv meningoencephalitis in new york, usa, highlight diagnostic techniques, neurologic outcomes, and the effect of powv on communities to which it is endemic. | 0 | 23969017 |
| possible future monoclonal antibody (mab)-based therapy against arbovirus infections. | more than 150 arboviruses belonging to different families are known to infect humans, causing endemic infections as well as epidemic outbreaks. effective vaccines to limit the occurrence of some of these infections have been licensed, while for the others several new immunogens are under development mostly for their improvements concerning safety and effectiveness profiles. on the other hand, specific and effective antiviral drugs are not yet available, posing an urgent medical need in particula ... | 2013 | 24058915 |
| biological transmission of arboviruses: reexamination of and new insights into components, mechanisms, and unique traits as well as their evolutionary trends. | among animal viruses, arboviruses are unique in that they depend on arthropod vectors for transmission. field research and laboratory investigations related to the three components of this unique mode of transmission, virus, vector, and vertebrate host, have produced an enormous amount of valuable information that may be found in numerous publications. however, despite many reviews on specific viruses, diseases, or interests, a systematic approach to organizing the available information on all f ... | 0 | 16223950 |
| imported arbovirus infections in canada 1974-89. | from 1974 to 1989, sera from symptomatic patients with histories of recent travel outside canada were tested for antibodies to several arboviruses, principally of the alphavirus and flavivirus families. diagnostic seroconversions were documented in 84 individuals from six provinces, including one alphavirus (chikungunya) and 83 flavivirus seroconvertors. dengue 1 virus was isolated from the blood of one patient. most flavivirus seroconvertors were likely infected with dengue virus, but infection ... | 0 | 22529717 |
| west nile virus in the united states - a historical perspective. | prior to 1999, west nile virus (wnv) was a bit player in the screenplay of global vector-borne viral diseases. first discovered in the west nile district of uganda in 1937, this culex sp.-transmitted virus was known for causing small human febrile outbreaks in africa and the middle east. prior to 1995, the last major human wnv outbreak was in the 1950s in israel. the epidemiology and ecology of wnv began to change in the mid-1990s when an epidemic of human encephalitis occurred in romania. the i ... | 2013 | 24335779 |
| structure of the st. louis encephalitis virus postfusion envelope trimer. | st. louis encephalitis virus (slev) is a mosquito-borne flavivirus responsible for several human encephalitis outbreaks over the last 80 years. mature flavivirus virions are coated with dimeric envelope (e) proteins that mediate attachment and fusion with host cells. e is a class ii fusion protein, the hallmark of which is a distinct dimer-to-trimer rearrangement that occurs upon endosomal acidification and insertion of hydrophobic fusion peptides into the endosomal membrane. herein, we report t ... | 2012 | 23115296 |
| ixodes scapularis and ixodes ricinus tick cell lines respond to infection with tick-borne encephalitis virus: transcriptomic and proteomic analysis. | ixodid ticks are important vectors of a wide variety of viral, bacterial and protozoan pathogens of medical and veterinary importance. although several studies have elucidated tick responses to bacteria, little is known about the tick response to viruses. to gain insight into the response of tick cells to flavivirus infection, the transcriptomes and proteomes of two ixodes spp cell lines infected with the flavivirus tick-borne encephalitis virus (tbev) were analysed. | 2015 | 26582129 |
| fatal neurological respiratory insufficiency is common among viral encephalitides. | neurological respiratory insufficiency strongly correlates with mortality among rodents infected with west nile virus (wnv), which suggests that this is a primary mechanism of death in rodents and possibly fatal west nile neurological disease in human patients. | 2013 | 23641019 |
| the contribution of rodent models to the pathological assessment of flaviviral infections of the central nervous system. | members of the genus flavivirus are responsible for a spectrum of important neurological syndromes in humans and animals. rodent models have been used extensively to model flavivirus neurological disease, to discover host-pathogen interactions that influence disease outcome, and as surrogates to determine the efficacy and safety of vaccines and therapeutics. in this review, we discuss the current understanding of flavivirus neuroinvasive disease and outline the host, viral and experimental facto ... | 2012 | 22592957 |
| arboviral bottlenecks and challenges to maintaining diversity and fitness during mosquito transmission. | the term arbovirus denotes viruses that are transmitted by arthropods, such as ticks, mosquitoes, and other biting arthropods. the infection of these vectors produces a certain set of evolutionary pressures on the virus; involving migration from the midgut, where the blood meal containing the virus is processed, to the salivary glands, in order to transmit the virus to the next host. during this process the virus is subject to numerous bottlenecks, stochastic events that significantly reduce the ... | 2014 | 25341663 |
| development of an algorithm for production of inactivated arbovirus antigens in cell culture. | arboviruses are medically important pathogens that cause human disease ranging from a mild fever to encephalitis. laboratory diagnosis is essential to differentiate arbovirus infections from other pathogens with similar clinical manifestations. the arboviral diseases branch (adb) reference laboratory at the cdc division of vector-borne diseases (dvbd) produces reference antigens used in serological assays such as the virus-specific immunoglobulin m antibody-capture enzyme-linked immunosorbent as ... | 2014 | 25102428 |
| underreporting of viral encephalitis and viral meningitis, ireland, 2005-2008. | viral encephalitis (ve) and viral meningitis (vm) have been notifiable infectious diseases under surveillance in the republic of ireland since 1981. laboratories have reported confirmed cases by detection of viral nucleic acid in cerebrospinal fluid since 2004. to determine the prevalence of these diseases in ireland during 2005-2008, we analyzed 3 data sources: hospital in-patient enquiry data (from hospitalized following patients discharge) accessed through health intelligence ireland, laborat ... | 0 | 23965781 |
| discovery of dengue virus ns4b inhibitors. | the four serotypes of dengue virus (denv-1 to -4) represent the most prevalent mosquito-borne viral pathogens in humans. no clinically approved vaccine or antiviral is currently available for denv. here we report a spiropyrazolopyridone compound that potently inhibits denv both in vitro and in vivo. the inhibitor was identified through screening of a 1.8-million-compound library by using a denv-2 replicon assay. the compound selectively inhibits denv-2 and -3 (50% effective concentration [ec50], ... | 0 | 26018165 |
| borrelia burgdorferi promotes the establishment of babesia microti in the northeastern united states. | babesia microti and borrelia burgdorferi, the respective causative agents of human babesiosis and lyme disease, are maintained in their enzootic cycles by the blacklegged tick (ixodes scapularis) and use the white-footed mouse (peromyscus leucopus) as primary reservoir host. the geographic range of both pathogens has expanded in the united states, but the spread of babesiosis has lagged behind that of lyme disease. several studies have estimated the basic reproduction number (r0) for b. microti ... | 2014 | 25545393 |
| ecuador paraiso escondido virus, a new flavivirus isolated from new world sand flies in ecuador, is the first representative of a novel clade in the genus flavivirus. | a new flavivirus, ecuador paraiso escondido virus (epev), named after the village where it was discovered, was isolated from sand flies (psathyromyia abonnenci, formerly lutzomyia abonnenci) that are unique to the new world. this represents the first sand fly-borne flavivirus identified in the new world. epev exhibited a typical flavivirus genome organization. nevertheless, the maximum pairwise amino acid sequence identity with currently recognized flaviviruses was 52.8%. phylogenetic analysis o ... | 2015 | 26355096 |
| new insights into flavivirus evolution, taxonomy and biogeographic history, extended by analysis of canonical and alternative coding sequences. | to generate the most diverse phylogenetic dataset for the flaviviruses to date, we determined the genomic sequences and phylogenetic relationships of 14 flaviviruses, of which 10 are primarily associated with culex spp. mosquitoes. we analyze these data, in conjunction with a comprehensive collection of flavivirus genomes, to characterize flavivirus evolutionary and biogeographic history in unprecedented detail and breadth. based on the presumed introduction of yellow fever virus into the americ ... | 2015 | 25719412 |
| identification of a flavivirus sequence in a marine arthropod. | phylogenetic analysis has yet to uncover the early origins of flaviviruses. in this study, i mined a database of expressed sequence tags in order to discover novel flavivirus sequences. flavivirus sequences were identified in a pool of mrna extracted from the sea spider endeis spinosa (pycnogonida, pantopoda). reconstruction of the translated sequences and blast analysis matched the sequence to the flavivirus ns5 gene. additional sequences corresponding to envelope and the ns5 mtase domain were ... | 2015 | 26717191 |
| usutu virus: an emerging flavivirus in europe. | usutu virus (usuv) is an african mosquito-borne flavivirus belonging to the japanese encephalitis virus serocomplex. usuv is closely related to murray valley encephalitis virus, japanese encephalitis virus, and west nile virus. usuv was discovered in south africa in 1959. in europe, the first true demonstration of circulation of usuv was reported in austria in 2001 with a significant die-off of eurasian blackbirds. in the subsequent years, usuv expanded to neighboring countries, including italy, ... | 2015 | 25606971 |
| characterization of a novel insect-specific flavivirus from brazil: potential for inhibition of infection of arthropod cells with medically important flaviviruses. | in the past decade, there has been an upsurge in the number of newly described insect-specific flaviviruses isolated pan-globally. we recently described the isolation of a novel flavivirus (tentatively designated 'nhumirim virus'; nhuv) that represents an example of a unique subset of apparently insect-specific viruses that phylogenetically affiliate with dual-host mosquito-borne flaviviruses despite appearing to be limited to replication in mosquito cells. we characterized the in vitro growth p ... | 2014 | 25146007 |
| lyme borreliosis: a review of data on transmission time after tick attachment. | lyme borreliosis is increasing rapidly in many parts of the world and is the most commonly occurring vector-borne disease in europe and the usa. the disease is transmitted by ticks of the genus ixodes. they require a blood meal at each stage of their life cycle and feed on a wide variety of wild and domestic animals as well as birds and reptiles. transmission to humans is incidental and can occur during visits to a vector habitat, when host mammals and their associated ticks migrate into the urb ... | 2014 | 25565881 |
| substitution of the premembrane and envelope protein genes of modoc virus with the homologous sequences of west nile virus generates a chimeric virus that replicates in vertebrate but not mosquito cells. | most known flaviviruses, including west nile virus (wnv), are maintained in natural transmission cycles between hematophagous arthropods and vertebrate hosts. other flaviviruses such as modoc virus (modv) and culex flavivirus (cxfv) have host ranges restricted to vertebrates and insects, respectively. the genetic elements that modulate the differential host ranges and transmission cycles of these viruses have not been identified. | 2014 | 25151534 |
| borrelia burgdorferi (lyme disease). | | 2014 | 25452659 |
| recovery of west nile virus envelope protein domain iii chimeras with altered antigenicity and mouse virulence. | flaviviruses are positive-sense, single-stranded rna viruses responsible for millions of human infections annually. the envelope (e) protein of flaviviruses comprises three structural domains, of which domain iii (eiii) represents a discrete subunit. the eiii gene sequence typically encodes epitopes recognized by virus-specific, potently neutralizing antibodies, and eiii is believed to play a major role in receptor binding. in order to assess potential interactions between eiii and the remainder ... | 2016 | 26912625 |
| monitoring human babesiosis emergence through vector surveillance new england, usa. | human babesiosis is an emerging tick-borne disease caused by the intraerythrocytic protozoan babesia microti. its geographic distribution is more limited than that of lyme disease, despite sharing the same tick vector and reservoir hosts. the geographic range of babesiosis is expanding, but knowledge of its range is incomplete and relies exclusively on reports of human cases. we evaluated the utility of tick-based surveillance for monitoring disease expansion by comparing the ratios of the 2 inf ... | 2014 | 24447577 |
| factors responsible for the emergence of arboviruses; strategies, challenges and limitations for their control. | slave trading of africans to the americas, during the 16th to the 19th century was responsible for the first recorded emergence in the new world of two arthropod-borne viruses (arboviruses), yellow fever virus and dengue virus. many other arboviruses have since emerged from their sylvatic reservoirs and dispersed globally due to evolving factors that include anthropological behaviour, commercial transportation and land-remediation. here, we outline some characteristics of these highly divergent ... | 2015 | 26038768 |
| state health department perceived utility of and satisfaction with arbonet, the u.s. national arboviral surveillance system. | we assessed the perceived utility of data collected through arbonet, the national arboviral surveillance system, and evaluated state health department user satisfaction with system function. | 0 | 22753981 |
| human coinfection with borrelia burgdorferi and babesia microti in the united states. | borrelia burgdorferi, the causative agent of lyme disease, and babesia microti, a causative agent of babesiosis, are increasingly implicated in the growing tick-borne disease burden in the northeastern united states. these pathogens are transmitted via the bite of an infected tick vector, ixodes scapularis, which is capable of harboring and inoculating a host with multiple pathogens simultaneously. clinical presentation of the diseases is heterogeneous and ranges from mild flu-like symptoms to n ... | 2015 | 26697208 |
| inhibitors of tick-borne flavivirus reproduction from structure-based virtual screening. | flaviviruses form a large family of enveloped viruses affecting millions of people over the world. to date, no specific therapy was suggested for the infected people, making the treatment exclusively symptomatic. several attempts were performed earlier for the design of fusion inhibitors for mosquito-borne flaviviruses, whereas for the tick-borne flaviviruses such design had not been performed. we have constructed homology models of envelope glycoproteins of tick-transmitted flaviviruses with th ... | 2013 | 24900762 |
| ilheus virus isolation in the pantanal, west-central brazil. | the wetlands of the brazilian pantanal host large concentrations of diverse wildlife species and hematophagous arthropods, conditions that favor the circulation of zoonotic arboviruses. a recent study from the nhecolândia sub-region of pantanal reported serological evidence of various flaviviruses, including west nile virus and ilheus virus (ilhv). according to the age of seropositive horses, at least three flaviviruses, including ilhv, circulated in the brazilian pantanal between 2005 and 2009. ... | 2013 | 23875051 |
| case definitions, diagnostic algorithms, and priorities in encephalitis: consensus statement of the international encephalitis consortium. | encephalitis continues to result in substantial morbidity and mortality worldwide. advances in diagnosis and management have been limited, in part, by a lack of consensus on case definitions, standardized diagnostic approaches, and priorities for research. | 2013 | 23861361 |
| a multiplex pcr/ldr assay for the simultaneous identification of category a infectious pathogens: agents of viral hemorrhagic fever and variola virus. | cdc designated category a infectious agents pose a major risk to national security and require special action for public health preparedness. they include viruses that cause viral hemorrhagic fever (vhf) syndrome as well as variola virus, the agent of smallpox. vhf is characterized by hemorrhage and fever with multi-organ failure leading to high morbidity and mortality. smallpox, a prior scourge, has been eradicated for decades, making it a particularly serious threat if released nefariously in ... | 2015 | 26381398 |
| flaviviruses in europe: complex circulation patterns and their consequences for the diagnosis and control of west nile disease. | in europe, many flaviviruses are endemic (west nile, usutu, tick-borne encephalitis viruses) or occasionally imported (dengue, yellow fever viruses). due to the temporal and geographical co-circulation of flaviviruses in europe, flavivirus differentiation by diagnostic tests is crucial in the adaptation of surveillance and control efforts. serological diagnosis of flavivirus infections is complicated by the antigenic similarities among the flavivirus genus. indeed, most flavivirus antibodies are ... | 2013 | 24225644 |
| s-adenosyl-homocysteine is a weakly bound inhibitor for a flaviviral methyltransferase. | the methyltransferase enzyme (mtase), which catalyzes the transfer of a methyl group from s-adenosyl-methionine (adomet) to viral rna, and generates s-adenosyl-homocysteine (adohcy) as a by-product, is essential for the life cycle of many significant human pathogen flaviviruses. here we investigated inhibition of the flavivirus mtase by several adohcy-derivatives. unexpectedly we found that adohcy itself barely inhibits the flavivirus mtase activities, even at high concentrations. adohcy was als ... | 2013 | 24130807 |
| the tortoise or the hare? impacts of within-host dynamics on transmission success of arthropod-borne viruses. | arthropod-borne viruses (arboviruses) are maintained in a cycle of alternating transmission between vertebrate hosts and arthropod vectors. arboviruses possess rna genomes capable of rapid diversification and adaptation, and the between-host trade-offs inherent to host alternation impose well-documented constraints on arbovirus evolution. here, we investigate the less well-studied within-host trade-offs that shape arbovirus replication dynamics and transmission. arboviruses generally establish l ... | 0 | 26150665 |
| assessment of arbovirus surveillance 13 years after introduction of west nile virus, united states. | before 1999, the united states had no appropriated funding for arboviral surveillance, and many states conducted no such surveillance. after emergence of west nile virus (wnv), federal funding was distributed to state and selected local health departments to build wnv surveillance systems. the council of state and territorial epidemiologists conducted assessments of surveillance capacity of resulting systems in 2004 and in 2012; the assessment in 2012 was conducted after a 61% decrease in federa ... | 0 | 26079471 |
| experimental transmission of karshi (mammalian tick-borne flavivirus group) virus by ornithodoros ticks >2,900 days after initial virus exposure supports the role of soft ticks as a long-term maintenance mechanism for certain flaviviruses. | members of the mammalian tick-borne flavivirus group, including tick-borne encephalitis virus, are responsible for at least 10,000 clinical cases of tick-borne encephalitis each year. to attempt to explain the long-term maintenance of members of this group, we followed ornithodoros parkeri, o. sonrai, and o. tartakovskyi for >2,900 days after they had been exposed to karshi virus, a member of the mammalian tick-borne flavivirus group. | 2015 | 26285211 |
| experimental therapies for yellow fever. | a number of viruses in the family flaviviridae are the focus of efforts to develop effective antiviral therapies. success has been achieved with inhibitors for the treatment of hepatitis c, and there is interest in clinical trials of drugs against dengue fever. antiviral therapies have also been evaluated in patients with japanese encephalitis and west nile encephalitis. however, no treatment has been developed against the prototype flavivirus, yellow fever virus (yfv). despite the availability ... | 2012 | 23237991 |
| a quantitative and novel approach to the prioritization of zoonotic diseases in north america: a public perspective. | zoonoses account for over half of all communicable diseases causing illness in humans. as there are limited resources available for the control and prevention of zoonotic diseases, a framework for their prioritization is necessary to ensure resources are directed into those of highest importance. although zoonotic outbreaks are a significant burden of disease in north america, the systematic prioritization of zoonoses in this region has not been previously evaluated. | 2012 | 23133639 |
| human granulocytic anaplasmosis: first reported case in canada. | human granulocytic anaplasmosis (hga) is a tick-borne rickettsial infection of peripheral blood neutrophils caused by anaplasma phagocytophilum. while this infection is increasingly recognized as endemic throughout much of the united states, no canadian cases have been previously described, despite the agent being identified in canadian ticks. herein we present a case of hga acquired in an urban alberta centre. canadian physicians must be aware of the possibility of tick-borne rickettsial diseas ... | 2009 | 20808448 |
| loop analysis for pathogens: niche partitioning in the transmission graph for pathogens of the north american tick ixodes scapularis. | in population biology, loop analysis is a method of decomposing a life cycle graph into life history pathways so as to compare the relative contributions of pathways to the population growth rate across species and populations. we apply loop analysis to the transmission graph of five pathogens known to infect the black-legged tick, ixodes scapularis. in this context loops represent repeating chains of transmission that could maintain the pathogen. they hence represent completions of the life cyc ... | 2010 | 20950628 |
| mutational analysis of three predicted 5'-proximal stem-loop structures in the genome of tick-borne encephalitis virus indicates different roles in rna replication and translation. | flavivirus gene expression is modulated by rna secondary structure elements at the terminal ends of the viral rna molecule. for tick-borne encephalitis virus (tbev), four stem-loop (sl) elements have been predicted in the first 180 nucleotides of the viral genome: 5'-sl1, 5'-sl2, 5'-sl3 and 5'-sl4. the last three of these appear to be unique to tick-borne flaviviruses. here, we report their characterization by mutagenesis in a tbev luciferase reporter system. by manipulating their thermodynamic ... | 2011 | 21645915 |
| the role of viral persistence in flavivirus biology. | in nature, vector-borne flaviviruses are persistently cycled between either the tick or mosquito vector and small mammals such as rodents, skunks, and swine. these viruses account for considerable human morbidity and mortality worldwide. increasing and substantial evidence of viral persistence in humans, which includes the isolation of rna by rt-pcr and infectious virus by culture, continues to be reported. viral persistence can also be established in vitro in various human, animal, arachnid, an ... | 2014 | 24737600 |
| flavivirus rna cap methyltransferase: structure, function, and inhibition. | many flaviviruses are significant human pathogens. the plus-strand rna genome of a flavivirus contains a 5' terminal cap 1 structure (m(7)gpppamg). the flavivirus encodes one methyltransferase (mtase), located at the n-terminal portion of the ns5 rna-dependent rna polymerase (rdrp). here we review recent advances in our understanding of flaviviral capping machinery and the implications for drug development. the ns5 mtase catalyzes both guanine n7 and ribose 2'-oh methylations during viral cap fo ... | 2010 | 21927615 |
| molecular archaeology of flaviviridae untranslated regions: duplicated rna structures in the replication enhancer of flaviviruses and pestiviruses emerged via convergent evolution. | rna secondary structures in the 3'untranslated regions (3'utr) of the viruses of the family flaviviridae, previously identified as essential (promoters) or beneficial (enhancers) for replication, have been analysed. duplicated enhancer elements are revealed as a global feature in the evolution of the 3'utr of distantly related viruses within the genera flavivirus and pestivirus. for the flaviviruses, duplicated structures occur in the 3'utr of all four distantly related ecological virus subgroup ... | 2014 | 24647143 |
| viruses infecting reptiles. | a large number of viruses have been described in many different reptiles. these viruses include arboviruses that primarily infect mammals or birds as well as viruses that are specific for reptiles. interest in arboviruses infecting reptiles has mainly focused on the role reptiles may play in the epidemiology of these viruses, especially over winter. interest in reptile specific viruses has concentrated on both their importance for reptile medicine as well as virus taxonomy and evolution. the imp ... | 2011 | 22163336 |
| changes in the proteome of langat-infected ixodes scapularis ise6 cells: metabolic pathways associated with flavivirus infection. | ticks (family ixodidae) transmit a variety of disease causing agents to humans and animals. the tick-borne flaviviruses (tbfs; family flaviviridae) are a complex of viruses, many of which cause encephalitis and hemorrhagic fever, and represent global threats to human health and biosecurity. pathogenesis has been well studied in human and animal disease models. equivalent analyses of tick-flavivirus interactions are limited and represent an area of study that could reveal novel approaches for tbf ... | 2016 | 26859745 |
| zika virus on a spreading spree: what we now know that was unknown in the 1950's. | zika virus (zikv) is a mosquito-borne flavivirus that is transmitted through the bite of aedes spp mosquitoes and less predominantly, through sexual intercourse. prior to 2007, zikv was associated with only sporadic human infections with minimal or no clinical manifestations. recently the virus has caused disease outbreaks from the pacific islands, the americas, and off the coast of west africa with approximately 1.62 million people suspected to be infected in more than 60 countries around the g ... | 2016 | 27716242 |
| flavidb: a data mining system for knowledge discovery in flaviviruses with direct applications in immunology and vaccinology. | the flavivirus genus is unusually large, comprising more than 70 species, of which more than half are known human pathogens. it includes a set of clinically relevant infectious agents such as dengue, west nile, yellow fever, and japanese encephalitis viruses. although these pathogens have been studied extensively, safe and efficient vaccines lack for the majority of the flaviviruses. | 0 | 25544857 |
| Crystal structure of the Japanese encephalitis virus envelope protein. | Japanese Encephalitis Virus (JEV) is the leading global cause of viral encephalitis. The JEV envelope protein (E) facilitates cellular attachment and membrane fusion and is the primary target of neutralizing antibodies. Herein, we have determined the 2.1Å resolution crystal structure of the JEV E ectodomain refolded from bacterial inclusion bodies. The E protein possesses the three domains characteristic of flavivirus envelopes and epitope mapping of neutralizing antibodies onto the structure re ... | 2011 | 22156523 |
| trim79α, an interferon-stimulated gene product, restricts tick-borne encephalitis virus replication by degrading the viral rna polymerase. | in response to virus infection, type i interferons (ifns) induce several genes, most of whose functions are largely unknown. here, we show that the tripartite motif (trim) protein, trim79α, is an ifn-stimulated gene (isg) product that specifically targets tick-borne encephalitis virus (tbev), a flavivirus that causes encephalitides in humans. trim79α restricts tbev replication by mediating lysosome-dependent degradation of the flavivirus ns5 protein, an rna-dependent rna polymerase essential for ... | 2011 | 21925107 |
| dose-dependent viremia and the differential immunoglobulin response of hamsters to powassan virus. | | 2013 | 4624393 |
| transmission bottlenecks and rnai collectively influence tick-borne flavivirus evolution. | arthropod-borne rna viruses exist within hosts as heterogeneous populations of viral variants and, as a result, possess great genetic plasticity. understanding the micro-evolutionary forces shaping these viruses can provide insights into how they emerge, adapt, and persist in new and changing ecological niches. while considerable attention has been directed toward studying the population dynamics of mosquito-borne viruses, little is known about tick-borne virus populations. therefore, using a mo ... | 2016 | 28058113 |
| aedes aegypti d7 saliva protein inhibits dengue virus infection. | aedes aegypti is the primary vector of several medically relevant arboviruses including dengue virus (denv) types 1-4. ae. aegypti transmits denv by inoculating virus-infected saliva into host skin during probing and feeding. ae. aegypti saliva contains over one hundred unique proteins and these proteins have diverse functions, including facilitating blood feeding. previously, we showed that ae. aegypti salivary gland extracts (sges) enhanced dissemination of denv to draining lymph nodes. in con ... | 2016 | 27632170 |
| 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 ... | 2013 | 23568288 |
| [pathomorphology of experimental infection caused by powassan virus isolated in the primorskiĭ territory]. | pathomorphology of the infection caused by powassan virus strains isolated in the primorsky kray was studied in white mice. the central nervous system of the animals sacrificed in the time course of the infectious process was studied by light and luminescent microscopy. severe diffuse inflammatory-degenerative changes were found in the brain and spinal cord. immunofluorescence revealed cytoplasmic localization of the virus antigen in neurons, glial and connective tissue cells. | 1992 | 206027 |
| spinal cord ventral horns and lymphoid organ involvement in powassan virus infection in a mouse model. | powassan virus (powv) belongs to the family flaviviridae and is a member of the tick-borne encephalitis serogroup. transmission of powv from infected ticks to humans has been documented in the usa, canada, and russia, causing fatal encephalitis in 10% of human cases and significant neurological sequelae in survivors. we used c57bl/6 mice to investigate powv infection and pathogenesis. after footpad inoculation, infected animals exhibited rapid disease progression and 100% mortality. immunohistoc ... | 2016 | 27529273 |
| in vitro antiviral activity of adenosine analog nitd008 against tick-borne flaviviruses. | there are currently no antiviral therapies available for the tick-borne flaviviruses associated with hemorrhagic fevers: kyasanur forest disease virus (kfdv), both classical and the alkhurma hemorrhagic fever virus (ahfv) subtype, and omsk hemorrhagic fever virus (ohfv). in this brief study, we describe the in vitro antiviral activity of adenosine analog nitd008 against kfdv, ahfv, ohfv, as well as tick-borne encephalitis virus (tbev). alongside the well-established activity of nitd008 against m ... | 2016 | 27016316 |
| [electron microscopic study of the an-750 strain of powassan virus isolated in the soviet union]. | electron microscopic examinations of brains of white mice inoculated with the an 750 strain isolated for the first time from adult mosquitoes and with the prototype lb strain of powassan virus were carried out. the method of combination of light and electron microscopy used in the study permitted to compare ultrastructural changes in one cell with the results of light microscopy. sizes of virions and their localizations in the brain cells were determined. virus particles were found in large and ... | 1987 | 211734 |
| direct molecular detection and genotyping of borrelia burgdorferi from whole blood of patients with early lyme disease. | direct molecular tests in blood for early lyme disease can be insensitive due to low amount of circulating borrelia burgdorferi dna. to address this challenge, we have developed a sensitive strategy to both detect and genotype b. burgdorferi directly from whole blood collected during the initial patient visit. this strategy improved sensitivity by employing 1.25 ml of whole blood, a novel pre-enrichment of the entire specimen extract for borrelia dna prior to a multi-locus pcr and electrospray i ... | 2012 | 22590620 |
| analysis of the langat virus genome in persistent infection of an ixodes scapularis cell line. | tick-borne flaviviruses (tbfvs) cause a broad spectrum of disease manifestations ranging from asymptomatic to mild febrile illness and life threatening encephalitis. these single-stranded positive-sense (ss(+)) rna viruses are naturally maintained in a persistent infection of ixodid ticks and small-medium sized mammals. the development of cell lines from the ixodid ticks has provided a valuable surrogate system for studying the biology of tbfvs in vitro. when we infected ise6 cells, an ixodes sc ... | 2016 | 27626437 |
| first evidence of established populations of the taiga tick ixodes persulcatus (acari: ixodidae) in sweden. | the tick species ixodes ricinus and i. persulcatus are of exceptional medical importance in the western and eastern parts, respectively, of the palaearctic region. in russia and finland the range of i. persulcatus has recently increased. in finland the first records of i. persulcatus are from 2004. the apparent expansion of its range in finland prompted us to investigate if i. persulcatus also occurs in sweden. | 2016 | 27370406 |
| vaccination against lyme disease: past, present, and future. | lyme borreliosis is a zoonotic disease caused by borrelia burgdorferi sensu lato bacteria transmitted to humans and domestic animals by the bite of an ixodes spp. tick (deer tick). despite improvements in diagnostic tests and public awareness of lyme disease, the reported cases have increased over the past decade to approximately 30,000 per year. limitations and failed public acceptance of a human vaccine, comprised of the outer surface a (ospa) lipoprotein of b. burgdorferi, led to its demise, ... | 2013 | 23407755 |
| climate change and ixodes tick-borne diseases of humans. | the evidence that climate warming is changing the distribution of ixodes ticks and the pathogens they transmit is reviewed and evaluated. the primary approaches are either phenomenological, which typically assume that climate alone limits current and future distributions, or mechanistic, asking which tick-demographic parameters are affected by specific abiotic conditions. both approaches have promise but are severely limited when applied separately. for instance, phenomenological approaches (e.g ... | 2015 | 25688022 |
| diversity of viruses in ixodes ricinus, and characterization of a neurotropic strain of eyach virus. | ticks transmit more pathogens-including bacteria, parasites and viruses-than any other arthropod vector. although the epidemiological status of many tick-borne bacteria is very well characterized, tick-borne viruses are still relatively under-studied. recently, several novel tick-borne viruses have been isolated from human febrile illnesses following tick bites, indicating the existence of other potential new and unknown tick-borne viruses. we used high-throughput sequencing to analyse the virom ... | 2016 | 27158509 |
| four emerging arboviral diseases in north america: jamestown canyon, powassan, chikungunya, and zika virus diseases. | arthropod-borne viruses, or arboviruses, are viruses that are transmitted through the bites of mosquitoes, ticks, or sandflies. there are numerous arboviruses throughout the world capable of causing human disease spanning different viral families and genera. recently, jamestown canyon, powassan, chikungunya, and zika viruses have emerged as increasingly important arboviruses that can cause human disease in north america. unfortunately, there are currently no proven disease-modifying therapies fo ... | 2016 | 26903031 |
| accelerated phenology of blacklegged ticks under climate warming. | the phenology of tick emergence has important implications for the transmission of tick-borne pathogens. a long lag between the emergence of tick nymphs in spring and larvae in summer should increase transmission of persistent pathogens by allowing infected nymphs to inoculate the population of naive hosts that can subsequently transmit the pathogen to larvae to complete the transmission cycle. in contrast, greater synchrony between nymphs and larvae should facilitate transmission of pathogens t ... | 2015 | 25688016 |
| established population of blacklegged ticks with high infection prevalence for the lyme disease bacterium, borrelia burgdorferi sensu lato, on corkscrew island, kenora district, ontario. | we document an established population of blacklegged ticks, ixodes scapularis, on corkscrew island, kenora district, ontario, canada. primers of the outer surface protein a (ospa) gene, the flagellin (fla) gene, and the flagellin b (flab) gene were used in the pcr assays to detect borrelia burgdorferi sensu lato (s.l.), the lyme disease bacterium. in all, 60 (73%) of 82 adult i. scapularis, were infected with b. burgdorferi s.l. as well, 6 (43%) of 14 unfed i. scapularis nymphs were positive for ... | 2016 | 27877080 |
| tick-borne encephalitis virus subtypes emerged through rapid vector switches rather than gradual evolution. | tick-borne encephalitis is the most important human arthropod-borne virus disease in europe and russia, with an annual incidence of about 13 thousand people. tick-borne encephalitis virus (tbev) is distributed in the natural foci of forest and taiga zones of eurasia, from the pacific to the atlantic coast. currently, there are three mutually exclusive hypotheses about the origin and distribution of tbev subtypes, although they are based on the same assumption of gradual evolution. recently, we h ... | 2014 | 25540692 |
| transcriptome of the female synganglion of the black-legged tick ixodes scapularis (acari: ixodidae) with comparison between illumina and 454 systems. | illumina and 454 pyrosequencing were used to characterize genes from the synganglion of female ixodes scapularis. go term searching success for biological processes was similar for samples sequenced by both methods. however, for molecular processes, it was more successful for the illumina samples than for 454 samples. functional assignments of transcripts predicting neuropeptides, neuropeptide receptors, neurotransmitter receptors and other genes of interest was done, supported by strong e-value ... | 2014 | 25075967 |
| tick-borne encephalitis virus sequenced directly from questing and blood-feeding ticks reveals quasispecies variance. | the increased distribution of the tick-borne encephalitis virus (tbev) in scandinavia highlights the importance of characterizing novel sequences within the natural foci. in this study, two tbev strains: the norwegian mandal 2009 (questing nymphs pool) and the swedish saringe 2009 (blood-fed nymph) were sequenced and phylogenetically characterized. interestingly, the sequence of mandal 2009 revealed the shorter form of the tbev genome, similar to the highly virulent hypr strain, within the 3' no ... | 2014 | 25058476 |
| comparative pathogenesis of alkhumra hemorrhagic fever and kyasanur forest disease viruses in a mouse model. | kyasanur forest disease virus (kfdv) and alkhumra hemorrhagic fever virus (ahfv) are genetically closely-related, tick-borne flaviviruses that cause severe, often fatal disease in humans. flaviviruses in the tick-borne encephalitis (tbe) complex typically cause neurological disease in humans whereas patients infected with kfdv and ahfv predominately present with hemorrhagic fever. a small animal model for kfdv and ahfv to study the pathogenesis and evaluate countermeasures has been lacking mostl ... | 2014 | 24922308 |
| detection of rickettsia amblyommii in ticks collected from missouri, usa. | | 2014 | 26038740 |
| proinflammatory cytokines and chemokines at the skin interface during powassan virus transmission. | | 2014 | 24658509 |
| a blood meal-induced ixodes scapularis tick saliva serpin inhibits trypsin and thrombin, and interferes with platelet aggregation and blood clotting. | ixodes scapularis is a medically important tick species that transmits causative agents of important human tick-borne diseases including borreliosis, anaplasmosis and babesiosis. an understanding of how this tick feeds is needed prior to the development of novel methods to protect the human population against tick-borne disease infections. this study characterizes a blood meal-induced i. scapularis (ixsc) tick saliva serine protease inhibitor (serpin (s)), in-house referred to as ixscs-1e1. the ... | 2014 | 24583183 |
| 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. | 0 | 24274336 |
| powassan virus encephalitis, minnesota, usa. | | 0 | 23750562 |
| deorphanization and target validation of cross-tick species conserved novel amblyomma americanum tick saliva protein. | we previously identified a cross-tick species conserved tick feeding stimuli responsive amblyomma americanum (aam) av422 gene. this study demonstrates that aamav422 belongs to a novel group of arthropod proteins that is characterized by 14 cysteine amino acid residues: c(23)-x7/9-c(33)-x23/24-c(58)-x8-c(67)-x7-c(75)-x23-c(99)-x15-c(115)-x10-c(126)-x24/25/33-c(150)c(151)-x7-c(159)-x8-c(168)-x23/24-c(192)-x9/10-c(202) predicted to form seven disulfide bonds. we show that aamav422 protein is a ubiq ... | 2013 | 23428900 |
| epidemiology of tick-borne encephalitis (tbe) in europe and its prevention by available vaccines. | tick-borne encephalitis (tbe), which is caused by a flavivirus, is the most common tick-transmitted disease in central and eastern europe and russia. today, tbe is endemic in 27 european countries, and has become an international public health problem. the epidemiology of tbe is changing owing to various factors, such as improvements in diagnosis and case reporting, increased recreational activities in areas populated by ticks, and changes in climatic conditions affecting tick habitats. vaccinat ... | 2013 | 23377671 |
| lyme disease risk in southern california: abiotic and environmental drivers of ixodes pacificus (acari: ixodidae) density and infection prevalence with borrelia burgdorferi. | tick-borne diseases, particularly lyme disease, are emerging across the northern hemisphere. in order to manage emerging diseases and predict where emergence will likely occur, it is necessary to understand the factors influencing the distribution, abundance and infection prevalence of vector species. in north america, lyme disease is the most common vector-borne disease and is transmitted by blacklegged ticks. this study aimed to explore the abiotic and environmental drivers of density and infe ... | 2017 | 28057067 |
| encephalitis surveillance through the emerging infections program, 1997-2010. | encephalitis is a devastating illness that commonly causes neurologic disability and has a case fatality rate >5% in the united states. an etiologic agent is identified in <50% of cases, making diagnosis challenging. the centers for disease control and prevention emerging infections program (eip) encephalitis project established syndromic surveillance for encephalitis in new york, california, and tennessee, with the primary goal of increased identification of causative agents and secondary goals ... | 2015 | 26295485 |
| viral meningitis. | | 1998 | 20401229 |
| biologically hazardous agents at work and efforts to protect workers' health: a review of recent reports. | because information on biological agents in the workplace is lacking, biological hazard analyses at the workplace to securely recognize the harmful factors with biological basis are desperately needed. this review concentrates on literatures published after 2010 that attempted to detect biological hazards to humans, especially workers, and the efforts to protect them against these factors. it is important to improve the current understanding of the health hazards caused by biological factors at ... | 2014 | 25180133 |
| the relationship between the structure of the tick-borne encephalitis virus strains and their pathogenic properties. | tick-borne encephalitis virus (tbev) is transmitted to vertebrates by taiga or forest ticks through bites, inducing disease of variable severity. the reasons underlying these differences in the severity of the disease are unknown. in order to identify genetic factors affecting the pathogenicity of virus strains, we have sequenced and compared the complete genomes of 34 far-eastern subtype (fe) tbev strains isolated from patients with different disease severity (primorye, the russian far east). w ... | 2014 | 24740396 |
| transcriptome analysis reveals a signature profile for tick-borne flavivirus persistence in hek 293t cells. | tick-borne flaviviruses (tbfvs) cause febrile illnesses, which may progress to severe encephalitis and/or death in humans globally. most people who recover from severe acute disease suffer from debilitating neurological sequelae, which may be due to viral persistence, infection-induced neurological cell damage, host response, or some combination of these. acute tbfv infection of human embryonic kidney (hek) 293t cells in vitro results in the death of >95% of infected cells by day 5. however, rep ... | 2016 | 27222466 |
| a preliminary randomized double blind placebo-controlled trial of intravenous immunoglobulin for japanese encephalitis in nepal. | japanese encephalitis (je) virus (jev) is a mosquito-borne flavivirus found across asia that is closely related to west nile virus. there is no known antiviral treatment for any flavivirus. results from in vitro studies and animal models suggest intravenous immunoglobulin (ivig) containing virus-specific neutralizing antibody may be effective in improving outcome in viral encephalitis. ivig's anti-inflammatory properties may also be beneficial. | 2015 | 25886645 |
| a quantitative approach to the prioritization of zoonotic diseases in north america: a health professionals' perspective. | currently, zoonoses account for 58% to 61% of all communicable diseases causing illness in humans globally and up to 75% of emerging human pathogens. although the impact of zoonoses on animal health and public health in north america is significant, there has been no published research involving health professionals on the prioritization of zoonoses in this region. | 2013 | 23991057 |
| development of a model system for tick-borne flavivirus persistence in hek 293t cells. | we devised a model system to study persistent infection by the tick-borne flavivirus langat virus (lgtv) in 293t cells. infection with a molecularly cloned lgtv strain produced an acute lytic crisis that left few surviving cells. the culture was repopulated by cells that were ~90% positive for lgtv e protein, thus initiating a persistent infection that was maintained for at least 35 weeks without additional lytic crises. staining of cells for viral proteins and ultrastructural analysis revealed ... | 2015 | 26045539 |
| west nile virus and other arboviral diseases--united states, 2012. | arthropod-borne viruses (arboviruses) are transmitted to humans primarily through the bites of infected mosquitoes and ticks. west nile virus (wnv) is the leading cause of domestically acquired arboviral disease in the united states. however, several other arboviruses also cause sporadic cases and seasonal outbreaks of neuroinvasive disease (e.g., meningitis, encephalitis, and acute flaccid paralysis). in 2012, cdc received reports of 5,780 nationally notifiable arboviral disease cases (excludin ... | 2013 | 23803959 |
| emerging causes of arbovirus encephalitis in north america: powassan, chikungunya, and zika viruses. | arboviruses are arthropod-borne viruses transmitted by the bite of mosquitoes, ticks, or other arthropods. arboviruses are a common and an increasing cause of human illness in north america. powassan virus, chikungunya virus, and zika virus are arboviruses that have all recently emerged as increasing causes of neurologic illness. powassan virus almost exclusively causes encephalitis, but cases are rare, sporadic, and restricted to portions of north america and russia. chikungunya virus has sprea ... | 2017 | 28229397 |
| kyasanur forest disease. | in the spring of 1957, an outbreak of severe disease was documented in people living near the kyasanur forest in karnataka state, india, which also affected wild nonhuman primates. collection of samples from dead animals and the use of classical virological techniques led to the isolation of a previously unrecognized virus, named kyasanur forest disease virus (kfdv), which was found to be related to the russian spring-summer encephalitis (rsse) complex of tick-borne viruses. further evaluation f ... | 2012 | 23110991 |
| 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. | 2016 | 26668338 |
| detection of quang binh virus from mosquitoes in china. | flaviviruses present a wide range of genetic diversity and exhibit diverse host relationships. mosquito-borne flaviviruses have recently been isolated and characterized worldwide. yunnan province of china is one of the richest areas of species diversity and is the center of multi-species evolution in mainland asia, which supports the circulation of numerous arthropod-borne viruses (arboviruses). in a screening program of arboviruses, mosquitoes were collected during the mosquito activity season ... | 2014 | 24342141 |
| west nile virus and other nationally notifiable arboviral diseases - united states, 2014. | arthropod-borne viruses (arboviruses) are transmitted to humans primarily through the bites of infected mosquitoes and ticks. west nile virus (wnv) is the leading cause of domestically acquired arboviral disease in the united states (1). however, several other arboviruses also cause sporadic cases and seasonal outbreaks. this report summarizes surveillance data reported to cdc in 2014 for wnv and other nationally notifiable arboviruses, excluding dengue. forty-two states and the district of colu ... | 2015 | 26334477 |
| west nile virus and other arboviral diseases - united states, 2013. | arthropod-borne viruses (arboviruses) are transmitted to humans primarily through the bites of infected mosquitoes and ticks. west nile virus (wnv) is the leading cause of domestically acquired arboviral disease in the united states. however, several other arboviruses also cause sporadic cases and seasonal outbreaks of neuroinvasive disease (i.e., meningitis, encephalitis, and acute flaccid paralysis). this report summarizes surveillance data reported to cdc in 2013 for wnv and other nationally ... | 2014 | 24941331 |